Sidney F. Bottoms

Low-Dose Aspirin to Prevent Preeclampsia in Women at High Risk

Background Whether low-dose aspirin prevents preeclampsia is unclear. It is not recommended as prophylaxis in women at low risk for preeclampsia but may reduce the incidence of the disease in women at high risk. Methods We conducted a double-blind, randomized, placebo-controlled trial in four groups of pregnant women at high risk for preeclampsia, including 471 women with pregestational insulin-treated diabetes mellitus, 774 women with chronic hypertension, 688 women with multifetal gestations, and 606 women who had had preeclampsia during a previous pregnancy. The women were enrolled between gestational weeks 13 and 26 and received either 60 mg of aspirin or placebo daily. Results Outcome data were obtained on all but 36 of the 2539 women who entered the study. The incidence of preeclampsia was similar in the 1254 women in the aspirin group and the 1249 women in the placebo group (aspirin, 18 percent; placebo, 20 percent; P = 0.23). The incidences in the aspirin and placebo groups for each of the four hi...

The Increase in the Cesarean Birth Rate

THE threefold increase in the cesarean birth* rate that has occurred in the United States during the last 10 years has been a source of concern to both obstetricians and the general public.1 2 3 Th...

Cadmium levels in maternal blood, fetal cord blood, and placental tissues of pregnant women who smoke.

Previous studies have reported that cigarette smoking is a major source of exposure to cadmium (Cd). This study was carried out to determine the degree of exposure to Cd of pregnant women who smoke and to determine the degree of exposure to Cd of pregnant women who smoke and to determine the disposition of the Cd in the maternal-fetoplacental unit. Our data reveal that pregnant women who smoke expose themselves and their placentas to levels of Cd higher than those to which they would normally be exposed. The percentage increase in Cd due to smoking was 32% in the placenta and 59% in maternal blood; these increases are statistically significant. The mean levels of Cd in maternal blood, cord blood, and placental tissues of pregnant women who smoked were all higher than the mean levels of Cd in the same tissues and blood of pregnant women who did not smoke. In addition, the levels of Cd in the maternal blood of smokers were significantly higher than levels of Cd in the cord blood of their infants; this relationship was not found in nonsmokers. On the basis of the Cd data on cord blood and placental tissues, the fetuses found in nonsmokers. On the basis of the Cd data on cord blood and placental tissues, the fetuses of pregnant women who smoke apparently receive very little additional exposure to Cd; however, this does not lessen concern for the fetus. The presently reported increase in exposure to Cd of pregnant women due to smoking must be viewed as undesirable because Cd has been shown to alter placental function in animals, and because Cd has no known biologic function.

The Preterm Prediction Study: Association of cesarean delivery with increases in maternal weight and body mass index

OBJECTIVE Our purpose was to evaluate whether maternal weight and body mass index measured either before or during pregnancy are associated with an increased risk of cesarean delivery. STUDY DESIGN Maternal weight and height were prospectively collected on 2929 women in the National Institutes of Health Maternal-Fetal Medicine Units Network Preterm Prediction Study. Prepregnancy and 27- to 31-week maternal weight and height were used to calculate the body mass index, and its contribution to the risk of cesarean delivery was determined. Women with prenatally diagnosed congenital anomalies (n = 89) and pregestational diabetes (n = 31) were excluded from analysis. RESULTS Univariate analysis of risk factors for cesarean delivery in the 2809 eligible women revealed a decreased risk of cesarean delivery with maternal age < 18 years and multiparity; increased risk of cesarean delivery was noted with maternal age > 35 years and a male fetus. Increases in either prepregnancy or 27- to 31-week maternal weight (5-pound units) or body mass index (1.0 kg/m2 units) were significantly associated with an increased odds of cesarean delivery (p = 0.0001). Each unit increase in prepregnancy or 27- to 31-week body mass index resulted in a parallel increase in the odds of cesarean delivery of 7.0% and 7.8%, respectively. Multivariable stepwise logistic regression analysis confirmed the association of male fetus, age, nulliparity, and body mass index as significant variables contributing to cesarean delivery risk. CONCLUSIONS The risk of cesarean delivery is associated with incremental changes in maternal weight and body mass index before and during pregnancy after adjustment for potential confounding factors. Prepregnancy counseling about optimizing maternal weight and monitoring weight gain during pregnancy to decrease the risk of cesarean delivery are supported by this study.

Underappreciated risks of the elderly multipara

OBJECTIVE Our purpose was to identify the age-related increased risks of the elderly gravida by clarifying the effects of age and parity, their combination, and their interaction. STUDY DESIGN We studied 9556 singleton pregnancies in women aged 20 to 29 years or > or = 35 years delivered over an 8-year period. Data were analyzed by stepwise multiway contingency table analysis, with p < 0.002 considered significant. RESULTS Many of the previously reported risks of the elderly gravida are expected on the basis of age and parity. Significant associations (primarily related to advanced age) included higher frequencies of obesity, chronic hypertension, gestational diabetes, and large-for-gestational-age and macrosomic infants. These elderly gravidas, on the other hand, had fewer postdates pregnancies. Although often overlooked, the greatest age-related increases in risk for induction (1.8 times), preeclampsia (2.7 times), gestational diabetes (4.5 times), clinical diabetes (3.2 times), oxytocin use (1.7 times), and macrosomia (1.6 times) occur in multiparas, not nulliparas. The risk for preeclampsia in the elderly multipara is significantly higher than expected on the basis of age and parity. CONCLUSION The increased risks of the elderly multipara may have been overshadowed by the previous focus on the elderly nullipara. It is important to recognize the increases in age-related risks of the elderly multipara to appropriately counsel and manage this group of patients.

Limited usefulness of fetal weight in predicting neonatal brachial plexus injury

OBJECTIVE The objectives were to determine the neonatal morbidity rate from vaginal birth and examine fetal weight-based injury-prevention strategies. STUDY DESIGN Selected neonatal morbidities were categorized by birth weight for all vertex vaginal deliveries occurring during a 12-year period. Sensitivity, specificity, and predictive values for brachial palsy were calculated at increasing birth weight cutoff levels. A policy of cesarean delivery for macrosomic infants was evaluated. RESULTS There were 80 cases of brachial palsy among 63,761 infants (0.13%). In mothers without diabetes, rates in the 4500- to 4999-g and >5000-g groups were 3.0% and 6.7%, respectively. A threshold of 3700 g had a sensitivity of 71% and a specificity of 86%; the positive predictive value was 0.56%. To prevent a single case of permanent injury, 155 to 588 cesarean deliveries are required at the currently recommended cutoff weight of 4500 g. CONCLUSIONS The rates of lasting morbidity do not justify routine cesarean delivery for infants without diabetic complications weighing <5000 g.

Maternal passive smoking and fetal serum thiocyanate levels.

Passive smoking, exposure of the nonsmoker to air contaminated with tobacco smoke, has been reported to have several adverse consequences for health. However, its effects on the fetus are unknown. Detailed smoking histories and fetal SCN (thiocyanate) levels were obtained in 107 low-risk pregnancies in order to evaluate fetal exposure to this metabolic byproduct of tobacco smoke. Among nonsmokers, fetal SCN levels were increased in association with passive smoking in the home (p less than 0.05). Significant differences in clinical characteristics were associated with passive smoking, but none of these differences were accounted for a significant increase in fetal SCN levels. These findings suggest that maternal passive smoking exposes the fetus to SCN, which is reported to be an effective biochemical marker of overall exposure to smoking, and which is known to be toxic in higher doses.

Preeclampsia, delivery, and the hemostatic system

To determine the effects of preeclampsia and delivery, the hemostatic system was evaluated before and 24 to 48 hours after delivery in 59 nulliparous patients without clinical signs of disseminated intravascular coagulation. Fifteen patients with mild preeclampsia and 18 with severe preeclampsia were compared with 26 pregnant control patients. Preeclampsia was associated with high fibronectin (p less than 0.001), low antithrombin III (p less than 0.001), and low alpha 2-antiplasmin (p less than 0.005), suggesting endothelial injury, clotting, and fibrinolysis, respectively. After delivery, fibronectin decreased only in preeclamptic patients (p less than 0.005); alpha 2-antiplasmin increased in all groups (p less than 0.001). Endothelial injury in preeclampsia appeared to resolve soon after delivery, which could contribute to the rapid clinical improvement noted in the early puerperium.

Incidence of preeclampsia among asthmatic patients lower with theophylline

The incidence of preeclampsia was reduced among asthmatic patients taking theophylline (one of 85) compared to other asthmatic patients (six of 68, p less than 0.05). Other factors did not appear to account for these results. Theophylline, which is known to inhibit platelet aggregation and alter vascular tone, may reduce the incidence of preeclampsia, at least among asthmatic patients.

Changes in hemostasis activity during delivery and theimmediate postpartum period

Postpartum deep vein thrombosis is believed to be related to increased activation of the hemostasis system at the time of delivery. To date, studies designed to test this hypothesis have had relatively small sample sizes or used the measurement of specific coagulation factors and functional tests reflecting hemostasis activity in vitro. With the use of recent technologic advances we determined the effect of delivery on hemostasis in vivo by measuring 11 hemostatic indices simultaneously in 70 healthy pregnant women. Significant increases were found in fibrinopeptide A (p less than 0.001), beta-thromboglobulin (p less than 0.001), and platelet factor 4 (p less than 0.001), suggesting maximum platelet activation and fibrin formation at the time of delivery. In addition to continued clotting activity at 3 hours post partum, increased D-dimer, fibrin-fibrinogen degradation products, and decreased alpha 2-antiplasmin levels suggest maximum fibrinolysis. These changes reflect a peak in hemostatic activity at delivery and in the immediate postpartum period that may predispose the development of deep vein thrombosis.