152480273 Ectopic Pregnancy Rates in the Medicaid Population

7/22/2019 152480273 Ectopic Pregnancy Rates in the Medicaid Population

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G E N E R A L G Y N E C O L O G Y

Ectopic pregnancy rates in the Medicaid populationDebra B. Stulberg, MD; Loretta R. Cain, PhD; Irma Dahlquist, BS; Diane S. Lauderdale, PhD

OBJECTIVE:The Centers for Disease Control and Prevention last esti-mated a national ectopic pregnancy rate in 1992, when it was1.97% of

all reported pregnancies. Since then rates have been reported among

privately insured women and regional health care provider populations,

ranging from 1.62.45%. This study assessed therate of ectopic preg-

nancy among Medicaid beneficiaries (New York, California, and Illinois,

2000-03), a previously unstudied population.

STUDY DESIGN:We identified Medicaid administrative claims records for

inpatient andoutpatient encounterswith a principal InternationalClassifica-

tion of Diseases9thRevision diagnosiscode forectopic pregnancy.We cal-

culatedthe ectopicpregnancyrate amongfemalebeneficiariesaged 15-44

as the number of ectopic pregnancies divided by the number of total preg-

nancies, whichincluded spontaneous abortions, inducedabortions,ectopic

pregnancies, and all births. We used Poisson regression to assess the risk

of ectopic pregnancyby age and race.

RESULTS:Four-year Medicaid ectopic pregnancy rates were 2.38% ofpregnancies in New York, 2.07% in California, and 2.43% in Illinois.

Risk was higher among black women compared with whites in allstates

(relative risk, 1.26; 95% confidence interval, 1.251.28; P .0001),

and among older women compared with younger women (trendfor age,

P .001).

CONCLUSION:Medicaid beneficiaries in these 3 states experienced

higher rates of ectopic pregnancy than reported for privately insured

women nationwide in the same years. Relying on private insurance da-

tabases may underestimate ectopic pregnancys burden in the United

States population. Furthermore, within this low-income population ra-

cial disparities exist.

Key words:ectopic pregnancy, health care disparities, Medicaid

Cite this article as: Stulberg DB, Cain LR, Dahlquist I, et al. Ectopic pregnancy rates in the Medicaid population. Am J Obset Gynecol 2013;208:274.e1-7.

Ectopic pregnancy is an importantcause of maternal morbidity andmortality in the United States. Defined as

implantation of a fertilized egg outside the

uterine endometrium, ectopic pregnancy

caused an estimated 876 US deaths be-tween 1980 and 2007.1 In 1992 the Cent-

ers for Disease Control and Prevention

(CDC) estimated the US ectopic preg-

nancy rate at 1.97% of all pregnancies.2

Since then, CDC has acknowledged that

their surveillance using national health

care surveys no longer produces a reliableectopic pregnancy rate.3 This is primarily

because ectopic pregnancy care has

changed to involve multiple health care

encounters in different settings: emer-

gency department, outpatient, and inpa-

tient. CDC surveysdo not track individual

patients throughmultiple health care visits

so they risk over- or undercounting cases.

Instead, researchers have moved to using

insurance-based databases in which en-

counters can be linked to calculate ectopic

pregnancy rates within their covered pop-

ulations. Van Den Eeden and colleagues4

reported a rate within Kaiser Permanente

Northern California of 2.07% during

1997-2000. Trabert and colleagues5 re-

ported that among patients at Group

Health Cooperative, a health plan serving

Washington and Idaho, the rate increased

from 1.78% in 1993-95, to 2.45% in 2005-

07. Hoover and colleagues6 reported a

2002-07 treated ectopic pregnancy rate of

0.64% among women in MarketScan, anationwide administrative database of

more than 200 US commercial insurers;

looking at allectopic pregnancy diagnoses,

the rate in this population was 1.6.

Prior research gives indirect evidence

that ectopic pregnancy may be more prev-

alent among low-income women than inthe general population. Forexample, CDC

surveillance from 1970-89 found higher

rates among nonwhite women compared

with whites in all age groups and across all

years (rate ratio 1.4), without control-

ling for socioeconomic factors.7 Because

nonwhites were more likely to be poor

compared with whites in the US during

this surveillance period, it is impossible to

know if the observed racial disparity was

attributablein part or entirelyto socio-

economic factors and access to appropri-

ate health care services. The hypothesis

that access to care plays an important role

is supported by the fact that the racial dis-

parity is evengreater forectopicpregnancy

mortality than it is for ectopic pregnancy

incidence.From2003-07,theectopicpreg-

nancy mortality ratio (deaths per 100,000

livebirths) was6.8 times higherforAfrican

American women compared with whites.1

Recent studies assessing access to urgent

care for ectopic pregnancy8

and outcomesfrom ectopic pregnancy hospitalizations9

From the Departments of Family Medicine (DrsStulberg and Cain and Ms Dahlquist),Obstetrics and Gynecology (Dr Stulberg), andHealth Studies (Dr Lauderdale) and theMacLean Center for Clinical Medical Ethics (DrStulberg), University of Chicago, Chicago, IL.

Received Oct. 11, 2012; revised Dec. 14,2012; accepted Dec. 27, 2012.

Supported by a career development award to

Dr Stulberg (1 K08 HD060663) from theEuniceKennedy ShriverNational Institute of ChildHealth and Human Development.

The authors report no conflict of interest.

Presented as a poster at the 2012 Summit onthe Science of Eliminating Health Disparities,National Harbor, MD, Dec. 17-19, 2012.

Reprints: Debra Stulberg, MD, AssistantProfessor, Department of Family Medicine, TheUniversity of Chicago, 5841 S. Maryland Ave.MC 7110, Chicago, IL [email protected].

0002-9378/$36.00

2013 Mosby, Inc. All rights reserved.

http://dx.doi.org/10.1016/j.ajog.2012.12.038

Research www.AJOG.org

274.e1 American Journal of Obstetrics &Gynecology APRIL 2013
mailto:[email protected]:[email protected]://dx.doi.org/10.1016/j.ajog.2012.12.038http://dx.doi.org/10.1016/j.ajog.2012.12.038mailto:[email protected]


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confirm that women with Medicaid or noinsurance are disproportionately affected.However, no studies have directly exam-ined ectopic pregnancy rates among low-income women. Previous insurance pop-ulation studies have included few or noMedicaid beneficiaries: Kaiser Perma-nente Northern California and GroupHealth Cooperative each estimate that ap-

proximately 5% of their population is in-sured by Medicaid, whereas the Market-Scan database includes private insuranceonly.

Medicaid, the publicinsurance programforlow-income residents of the US, covers12% of all nonelderly women in the US,and 41% of all births.10 We conducted thisstudy to measure the rate of ectopic preg-nancy among Medicaid beneficiaries in 3of the largest US states during the years2000 through 2003, the most recent years

for which data were available when thisstudy wasinitiated.We alsoaimedto assesswhether the racial disparity in ectopicpregnancy ratethat haspreviouslybeenre-ported for the US population is observedwithin the Medicaid population.

MATERIALS AND METHODS

We obtained Medicaid Analytic Extractdata files from the Centers for Medicareand Medicaid Services (CMS) under anapproved Data Use Agreement. The

University of Chicago Biological Sci-ences Institutional Review Board ac-

knowledged the study as exempt fromreview, as is typical with studies involv-ing analysis of existing deidentified data.We examined Medicaid claims for all fe-male Medicaid beneficiaries aged 6-64

years of age in New York, California, andIllinois, 2000-03. Thesestates represent24% of births in the US,11-18 are locatedin different regions of the country and

are each racially and ethnically diverse.These data files include person-levelinformation on Medicaid enrollees andencounter-level information for allMedicaid claims for inpatient hospital

care and other therapies such as physi-cian services, radiology, and clinic visits.We limited our analysis to women aged15-44 to make it comparable to otherstudies of women of reproductive age.

We identified ectopic pregnancy cases

from both inpatient and outpatient

claims containing the International Clas-sification of Diseases9th revision (ICD9)diagnosis code 633.xx as principal diag-nosis. We calculated the ectopic preg-nancy rate among beneficiaries aged15-44 as the number of ectopic pregnan-cies (by principal diagnosis code) di-

vided by the number of total pregnan-cies, identified using ICD9 diagnosiscodes for all pregnancy-related care andoutcomes (Table 1). Encounters withone of these codes in any diagnosis field

principal, secondary, or otherwere in-cluded in the denominator. This strategy

was designed to produce the most con-servative (lowest) estimate of the ectopicpregnancy rate, because the case defini-tion for the numerator required a prin-cipal diagnosis of ectopic pregnancy,whereas any possible pregnancy would

be captured in the denominator. Weconducted exploratory analyses to deter-mine the effect of adjusting the numera-tor and denominator case definitionsby making them broader (by includingmore diagnosis codes) or narrower(fewer diagnosis codes).

For both the numerator and denomi-nator counts, repeat pregnancy-relatedencounters within 9 months (270 days)were considered part of the same preg-nancy. Repeat pregnancy-related en-

counters for the same beneficiary after 9months were treated as a new pregnancyepisode and each pregnancy episode(in 9-month groupings of claims) wascounted separately. We further con-ducted exploratory analysis to determinethe effect on rate calculations of varyingthis time definition of a single preg-nancy, comparing our 9-month assump-tion with shorter (6 month) and longer(10 month) assumptions.

We examined ectopic pregnancy rates

by race/ethnicity and age group. Age wascalculated by subtracting the beginningdate of service for the first pregnancy en-counter from the beneficiarys date ofbirth. Race/ethnicity was obtained fromthe Inpatient and Other Therapy files.The race/ethnicity variable in Medicaidfiles is coded as: white, black, Hispanic,Asian, American indian/Alaskan native,native Hawaiian/Pacific Islander, ormultiracial. Because the outcome vari-able was a rate, we used Poisson multi-

variable regression models to estimatethe relative risks for ectopic pregnancyby race/ethnicity and age group withineach state.

RESULTS

There were 19,132,067 person-years ofenrollment in Medicaid among womenaged 15-44 in New York, California, andIllinois combined during the 2000-03period (Table 2), representing 8,452,457

unique individuals. Overall, there were48,500 unique cases of ectopic preg-

TABLE 1

ICD9 diagnosis codes for ectopic pregnancy and all pregnancies

Diagnosis ICD9 code Diagnosis field (variable)

Ectopic pregnancy 633.xx Principal diagnosis..............................................................................................................................................................................................................................................

All pregnancies.....................................................................................................................................................................................................................................

Ectopic, molar, or abortive 63x.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

Complications of pregnancy 64x.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

Normal labor and delivery 65x.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

Complications of labor anddelivery

66x.xx Principal, secondary, or other diagnosis

.....................................................................................................................................................................................................................................

Normal pregnancy V22.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

High-risk pregnancy V23.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

Outcome of del ivery V27.xx Principal, secondary, or other diagnosis.....................................................................................................................................................................................................................................

Antenatal screening V28.xx Principal, secondary, or other diagnosis..............................................................................................................................................................................................................................................

ICD9, International Classification of Diseases9th revision.

Stulberg.Ectopicpregnancy in Medicaid.Am J Obstet Gynecol 2013.

www.AJOG.org General Gynecology Research

APRIL 2013 American Journal of Obstetrics &Gynecology 274.e2


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nancy in this population, and 2,182,042total pregnancies, for an ectopic preg-nancy rate of 2.22% (2.22 per 100 re-ported pregnancies) or 2.54 per 1000woman-years.Table 3 presents ectopicpregnancy rates for each state, stratified

by race/ethnicity, and age group. The ec-topic pregnancy rate is similar amongwhite women in each state: 2.26% inNew York, 2.29% in California, and2.45% in Illinois. The ectopic pregnancyrate among black women is greater than3% in both Illinois and California.

Table 4presents the multivariable re-gression models for risk of ectopic preg-nancy that include both race/ethnicityandage, separately by state. In all3 states,the age-adjusted risk of ectopic preg-

nancy was statistically significantly hi-gher among African American womenand lower among Asian women incomparison to white women. The riskassociated with Hispanic and Ameri-can indian race/ethnicity varied bystate. (The interaction between race/ethnicity and state was significantwhen tested in a pooled model that in-cluded all 3 states.) In the states wherethey were identified, native Hawaiian/Pacific Islander and multiracial women

were at lower risk of ectopic pregnancythan white women.There was a general trend toward

higher ectopic pregnancy risk amongolder women compared with youngerwomen in all states (overall age trend 0.15, P .001), thoughin NewYorkand Illinois the risk peaked in the 35-39year old groups and declined slightlyamong 40-44 year olds, when comparedwith the youngest group.

In exploratory analyses designed to

test specific elements of our case ascer-tainment method, we found that broad-ening or narrowing the definitions of anectopic pregnancy or any pregnancy di-agnosis had little effect on the overallcounts. For example, the diagnosis code761.4 (fetus or newborn affected by ma-ternal ectopic pregnancy) did not addany cases of ectopic pregnancy. In defin-ing total pregnancy, if we removed pre-natal care diagnosis codes V22 and V23,we missed a significant number of preg-

nancies. But when we attempted tobroaden the definition by adding proce-

dure codes for birth (72.xx75.xx)and abortion procedures (69.01, 69.02,69.51, 69.52) this did not result in cap-turing more pregnancies. Removing di-agnosis codes for spontaneous (634.xx)or induced (635.xx, 636.xx, 638.xx)abortion had no significant effect on ouroverall rate calculations.

Similarly, lengthening or shorteningthe definition of a single episode of preg-

nancy had minimal effect. For example,in Illinois our method of counting allpregnancy claims within a 270-day pe-riod as a single pregnancy resulted in acount of 9229 ectopic pregnancies. If weshortened this to 180 days (meaning arepeat diagnosis code 181 days afterthe last code would be counted as a sec-ond ectopic pregnancy), we would add59 ectopic pregnancies; if we lengthenedit to 300 days, we would lose 11 ectopicpregnancies. In the denominator the ef-

fect would be greater, because many full-term and near-term pregnancies would

be counted twice if 2 diagnosis codes 6

months apart were considered 2 differ-

ent pregnancies. In Illinois, for example,

using a 6-month (180-day) cutoff in the

numerator and denominator would

lower the rate calculation from 2.4% to

1.9%. We cannot rule out that repeat

early pregnancy losses (ectopic or intra-

uterine) and terminations may be

missed in the denominator if the second

full episode of care occurred within 9months. However, given the clinical rea-

soning that many pregnancies last longer

than 6 months although few repeat ecto-

pic pregnancies, miscarriages, and in-

duced abortion episodes of care occur

completely within 9 months (as demon-

strated by the small change in case

counts with these 2 cutoffs), we opted to

use a consistent cutoff of 270 days in the

numerator and denominator. Women

with repeat (2 or more) ectopic pregnan-cies after 9 months represented only

TABLE 2

Person-years of enrollment, women aged 15-44 in Medicaid,New York, California, and Illinois 2000-03

Demographic

New York(n 3,644,214)n (%)

California(n 13,686,040)n (%)

Illinois(n 1,801,813)n (%)

Age group.....................................................................................................................................................................................................................................

15-19 710,708 (19.5) 2,964,083 (22.2) 415,703 (23.1).....................................................................................................................................................................................................................................

20-24 741,069 (20.4) 321,7602 (24.1) 407,900 (22.6).....................................................................................................................................................................................................................................

25-29 606,778 (16.7) 2,653,940 (19.9) 329,315 (18.3).....................................................................................................................................................................................................................................

30-34 560,527 (15.4) 2,096,293 (15.7) 251,881 (14.0).....................................................................................................................................................................................................................................

35-39 528,670 (14.5) 1,536,423 (11.5) 198,702 (11.0).....................................................................................................................................................................................................................................

40-44 363,716 (10.0) 879,392 (6.6) 116,795 (6.5).....................................................................................................................................................................................................................................

Unknown/not documented 132,746 (3.6) 338,307 (6.6) 81,517 (4.5)..............................................................................................................................................................................................................................................

Race/ethnicity.....................................................................................................................................................................................................................................

White 1,071,643 (29.4) 2,865,284 (20.9) 640,624 (35.6).....................................................................................................................................................................................................................................Black 956,814 (26.3) 1,243,927 (9.1) 748,454 (41.5).....................................................................................................................................................................................................................................

American Indian/Alaskannative

66,635 (1.8) 66,570 (0.5) 3493 (0.2)

.....................................................................................................................................................................................................................................

Asian 150,489 (4.1) 593,274 (4.3) 33,517 (1.9).....................................................................................................................................................................................................................................

Hispanic 703,674 (19.1) 8,190,938 (59.9) 341,632 (19.0).....................................................................................................................................................................................................................................

Native Hawaiian/PacificIslander

0 (0.0) 324,555 (2.4) 0 (0.0)

.....................................................................................................................................................................................................................................

More than 1 race 0 (0.0) 0 (0.0) 1194 (0.1).....................................................................................................................................................................................................................................

Unknown/not documented 694,959 (19.1) 401,492 (2.9) 32,899 (1.8)..............................................................................................................................................................................................................................................

Stulberg.Ectopicpregnancyin Medicaid.Am J Obstet Gynecol 2013.

Research General Gynecology www.AJOG.org



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2.3% of those with any ectopic preg-nancy, and the decision to include thesein the total count had no effect on theoverall rate estimates.

COMMENT

This analysis of Medicaid claims datafound that 2.22% of all reported preg-nancies among women with Medicaid inCalifornia, Illinois, and New York, 2000-03, were ectopic. Women in this popula-tion experienced 2.54 ectopic pregnan-cies per 1000 person-years. These arehigher than the rates reported in otherstudies for privately insured 6 and pro-vider-specific populations.4,5 Within theMedicaid population, African American

women faced higher risk of ectopic preg-nancy than whites in all states, and His-panics faced higher risk than non-His-panic whites in New York but lower risksin Illinois and California. Overall, in-creasing age was associated with higherrisk of ectopic pregnancy, although in 2states women aged 40-44 years had aslightly lower relative risk (vs the young-est group) than those aged 35-39 years.

The strength of our approach is that itprovides a complete population count of

ectopic pregnancy cases among womenwith Medicaid insurance in the statesand years studied. Previous ectopic preg-nancy surveillance studies in the USsince 1992 have largely excluded thispopulation. However, our study also hasseveral limitations. First, we only ana-lyzedadministrativeclaims data, with noclinical validation. As a consequence, aproportion of the ectopic pregnanciesreported herein may be false diagnoses,representing anything from clerical er-

rors in coding to the use of the diagnosiscode when ectopic pregnancy is only 1 ofseveral possible (rule out) diagnoses.However,because our denominator cap-tures all pregnancies with an even morepermissive definition, we believe the riskof overcounting is at least as high in thedenominator as the numerator, therebydecreasing the risk that we are overesti-mating the ectopic pregnancy rate. (Forexample, a single diagnosis code forspontaneous abortion was enough to

count as a pregnancy case in the denom-inator.) Although our method captures

TABLE 3

Ectopic pregnancy rates among Medicaid beneficiaries,New York, Illinois, and California 2000-03

VariableNo. of ectopicpregnancies (A)

No. of totalpregnancies (B)

Ectopic pregnancyrate (A/B) 100

New York 15,224 638,849 2.38%.....................................................................................................................................................................................................................................Race/ethnicity

............................................................................................................................................................................................................................

White 4738 209,462 2.26%............................................................................................................................................................................................................................

Black 4658 182,786 2.55%............................................................................................................................................................................................................................


279 23,087 1.21%

............................................................................................................................................................................................................................

Asian 401 33,773 1.19%............................................................................................................................................................................................................................

Hispanic 3240 117,437 2.76%............................................................................................................................................................................................................................

Unknown/missing 1908 72,304 2.64%.....................................................................................................................................................................................................................................

Age group............................................................................................................................................................................................................................

15-19 1389 86,449 1.61%............................................................................................................................................................................................................................20-24 4662 205,845 2.26%............................................................................................................................................................................................................................

25-29 3888 161,651 2.41%............................................................................................................................................................................................................................

30-34 2858 106,077 2.69%............................................................................................................................................................................................................................

35-39 1837 59,000 3.11%............................................................................................................................................................................................................................

40-44 590 19,827 2.98%..............................................................................................................................................................................................................................................

California 24,047 1,163,036 2.07%.....................................................................................................................................................................................................................................

Race/ethnicity............................................................................................................................................................................................................................

White 4236 185,034 2.29%............................................................................................................................................................................................................................

Black 3194 102,234 3.12%............................................................................................................................................................................................................................


125 5355 2.33%

............................................................................................................................................................................................................................

Asian 878 44,162 1.99%............................................................................................................................................................................................................................

Hispanic 14,487 752,066 1.93%............................................................................................................................................................................................................................

Native Hawaiian/PacificIslands

555 26,376 2.10%

............................................................................................................................................................................................................................

Unknown/missing 572 47,809 1.20%.....................................................................................................................................................................................................................................

Age group............................................................................................................................................................................................................................

15-19 2403 183,790 1.31%............................................................................................................................................................................................................................

20-24 6585 373,876 1.76%............................................................................................................................................................................................................................

25-29 6364 288,755 2.20%............................................................................................................................................................................................................................30-34 4819 187,434 2.57%............................................................................................................................................................................................................................

35-39 2843 97,082 2.93%............................................................................................................................................................................................................................

40-44 1033 32,099 3.22%..............................................................................................................................................................................................................................................

Illinois 9229 380,157 2.43%.....................................................................................................................................................................................................................................

Race/ethnicity............................................................................................................................................................................................................................

White 2624 117,489 2.45%............................................................................................................................................................................................................................

Black 3786 119,378 3.51%..............................................................................................................................................................................................................................................

Stulberg. E ctopic p regnancy i n Medicaid. A m J Obstet G ynecol 2 013. (continued )




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all pregnancy care covered by Medicaid,

we cannot rule out that underreporting

of abortion depressed our total preg-

nancy count.

A second limitation is our inability to

determine patients treatment. The data

included patients treated both inpatient

and outpatient, surgically and nonsurgi-

cally. Although surgical procedures are

well documented,the lack of ICDor CPT

code for medical treatment of ectopic

pregnancy has been described elsewhere

as a challenge for ectopic pregnancy sur-

veillance,3 and we unfortunately were

subject to the same limitation. We re-

viewed Medicaid prescription drug files,

which list pharmacy-dispensed medica-

tions by National Drug Code, but foundno entries for methotrexate among our

identified ectopic pregnancy patients.

This is most likely because hospitals,

clinics, and offices that treat ectopic

pregnancy patients with methotrexate

dispense the medication themselves

rather than writing the patient a pre-

scription andsending her to a pharmacy;

these nonpharmacy-dispensed medica-

tions are not included in Medicaid pre-

scription drug files.

A third limitation is the possibleexclu-sion of women within Medicaid who are

enrolled in prepaid managed care pro-

grams. Medicaid managed care is grow-

ing, and to the extent that these pro-

grams paid providers with capitated

payments rather than based on service

claims submitted, our study risks miss-

ing relevant claims. However, many

Medicaid managed care enrollees partic-

ipate in limited programs, such as for the

management of behavioral health care,

or inpatient care. Pregnancy-related care

could still be paid on a fee-for-service

basis. Therefore, many managed care

beneficiaries excluded from the numer-

ator would also be excluded from the

denominator.

Finally, these data represent only 3

states during the years 2000-03. Al-though very large in population, these

states cannot be said to represent all

Medicaid beneficiaries in the US. At the

time this research began, Medicaid data

files were not available for more recent

years. With more recent Medicaid data

now available, future work will be able to

examine current trends.

Given variations in data sources and

methods used in different studies, it is

impossible to make direct comparisons

across populations. However, our ap-proach is similar to those used by

Hoover et al,6 who calculated a diag-

nosed ectopic pregnancy rate of 1.6%

among women with private insurance

during 2000-07, and Trabert et al5 in

their reported ectopic pregnancy rates

from Group Health Cooperative of

1.94% (1999-2001) and 2.00% (2002-04). The states included in our analysis

are not represented in the Group Health

Cooperative population studied, so geo-

graphic variation may account for some

of the observed difference. Higher rates

of ectopic pregnancy among Medicaid

populations could also be due to lower

coverage of abortion compared with pri-

vate insurance.

In considering possible causes and ex-

planations for high ectopic pregnancy

rates among Medicaid beneficiaries

compared with privately insured women

and among African American women

compared with white women, it is im-

portant to consider underlying risk fac-

tors for the condition, as well as factors

affecting a persons progression from

risk factor to disease. Patient factors such

as behavior and genetics, and health care

factors such as access to and quality of

care, are likely to interact in complex

ways. The 2 known primary risk factorsare smoking and a history of exposure to

chlamydia, both of which can cause fal-

lopian tube damage and dysfunction.19

Specifically, chlamydia that goes un-

treated is thought to cause more damage

to fallopian tubes(through clinically rec-

ognized or subclinical pelvic inflamma-

tory disease) compared with chlamydial

infections that are diagnosed and treated

while confined to the cervix. Other

known risk factors for ectopic pregnancy

include prior ectopic pregnancy, priortubal surgery, and prior tubal infertility.

However, these ought notto be considered

primary riskfactorsfor ectopic pregnancy,

because they generally occur secondary to

underlying fallopian tube impairment. Fi-

nally,theuseof assisted reproductive treat-

ments (ART) may further increase (be-

yond the contribution of the underlying

infertility) a womans risk of ectopic preg-

nancy becausetheembryo itself, thetrans-

fer process, or the use of multiple embryosmay confer added risk.

TABLE 3

Ectopic pregnancy rates among Medicaid beneficiaries,New York, Illinois, and California 2000-03 (continued)

VariableNo. of ectopicpregnancies (A)

No. of totalpregnancies (B)

Ectopic pregnancyrate (A/B) 100

American Indian/Alaskannative 21 730 3.11%............................................................................................................................................................................................................................

Asian 156 8969 1.90%............................................................................................................................................................................................................................

Hispanic 2502 120,432 2.29%............................................................................................................................................................................................................................

Multiracial 15 1013 1.50%............................................................................................................................................................................................................................

Unknown/missing 125 12,146 1.21%.....................................................................................................................................................................................................................................

Age group............................................................................................................................................................................................................................

15-19 1295 67,481 1.92%............................................................................................................................................................................................................................

20-24 3295 142,193 2.32%............................................................................................................................................................................................................................

25-29 2451 92,039 2.66%............................................................................................................................................................................................................................

30-34 1377 49,442 2.79%............................................................................................................................................................................................................................35-39 663 22,493 2.95%............................................................................................................................................................................................................................

40-44 148 6509 2.27%..............................................................................................................................................................................................................................................





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Smoking rates among women of re-productive age are not reported stratifiedby income or health insurance, butwomen with any college education aresignificantly less likely to smoke thanthose with less education, suggesting apossible socioeconomic trend. Thesetrends would indicate that smoking maycontribute to higher ectopic pregnancyrates among poor women than amongthe more well-off. Smoking has beenidentified as an important factor causing

higher rates of other poor pregnancyoutcomes, such as preterm birth and in-trauterine growth restriction, amongwomen of lower socioeconomic status.20

However, smoking cannot explain ecto-pic pregnancy disparities by race or eth-nicity. Among women of reproductiveage, smoking is most common amongwhite non-Hispanics (24.5%), withlower rates among black non-Hispanics(16.3%) and Hispanics (10.5%).21 Onthe other hand, chlamydia rates are re-

ported to be markedly higher amongblack non-Hispanic (rate ratio 7.8)

and Hispanic (rate ratio

3.1) womencompared with white non-Hispanics.22

These differing chlamydia rates, possiblycoupled with a higher risk of delayedtreatment and subsequent tubal damage,likely contribute to the population-wideracial disparity in ectopic pregnancy.

The varying effect of Hispanic ethnic-ity by state that we found is consistentwith overall trends in health statuswithin the US Hispanic population. Peo-ple who identify as Hispanic of Mexican

origin generally are in better health thanthose who identify as Hispanic of PuertoRican origin.23 Because the Hispanicpopulations are predominantly of Mex-ican origin in California (77%) and Illi-nois (75%), although New Yorks His-panic population has a small proportionof people of Mexican origin (9.1%) andmore of Puerto Rican origin (37%), theectopic pregnancy rates seem to mirrorother reported health outcomes.24

The ectopic pregnancy trends by age

reported herein are similar to those inother US populations.4,6 The harmful ef-

fects of smoking, chlamydia, and otherexposures on fallopian tube function are

likely to accumulate during a womans

lifetime, leading to higher risk with age.

Finally, ART is generally inaccessible

to women on Medicaid and thus is un-

likely to contribute to the higher rate of

ectopic pregnancy in this population.

The availability of ART to the privately

insured patients may mask the extent of

the disparity among women not receiv-

ing ART.

The findings in this study raise theconcern that surveillance methods rely-

ing entirely on private insurance data-

bases may underestimate ectopic preg-

nancies in the whole US population.

Primary prevention efforts, in particular

screening to diagnose and treat chla-

mydia early, as well as smoking cessation

campaigns and safer sex education, re-

main important public health priorities

to reduce the risk of ectopic pregnancy

and eliminate racial and economicdisparities. f

TABLE 4

Multivariable analysis for risk of ectopic pregnancy by race/ethnicity and ageamong Medicaid beneficiaries in New York, California, and Illinois, 2000-03

Demographic

New York California Illinois

RR 95% CI Pvalue RR 95% CI Pvalue RR 95% CI Pvalue

Race/Ethnicity................................................................................................................................................................................................................................................................................................................................................................................

White Reference Reference Reference.......................................................................................................................................................................................................................................................................................................................................................................

Black 1.12 1.11.14 .0001 1.36 1.341.39 .0001 1.45 1.421.48 .0001.......................................................................................................................................................................................................................................................................................................................................................................

American Indian/Alaskan native 0.56 0.500.56 .0001 1.04 0.961.12 .3416 1.27 1.051.55 .0141.......................................................................................................................................................................................................................................................................................................................................................................

Asian 0.49 0.470.51 .0001 0.79 0.770.81 .0001 0.73 0.680.79 .0001.......................................................................................................................................................................................................................................................................................................................................................................

Hispanic 1.21 1.191.24 .0001 0.83 0.820.84 .0001 0.90 0.880.93 .0001.......................................................................................................................................................................................................................................................................................................................................................................

Native Hawaiian/Pacific Islands 0.85 0.820.88 .0001 .......................................................................................................................................................................................................................................................................................................................................................................

Multiracial 0.68 0.550.85 .0008.......................................................................................................................................................................................................................................................................................................................................................................

Unknown/missing 1.07 1.051.10 .0001 0.71 0.45 0.410.49 .0001................................................................................................................................................................................................................................................................................................................................................................................

Age group.......................................................................................................................................................................................................................................................................................................................................................................

15-49 Reference Reference Reference.......................................................................................................................................................................................................................................................................................................................................................................

20-24 1.43 1.401.48 .0001 1.31 1.281.33 .0001 1.26 1.231.30 .0001.......................................................................................................................................................................................................................................................................................................................................................................

25-29 1.55 1.511.60 .0001 1.65 1.621.69 .0001 1.49 1.451.54 .0001.......................................................................................................................................................................................................................................................................................................................................................................

30-34 1.74 1.691.79 .0001 1.93 1.891.97 .0001 1.59 1.541.65 .0001.......................................................................................................................................................................................................................................................................................................................................................................

35-39 2.00 1.942.06 .0001 2.20 2.152.25 .0001 1.67 1.601.75 .0001.......................................................................................................................................................................................................................................................................................................................................................................

40-44 1.91 1.831.98 .0001 2.40 2.322.47 .0001 1.22 1.131.31 .0001................................................................................................................................................................................................................................................................................................................................................................................

CI, confidence interval;RR, relative risk.





7/7

ACKNOWLEDGMENT

We thank Rangesh Kunnavakam (University ofChicago) for technical assistance.

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