The effect of labour induction on the risk of caesarean delivery: using propensity scores to control confounding by indication.

OBJECTIVE: To use propensity score methods to control for confounding by indication in the association between labour induction and caesarean delivery. DESIGN: Cross-sectional analysis of administrative hospital discharge data supplemented by medical record information. SETTING: Fourteen US member hospitals of the National Perinatal Information Center. SAMPLE: A cohort of 166 559 singleton liveborn deliveries in the period 2007-2012. METHODS: We used propensity scores (PSs) to balance 83 covariates between induced and non-induced women, and compared estimates with traditional covariate adjustment. We estimated PSs for labour induction versus expectant management of pregnancy each week from 34 to 42 weeks of gestation. We estimated risk ratios (RRs) for the association between labour induction and primary caesarean delivery from models with no adjustment, traditional adjustment of five covariates, matched PS, and adjustment for continuous PS. MAIN OUTCOME MEASURE: Caesarean delivery in current or subsequent week of gestation. RESULTS: In crude models labour induction increased the risk of caesarean delivery in all weeks (RR 1.06-1.52), excepting 39 weeks of gestation (RR 0.89). After matching on PS, the analysis showed a significantly decreased risk of caesarean delivery with labour induction during weeks 35-39 (RR 0.77-0.92), and a significantly elevated risk at weeks 40 (RR 1.22) and 41 (RR 1.39). Traditional covariate and PS adjustment resulted in RRs between those from crude and PS-matched models. CONCLUSIONS: There is evidence of considerable confounding by indication in the association of labour induction and caesarean delivery, particularly for preterm deliveries. Using PS methods, we found a reduced risk of caesarean delivery with labour induction before 40 weeks of gestation, and an elevated risk for weeks 40-42. TWEETABLE ABSTRACT: With confounding adjustment, labour induction does not increase the risk of caesarean at 34-39 weeks of gestation.

Postpartum contraception needs of women with preterm infants in the neonatal intensive care unit.

OBJECTIVES: To evaluate postpartum contraception experiences of mothers with premature infants in the neonatal intensive care unit (NICU), their knowledge of risk factors for preterm delivery and their interest in a family planning clinic located near the NICU. STUDY DESIGN: This is a cross-sectional survey of English or Spanish-speaking women 18 or older whose premature neonate had been in the NICU for 5 days or more in a current stable condition. RESULTS: A total of 95 women were interviewed at a median of 2.7 weeks postpartum (range 0.6-12.9). Approximately 75% of women were currently using or planning to use contraception, with 33% using less effective methods. Half of women reported they would obtain contraception at a family planning clinic near the NICU. Only 32% identified a short interpregnancy interval as a risk factor for preterm delivery. CONCLUSION: Lack of knowledge of short interpregnancy interval as a risk factor for a future preterm delivery highlights the need to address postpartum contraception education and provision in this high-risk population.

Progesterone, inhibin, and hCG multiple marker strategy to differentiate viable from nonviable pregnancies.

OBJECTIVE: To determine whether a combination of serum and urine biomarkers drawn from symptomatic pregnant women will help early differentiation of viable from nonviable pregnancies. METHODS: We conducted a prospective cohort study of 220 women who presented in the first trimester of pregnancy with complaints of pain, cramping, bleeding, or spotting. Serum samples for progesterone, inhibin A, and hCG, and urine beta-core hCG, were collected at presentation. To evaluate whether those biomarkers could predict viable and nonviable outcomes in pregnancy, we used likelihood ratios to compare operating characteristics of single and multiple biomarker strategies. RESULTS: Of 220 pregnancies studied, 98 were viable and 122 nonviable. Among single biomarkers, progesterone alone appears to have the greatest utility (area under the receiver operator characteristic curve = 0.923). Among dual-biomarker strategies, progesterone plus hCG and progesterone plus inhibin A improved specificity but not sensitivity. At 95% sensitivity, the combination of progesterone and hCG improved specificity from 0.29 to 0.66 (improvement = 0.37 [95% confidence interval 0.23, 0.52]). A triple-biomarker combination did not show substantial improvement over the dual-biomarker strategy. Also, combinations that used urine beta-core hCG did not improve diagnostic accuracy. CONCLUSION: Serum progesterone appeared to be the single most specific biomarker for distinguishing viable from nonviable pregnancies. When a dual-biomarker strategy was applied, combining serum progesterone with hCG, specificity improved significantly, which suggests that a multiple biomarker strategy might help distinguish viable from nonviable pregnancies in early gestation.

Demographic and relationship predictors of paternity establishment for infants born to adolescent mothers.

STUDY OBJECTIVE: To identify demographic and relationship characteristics associated with paternity establishment for children born to adolescent mothers. PARTICIPANTS, SETTING, AND DESIGN: This prospective cohort study included 300 pregnant adolescents 12-19 years old, presenting for prenatal care between March 2002 and February 2005. Demographic and relationship characteristics were compared based on paternity establishment (father's name on the infant's birth certificate). MAIN OUTCOME MEASURE: Paternity establishment (father's name on the infant's birth certificate). RESULTS: Of the 273 participants with outcome data, 54% established paternity. Paternity establishment differed by maternal race/ethnicity (69% Hispanic vs 36% non-Hispanic Black vs 52% non-Hispanic White, P = .01), maternal age (37% for 12-15 years vs 64% for 18-19 years, P = .01), maternal country of birth (48% U.S. born vs 76% non-U.S. born, P = .01), relationship with father of the infant, and father involvement at the time of delivery. CONCLUSION: Paternity establishment rates for children born to teens were low overall. To increase rates of paternity establishment, policies and programs need to consider the unique characteristics and circumstances of teen parents.

Observational studies.

Observational studies are important methodologies to evaluate exposures and risk factors that are not amenable to experimental trials. They offer the advantage of being more generalizable to our patients, as these studies may have more liberal inclusion criteria than the typical randomized trial. Their disadvantage is their susceptibility to biases and their inability to control for unknown factors that may impact on the outcome of interest. Establishing causality of an association noted in observational studies is an intricate process that requires careful assessment. Clinicians and researchers should be familiar with observational studies so they may better evaluate a proposed causal relationship and the quality of reports claiming such relationships. Only then can they determine if the findings are valid and applicable to their patient population.