PREGNANCY
Written by
Happiest Baby Staff
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In recent years, caesarean births have become increasingly common in the UK. In fact, NHS data shows that around one in three babies are now born via caesarean section. While C-sections are often medically necessary and lifesaving, research suggests they may also carry some long-term health considerations for babies. Studies have linked caesarean birth with a higher risk of conditions like obesity, allergies, and certain neurodevelopmental issues—possibly because these babies miss out on early exposure to beneficial bacteria during vaginal birth.
So, is there a way to mimic that microbial exposure for babies born via C-section? That’s where the practice of vaginal seeding comes in.
During a vaginal birth, babies are naturally exposed to the mother's microbiome as they pass through the birth canal. This contact helps colonise the baby’s skin, mouth, and gut with good bacteria that play an important role in shaping the immune system, digestion, and even brain development.
Babies born via C-section, however, are typically exposed to skin and environmental microbes instead, which may impact how their microbiome develops.
Vaginal seeding is a technique that aims to replicate the microbial exposure of vaginal birth. It involves placing a sterile gauze in the mother’s vagina before surgery. After the baby is delivered, the gauze is used to gently swab the newborn’s mouth, face, and body—essentially transferring the maternal bacteria to help kickstart the baby’s microbiome.
Studies suggest that vaginal seeding can shift a baby’s microbiome to more closely resemble that of a vaginally born baby. In a 2023 randomised controlled trial published in Cell Host & Microbe, researchers found that vaginal seeding successfully transferred maternal bacteria to the baby.
Even more intriguing, a 2024 study using a mouse model found that mice exposed to stool from vaginally seeded babies had lower levels of intra-abdominal fat—a type linked with metabolic concerns later in life. While these findings don’t yet confirm health outcomes in humans, they point to the potential long-term benefits of restoring microbial exposure.
Although the early results are promising, there’s still limited data on whether vaginal seeding can reduce rates of asthma, allergies, or obesity. One small clinical trial didn’t find differences in allergy or BMI outcomes between babies who received vaginal seeding and those who didn’t. However, several large-scale studies are currently underway to explore these outcomes more thoroughly.
So far, clinical studies suggest that vaginal seeding is safe when carried out in a carefully controlled, medical environment. However, experts remain cautious. The main concern is the potential transmission of infections like Group B Streptococcus (GBS), herpes simplex virus (HSV), chlamydia, or HIV—conditions that can be very serious for newborns.
Because of these risks, vaginal seeding is not currently recommended for routine use in the UK. The National Institute for Health and Care Excellence (NICE) has not issued specific guidance, but organisations such as the American College of Obstetricians and Gynecologists (ACOG) advise against performing vaginal seeding outside of a research setting.
Researchers recommend that families interested in vaginal seeding only do so under the guidance of a healthcare professional and as part of a clinical trial. DIY or unsupervised approaches are strongly discouraged due to infection risks.
As science around the microbiome evolves, researchers are looking into other ways to support a healthy gut microbiome in C-section babies. These include:
In the future, scientists hope to create targeted microbial therapies—like a “starter kit” for the gut—to support newborns who miss out on vaginal microbial exposure.
In the meantime, there are well-established ways to support your baby’s microbiome:
Vaginal seeding is a fascinating concept that may help babies born via C-section get some of the early microbial exposure that vaginally born babies receive. While current evidence suggests it could support early immune and metabolic development, more research is needed before it can be safely recommended as standard practice.
For now, experts advise that vaginal seeding only be done within a clinical trial or research setting. As studies continue, this simple technique could one day become a powerful tool for supporting the long-term health of C-section babies.
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Disclaimer: The information on our site is NOT medical advice for any specific person or condition. It is only meant as general information. If you have any medical questions and concerns about your child or yourself, please contact your health provider. Breastmilk is the best source of nutrition for babies. It is important that, in preparation for and during breastfeeding, mothers eat a healthy, balanced diet. Combined breast- and bottle-feeding in the first weeks of life may reduce the supply of a mother's breastmilk and reversing the decision not to breastfeed is difficult. If you do decide to use infant formula, you should follow instructions carefully.
