Associations Between Psychosocial Factors

and Intrauterine Growth Retardation

Sharon Durousseau MD, MPH

California Department of Health Services

Maternal Child Health Branch

Intrauterine Growth Retardation

• Intrauterine growth retardation (IUGR)

– Babies born too small for gestational age

• Over 10,000 full-term infants with IUGR born in California annually

• Increased risk for death and disability

• Long-term effects

Incidence Rate of IUGR, CA 1992-1999

0

1

2

3

1992 1993 1994 1995 1996 1997 1998 1999

Year

per

100

live

bir

ths

Incidence of IUGR by Race/Ethnicity, CA 1999

2

4.1

1.7

2.8

1.3

0

1

2

3

4

5

White/Other AfricanAmerican

AmericanIndian/Alaskan

Native

Asian/PacificIslander

Hispanic

per

100

live

birt

hs

Psychosocial Factors and IUGR?

• Risk factors include

– Smoking

– Poor nutrition– Prior pregnancy history

• Stress and social factors might affect fetal growth

Study objectives

• Can we identify women at risk by the psychosocial profile?

• Can social support programs affect IUGR rates?

Maternal Infant Health Assessment

• Annual population-based survey • Includes mothers with singleton live

births • Surveys maternal behaviors and

conditions before, during, and after pregnancy

All live births in California Feb. to May 1999

165,898

Sampling Design

All live births in California Feb. to May 1999

165,898

Sampling Design

Excluded:-Mothers aged <15 yrs-Infants adopted-Mothers deceased-Incomplete contact information

All live births in California Feb. to May 1999

Eligible Population

165,898

156,514

Sampling Design

Excluded:-Mothers aged <15 yrs-Infants adopted-Mothers deceased-Incomplete contact information

All live births in California Feb. to May 1999

Stratified by race/ethnicity,region and education

Eligible Population

165,898

156,514

4,967

Sampling Design

Excluded:-Mothers aged <15 yrs-Infants adopted-Mothers deceased-Incomplete contact information

Random sample strata

All live births in California Feb. to May 1999

Stratified by race/ethnicity,region and education

70.1% response

Eligible Population

165,898

156,514

4,967

3,483

Sampling Design

Excluded:-Mothers aged <15 yrs-Infants adopted-Mothers deceased-Incomplete contact information

Random sample strata

IUGR Case Definition

• A case defined as a mother of a term infant ( >37 weeks gestational age) weighing < 2500 grams at birth

• All other term infants were non-cases

Cases and Non-cases

3,127 mothers ofterm infants

3,483

Cases and Non-cases716 preterm excluded

3,127 mothers ofterm infants

3,483

73 cases 3,054 non-cases

Cases and Non-cases716 preterm excluded

3,127 mothers ofterm infants

3,483

Psychosocial Factors

• Wanting to become pregnant

• Initial happiness about becoming pregnant

• Maternal sense of control score

Statistical Methods• Univariate Analysis with SPSS/SUDAAN

• Logistic regression controlling for

Race/ethnicity Maternal age

Prior low birthweight Smoking status

Education Marital status

Poverty• Data weighted to reflect state population• Tested for interaction

IUGR Risk Factors

Crude OR 95% CI

< 19 years old 2.4 (1.3, 4.5)> 19 years (ref)

African-American 3.1 (1.6 , 6.2)Native American 3.7 (0.5, 29.2)Asian/Pacific Islander 2.9 (1.3, 6.3)Hispanic 1.4 (0.7, 2.6)White/Other (ref)

IUGR Risk Factors

Crude OR 95% CI

< 12 Years education 1.7 (1.01, 2.9)

Unmarried 1.7 (1.05, 2.9)

Medicaid 1.8 (1.04, 2.9)

Income < federal poverty level 2.4 (1.4, 4.1)

IUGR Risk Factors

Crude OR 95% CI

Prior Low Birth Weight Infant 12.7 (5.6,28.8)Underweight prior to pregnancy 2.4 (1.3, 4.2)

Smoked during pregnancy 1.7 (0.9, 3.3)

Alcohol use during pregnancy 0.8 (0.4, 1.6)

No first trimester Prenatal Care 0.9 (0.4, 1.9)

Univariate Analysis: Wanting to Become Pregnant

1.9

0

0.5

1

1.5

2

2.5

3

3.5

4

Wanted now or later (ref) Did not want/unsure

Cru

de

Od

ds

Rat

io

Univariate Analysis: Happiness About Becoming Pregnant

11.3

1.6

3.2

0123456789

Very happy(ref)

Somewhathappy

Somewhatunhappy

Very Unhappy

Cru

de O

dds

Rat

io

Univariate Analysis: Maternal Sense of Control Scores

1.91.1

0

1

2

3

4

5

6

7

8

High (ref) Medium Low

Cru

de O

dds

Rat

io

Multivariate Analysis

OR 95% CI

Did not want/Unsure 2.2 (0.8, 6.7)

Very unhappy 1.5 (0.2, 9.5)

Low control score 1.3 (0.2, 9.2)

Strengths and Weaknesses

• Strengths– Population based sample– Diverse population

• Weaknesses– Retrospective, possible recall bias– Limited detail– Possible low power

Conclusions

• Psychosocial factors associated with IUGR include– Not wanting/being unsure about becoming

pregnant – Being unhappy about becoming pregnant

• After adjusting for other variables, these factors are not statistically significant.

Implications

• Assessing maternal feelings toward pregnancy not sufficient to identify women at risk for having infant with IUGR

• Consider other risk factors

• More focused or prospective study might be needed to explore relationship further

Acknowledgements

• Gilberto Chavez

• Don Taylor

• Kristen Marchi

• Paula Braveman

• Rhonda Sarnoff

• Andrea Winquist

Pregnancy Wantedness

• “ Thinking back to just before you got pregnant, how did you feel about getting pregnant? ”

• I wanted to get pregnant then.• I wanted to get pregnant later.• I did not want to get pregnant then or

in the future.• I wasn’t sure what I wanted.

Initial Happiness About Becoming Pregnant

• How did you feel when you found out you really were pregnant ?– Very happy– Somewhat happy– Somewhat unhappy– Very unhappy

Maternal Sense of Control

• Aggregate score from series of seven questions

• “ How much do you agree with each of the following statements ? ” – Sample questions:

• “ I have little control over the things that happen to me.”

• “ What happens to me in the future mostly depends on me.”

Power Calculations

• Sample sizes needs to detect 50% difference for each variable ( = 0.05 and = .20)– wantedness 1,088– happiness 4,702– control score 7,738

• Power calculation done in EPI 6.0.