Kathleen Belanger

Indications Contributing to the Increasing Cesarean Delivery Rate

OBJECTIVE: To examine physician-documented indications for cesarean delivery in order to investigate the specific factors contributing to the increasing cesarean delivery rate. 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 and 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, preeclampsia, suspected macrosomia, and maternal request increased over time, whereas 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: nonreassuring fetal status (32%), labor arrest disorders (18%), multiple gestation (16%), suspected macrosomia (10%), preeclampsia (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 cesarean deliveries, more subjective indications (nonreassuring fetal status and arrest of dilation) contributed larger proportions than more objective indications (malpresentation, maternal-fetal, and obstetric conditions). LEVEL OF EVIDENCE: III

Ambient air pollution and low birth weight in Connecticut and Massachusetts.

Background Several 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. Objectives We 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. Methods Analysis 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. Results An 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. Conclusions Results indicate that exposure to air pollution, even at low levels, may increase risk of low birth weight, particularly for some segments of the population.

Asthma prevalence among pregnant and childbearing-aged women in the United States: estimates from national health surveys.

PURPOSE Asthma is a major complication of pregnancy, but there are currently no reliable national estimates for the United States of asthma prevalence in pregnancy or in the childbearing years. METHODS The prevalence of asthma among pregnant women and all childbearing-aged women was estimated and examined by age group using the National Health Interview Survey (NHIS), 1997-2000, the Behavioral Risk Factor Surveillance System (BRFSS), 2000-2001, and the Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994. Time trends were explored using NHANES II (1976-1980) and NHANES III (1988-1994). RESULTS Asthma was estimated to affect from 88,573 to 190,650 pregnant women between 1997 and 2001, or approximately 3.7% to 8.4% of pregnant women in the United States. A slightly lower estimate of 3.2% was obtained for the period between 1988 and 1994. Among adult women of childbearing age, a two-fold increase in asthma from 2.9% to 5.8% occurred between 1976-1980 and 1988-1994. Among women aged 18 to 24, the increase was three-fold, from 1.8% to 6.0%. CONCLUSION The prevalence of asthma during pregnancy may be higher than previously estimated and appears to be continuing to increase.

Asthma symptoms, severity, and drug therapy: a prospective study of effects on 2205 pregnancies.

OBJECTIVE To prospectively examine in pregnant women whether asthma or asthma therapy influenced preterm delivery, intrauterine grown restriction (IUGR), or birthweight. METHODS We enrolled 873 pregnant women with a history of asthma, of whom 778 experienced asthma symptoms or took medication, and 1333 women with no asthma history, including 884 women with neither asthma diagnosis nor symptoms and 449 with symptoms but no diagnosis. Asthma symptoms, medication, and severity were classified according to 2002 Global Initiative for Asthma guidelines. RESULTS Preterm delivery was not associated with asthma diagnosis, severity, or symptoms but was associated with use of controller medications, independent of symptoms, specifically oral steroids and theophylline. Gestation was reduced by 2.22 weeks in women using oral steroids daily (P =.001) and 1.11 weeks after theophylline (P =.002). We observed a 24% (5-47%) increased risk for IUGR with each increased symptom step, which increased further in symptomatic women with no asthma diagnosis (31%, 4-65%) compared with women with neither asthma nor symptoms. CONCLUSIONS 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.

The relation between fungal propagules in indoor air and home characteristics

Background: Questionnaires are commonly used in epidemiologic studies to obtain information about house characteristics in order to predict the household aeroallergen exposure levels. However, the reliability of the predictions made with the questionnaires has not been evaluated. To address this issue, we compared objectively measured fungal propagules including the most frequently isolated mold genera (i.e., Alternaria, Aspergillus, Cladosporium, Penicillium, etc.) in a large sample of homes and compared these measured values to the questionnaire‐determined household characteristics.

Prenatal Exposure to Fine Particulate Matter and Birth Weight: Variations by Particulate Constituents and Sources

Background: Exposure to fine particles (PM2.5) during pregnancy has been linked to lower birth weight; however, the chemical composition of PM2.5 varies widely. The health effects of PM2.5 constituents are unknown. Methods: We investigated whether PM2.5 mass, constituents, and sources are associated with birth weight for term births. PM2.5 filters collected in 3 Connecticut counties and 1 Massachusetts county from August 2000 through February 2004 were analyzed for more than 50 elements. Source apportionment was used to estimate daily contributions of PM2.5 sources, including traffic, road dust/crustal, oil combustion, salt, and regional (sulfur) sources. Gestational and trimester exposure to PM2.5 mass, constituents, and source contributions were examined in relation to birth weight and risk of small-at-term birth (term birth <2500 g) for 76,788 infants. Results: Road dust and related constituents such as silicon and aluminum were associated with lower birth weight, as were the motor-vehicle-related species such as elemental carbon and zinc, and the oil-combustion-associated elements vanadium and nickel. An interquartile range increase in exposure was associated with low birthweight for zinc (12% increase in risk), elemental carbon (13%), silicon (10%), aluminum (11%), vanadium (8%), and nickel (11%). Analysis by trimester showed effects of third-trimester exposure to elemental carbon, nickel, vanadium, and oil-combustion PM2.5. Conclusions: Exposures of pregnant women to higher levels of certain PM2.5 chemical constituents originating from specific sources are associated with lower birth weight.

Symptoms and Medication Use in Children with Asthma and Traffic-Related Sources of Fine Particle Pollution

Background Exposure to ambient fine particles [particulate matter ≤ 2.5 μm diameter (PM2.5)] is a potential factor in the exacerbation of asthma. National air quality particle standards consider total mass, not composition or sources, and may not protect against health impacts related to specific components. Objective We examined associations between daily exposure to fine particle components and sources, and symptoms and medication use in children with asthma. Methods Children with asthma (n = 149) 4–12 years of age were enrolled in a year-long study. We analyzed particle samples for trace elements (X-ray fluorescence) and elemental carbon (light reflectance). Using factor analysis/source apportionment, we identified particle sources (e.g., motor vehicle emissions) and quantified daily contributions. Symptoms and medication use were recorded on study diaries. Repeated measures logistic regression models examined associations between health outcomes and particle exposures as elemental concentrations and source contributions. Results More than half of mean PM2.5 was attributed to traffic-related sources motor vehicles (42%) and road dust (12%). Increased likelihood of symptoms and inhaler use was largest for 3-day averaged exposures to traffic-related sources or their elemental constituents and ranged from a 10% increased likelihood of wheeze for each 5-μg/m3 increase in particles from motor vehicles to a 28% increased likelihood of shortness of breath for increases in road dust. Neither the other sources identified nor PM2.5 alone was associated with increased health outcome risks. Conclusions Linking respiratory health effects to specific particle pollution composition or sources is critical to efforts to protect public health. We associated increased risk of symptoms and inhaler use in children with asthma with exposure to traffic-related fine particles.

Heterogeneity in assessing self-reports of caffeine exposure: Implications for studies of health effects

Background. Coffee and its metabolite caffeine are widely studied for their health effects but with inconclusive results. Caffeine is particularly difficult to assess, and therefore we explore heterogeneity of caffeine exposure. Methods. We categorized caffeine exposure among 2,478 pregnant women in southern New England during 1996–2000 by the traditional laboratory-based methods of M. Bunker and M. McWilliams. A subsample was examined to ascertain caffeine levels of brewed or purchased beverages actually consumed. Results. More than half (56.6%) of women drank coffee since becoming pregnant. Serving sizes ranged from 2 to 32 oz and are considerably larger than laboratory standards, which are typically 8–10 oz, as compared with the standard of 5 to 6 oz. Conversely, caffeine content per serving of coffee was one-third the laboratory standard, eg, 100 mg caffeine compared with 300 mg for a 10-oz cup. Tea brewed more than 3 minutes contained 42 mg caffeine as compared with the standard of 94 mg. When the amount of caffeine actually consumed was measured, one-quarter (24.8%) of subjects traditionally classified as consuming 300+ gm caffeine daily were reclassified as consuming 150–299 mg. Conclusion. Misclassification of caffeine consumption increases difficulty in identifying health effects from caffeine. Some combination of more precise consumption data and a biomarker such as paraxanthine may more precisely estimate exposure.

maternal Caffeine Consumption and Spontaneous Abortion: A Prospective Cohort Study

&NA; We investigated the relation between caffeine beverage consumption and spontaneous abortion in 2,967 pregnant women planning to deliver at Yale‐New Haven Hospital in 1988–1992. We evaluated coffee, tea, and soda drinking in the first month of pregnancy in interviews before the end of the sixteenth week of gestation. We obtained information on 98.2% of the pregnancies (including 2,714 singleton livebirths and 135 spontaneous abortions). As compared with abstention from caffeine beverages (coffee, tea, and soda), the adjusted odds ratios for spontaneous abortion associated with consumption of 1–150, 151–300, and >300 mg caffeine daily were 0.81 [95% confidence interval (CI) = 0.54–1.20], 0.89 (95% CI = 0.48–1.64), and 1.75 (95% CI = 0.88–3.47), respectively. Drinking ≥3 cups of tea or coffee was associated with elevated risks of spontaneous abortion (adjusted odds ratio = 2.33, 95% CI = 0.92–5.85; and adjusted odds ratio = 2.63, 95% CI = 1.29–5.34, respectively). These results, if replicated, suggest that some ingredient (or correlate) of tea or coffee may account for some of the observed association of caffeine with spontaneous abortion. In this study, caffeine consumption is more strongly related to spontaneous abortion than alcohol or cigarette use in early pregnancy.

Does antidepressant use attenuate the risk of a major depressive episode in pregnancy

Background: Many women become pregnant while undergoing antidepressant treatment and are concerned about continuing antidepressant medication. However, antidepressant discontinuation may increase the risk of a new episode of major depressive disorder. We sought to estimate differences in the risk of developing a new major depressive episode among pregnant and postpartum women with recurrent illness who either did or did not use antidepressants. Methods: Participants were recruited from obstetrical settings; we analyzed a subgroup of 778 women with a history of a depressive disorder. Diagnoses were determined by the Composite International Diagnostic Interview administered twice in pregnancy and once after delivery. We used Cox Regression to model onset of a major depressive episode with a time-dependent predictor of antidepressant use. Results: There was no clear difference in risk of a major depressive episode between women who took antidepressants and women who did not (hazard ratio [HR] = 0.88; 95% CI = 0.51-1.50). After accounting for antidepressant use, clearly hazardous factors included 4 or more depressive episodes before pregnancy (HR = 1.97; 95% CI = 1.09-3.57), black race (HR = 3.69; 95% CI = 2.16-6.30), and Hispanic ethnicity (HR = 2.33; 95% CI = 1.47-3.69). Conclusions: Failure to use or discontinuation of antidepressants in pregnancy did not have a strong effect on the development of a major depressive episode. Women with 4 or more episodes before pregnancy were at high risk of a major depressive episode, independent of antidepressant use. Black and Hispanic women also were at high risk of a major depressive episode, but it is possible that this effect is attributable to unmeasured factors.