The Best Possible Birth The most important thing to ever happen to your microbiome happens the moment you’re born. Babies born vaginally get their first major dose of microbes from their mothers as they pass through the birth canal. These beneficial bacteria include Lactobacillus, which helps breakdown the lactose in milk to make energy. More Lactobacillus colonize the mother’s vagina as her due date nears, ready to jump ship to her baby and help it digest breast milk. Babies delivered via C-section surgery get their first dose of microbes from their mothers’ skin and the skin of doctors and nurses in the delivery room. Researchers worry that because C-section infants don’t get the bacteria their mothers evolved to give them, it will set these children on the road to poor development. Studies are showing that our native bacteria help train our immune system to recognize friend from foe. Without proper training, the theory goes, the immune system is weak and the body is more likely to overreact to everyday substances like dust and peanuts. “Evidence supports the idea that microbial colonization of the gastrointestinal and respiratory tract in the period [around birth] has an important role in the predisposition to chronic inflammation, autoimmune, allergic, and chronic illness,” Dr. Uma Perni, an OB-GYN at the Cleveland Clinic, told Healthline. Worldwide, C-section rates vary quite a bit, but cesareans are the most common inpatient surgeries in the United States, where C-section rates increased from less than 21 percent in 1996 to nearly 33 percent in 2009. The World Health Organization (WHO) estimates countries should have no more than a 10 to 15 percent C-section rate. Maria Gloria Dominguez-Bello, Ph.D., an assistant professor and microbiome researcher at New York University’s (NYU) Langone Medical Center, is testing a fast and easy work-around called the “gauze-in-the-vagina technique.” It’s exactly what it sounds like: doctors soak a gauze pad in the mother’s vagina for one hour and remove it just before her C-section. When doctors remove the baby from the womb, they quickly swab it from head to toe with the gauze. Dominguez-Bello reports the gauze technique doubles the numbers of vaginal bacteria C-section newborns get, though a traditional birth still delivers six times more. Dominguez-Bello’s husband and fellow microbiome researcher at NYU, Dr. Martin Blaser, says an added danger of moving away from traditional modes of birth is the routine use of antibiotics. Pregnant women get antibiotics to fight Group B strep bacteria and to prevent infection after a C-section, and newborns get dosed to prevent a rare eye infection caused by a mother’s gonorrhea. Antibiotics kill bugs indiscriminately, and many good microbes fall victim to this “friendly fire.” Another best practice for keeping your baby’s microbiome healthy is breast-feeding. It’s no secret breast-feeding is beneficial — it gives babies vital nutrients, helps the immune system develop, and may even boost IQ. But breast-feeding also delivers good bacteria to jump-start microbial health. “Breast-feeding is best for many reasons. Breast milk seeds the infant’s gut with beneficial nutrients, including microbes that are crucial for proper growth, development, and function. Some studies support the use of probiotic support in non-breast-fed infants,” Dr. Mary Rosser, an OB-GYN at Montefiore Medical Center in New York City, told Healthline. Learn 8 Ways Greek Yogurt Benefits Health » MaryBeth Reardon, R.D.N., L.D.N., a dietician in Massachusetts, also recommends probiotics for infants and children who took antibiotics or were bottle-fed. She uses probiotics — helpful bacteria in the form of a pill or naturally fermented food — to help kids in her practice with constipation and other gut troubles. The evidence to support vaginal birth and breast-feeding for microbiome health is strong and growing every year. But recently, scientists have found evidence mothers can also give their babies a leg up on microbial development well before they go into labor. Studies are demonstrating that a mother’s weight and diet, even before pregnancy, impact her personal microbiome, which in turn affects which bacteria she passes to her offspring. An unbalanced microbiome can affect a woman’s metabolism, predisposing her to weight gain and passing that risk on to her child. The microbiome may be the reason parental obesity is one of the biggest risk factors for childhood obesity. “You are what you eat. We can control what goes into and onto our bodies. The gut microbiome of mom affects the developing fetus. Bad nutrition and extra weight change the microbiome of the maternal gut and offer an unstable and unhealthy balance,” Rosser said. Read More: Will Antibiotics Make Your Baby an Obese Adult? » If you think your baby is protected in its walled-in placenta, think again. A study published last year showed for the first time that the placenta harbors its own unique community of bacteria, similar to those found in the mouth. The authors found the placental microbiome is affected if the mother gets an infection. It’s also linked to the risk of preterm birth, suggesting bacteria in the placenta may play a role in premature labor. Perni says doctors don’t have enough information to give women specific advice for how to keep their placental microbiome in ship shape, but research is ongoing.