Sharon L. Dooley

Risk of cesarean delivery with elective induction of labor at term in nulliparous women

OBJECTIVE To quantify the risk of cesarean delivery associated with elective induction of labor in nulliparous women at term. METHODS We performed a cohort study on a major urban obstetric service that serves predominantly private obstetric practices. All term, nulliparous women with vertex, singleton gestations who labored during an 8-month period (n = 1561) were divided into three groups: spontaneous labor, elective induction, and medical induction. The risk of cesarean delivery in the induction groups was determined using stepwise logistic regression to control for potential confounding factors. RESULTS Women experiencing spontaneous labor had a 7.8% cesarean delivery rate, whereas women undergoing elective labor induction had a 17.5% cesarean delivery rate (adjusted odds ratio [OR] 1.89; 95% confidence interval [CI] 1.12, 3.18) and women undergoing medically indicated labor induction had a 17.7% cesarean delivery rate (OR 1.69; 95% CI 1.13, 2.54). Other variables that remained significant risk factors for cesarean delivery in the model included: epidural placement at less than 4 cm dilatation (OR 4.66; 95% CI 2.25, 9.66), epidural placement after 4 cm dilatation (OR 2.18; 95% CI 1.06, 4.48), chorioamnionitis (OR 4.61; 95% CI 2.89, 7.35), birth weight greater than 4000 g (OR 2.59; 95% CI 1.69, 3.97), maternal body mass index greater than 26 kg/m2 (OR 2.36; 95% CI 1.61, 3.47), Asian race (OR 2.35; 95% CI 1.04, 5.34), and magnesium sulfate use (OR 2.18; 95% CI 1.04, 4.55). CONCLUSION Elective induction of labor is associated with a significantly increased risk of cesarean delivery in nulliparous women. Avoiding labor induction in settings of unproved benefit may aid efforts to reduce the primary cesarean delivery rate.

Gestational Diabetes Mellitus: Heterogeneity of Maternal Age, Weight, Insulin Secretion, HLA Antigens, and Islet Cell Antibodies and the Impact of Maternal Metabolism on Pancreatic B-Cell and Somatic Development in the Offspring

We have examined gravida with gestational diabetes mellitus (GDM), as defined by the National Diabetes Data Group (Diabetes 1979; 28:1039), for phenotypic and genotypic heterogeneity. Fasting plasma glucose (FPG) at diagnosis was used for further stratification of GDM according to putative metabolic severity into class A, (FPG < 105 mg/dl [N = 129]), class A2 (FPG 105–129 mg/dl [N = 47]), and class B1 (FPG ≥ 130 mg/dl [N = 23]). All GDM classes tended to be older and heavier than consecutive gravida with documented normal glucose tolerance (controls, N = 148). Subdivision into “lean” and “obese” indicated that plasma immunoreactive insulin (IRI) was greater after overnight fast in the obese of all groups except B1. However, absolute increases in IRI above fasting levels in response to glucose during OGTT were significantly enhanced by obesity only in class A2 gravida. Adjustment for the effects of age and weight by covariate analysis indicated that the IRI response to glycemic stimulation is usually attenuated in all forms of GDM. Mean values for increases in IRI above fasting values during the first 15 min and IRI increments relative to the increases in plasma glucose throughout the 180-min OGTT were below control values in all GDM groups and progressively so, i.e.,A1 < A2 < B1. The absolute insulinopenia was not invariable; a small number of gravida from all GDM groups displayed well-preserved IRI responses to oral glucose. Genotypic evaluation of the GDM population disclosed an increased occurrence of “markers” known to be associated with type I diabetes mellitus. HLA antigens DR3 and DR4 were more frequent in all GDM groups, and the incidence of cytoplasmic islet cell antibodies was enhanced significantly in class A2, and even more so in class B1. Thus, GDM appears to be a heterogeneous entity with substantial phenotypic and genotypic diversity in the mothers. Offspring from some class A1 and diet-treated class A2 gravida were examined to assess whether minimal abnormalities in maternal metabolism suffice to impact on intrauterine development independent of maternal diversity. Amniotic fluid insulin at 36 ± 0.1 wk of gestation and cord plasma C-peptide at birth were increased in offspring of mothers with class A1 GDM, thus indicating that even the mildest forms of GDM can cause accelerated maturation of fetal islet function. Birth weight and symmetry index in the newborn from class A1 arid diet-treated class A2 gravida were significantly increased above control values, even after adjustment for maternal age and weight, thus documenting for the first time that GDM per se can influence the anthropometric characteristics of the neonate. The findings underscore that GDM constitutes an independent risk factor with particular implications for islet and somatic development during fetal life. These unequivocal effects of maternal metabolism on cell development in the fetus may provide the most compelling reason for aggressive approaches to GDM, especially if prospective as well as retrospective studies continue to support their postulated association with increased obesity and diabetes in later life (i.e., “fuel-mediated teratogenesis”; Diabetes 1980; 29:1023).

Prenatal and perinatal influences on long-term psychomotor development in offspring of diabetic mothers☆

OBJECTIVE Our purpose was to assess to what extent disturbances in antepartum maternal metabolism and perinatal complications and morbidities contribute to poorer psychomotor development in offspring of diabetic mothers. STUDY DESIGN One hundred ninety-six pregnant women and their singleton offspring participated in this prospective cohort-analytic study. Ninety-five women had pregestational diabetes mellitus, and 101 women had gestational diabetes mellitus. Serial estimates of circulating maternal fuels were obtained throughout each index pregnancy along with detailed records of the perinatal course and outcome. Offspring were administered the psychomotor development index of the Bayley Scales of Infant Development at age 2 years and the Bruininks-Oseretsky Test Of Motor Proficiency at ages 6, 8, and 9 years. Tests were performed blinded to the mothers antepartum metabolic status, and perinatal history, and the childs previous test scores. Partial correlations and analyses of covariance were used to control for other influences and confounds, such as family socioeconomic status, racial or ethnic origin, patient group (i.e., pregestational or gestational diabetes mellitus), and sex of child. RESULTS Childrens average score on the Bruininks-Oseretsky test at ages 6 to 9 years correlated significantly with maternal second (p < 0.02) and third trimester (p < 0.001) beta-hydroxybutyrate. There was also a borderline association between the childrens scores on the psychomotor development index at age 2 years and maternal third-trimester beta-hydroxybutyrate levels (p = 0.06). No other correlations approached significance. CONCLUSIONS Intrauterine metabolic experiences continue to influence the neurodevelopmental course in offspring of diabetic mothers. Prevailing practices in diabetes management and obstetric and neonatal care appear to effectively mitigate the potential long-term effects of most perinatal complications and morbidities. Management and obstetric and neonatal care appear to effectively miltigate the potential long-term effects of most perinatal complications and morbidities.

Effect of Pregnancy On Renal Function in Patients With Moderate-to-Severe Diabetic Renal Insufficiency

OBJECTIVE Previous studies of patients with diabetic nephropathy and mild renal impairment have suggested no determination in renal function as a result of pregnancy. The objective of this study was to determine whether pregnancy may permanently worsen renal function in women with diabetic nephropathy and moderate-to-severe renal insufficiency. RESEARCH DESIGN AND METHODS Eleven patients were identified with diabetic nephropathy and moderate-to-severe renal dysfunction (creatinine [Cr] ≥ 124 μmol/l [1.4 mg/dl]) at pregnancy onset by retrospective chart review. Alterations in glomerular filtration rate were estimated by using linear regression of the reciprocal of Cr over time. An equal number of nonpregnant premenopausal type 1 diabetic women with similar degrees of renal dysfunction served as a comparison group for nonpregnant rate of decline of renal function and potential contributing factors. RESULTS Mean serum Cr rose from 159 μmol/l (1.8 mg/dl) prepregnancy to 221 μmol/l (2.5 mg/dl) in the third trimester. Renal function was stable in 27%, showed transient worsening in pregnancy in 27%, and demonstrated a permanent decline in 45%. Proteinuria increased in pregnancy in 79%. Exacerbation of hypertension or preeclampsia occurred in 73%. Seven patients progressed to dialysis 6–57 months postpartum, with 71% (five of seven) of these cases attributed to acceleration of disease during the pregnancy. Students t tests and repeated-measures analysis of variance support a pregnancy-induced acceleration in the rate of decline of renal function. CONCLUSIONS In this series, patients with diabetic nephropathy and moderate-to-severe renal insufficiency were found to have a > 40% chance of accelerated progression of their disease as a result of pregnancy.

Care of the Pregnant Woman with Insulin-Dependent Diabetes Mellitus

THE expectations for a viable birth in pregnancy complicated by diabetes have never been better in centers where a large number of diabetic pregnant women receive their care from teams of specially...

Reducing cesarean births at a primarily private university hospital

OBJECTIVE The rise in cesarean birth at Northwestern Memorial Hospital in 1986 to 27.3% prompted implementation of three initiatives to reverse the escalating cesarean section rate. STUDY DESIGN First, vaginal birth after cesarean section was more strongly encouraged. Second, after the 1988 calendar year the cesarean section rate of every obstetrician was circulated annually to each attending physician. Third, on completion of a prospective, randomized trial of the active management of labor in early 1991, this protocol was recommended as the preferred method of labor management for term nulliparous patients. RESULTS The total, primary, and repeat cesarean section rates declined from 27.3%, 18.2%, and 9.1% in 1986 to 16.9%, 10.6%, and 6.4%, respectively, in 1991. At the same time the perinatal mortality dropped from 19.5 to 10.3. Significant reductions in abdominal deliveries occurred for both private patients (30.3% to 19.1%, p < 0.0001) and clinic patients (20.8% to 11.5%, p < 0.0001). A decline in operative deliveries for dystocia and an increase in vaginal birth after prior cesarean section were the principal factors contributing to the lower cesarean section rates. However, in 1991 individual private physicians still had wide variations in primary cesarean section rates (4.6% to 21.1%) and use of vaginal birth after prior cesarean section (5.3% to 90%). CONCLUSION The cesarean section rate has been significantly reduced for both private and clinic patients. Differences in population demographics and individual physician practice patterns contributed to a higher incidence of cesarean birth on the private service.

Diminished growth in fetuses born preterm after spontaneous labor or rupture of membranes

We examined biparietal diameter, abdominal circumference, and birth weight in 148 preterm infants to assess fetal growth. A statistically significant proportion of preterm fetuses had biparietal diameter and abdominal circumference values below the fiftieth and tenth percentile levels as compared with that expected in normal fetuses. Similarly, birth weight of infants in the study fell significantly below the fiftieth and tenth percentiles relative to Brenners curve. We conclude that diminished fetal growth is associated with early delivery secondary to preterm labor or preterm premature rupture of membranes or both. Additionally, since biparietal diameters in preterm fetuses are smaller than those of normal fetuses the prediction of gestational age by cephalometry should be advanced by 7 to 10 days.

Shoulder dystocia and birth trauma in gestational diabetes: A five-year experience

Over a 5-year period, 210 patients with gestational diabetes mellitus were delivered of offspring weighing greater than or equal to 3500 gm. Only three primary cesarean sections were performed electively because of suspected macrosomia. One hundred twenty patients were delivered vaginally. There were 15 shoulder dystocias but only one permanent brachial plexus injury. Seven of the 15 shoulder dystocias occurred in offspring weighing less than 4000 gm. Of variables examined, only the use of forceps was clearly associated with an increased risk of shoulder dystocia (odds ratio, 5.1). A policy to deliver by cesarean section all fetuses estimated to weigh greater than 4000 gm would considerably increase the number of cesarean sections with minimal fetal benefit.

Meconium below the vocal cords at delivery: Correlation with intrapartum events

Intrapartum events were studied in 272 patients with meconium-stained amniotic fluid. All infants underwent DeLee suction followed by intubation and 58 of 272 had meconium present below the vocal cords at delivery. Neither the total duration of variable fetal heart rate decelerations or a continuous saltatory pattern nor the presence or absence of late decelerations could be related to an increased risk of meconium below the vocal cords. When a rising baseline fetal heart rate and decreased variability were present as well, a significantly greater proportion of patients had meconium below the vocal cords. Routine obstetric and pediatric suctioning did not prevent the single death that occurred in a fetus who had deep meconium aspiration in utero.

Risk adjustment for interhospital comparison of primary cesarean rates

OBJECTIVE To create a method of controlling for case mix so that inferences could be made about variation in cesarean rates among hospitals. METHODS A total of 160,753 births from 1991 Illinois birth certificate data were analyzed. A multivariate model of characteristics independently associated with cesarean delivery was developed from a random 25% sample, validated on the other 75%, and used to create a probability of cesarean delivery for each woman. The validated model was used to calculate a predicted primary cesarean delivery rate for the 154 hospitals in Illinois that did at least 100 deliveries per year. RESULTS The final model included both medical and sociodemographic risk factors and predicted primary cesarean rates accurately over a full range of rates. Thirty-five hospitals (23%) had actual rates that were higher than their individual predicted 95% confidence interval (CI). Eighty-nine hospitals (58%) had actual rates within predicted CIs. Thirty hospitals (20%) had actual rates that were lower than the predicted 95% CI. Twenty-three percent of hospitals with actual rates greater than predicted rates were not in the top quartile of actual rates. Twenty-seven percent of hospitals with actual rates in the top quartile were doing cesarean deliveries appropriate for the risk status of the population served. CONCLUSION Risk adjusting for hospital case mix more accurately identifies outlier hospitals than raw, unadjusted primary cesarean delivery rates. We believe that risk adjusting should be the first step in understanding variations in primary cesarean delivery rates.