Preconception and early post conception

counseling in D.M

Fakhrolmolouk Yassaee. MD. Assistant professor OBS & GYN.Obstetric & gynecologic department, perinatology center Taleghani Hospital Shaheed Beheshti medical science university Evin, Tehran, IRAN

The question raised most frequently by diabetic women are:

1) What is know about the heritability of diabetes?2) What health measure can be implemented before

conception?3) What type of obstetric care is recommended?4) Will retinal and renal complications worsen

during pregnancy and shorten life expectancy?5) What sort of malformations do infants of diabetic

mothers have and what causes them?

The obstetrician, internist, genetic counselor all have important roles in providing advice to diabetic women both before and throughout pregnancy. Genetic transmission of diabetes is complex and depends upon the type of carbohydrate intolerance.

It is a chronic autoimmune disorder that occurs in genetically susceptible individuals. Major histocompatibility haplotype (HLA) strongly

influence susceptibility. No genetic marker has been identified for IDDM but a major component of genetic susceptibility has been identified as a gene or genes located near within the HLA complex on the short arm of chromosome 6.

Genetic couseling and a careful medical assessment before conception are recommended for all diabetic women and those with a history of gestational diabetes during a previous pregnancy. In infants of diabetic mother (IDM), congenital malformation occur about 2-3 times as often as in those of nondiabetic women. (Mill 1982)

Ylinen and associates (1984) have also reported a higher risk of minor and major malformation is infants of diabetic mothers with elevated HbA1c concentrations.

The majority of lesions involve the central nervous system and the cardiovascular system, genitourinary and limb defects (cousins 1991).

There is no increase in birth defects among offspring of diabetic fathers, prediabetic women, and women who develop gestational diabetes after the first trimester, suggesting that glycemic control during embryogenesis is the main factor in the genesis of diabetes- associated birth defects.

Miller and coauthors( 1981) compared the frequency of congenital anomalies in patients with normal or high first- trimester maternal glycohemoglobin and found only 3.4% rate of anomalies with HbA1c less than 8.5% whereas the rate of malformations in patient with poorer glycemic control in the periconceptional period (HbA1c > 8.5) was 22.4%

Because the critical time for teratogenesis is during the period 3-6 weeks after conception, nutritional and metabolic intervention must be institutes preconseptionally to be effective.

Fetal overgrowth is a major problem in pregnancies complicated by diabetes. Defined typically as birth weight above the 90th percentile for gestational age or greater than 4000 g, macrosomia occurs in 15- 45% of diabetic pregnancies.

Neonatal morbidity: hypoglycemia, macrosomia, neonatal jaundice, one fifth of IDMS had disproportionate macrosomia (Hunter ,1993)

(abdominal circumference greater than head circumference) compared with 1% control infants (Ballard, 1993)

Birth injury, including shoulder dystocia and brachial plexus trauma is more common among IDM, and macrosomic fetuses are at the highest risk.( Keller 1991)

Acceleration of growth, stimulated by excessive glucose delivery during diabetic pregnancy, may extend into childhood and adult life. Silverman (1995) reported on the follow up of macrosomic IDMS through 8 years of age in which half of the IDMS weighed more than the heaviest 10% of the nondiabetic children. These investigator also found that the diabetic offspring have permanent derangement in glucose- insulin kinetics, resulting in increased incidence of impaired glucose tolerance in later childhood.

The macrosomic IDM dose not follow the growth pattern observed in euglycemic pregnancies. During the first and second trimesters, differentiation of diabetic from nondiabetic fetuses is extremely difficult using ultrasound measurements, suggesting that the period of fetal fat deposition (28 weeks and onward) is when abnormal fetal growth primarily occurs.

Morphologic studies of the IDM neonate indicate that the increased growth of the abdominal circumference (AC) is due to deposition of fat in the abdominal and interscapular area. This central deposition of fat is a key characteristic of diabetic macrosomic and underlies the dangers associated with vaginal delivery in these pregnancies. Acker (1980) reported that although the incidence of shoulder dystocia is 3% among infants weighing greater than 4000g, 16% of infant from diabetic pregnancies weighing greater than 4000g, sustained shoulder dysticia.

Key features of a preconceptional diabetes management program should include the following:

A through assessment of cardiovascular, renal, ophthalmologic, status. Blood pressures, 24- hour protein and creatinine, and retinal examination should be performed. Thyroid function ( TSH and FT4) should be evaluated. Antihypertensive agents should be initiated and regulated

A regimen of frequent and regular monitoring of both pre-prandial and postprandial glucose capillary glucose levels.

Target levels are fasting glucose 80- 95 mg/dl and 1- hour postprandial glucose less than 130mg/dl or 2 hour postprandial glucose less than 120 mg/dl

The insulin regimen should result in a smooth glucose profile throughout the day with no hypoglycemic reaction between meals or at night. The regimen should be initiated early enough before pregnancy so that the glycohemoglobin level is lowered into the normal range for at least 3 months prior to conception.

Taking a daily prenatal vitamin ( including 400 μg of folic acid ) at least 3 months prior to conception to minimize risk of neural tube defects in fetus.

Particular attention should be paid to support systems that permit extended bed rest in the third trimester if necessary.

The goals of management of diabetic pregnancy are to prevent stillbirth and asphyxia while minimizing maternal morbidity associated with delivery. This involves monitoring fetal growth in order to select the proper timing and route of delivery. The first is testing fetal well- being at frequent intervals and fetal size.

Fetal surveillance in type I and type II diabetic pregnancies

Time TestPreconception Maternal glycemic control8-10 w sonographic crown –rump measurement16 w Maternal serum alpha- fetoprotein level20-22 w high – resolution sonography, fetal cardiac

echography in women in in suboptimal diabetic control (HbA1c ) at first prenatal visit

24w Baseline sonographic growth assessment of the fetus 28 w Daily fetal movement counting by the mother32 w Repeat sonography for fetal growth 34 w Biophysical seting: 2X weekly NST or weekly CST or weekly biophysical profile36w Estimation of fetal weight by sonography 37-38.5 w Amniocentesis and delivery for patients in poor control

(persistent daily hyperglycemia)38.5 – 40 w Delivery without amniocentesis for patients in good control who

have excellent dating criteria

TESTS OF FETAL WELL - BEING

testfrequencyReassuring resultcomment

Fetal movement counting

Every night from 28 w

Ten movement in <60 minPerformed in all patients

Non- stress testTwice weekly

Two heart – rate acceleration in 20 minutes

Being at 28-34 w with insulin dependent diabetes

Contraction stress test

weeklyNo heart rate decelerations in response to ≥ 3 contrations in 10 minutes

Same as for non stress test

Ultrasound biophysical profile

weeklyScore of 8 in 30 minutes3 movement =2

1 flexion = 2

30 sec breathing = 2

2 cm amniotic fluid = 2

CHOOSING TIMING AND ROUTE OF DELIVERY

Timing of delivery should be selected to minimize maternal and neonatal morbidity and mortality and mortality. Delivery delaying as near as possible to the EDC helps maximize cervical ripeness and improves the chances of spontaneous labor and vaginal delivery. Yet at the risks of fetal macrosomia, birth injury, and fetal death increase.

( Rasmussen, 1992). Although earlier delivery at 37 wks. gestation might reduce the risk of shoulder dystocia, an increase in failed labor induction and poor neonatal pulmonary status must be considered. Thus, an optimal time for delivery of most diabetic pregnancies is between 38.5 and 40 wks.

Indication for delivery diabetic pregnancy

Fetal Non reactive NST Positive CST Reactive NST, positive CST, mature fetus Sonographic evidence of fetal growth arrest Decline in fetal growth rate with decreased amnionic fluid 40 – 41 w gestation

Maternal Severe preeclampsia Mild preeclampsia, mature fetus Markedly falling renal function

Obstetric preterm labor with failure of tocolysis

Mature fetus , inducible cervix

CONFIRMATION OF FETAL MATURTY BEFORE INDUCTION OF LABOR OR PLANNING CESAREAN DELIVERY W DIABETIC PREGNANCY

1. Phosphatidyl glycerol > 3% in amniotic fluid collected from vaginal pool or by amniocentesis

2. Completion of 38.5 weeks gestation3. Normal LMP4. First pelvic examination before 12 weeks confirm

dates.5. Sonogram before 24 weeks confirm dates6. Documentation of more than 18 weeks by fetoscope of

FHT

After 38.5 weeks gestation, the obstetrician can await spontaneous labor if the fetus is not macrosomic and biophysical testing is reassuring. In patients with GDM and super glycemic control, continued fetal testing and expectant management can be considered until 41 weeks ( Lurie 1992)

In the fetus with on AC measurably greater than head circumference, induction should be considered. After 40 + weeks, the benefits of continued conservative management are likely to be less than the danger of fetal compromise. Induction of labor 42 weeks in diabetic pregnancy- regardless of the readiness of the cervix- is prudent.

Given these data, the decision to attempt vaginal delivery or perform a cesarean is inevitably based on very limited data. The patient’s past obstetric history, the best EFW, a fetal adipose profile (abdomen larger than head), and clinical pelvimetry should all be considered. Most large series of diabetic pregnancies report a cesarean section rate of 30- 50%. The best means by which this rate can be lowered is by early and strict glycemic control in pregnancy. Conducting long labor inductions in patients with a large fetus and marginal pelvis may increase morbidity and costs.