Researchers called for a review of the guidelines for non-essential cesarean delivery, citing a potential association between the procedure and several chronic childhood conditions.
Jan Blustein, MD, PhD, of the NYU Wagner School of Medicine in New York City and Jianmeng Liu, of the Peking University School of Public Health in Beijing, examined recent studies that have linked increased rates of type 1 diabetes, childhood obesity, and childhood asthma with cesarean deliveries.
Combining results of several meta-analyses, Blustein and Liu developed an adjusted risk analysis indicating that cesarean delivery increased the relative risk of type 1 diabetes by 19% (based on 20 studies), with similar increases found for asthma (23 studies) and obesity (nine studies), they wrote in the BMJ.
The authors applied the prevalence of U.S. cesarean rates (32.7%) to the prevalence of chronic childhood diseases to estimate the association between cesarean delivery and increased risk for these diseases:
- Childhood obesity rate: 17% (15.8% vaginal delivery, 19.4% cesarean delivery)
- Childhood asthma rate: 8.4% (7.9% vaginal delivery, 9.5% cesarean delivery)
- Childhood type 1 diabetes rate: 1.9/1,000 (1.79/1,000 vaginal delivery, 2.13/1,000 cesarean delivery)
They note the evidence for type 1 diabetes is particularly compelling, given the detailed sets of confounders, such as birth weight, gestational age, maternal age, birth order, maternal diabetes, and breastfeeding found in combined cohort and case control studies.
Researchers cited the six randomized trials done on cesarean deliveries in healthy pregnancies, explaining that only one had any follow-up data beyond the perinatal period. For that trial, a greater portion of children at 2 years of age delivered by cesarean were associated with more medical problems than those delivered vaginally (20.8% versus 14.8%, P=0.02), which included:
- Upper respiratory
- Gastrointestinal
- Ear
- Skin
- Allergic
- Other problems by parental report
The authors also discussed non-twin sibling studies, where one sibling was delivered vaginally and another by cesarean, where association with chronic diseases was closer to zero than in other cohort analyses. However, they note these types of studies may be more vulnerable to bias due to unmeasured confounders and being less precise than other studies.
Recent studies offer some explanation for why the type of delivery impacts early childhood development, mainly due to the colonization of the infant gut microbiome, which has a role in energy uptake and immune function.
“For vaginally born babies, intestinal colonization follows from exposure to maternal vaginal and fecal flora; elective cesarean bypasses this,” the authors wrote.
Noting that risks may vary depending on the timing of cesarean delivery — as infants delivered by cesarean after labor starts may already be exposed to maternal microflora, they also cite the potential role of intrapartum stress (in emergency cesareans, for example), suggesting further investigation into these factors is needed.
The Role of Elective Cesarean Delivery
Blustein and Liu discussed the lack of distinction in most studies or current guidelines between medically necessary C-section and cesarean delivery “on maternal request.” They identified only one study specifically about elective cesarean delivery, which found an increased risk of child overweight.
Neither the American College of Obstetrics and Gynecology nor the U.K.’s National Institute for Healthcare Excellence mentions the long-term risk of chronic childhood disease in their current guidelines for cesarean on maternal request.
In a separate interview with MedPage Today, Blustein said that knowing about these childhood health risks could add to the discussion between clinicians and patients when cesarean is not a medical necessity.
“What we’re suggesting is that a review of the evidence would help to sort out what’s useful from what isn’t and help guide clinical decision making,” she said. “That’s an issue where there may be sort of a cool moment of discussion of preferences, and knowledge about potential risk to child health could be important in that discussion where risks and benefits are being weighed.”
While elective cesarean is not as prevalent in the U.S. (only 3% of all deliveries), repeat cesarean is a larger concern. A study found that of the women who had one cesarean birth, over 90% delivered by cesarean again. The authors cite a recent study that found offering decision aids to pregnant women with a prior cesarean birth led to an increased rate of vaginal birth after C-section.
They offer several opportunities for further research, including randomized trials of cesarean delivery versus vaginal delivery in healthy pregnancies, randomized trials of breech or repeat cesarean, or even attempting to follow up with the participants of the six randomized trials in an attempt to discern current child health.
Blustein suggested clinicians could potentially raise this issue with their peers and express their preferences as members of these organizations, but seemed to express optimism about the direction of this discussion.
“As clinicians know, it takes a long time for research to sort of percolate through the expert and clinician community and guidelines are really important in that process, and it takes a long time for things to get on the radar screen of a guideline committee,” she said. “I think this is an issue whose time has come and it’s time to look at the evidence, and different people will have different takes on the evidence, as always.”
Source: MedpageToday
