Marit L. Bovbjerg

Outcomes of Care for 16,924 Planned Home Births in the United States: The Midwives Alliance of North America Statistics Project, 2004 to 2009

INTRODUCTION Between 2004 and 2010, the number of home births in the United States rose by 41%, increasing the need for accurate assessment of the safety of planned home birth. This study examines outcomes of planned home births in the United States between 2004 and 2009. METHODS We calculated descriptive statistics for maternal demographics, antenatal risk profiles, procedures, and outcomes of planned home births in the Midwives Alliance of North American Statistics Project (MANA Stats) 2.0 data registry. Data were analyzed according to intended and actual place of birth. RESULTS Among 16,924 women who planned home births at the onset of labor, 89.1% gave birth at home. The majority of intrapartum transfers were for failure to progress, and only 4.5% of the total sample required oxytocin augmentation and/or epidural analgesia. The rates of spontaneous vaginal birth, assisted vaginal birth, and cesarean were 93.6%, 1.2%, and 5.2%, respectively. Of the 1054 women who attempted a vaginal birth after cesarean, 87% were successful. Low Apgar scores (< 7) occurred in 1.5% of newborns. Postpartum maternal (1.5%) and neonatal (0.9%) transfers were infrequent. The majority (86%) of newborns were exclusively breastfeeding at 6 weeks of age. Excluding lethal anomalies, the intrapartum, early neonatal, and late neonatal mortality rates were 1.30, 0.41, and 0.35 per 1000, respectively. DISCUSSION For this large cohort of women who planned midwife-led home births in the United States, outcomes are congruent with the best available data from population-based, observational studies that evaluated outcomes by intended place of birth and perinatal risk factors. Low-risk women in this cohort experienced high rates of physiologic birth and low rates of intervention without an increase in adverse outcomes.

Exercise during pregnancy and cesarean delivery: North Carolina PRAMS, 2004-2005.

BACKGROUND The current rate of cesarean delivery in the United States is 31 percent. Previous studies have suggested that exercise during pregnancy may be associated with a lower risk of cesarean delivery, but sample sizes were small and methods often inadequate. This study examined whether or not an association exists between prenatal exercise and delivery mode using data from the 2004 and 2005 North Carolina Pregnancy Risk Assessment Monitoring System (PRAMS) survey. METHODS PRAMS postpartum questionnaire responses about frequency of exercise during the last 3 months of pregnancy for 1,955 women without a prior cesarean delivery were linked to birth certificates. RESULTS Among 1,342 women delivering at term, exercise was not associated with delivery mode in this data set: compared with women exercising less than once a week, neither women exercising one to four times per week nor those exercising five times or more per week had an altered risk of cesarean (risk ratio [RR] [95% confidence limit] [CL] 0.89 [0.69-1.15], 1.04 [0.66-1.64], respectively, adjusted for parity, gestational age, hypertension). Among 613 women delivering preterm, the results were also not statistically significant, but a compelling trend toward a protective effect could be seen (RR [95% CL] 0.65 [0.38-1.13], 0.62 [0.29-1.33]). CONCLUSIONS Maternal self-reported frequency of exercise during pregnancy was not associated with a reduced risk of cesarean delivery. Larger studies with better exposure ascertainment may provide a more definitive answer.

Development and Validation of a National Data Registry for Midwife‐Led Births: The Midwives Alliance of North America Statistics Project 2.0 Dataset

INTRODUCTION In 2004, the Midwives Alliance of North Americas (MANAs) Division of Research developed a Web-based data collection system to gather information on the practices and outcomes associated with midwife-led births in the United States. This system, called the MANA Statistics Project (MANA Stats), grew out of a widely acknowledged need for more reliable data on outcomes by intended place of birth. This article describes the history and development of the MANA Stats birth registry and provides an analysis of the 2.0 datasets content, strengths, and limitations. METHODS Data collection and review procedures for the MANA Stats 2.0 dataset are described, along with methods for the assessment of data accuracy. We calculated descriptive statistics for client demographics and contributing midwife credentials, and assessed the quality of data by calculating point estimates, 95% confidence intervals, and kappa statistics for key outcomes on pre- and postreview samples of records. RESULTS The MANA Stats 2.0 dataset (2004-2009) contains 24,848 courses of care, 20,893 of which are for women who planned a home or birth center birth at the onset of labor. The majority of these records were planned home births (81%). Births were attended primarily by certified professional midwives (73%), and clients were largely white (92%), married (87%), and college-educated (49%). Data quality analyses of 9932 records revealed no differences between pre- and postreviewed samples for 7 key benchmarking variables (kappa, 0.98-1.00). DISCUSSION The MANA Stats 2.0 data were accurately entered by participants; any errors in this dataset are likely random and not systematic. The primary limitation of the 2.0 dataset is that the sample was captured through voluntary participation; thus, it may not accurately reflect population-based outcomes. The datasets primary strength is that it will allow for the examination of research questions on normal physiologic birth and midwife-led birth outcomes by intended place of birth.

Characteristics related to effective contraceptive use among a sample of nonurban latinos.

CONTEXT A better understanding of effective contraceptive use among Latinos is needed to reduce their high rate of unintended pregnancy. Most research has focused on urban Latinas and has overlooked the relationship context of effective contraceptive use. METHODS Interviews were conducted among a sample of 450 Latino women and men aged 18-25 in sexual relationships, who were recruited from community sites in four rural Oregon counties in 2006. Bivariate and multinomial logistic regression analyses were used to examine the associations between effective contraceptive use and -individual, cultural and relationship characteristics. RESULTS Half of participants reported effective contraceptive use in their primary relationships: Thirty-six percent consistently used a female method, and 15% consistently used condoms. Acculturation and confidence in ones -ability to practice contraception with a primary partner were associated with female method use rather than no effective use (risk ratios, 0.7 and 1.7, respectively). Participation in sexual decision making was positively associated with condom use rather than no effective method use (2.2) or female method use (1.9); partner involvement in birth control was positively associated with condom use rather than female method use (1.8). CONCLUSIONS Variations in effective contraceptive use among nonurban Latinos appear related to relationship characteristics and dynamics. Contraceptive counseling and unintended pregnancy prevention programs that are tailored to reflect relationship contexts and to include male partners where appropriate could improve the quality and cultural relevance of services among nonurban Latinos.

Maternal and Newborn Outcomes Following Waterbirth: The Midwives Alliance of North America Statistics Project, 2004 to 2009 Cohort

INTRODUCTION Data on the safety of waterbirth in the United States are lacking. METHODS We used data from the Midwives Alliance of North America Statistics Project, birth years 2004 to 2009. We compared outcomes of neonates born underwater waterbirth (n = 6534), neonates not born underwater nonwaterbirth (n = 10,290), and neonates whose mothers intended a waterbirth but did not have one intended waterbirth (n = 1573). Neonatal outcomes included a 5-minute Apgar score of less than 7, neonatal hospital transfer, and hospitalization or neonatal intensive care unit (NICU) admission in the first 6 weeks. Maternal outcomes included genital tract trauma, postpartum hospital transfer, and hospitalization or infection (uterine, endometrial, perineal) in the first 6 weeks. We used logistic regression for all analyses, controlling for primiparity. RESULTS Waterbirth neonates experienced fewer negative outcomes than nonwaterbirth neonates: the adjusted odds ratio (aOR) for hospital transfer was 0.46 (95% confidence interval [CI], 0.32-0.68; P < .001); the aOR for infant hospitalization in the first 6 weeks was 0.75 (95% CI, 0.63-0.88; P < .001); and the aOR for NICU admission was 0.59 (95% CI, 0.46-0.76; P < .001). By comparison, neonates in the intended waterbirth group experienced more negative outcomes than the nonwaterbirth group, although only 5-minute Apgar score was significant (aOR, 2.02; 95% CI, 1.40-2.93; P < 0001). For women, waterbirth (compared to nonwaterbirth) was associated with fewer postpartum transfers (aOR, 0.65; 95% CI, 0.50-0.84; P = .001) and hospitalizations in the first 6 weeks (aOR, 0.72; 95% CI, 0.59-0.87; P < 0.001) but with an increased odds of genital tract trauma (aOR, 1.11; 95% CI, 1.04-1.18; P = .002). Waterbirth was not associated with maternal infection. Women in the intended waterbirth group had increased odds for all maternal outcomes compared to women in the nonwaterbirth group, although only genital tract trauma was significant (aOR, 1.67; 95% CI, 1.49-1.87; P < .001). DISCUSSION Waterbirth confers no additional risk to neonates; however, waterbirth may be associated with increased risk of genital tract trauma for women.

Translation of fetal abdominal circumference-guided therapy of gestational diabetes complicated by maternal obesity to a clinical outpatient setting

Abstract Objective: To evaluate the effectiveness of fetal abdominal circumference-guided therapy for gestational diabetes (GDM) in an outpatient population characterized by highly-prevalent maternal obesity. Methods: Data for this translational retrospective cohort study come from medical records. Fetal abdominal circumference was assessed by ultrasound in late second trimester, and sex- and gestational age-specific percentiles assigned. Taking fetal abdominal circumference percentile as a marker for adequacy of fetal growth, maternal glucose targets were set accordingly: loose, moderate or tight. Associations between mother’s targets and neonatal outcomes (small for gestational age (SGA), large for gestational age (LGA), macrosomia, neonatal intensive care unit (NICU) admission, and neonatal hypoglycemia) were assessed using unconditional logistic regression, controlling for pre-gravid body mass index (BMI) and gestational weight gain. Results: In 419 consecutive pregnancies complicated by GDM, neonatal outcomes compared favorably with previous randomized trials of intensive GDM management. Importantly, adverse outcomes were observed less often than might be expected in an obese GDM population. BMI did not have an independent effect on neonatal outcomes. Conclusions: Ultrasound-guided therapy of GDM, in general clinic use, can limit excess macrosomia and LGA, even in a population with significant maternal obesity.

Exposure analysis methods impact associations between maternal physical activity and cesarean delivery

BACKGROUND Previous studies report conflicting results regarding a possible association between maternal physical activity (PA) and cesarean delivery. METHODS Seven-day PA recalls were collected by telephone from pregnant women (n = 1205) from North Carolina, without prior cesarean, during 2 time windows: 17 to 22 weeks and 27 to 30 weeks completed gestation. PA was treated as a continuous, nonlinear variable in binomial regressions (log-link function); models controlled for primiparity, maternal contraindications to exercise, preeclampsia, pregravid BMI, and percent poverty. We examined both total PA and moderate-to-vigorous PA (MVPA) at each time. Outcomes data came from medical records. RESULTS The dose-response curves between PA or MVPA and cesarean risk at 17 to 22 weeks followed an inverse J-shape, but at 27 to 30 weeks the curves reversed and were J-shaped. However, only (total) PA at 27 to 30 weeks was strongly associated with cesarean risk; this association was attenuated when women reporting large volumes of PA (> 97.5 percentile) were excluded. CONCLUSION We did not find evidence of an association between physical activity and cesarean birth. We did, however, find evidence that associations between PA and risk of cesarean may be nonlinear and dependent on gestational age at time of exposure, limiting the accuracy of analyses that collapse maternal PA into categories.

Rethinking Dr. Spock

I read with interest the “Voices From the Past” article that reprinted part of Dr. Spocks book, Decent and Indecent: Our Personal and Political Behavior.1 The accompanying brief biography of Dr. Spock was intriguing as well—we should all aspire to speak so vocally and publicly about issues pertaining to health and social justice in the United States. However, I think that it is inappropriate to present a biography—however brief—on Dr. Spock that references his best-selling book on child care, Baby and Child Care,2 as a “classic parenting guide,” yet fails to mention that this very book was the first to promote prone sleeping for infants. As we know in retrospect, prone sleeping drastically increases a babys risk of dying of sudden infant death syndrome (SIDS). Dr. Spocks book was not the only popular book to advocate prone sleeping at the time, but further revisions continued to make the recommendation nine years after solid epidemiological evidence had accumulated regarding the increased risk of SIDS for babies being placed on their stomachs for sleep.3 In a 2005 meta-analysis of SIDS, Gilbert et al. estimated that, between the 1950s and the early 1990s, over 60 000 infant deaths worldwide “were attributable to harmful health advice [i.e. advice favoring prone sleeping].”3 Dr. Spocks book was not only the first publication to advocate prone sleeping, it was also by far the most popular, selling 50 million copies worldwide in 42 languages.1 Antiwar and antinuclear proliferation efforts are certainly something about which we, as public health professionals, should concern ourselves, but in Dr. Spocks case, his exemplary social justice history is tempered by his poor judgment in recommending—without any scientific evidence to support him—the prone sleep position to millions of unsuspecting parents.

Outcomes of Care for 1,892 Doula-Supported Adolescent Births in the United States: The DONA International Data Project, 2000 to 2013

This is the largest study to-date to report on outcomes of care for a national sample of doula-supported adolescent births (n = 1,892, birth years 2000 to 2013). Descriptive statistics were calculated for maternal demographics, risk profiles, labor/birth interventions and occurrences, and birth outcomes. In this national sample, childbearing adolescents and their neonates experienced improved health outcomes and lower rates of intervention relative to national statistics for adolescent deliveries in the United States. Key findings are consistent with previous studies on the effects of doula care for marginalized and medically underserved communities. Results strengthen the case for doulas as a perinatal care strategy for improving maternal and infant health outcomes and decreasing inequities among childbearing adolescents.

The Curse of the Perinatal Epidemiologist: Inferring Causation Amidst Selection

Purpose of ReviewHuman reproduction is a common process and one that unfolds over a relatively short time, but pregnancy and birth processes are challenging to study. Selection occurs at every step of this process (e.g., infertility, early pregnancy loss, and stillbirth), adding substantial bias to estimated exposure-outcome associations. Here, we focus on selection in perinatal epidemiology, specifically, how it affects research question formulation, feasible study designs, and interpretation of results.Recent FindingsApproaches have recently been proposed to address selection issues in perinatal epidemiology. One such approach is the ongoing pregnancies denominator for gestation-stratified analyses of infant outcomes. Similarly, bias resulting from left truncation has recently been termed “live birth bias,” and a proposed solution is to control for common causes of selection variables (e.g., fecundity, fetal loss) and birth outcomes. However, these approaches have theoretical shortcomings, conflicting with the foundational epidemiologic concept of populations at risk for a given outcome.SummaryWe engage with epidemiologic theory and employ thought experiments to demonstrate the problems of using denominators that include units not “at risk” of the outcome. Fundamental (and commonsense) concerns of outcome definition and analysis (e.g., ensuring that all study participants are at risk for the outcome) should take precedence in formulating questions and analysis approaches, as should choosing questions that stakeholders care about. Selection and resulting biases in human reproductive processes complicate estimation of unbiased causal exposure-outcome associations, but we should not focus solely (or even mostly) on minimizing such biases.