Neonatal morbidity and mortality associated with triplet pregnancy.

OBJECTIVE: To compare neonatal morbidity and mortality in a large cohort of triplet pregnancies with singleton and twin neonates managed at a single tertiary center over a short time. METHODS: Records from all triplet pregnancies managed and delivered from 1992 to 1996 were reviewed for neonatal outcome data. Pregnancies delivered before 20 weeks' gestation and neonates with lethal congenital anomalies were excluded. The comparison group comprised all singleton and twin neonates managed in the same neonatal intensive care unit (NICU) during the same period. RESULTS: During the 5-year period, 55 triplet pregnancies and their resulting 165 neonates were managed and delivered at this center. Their outcomes were compared with those of 959 singleton and 357 twin neonates born at similar gestational ages. The median gestational age at delivery for triplets was 32.1 weeks, and 149 of the 165 infants were admitted. Sixteen triplet neonates were not admitted to our neonatal intensive care unit, 12 because of previable gestational age, three because of stillbirth, and one because of a lethal congenital anomaly. The crude perinatal mortality rate in triplets was 121 per 1000 births, and there was no significant difference in outcome based on triplet birth order. There were no significant differences in survival rates between singleton, twin, and triplet neonates, with an overall neonatal survival of 95%, 95%, and 97%, respectively. The only significant differences in morbidity were an increased incidence of mild intraventricular hemorrhage (relative risk [RR] 6.20; 95% confidence interval [CI] 2.64, 14.61), mild retinopathy of prematurity (RR 20.05; 95% CI 3.59, 111.79), and severe retinopathy of prematurity (RR 46.69; 95% CI 6.25, 348.85) in triplets compared with singletons, and severe retinopathy of prematurity (RR 6.83; 95% CI 1.24, 37.56) in triplets compared with twins. CONCLUSION: When stratified by gestational age, triplet neonates delivered at 24-34 weeks' gestation have similar outcomes as singleton and twin neonates, with the only clinically significant difference being an increased incidence of retinopathy of prematurity in triplets.

Dietary L-arginine prevents fetal growth restriction in rats.

OBJECTIVE: Alterations in maternal plasma arginine concentration accompany normal pregnancy. Nitric oxide is synthesized from L-arginine and influences fetal growth. We hypothesized that L-arginine would influence fetal growth and hypoxia-induced uricemia in a maternal hypoxia-induced fetal growth restriction model. STUDY DESIGN: Fetal growth on day 21 of gestation was assessed in timed pregnant Wistar rats with or without exposure to maternal hypobaric hypoxia. Animals exposed to hypoxia received either no supplement or supplementation of drinking water with 0.2% L-arginine, 2% L-arginine, or 2% glycine. On day 21 of gestation, fetuses were delivered by hysterotomy and fetal and placental weights were obtained. Maternal and fetal plasma were assayed for uric acid as an index of tissue hypoxia. Xanthine oxidase and xanthine dehydrogenase, precursors of uric acid and reactive oxygen species, were assayed in maternal tissue. Results were analyzed by analysis of variance with correction for multiple comparisons. RESULTS: Exposure of rats on normal diets to hypoxia resulted in a 30% reduction in fetal weights. L-Arginine, 2% or 0.2%, prevented the reduction in fetal weight (p < 0.0001). Isocaloric and isonitrogenous supplementation with glycine did not influence hypoxia-induced fetal growth restriction. CONCLUSION: L-Arginine, but not glycine, ameliorates maternal hypoxia-induced fetal growth restriction in the rat.

A comparison of neonatal outcomes of age-matched, growth-restricted twins and growth-restricted singletons.

A retrospective cohort study was performed to determine whether growth-restricted fetuses of a twin gestation are at increased risk of adverse neonatal outcome compared with growth-restricted singletons. One cohort was comprised of 48 growth-discordant twin pregnancies in which the birth weight of the smaller twin was less than the tenth percentile. The neonatal outcomes of the 48 growth-restricted twin infants were compared with a cohort of 96 singleton infants matched by gestational age, degree of growth restriction, and gender. Outcomes evaluated included: length of stay, days of assisted ventilation, and diagnoses of morbidities of prematurity, congenital abnormalities, and neonatal death. No significant difference was detected in rates of neonatal morbidity or mortality. The overall neonatal death rate in the twins was 125 of 1000 and in the singletons was 104 of 1000 (Odds ratio 1.2, 95% confidence interval [CI]0.4-3.3). Growth-restricted twins have similar rates of adverse neonatal outcomes as compared with growth-restricted singletons. Both have high rates of morbidity and neonatal death. Twins and singletons should receive comparable diagnostic evaluation and antepartum management for growth restriction.

Ultrasound predictors of neonatal outcome in intrauterine growth restriction.

Our purpose was to assess the value of commonly performed ultrasound parameters in predicting neonatal outcome of fetuses with intrauterine growth restriction (IUGR). One hundred twenty-seven patients were identified on ultrasound examination to have IUGR. Estimated weight percentile, amniotic fluid volume, umbilical artery Doppler velocimetry, and head circumference/abdominal circumference ratio were compared with neonatal outcome. Thirty infants had severely adverse courses. The degree of growth restriction was strongly associated with adverse outcome and neonatal death. Umbilical artery Doppler waveforms with absent or reverse end-diastolic flow were predicted of neonatal death, bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC), and adverse outcome in general. Oligohydramnios was predictive of adverse outcome and neonatal death. Logistic regression also showed that absent or reverse end-diastolic flow and oligohydramnios were independent predictors of adverse outcome. Ultrasound findings of low estimated weight percentile, absent or reverse end-diastolic umbilical blood flow, and oligohydramnios are independent predictors of adverse neonatal outcome of growth restricted fetuses.

Elevated endothelin levels are associated with increased placental resistance.

OBJECTIVE: The purpose of this study was to measure cord blood endothelin-1,2 concentrations in growth-restricted infants with abnormal flow velocity waveforms. STUDY DESIGN: Endothelin-1,2 concentrations were measured by radioimmunoassay in the cord blood of 16 growth-restricted infants with abnormal flow velocity waveforms before delivery, 16 growth-restricted infants with normal flow velocity waveforms before delivery, and 44 appropriately grown infants. Clinical data regarding pregnancy complications and neonatal outcome were collected. RESULTS: The mean endothelin-1,2 concentration in growth-restricted infants with abnormal flow velocity waveforms (50.2 +/- 16.4 pg/ml) was significantly higher than in growth-restricted infants with normal flow velocity waveforms (33.3 +/- 14.2 pg/ml, p < 0.05) or in appropriately grown infants (25.8 +/- 9.7 pg/ml, p < 0.05). Oligohydramnios was also associated with elevated endothelin levels. CONCLUSION: We conclude that endothelin-1,2 concentrations are elevated in growth-restricted infants with abnormal flow velocity waveforms and may play a role in the development of abnormal fetoplacental resistance.