OBJECTIVE To examine physician-documented indications for cesarean delivery in order to investigate the specific indications contributing to this increase. METHODS We analyzed rates of primary and repeat cesarean delivery, including indications for the procedure, among 32,443 live births at a major academic hospital between 2003–2009. Time trends for each indication were modeled to estimate the absolute and cumulative annualized relative risk of cesarean by indication over time and the relative contribution of each indication to the overall increase in primary cesarean delivery rate. RESULTS The cesarean delivery rate increased from 26% to 36.5% between 2003 and 2009; 50.0% of the increase was attributable to an increase in primary cesarean delivery. Among the documented indications, nonreassuring fetal status, arrest of dilation, multiple gestation, pre-eclampsia, suspected macrosomia, and maternal request increased over time, while arrest of descent, malpresentation, maternal-fetal indications, and other obstetric indications (eg, cord prolapse, placenta previa) did not increase. The relative contributions of each indication to the total increase in primary cesarean rate were: Non-reassuring fetal status (32%), labor arrest disorders (18%), multiple gestation (16%), suspected macrosomia (10%), pre-eclampsia (10%), maternal request (8%), maternal-fetal conditions (5%), and other obstetric conditions (1%). CONCLUSION Primary cesarean births accounted for 50% of the increasing cesarean rate. Among primary cesareans, more subjective indications (nonreassuring fetal status and arrest of dilation) contributed larger proportions than more objective indications (malpresentation, maternal-fetal, and obstetric conditions).

BackgroundSeveral studies have examined whether air pollution affects birth weight; however results vary and many studies were focused on Southern California or were conducted outside of the United States.ObjectivesWe investigated maternal exposure to particulate matter with aerodynamic diameter < 10, < 2.5 μm (PM10, PM2.5), sulfur dioxide, nitrogen dioxide, and carbon monoxide and birth weight for 358,504 births in Massachusetts and Connecticut from 1999 to 2002.MethodsAnalysis included logistic models for low birth weight (< 2,500 g) and linear models with birth weight as a continuous variable. Exposure was assigned as the average county-level concentration over gestation and each trimester based on mother’s residence. We adjusted for gestational length, prenatal care, type of delivery, child’s sex, birth order, weather, year, and mother’s race, education, marital status, age, and tobacco use.ResultsAn interquartile increase in gestational exposure to NO2, CO, PM10, and PM2.5 lowered birth weight by 8.9 g [95% confidence interval (CI), 7.0–10.8], 16.2 g (95% CI, 12.6–19.7), 8.2 g (95% CI, 5.3–11.1), and 14.7 g (95% CI, 12.3–17.1), respectively. Lower birth weight was associated with exposure in the third trimester for PM10, the first and third trimesters for CO, the first trimester for NO2 and SO2, and the second and third trimesters for PM2.5. Effect estimates for PM2.5 were higher for infants of black mothers than those of white mothers.ConclusionsResults indicate that exposure to air pollution, even at low levels, may increase risk of low birth weight, particularly for some segments of the population.

We found no effect of asthma symptoms or severity on preterm delivery but observed increased risks associated with use of oral steroid and theophylline. Intrauterine growth restriction was associated with asthma severity, which possibly reflects a hypoxic fetal effect. Women with asthma symptoms but no diagnosis were at particular risk of undermedication and delivering IUGR infants. These observations support guidelines that advocate active management of pregnant patients with mild or moderate asthma with beta(2) agonists, with oral steroids added only if severity increases. Symptomatic patients without an asthma diagnosis might need to be equally managed.