Can Caesarean section improve child and maternal health? The case of breech babies

How do physicians respond to new medical research?

What happens when the findings of a prominent medical study are overturned? Using a medical trial on breech births, we estimate the effect of the reversal of such a medical study on physician choices and infant health outcomes. Using the United States Birth Certificate Records from 1995 to 2010, we employ a difference-in-differences estimator for C-sections, low Apgar, and low birth weight measures. We find that the reversal of a multi-site, high profile, randomized control trial on the appropriate delivery of term breech births, the Term Breech Trial, led to a 15%-23% decline in C-sections for such births at a time when the overall trend in C-sections was rising. We find our largest estimated effects amongst traditionally disadvantaged groups (i.e., non-white, and minimal education). However, we do not find that such a change in practice had significant impacts on infant health. Contrary to prior studies, we find that physicians updated their beliefs quickly, and do indeed adjust to new medical research, particularly young physicians, prior to mandatory policy or professional guidelines.

Earlier routine induction of labor-Consequences on mother and child morbidity

A growing number of birth interventions had led to a concern for potential health consequences. This study investigates the consequences of earlier routine labor induction. It exploits a natural experiment caused by the introduction of new Danish obstetric guidelines in 2011. Consequently, routine labor induction was moved forward from 14 to 10-13 days past the expected due date (EDD) and extended antenatal surveillance was introduced from 7 days past the EDD. Using administrative data, I find that affected mothers on average had a 9-11 percentage points (32%-38%) higher risk of being induced the following years. Yet, mother and child short- and medium-term morbidity were largely unaffected.

Term breech presentation-Intended cesarean section versus intended vaginal delivery-A systematic review and meta-analysis

INTRODUCTION

Three per cent of all infants are born in breech presentation, still the preferred way to deliver them remains controversial. The objective of this systematic review was to assess the safety for the mother and child depending on intended mode of delivery when the baby is in breech position at term.

MATERIAL AND METHODS

The population (P) was pregnant women with a child in breech presentation, from gestational week 34⁺⁰ . The intervention (I) was the intention to deliver by cesarean section, the comparison (C) was the intention to deliver vaginally. Outcomes (O) were perinatal mortality, perinatal morbidity, maternal mortality, maternal morbidity, conversion of delivery mode, and the mother's experience. Systematic literature searches were performed. We included randomized trials, cohort studies with more than 500 women/group and case series for more than 15 000 women published between 1990 and October 2021, written in English or the Nordic languages. The certainty of evidence was assessed using the GRADE approach and data were pooled in meta-analyses. PROSPERO registration number: CRD42020209546.

RESULTS

Thirty-two articles were included (with 530 604 women). The certainty of evidence was moderate or low because the study designs were mostly retrospective cohort studies. The only randomized trial showed reduced risk of perinatal mortality for planned cesarean section, risk ratio (RR) 0.27 (95% confidence interval [CI] 0.08-0.97, 2078 women, low certainty of evidence), stillbirths excluded. A meta-analysis of cohort studies resulted in a similar estimate, RR 0.36 (95% CI 0.25-0.51, 21 studies, 388 714 women, low certainty of evidence). We also found reduced risk for outcomes representing perinatal morbidity 0-28 days: 5-min Apgar score less than 7 in one randomized controlled trial: RR 0.27 (95% CI 0.12-0.58, 2033 women, moderate certainty of evidence), and in a meta-analysis: RR 0.1 (95% CI 0.14-0.26, 18 studies, 217 024 women, moderate certainty of evidence); APGAR score less than 4 at 5 min: RR 0.39 (95% CI 0.19-0.81, five studies, 44 498 women, low certainty of evidence); and pH less than 7.0: RR 0.23 (95% CI 0.12-0.43, four studies, 13 440 women, low certainty of evidence). Outcomes for the mother were similar in the groups except for reduced risk for experience of urinary incontinence in the group of planned cesarean section: RR 0.62 (95% CI 0.41-0.93, one study, 1940 women, low certainty of evidence). The conversion rate from planned vaginal delivery to emergency cesarean section ranged from 16% to 51% (median 41.8%, 10 studies, 50 763 women, moderate certainty of evidence).

CONCLUSIONS

Intended cesarean section may reduce the risk of perinatal mortality and perinatal as well as some maternal morbidity compared with intended vaginal delivery. It is uncertain whether there is any difference in maternal mortality. The conversion rate from intended vaginal delivery to emergency cesarean section is high.

Delivery mode and severe maternal and neonatal morbidity among singleton term breech births: A population-based cohort study

OBJECTIVE

The aim of this study was to examine the association between delivery mode and severe maternal and neonatal morbidity in singleton term breech births.

STUDY DESIGN

This nationwide population-based cohort study includes 41 319 singleton term and post-term breech births (37 + 0-42 + 6 gestational weeks) in Sweden from 1998 to 2016. Data was retrieved from the Swedish Medical Birth Register. The primary outcomes were two separate composite outcomes, maternal and neonatal severe morbidity. Secondary outcomes were separate severe maternal and neonatal morbidity outcomes. Hospitalization and out-patient visits during childhood were also analyzed in ages 0-5 years. Logistic regression was used to estimate unadjusted and adjusted odds ratios (aOR) with 95% confidence intervals (CI) of severe maternal and neonatal morbidity in women with vaginal breech birth or intrapartum cesarean section. Women with a prelabor breech cesarean section was used as the reference group.

RESULTS

No difference between vaginal delivery and prelabor cesarean section was seen regarding maternal morbidity. Intrapartum cesarean section was associated with elevated odds for maternal morbidity (aOR 1.27, 95% CI 1.10-1.47) compared with prelabor cesarean section. A similar result was observed for vaginal delivery and intrapartum cesarean section combined (aOR 1.29, 95% CI 1.11-1.50). Vaginal delivery was associated with higher odds for composite neonatal morbidity (aOR 1.85, CI 1.54-2.21) and most separate outcomes, as well as increased number of hospital nights and out-patient visits during first year of life, compared with prelabor cesarean section.

CONCLUSIONS

Prelabor cesarean section in breech births improved short-term neonatal health without increasing risks for severe maternal short-term complications.

Fee equalization and appropriate health care

Fee equalization in health care brings under a unique tariff several medical treatments, coded under different Diagnosis Related Groups (DRGs). The aim is to improve healthcare quality and efficiency by discouraging unnecessary, but better-paid, treatments. We evaluate its effectiveness on childbirth procedures to reduce overuse of c-sections by equalizing the DRGs for vaginal and cesarean deliveries. Using data from Italy and a difference-in-differences approach, we show that setting an equal fee decreased c-sections by 2.6%. This improved the appropriateness of medical decisions, with more low-risk mothers delivering naturally and no significant changes in the incidence of complications for vaginal deliveries. Our analysis supports the effectiveness of fee equalization in avoiding c-sections, but highlights the marginal role of financial incentives in driving c-section overuse. The observed drop was only temporary and in about a year the use of c-sections went back to the initial level. We found a greater reduction in lower quality, more capacity-constrained hospitals. Moreover, the effect is driven by districts where the availability of Ob-Gyn specialists is higher and where women are predominant in the gender composition of Ob-Gyn specialists.

Maternity ward crowding, procedure use, and child health

This paper studies the impact of day-to-day variation in maternity ward crowding on medical procedure use and the health of infants and mothers. Exploiting data on the universe of Danish admissions to maternity wards in the years 2000-2014, we first document substantial day-to-day variation in admissions. Exploiting residual variation in crowding, we find that maternity wards change the provision of medical procedures and care on crowded days relative to less crowded days, and they do so in ways that alleviate their workload. We find very small and precisely estimated effects of crowding on child and maternal health. Thus our results suggest that, for the majority of uncomplicated births, maternity wards in Denmark can cope with the observed inside-ward variation in daily admissions without detectable health risks.

Cutting fertility? Effects of cesarean deliveries on subsequent fertility and maternal labor supply

Despite the growing incidence of cesarean deliveries (CDs), procedure costs and benefits continue to be controversially discussed. In this study, we identify the effects of CDs on subsequent fertility and maternal labor supply by exploiting the fact that obstetricians are less likely to undertake CDs on weekends and public holidays and have a greater incentive to perform them on Fridays and days preceding public holidays. To do so, we adopt high-quality administrative data from Austria. Women giving birth on different days of the week are pre-treatment observationally identical. Our instrumental variable estimates show that a non-planned CD at parity 0 decreases lifecycle fertility by almost 13.6%. This reduction in fertility translates into a temporary increase in maternal employment.

Another look at returns to birthweight

We revisit the causal effect of birthweight. Because variation in birthweight in developed countries primarily stems from variation in gestational age rather than intrauterine growth restriction, we depart from the widely-used twin fixed-effects estimator and employ an instrumental variable - the diagnosis of placenta previa, which provides exogenous variation in gestation length. We find protective effects of additional birthweight against infant mortality and health capital loss, such as cerebral palsy, but in contrast to sibling and twin studies, no strong evidence for non-health long-run outcomes, such as test scores. We also find that short-run birthweight effects have diminished significantly over the decades.

Mother's mental health after childbirth: Does the delivery method matter?

The dramatic increase in the utilization of caesarean section has raised concerns on its impact on public expenditure and health. While the financial costs associated with this surgical procedure are well recognized, less is known on the intangible health costs borne by mothers and their families. We contribute to the debate by investigating the effect of unplanned caesarean deliveries on mothers' mental health in the first nine months after the delivery. Differently from previous studies, we account for the unobserved heterogeneity due to the fact that mothers who give birth through an unplanned caesarean delivery may be different than mothers who give birth with a natural delivery. Identification is achieved exploiting exogenous variation in the position of the baby in the womb at the time of delivery while controlling for hospital unobserved factors. We find that mothers having an unplanned caesarean section are at higher risk of developing postnatal depression and this result is robust to alternative specifications.

It's about time: Cesarean sections and neonatal health

Cesarean sections have been associated in the literature with poorer newborn health, particularly with a higher incidence of respiratory morbidity. Most studies suffer, however, from potential omitted variable bias, as they are based on simple comparisons of mothers who give birth vaginally and those who give birth by cesarean section. We try to overcome this limitation and provide credible causal evidence by using variation in the probability of having a c-section that is arguably unrelated to maternal and fetal characteristics: variation by time of day. Previous literature documents that, while nature distributes births and associated problems uniformly, time-dependent variables related to physicians' demand for leisure are significant predictors of unplanned c-sections. Using a sample of public hospitals in Spain, we show that the rate of c-sections is higher during the early hours of the night compared to the rest of the day, while mothers giving birth at the different times are similar in observable characteristics. This exogenous variation provides us with a new instrument for type of birth: time of delivery. Our results suggest that non-medically indicated c-sections have a negative and significant impact on newborn health, as measured by Apgar scores, but that the effect is not severe enough to translate into more extreme outcomes.

Cesarean deliveries and maternal weight retention

BACKGROUND

Cesarean delivery accounts for nearly one-third of all births in the U.S. and contributes to an additional $38 billion in healthcare costs each year. Although Cesarean delivery has a long record of improving maternal and neonatal mortality and morbidity, increased utilization over time has yielded public health concerns and calls for reductions. Observational evidence suggests Cesarean delivery is associated with increased maternal postpartum weight, which may have significant implications for the obesity epidemic. Previous literature, however, typically does not address selection biases stemming from correlations of pre-pregnancy weight and reproductive health with Cesarean delivery.

METHODS

We used fetal malpresentation as a natural experiment as it predicts Cesarean delivery but is uncorrelated with pre-pregnancy weight or maternal health. We used hospital administrative data (including fields used in vital birth record) from the state of Wisconsin from 2006 to 2013 to create a sample of mothers with at least two births. Using propensity score methods, we compared maternal weight prior to the second pregnancy of mothers who delivered via Cesarean due to fetal malpresentation to mothers who deliver vaginally.

RESULTS

We found no evidence that Cesarean delivery in the first pregnancy causally leads to greater maternal weight, BMI, or movement to a higher BMI classification prior to the second pregnancy.

CONCLUSIONS

After accounting for correlations between pre-pregnancy weight, gestational weight gain, and mode of delivery, there is no evidence of a causal link between Cesarean delivery and maternal weight retention.

Regression discontinuity designs in healthcare research

Clinical decisions are often driven by decision rules premised around specific thresholds. Specific laboratory measurements, dates, or policy eligibility criteria create cut-offs at which people become eligible for certain treatments or health services. The regression discontinuity design is a statistical approach that utilizes threshold based decision making to derive compelling causal estimates of different interventions. In this review, we argue that regression discontinuity is underutilized in healthcare research despite the ubiquity of threshold based decision making as well as the design’s simplicity and transparency. Moreover, regression discontinuity provides evidence of “real world” therapeutic and policy effects, circumventing a major limitation of randomized controlled trials. We discuss the implementation, strengths, and weaknesses of regression discontinuity and review several examples from clinical medicine, public health, and health policy. We conclude by discussing the wide array of open research questions for which regression discontinuity stands to provide meaningful insights to clinicians and policymakers

Does Experience Rating Improve Obstetric Practices? Evidence from Italy

Using inpatient discharge records from the Italian region of Piedmont, we estimate the impact of an increase in malpractice pressure brought about by experience-rated liability insurance on obstetric practices. Our identification strategy exploits the exogenous location of public hospitals in court districts with and without schedules for noneconomic damages. We perform difference-in-differences analysis on the entire sample and on a subsample which only considers the nearest hospitals in the neighborhood of court district boundaries. We find that the increase in medical malpractice pressure is associated with a decrease in the probability of performing a C-section from 2.3 to 3.7 percentage points (7-11.6%) with no consequences for medical complications or neonatal outcomes. The impact can be explained by a reduction in the discretion of obstetric decision-making rather than by patient cream skimming.