Helping Pregnant Women Navigate Microbiome Research

Neonatal microbiome research holds promise, but it can trigger concerns among women who may worry they’re compromising their infant’s microbiome. Midwives can provide perspective.


There is a growing body of research that focuses on the “critical window in early life” from conception through the first year, when maternal and infant exposures may alter the initial bacterial colonization, or microbiome, in the newborn. Much of this research suggests that, as a species, humans have evolved to receive our mother’s bacteria during pregnancy, vaginal delivery, and an extended period of exclusive breastfeeding. These early bacterial colonizers are thought to teach the immune and metabolic systems how to function.

Exposures such as antibiotics, cesarean delivery, and formula feeding have been associated with disruptions in the baby’s microbial colonies, and this early microbiome disruption has been further associated with health problems later in life, including asthma, allergies, type I diabetes, and obesity, by researchers, including the authors of a recent Pediatrics article (

Potential and Promise

As news about the potential and promise of neonatal microbiome research spreads among the public, women are wondering what it all means. Midwives can play an important role in helping women put neonatal microbiome research into perspective.

I recently completed a study following 36 mothers from delivery through their baby’s first month of life to understand how certain birth interventions affect the newborn gut microbiome during that time. The mothers who participated were heroic in their commitment to the project. They carried sampling packets to their births, took swabs from themselves and their babies in the precious moments following delivery, and sampled dirty diapers in the midst of postpartum sleep deprivation. Yet in heavy counterbalance to their inspiring enthusiasm, was the darker side of the equation: the mother-worry that springs tangibly from our instinct to protect and nurture our young. Amplifying these concerns are our cultural imperatives to assume responsibility for every aspect of our children’s growth and development. Invariably, during the course of their participation, women would voice some version of that dark, nagging question: “Have I harmed my baby?”

A New Realm of Risk?

While microbiome research offers new insights that may strongly inform the way we care for women during pregnancy and birth, it also presents a powerful new addition to the long list of do’s and don’ts surrounding pregnant women and new mothers. In addition to concerns about age, testing, diet, medication, exercise, vitamins, delivery, parenting, breastfeeding, and lying too long on one’s back, women can now individualize and internalize a new realm of risk and responsibility—namely, whether they are robustly enough transmitting a vital, yet invisible, universe of bacteria to their newborns. The stakes of failure in this proposition can seem high. As the author of a 2017 Scientific American blog post ( put it, women who have a cesarean delivery or formula feed may be breaking “the chain of maternal heritage that stretches through female ancestry for thousands of generations.” This is a seriously daunting chain to break! Never mind that those thousands of generations haven’t actually been studied.

Encourage women not to individualize this risk, but, rather, to inform themselves about the kind of care they will receive.

An Empowering Response

So, when the women we care for come to us with microbiome worries, how do we help them find a rational and empowering response? Here are a few points to remember as you talk through a new mother’s questions:

• As an emerging area of science, the microbiome is being investigated in relation to many areas of human health, including depression, ADHD, obesity, asthma, and cancer, to name a few. However, all of these health outcomes are multi-factorial. Disruptive exposures during pregnancy and birth may or may not prove to be significant contributing factors in relation to other life events.

• Currently, neonatal microbiome research is based primarily on observational data, rather than randomized controlled trials. While associations have been noted between microbiome disruption and subsequent health outcomes, one cannot assume that these disruptions are responsible for causing the observed outcomes. The mechanism of action explaining these associations is not yet fully understood.

• As midwives are aware, making inferences about individuals based on observational data from groups is statistically inaccurate. Midwives can and should help women understand that microbiome research that aggregates population-level data cannot, and should not, be used directly to explain their individual experiences.

• A great deal of microbiome research is done on animal models. These models, again, cannot always be assumed to explain human experience directly.

• The findings of microbiome research are more relevant to healthcare delivery than to the behavior of an individual woman. That is, research findings generally support the proposition that the least possible intervention in the normal, physiologic process of pregnancy and childbirth is best in terms of preventing microbiome disruption. The key here is to encourage women not to individualize this risk, but, rather, to inform themselves about the kind of care they will receive. Do their providers tend to intervene without medical reason? Do they follow evidence-based practice for the wellness event of physiologic childbirth? Remind women that midwifery care is consistently associated with low-intervention, high-quality care with excellent outcomes for mothers and babies, as findings detailed in The Lancet ( midwifery) and elsewhere demonstrate.

• Microbiome research proposes radical new avenues for female power and self-acceptance. Consider sharing the message that vaginal bacteria is a healthy and life-supporting force, rather than something dirty, which must be scrubbed away. Encourage women to absorb this positive message and be part of changing the culture of the way we view and honor our natural bodies.

By Joan Combellick, CNM, MPH, MSN
Women’s Health Research Fellow at Connecticut VA