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376 SPO Abstracts

MATERNAL SERUM AFP, FETAL SEX AND PRETERM DELIVERY

RO Davis, RL Goldenberg, MB DuBardx, LR BootsX Department of Ob/Gyn, University of Alabama at Birmingham, Birmingham, Alabama

Maternal serum AFP (MSAFP) levels in 5210 singleton pregnancies were evaluated to assess fetal sex ratio and preterm delivery «37 wks). MSAFP levels were calculated from race specific medians, were weight adjusted and expressed as multiple of the median (MOM). The MSAFP values were divided into six MOM intervals: < .5, ~.5-<1, ~1-<1.5, ~1.5-<2.0, ~2.0-<2.5, ~2.5. Chi-square was used to determine statistical significance with p values <.05 considered significant. The overall male/female ratio was 1.06 and progressively and significantly increased from 0.7 at MSAFP levels <.5 MOM to 1.67 at levels ~2.5 MOM. The preterm delivery rate was 10.8% overall and 10.7% for males and 10.9% for females. Preterm delivery rose steadily and significantly from 8.8% at MSAFP levels <0.5 to 25.8% at levels ~2.5 MOM. The risk of preterm delivery was similar for male and female fetuses except at levels ~2.5 where the incidence of preterm delivery was 17% for males and 40% for females. We conclude that MSAFP levels are fetal sex dependent, with pregnancies with male fetuses having higher levels than those with female fetuses. The risk of preterm delivery was particularly increased for pregnancies with female fetuses and MSAFP values ~2.5 MOM.

SERIAL ULTRASOUND MEASUREMENTS IN FETUSES DESTINED TO DELIVER PRETERM AND TERM

RO Davis, RL Goldenberg, SP Cliverx, GR CutterX, HJ Hoffmanx, CG Brumfield. Department of Ob/Gyn, University of Alabama at Birmingham, Birmingham, Alabama and the NICHD.

We wanted to determine if fetuses destined to deliver preterm had smaller ultrasound measurements (i.e., were smaller) than fetuses that delivered at term. Serial measurements at approximately 18, 24, and 30 wks of biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL) were done on 1459 women participating in a research project evaluating fetal and infant growth. Term delivery was defined ~37 wks (n=1263). Preterm infants (n=196) were divided into two groups: those delivering between 26-32 wks and 33-36 wks. Gestational age (GA) was determined by two methods. In method #1, GA was based on menstrual dates if confirmed by ultrasound exam. If ultrasound was different by ±2 wks, the GA was set by the ultrasound estimate. In method #2, all GA's were set by the FL at the initial ultrasound exam done at <22 wks. Statistical methods included t-tests and regression analysis. There was no evidence that fetuses destined to deliver in either preterm group had significantly different GA specific ultrasound measurements or rate of growth over time than fetuses who ultimately delivered at term. These data suggest that intrauterine growth charts based on birthweight of liveborn infants accurately reflect intrauterine growth.

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Januar) 1991 Am J Obstct GynecoJ

TREATMENT OF IDIOPATHIC PRETERM RUPTURE OF MEMBRANES OR LABOR WITH ADJUNCTIVE AMPICILLIN. JF McCaulX, KG perryX, RW Martin, JC Morrison. Univ. of MS Med. Ctr., Jackson, MS.

Subclinical infection is likely etiologic in many cases of preterm rupture of the membranes (PROM) and preterm labor (PTL). We hypothesized that ampicillin (AMP) might delay delivery and/or decrease infectious morbidity in PROM or PTL. Patients from 19-34 weeks with PROM or PTL (but not both) were randomized to receive AMP vs placebo (PLA) in addition to usual therapy. PTL: N=36, 21 AMP/IS PLA. PROM: N=84, 41 MAP/43 PLA. Demographically the AMP and PLA groups were similar. There were no signifi­cant differences between the AMP and PLA groups with PTL or PROM. Outcome variables analyzed included: delivery delay, Apgars, neonatal infection and respiratory distress, chorioamnio­nitis, endometritis, and hospital days. Adjunctive AMP for treatment of idiopathic PTL or PROM is not beneficial.

BIRTHWEIGHT AND GESTATIONAL AGE SPECIFIC NEONATAL MORTALITY RATES

RL Copperx, RL Goldenberg, MB Davis, The Multicenter Study University of Alabama at Birmingham, Alabama

DuBardX, RO Group. The Birml.ngham,

Birthweight (Bwt) and gestational age (GA) specific mortality rates were compiled from the 5 centers which participated in a March of Dimes prematurity prevention trial. In each center, GA was assessed by standardized methods. Bwt and GA mortality charts by race, sex, and plurality were created using livebirth data. In each Bwt group, survival improved as the GA advanced; for each GA group, larger infants had better survival. Females <29 weeks tended to survive better than males. Racial differences in Bwt/GA mortality rates were not evident, but mortality in twins was higher. The largest improvement in survival occurred between 25-26 and 26-27 weeks. At 29 weeks, survival exceeded 90% and improved about 1% per week thereafter. When compared with previous reports, low Bwt/GA specific mortality rates have generally improved, especially prior to 32 weeks GA. These data may be useful in decision-making and counseling when confronted with patients at risk for preterm delivery.

GA Week Survival Impr/day

24 25 13% 18%

2% 1%

26 51%

5%

27 74%

3%

28 73%

29 92%

3%