Linda M. Hopkins

Gestational Weight Gain and Adverse Neonatal Outcome Among Term Infants

OBJECTIVE: To examine the relationship between gestational weight gain and adverse neonatal outcomes among infants born at term (37 weeks or more). METHODS: This was a retrospective cohort study of 20,465 nondiabetic, term, singleton births. We performed univariable and multivariable analyses of the associations between gestational weight gain and neonatal outcomes. We categorized gestational weight gain by the Institute of Medicine guidelines as well as extremes of gestational weight gain (less than 7 kg and more than 18 kg). RESULTS: Gestational weight gain above the Institute of Medicine guidelines was more common than gestational weight gain below (43.3% compared with 20.1%). In multivariable analyses, gestational weight gain above guidelines was associated with a low 5-minute Apgar score (adjusted odds ratio [AOR] 1.33, 95% confidence interval [CI] 1.01–1.76), seizure (AOR 6.50, 95% CI 1.43–29.65), hypoglycemia (AOR 1.52, 95% CI 1.06–2.16), polycythemia (AOR 1.44, 95% CI 1.06–1.94), meconium aspiration syndrome (AOR 1.79, 95% CI 1.12–2.86), and large for gestational age (AOR 1.98, 95% CI 1.74–2.25) compared with women within weight gain guidelines. Gestational weight gain below guidelines was associated with decreased odds of neonatal intensive care unit admission (AOR 0.66, 95% CI 0.46–0.96) and increased odds of small for gestational age (SGA; AOR 1.66, 95% CI 1.44–1.92). Gestational weight gain less than 7 kg was associated with increased risk of seizure, hospital stay more than 5 days, and SGA. Gestational weight gain more than 18 kg was associated with assisted ventilation, seizure, hypoglycemia, polycythemia, meconium aspiration syndrome, and large for gestational age. CONCLUSION: Gestational weight gain above guidelines was common and associated with multiple adverse neonatal outcomes, whereas gestational weight gain below guidelines was only associated with SGA status. Public health efforts among similar populations should emphasize prevention of excessive gestational weight gain. LEVEL OF EVIDENCE: II-2

Gestational weight gain, macrosomia, and risk of cesarean birth in nondiabetic nulliparas

OBJECTIVE: To examine how the association between excessive weight gain and cesarean birth is modified by infant birth weight in nondiabetic women. METHODS: We designed a retrospective cohort study of singleton, term, nulliparous women with cephalic presentations delivering at a single university hospital. Subjects with diabetes were excluded. Bivariate and multivariate analyses were performed. Regression models controlled for maternal age, maternal prepregnancy body mass index, gestational age, ethnicity, smoking, birth weight, and date of delivery. RESULTS: Women gaining above Institute of Medicine guidelines were more likely to have a cesarean birth, even if birth weight was less than 4,000 g. In the multivariate analysis, women with excessive weight gain had an odds ratio of 1.40 (95% confidence interval 1.22–1.59) for cesarean birth. When absolute weight gain (total pregnancy weight gain minus birth weight and placental weight) was used in the multivariate analysis, excessive weight gain was still an independent predictor of cesarean delivery. Although macrosomia was a stronger predictor of cesarean than weight gain alone, excessive weight gain was much more common than macrosomia in our cohort. CONCLUSION: Excessive weight gain during pregnancy is an independent risk factor for cesarean birth, even when birth weight is not excessive. Other mechanisms besides macrosomia may be involved in the association between high weight gain and cesarean birth. We estimate that of the approximately 288,000 primary cesarean deliveries performed in nulliparas annually in the United States, 64,000 would be prevented if no women gained above Institute of Medicine recommendations. LEVEL OF EVIDENCE: II-2

Chorionic villus sampling compared with amniocentesis and the difference in the rate of pregnancy loss.

OBJECTIVE: To compare loss rates following amniocentesis and chorionic villus sampling (CVS) over time. METHODS: A retrospective cohort study of all amniocentesis and CVS procedures resulting in a normal karyotype from 1983–2003 at a single prenatal diagnostic referral center was conducted. Pregnancy loss rates for amniocentesis, CVS, and nonintervention groups (ie, those who had nuchal translucency screening or counseling, but no procedure) were compared using the &khgr;2 test. Year of procedure, maternal age, parity, race or ethnicity, and gestational age at procedure were controlled for in multivariable logistic regression models. RESULTS: There were 9,886 CVS and 30,893 amniocentesis procedures performed during the study period that resulted in a normal karyotype. The overall loss rates were 3.12% for CVS and 0.83% for amniocentesis (P < .001). When examined by 5-year intervals, there was a statistically significant decrease in the CVS loss rate (P < .001) and a nonsignificant lesser decrease in the loss rate for amniocentesis over time. Although the pregnancy loss rate from CVS over the entire study period was higher than from amniocentesis (adjusted odds ratio 4.23, 95% confidence interval 2.29–7.81), in the most recent time period, 1998 to 2003, there was no difference between the two procedures (adjusted odds ratio 1.03, 95% confidence interval 0.23–4.52). CONCLUSION: The loss rates for both amniocentesis and CVS at our institution have decreased over time. Because the decrease in loss rate for CVS has been greater, there is no longer a statistically significant difference between the two. These results are informative in both patient counseling and establishing widespread prenatal diagnostic and screening programs. LEVEL OF EVIDENCE: II-2

The association between the length of first stage of labor, mode of delivery, and perinatal outcomes in women undergoing induction of labor.

OBJECTIVE To estimate the association between the lengths of the first stage of labor, mode of delivery, and perinatal outcomes in women undergoing labor induction. STUDY DESIGN Retrospective cohort study of singleton, term pregnancies with labor induction and delivered during the second stage. The length of the first stage was examined by 6-hour intervals as predictors of mode of delivery and perinatal morbidity using chi(2) test and multivariable logistic regression analysis. RESULTS There were 3620 women who met study criteria. Compared with women with a first stage between 0-12 hours, women with longer first stages had a higher risk of cesarean delivery during the second stage, up to an adjusted odds ratio of 7.44 in those with a first stage > or =24 hours (95% confidence interval [CI], 3.43-16.1). Women with a first stage > or =24 hours also had higher odds of postpartum hemorrhage (adjusted odds ratio [aOR], 3.16; 95% CI, 1.73-5.79), chorioamnionitis (aOR, 2.83; 95% CI, 1.19-6.69), and neonatal admission to the intensive care nursery (aOR, 2.03; 95% CI, 1.10-3.74). CONCLUSION In women who underwent induction of labor, even when a second stage of labor was reached, the risk for cesarean delivery and maternal morbidity remained increased when the length of the first stage was longer than 24 hours. However, in this clinical scenario, the frequency of cesarean delivery remains less than 50%. The decision for surgical intervention thus should not be based on the elapse of time alone.

The Use of Ultrasound in Fetal Surgery

Obstetric ultrasound (US) is an integral part of fetal surgery for open and minimally invasive techniques. With advances in US imaging, the ability to refine diagnosis, predict prognosis, and contribute to fetal treatment continues to grow. Current research in fetal diagnosis and treatment includes identifying the most reliable sonographic features for determining prognosis before and after surgery.