Illustration of the maternal microbiome and the impact of antibiotics during pregnancy.

Antibiotics During Pregnancy: How They Affect Your Baby's Health

Mira Elwood in Health & Wellness December 2025 • 4 min read.

"A deeper look at maternal antibiotic use, gut health, and infant infection risk."

The use of antibiotics during pregnancy is a common concern for expecting parents. While these medications can be essential for treating infections in the mother, there are questions about how they might affect the developing baby. Research is ongoing to clarify these effects, especially concerning the infant's developing immune system and gut health.

A study published in the 'International Journal of Epidemiology' delves into the complexities of this issue, specifically addressing the impact of maternal antibiotic exposure during pregnancy and hospitalization with infection on offspring infection. The study seeks to disentangle the various factors that contribute to a child's susceptibility to infection, including the role of the maternal microbiome and antibiotic-related dysbiosis (an imbalance in the gut bacteria).

This article breaks down the key findings of this research, offering insights into how pre-pregnancy and pregnancy antibiotic use might influence a child's health. We'll explore the delicate balance of the maternal microbiome, the potential risks and benefits of antibiotic use, and what this all means for parents navigating these important decisions.

The Maternal Microbiome: A Key Player

Illustration of the maternal microbiome and the impact of antibiotics during pregnancy.

The maternal microbiome, the collection of bacteria, viruses, and other microorganisms living in the mother's body, plays a crucial role in shaping the infant's developing immune system. Antibiotics, while targeting harmful bacteria, can also disrupt this delicate balance, potentially leading to dysbiosis. This disruption can have implications for the child's susceptibility to infections.

The research highlights that antibiotic use, both before and during pregnancy, might indicate an increased underlying susceptibility to infection in the mother. This susceptibility, in turn, could increase the risk of offspring infection, beyond the effects of antibiotic-induced dysbiosis. It's a complex interplay of factors that researchers are still working to fully understand.

Pre-Pregnancy Antibiotics: Antibiotic use before pregnancy may suggest an existing vulnerability to infection in the mother.
Pregnancy Antibiotics: Antibiotic use during pregnancy can further disrupt the maternal microbiome and potentially impact the child.
Infection Risk: The association between pregnancy antibiotics and offspring infection was somewhat weakened when researchers accounted for pre-pregnancy antibiotic use, suggesting that an underlying susceptibility to infection plays a role.

The study also acknowledges the importance of considering how infants are delivered. Babies born via Cesarean section (C-section) do not receive the same initial exposure to the maternal vaginal microbiome as vaginally born infants. Instead, their microbiome is more influenced by the maternal skin and the hospital environment. This difference further complicates the picture when assessing the impact of pregnancy antibiotics on postnatal offspring infection.

What Does This Mean for Parents?

The research underscores the complex relationship between maternal antibiotic use, the microbiome, and infant health. While antibiotics are sometimes necessary during pregnancy, understanding the potential impact on the child is crucial. It is essential to discuss any concerns about antibiotic use with your healthcare provider.

More research is needed to fully disentangle the various factors at play and to develop strategies to mitigate any potential risks associated with antibiotic use during pregnancy. This includes exploring ways to support a healthy maternal microbiome and promote optimal infant gut health.

Ultimately, informed decision-making, in consultation with healthcare professionals, is key to ensuring the best possible outcomes for both mother and child. While it’s important to be aware of potential risks, it’s equally important to remember that antibiotics can be life-saving when used appropriately.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1093/ije/dyy097, Alternate LINK

Title: Maternal Antibiotic Exposure During Pregnancy And Hospitalization With Infection In Offspring: Authors’ Reply

Subject: General Medicine

Journal: International Journal of Epidemiology

Publisher: Oxford University Press (OUP)

Authors: Jessica E Miller, Chunsen Wu, Lars Henning Pedersen, Nicholas De Klerk, Jørn Olsen, David Burgner

Published: 2018-05-30

Everything You Need To Know

Why is the maternal microbiome so important during pregnancy, and how do antibiotics affect it?

The maternal microbiome, comprising bacteria, viruses, and other microorganisms in the mother's body, is crucial for shaping the infant's developing immune system. Antibiotics, while intended to eliminate harmful bacteria, can also disrupt this delicate balance, potentially leading to dysbiosis. This disruption might increase the child's susceptibility to infections. Factors such as pre-pregnancy antibiotic use and delivery method (C-section vs. vaginal birth) further influence the microbiome's impact.

Does taking antibiotics before pregnancy affect my baby's infection risk?

Research suggests that antibiotic use, both before and during pregnancy, may indicate an increased underlying susceptibility to infection in the mother. This susceptibility could elevate the risk of offspring infection, beyond the direct effects of antibiotic-induced dysbiosis. Accounting for pre-pregnancy antibiotic use weakens the association between pregnancy antibiotics and offspring infection, highlighting the role of the mother's pre-existing vulnerability to infection.

How does having a C-section affect my baby's gut bacteria compared to a vaginal birth, especially if I've taken antibiotics?

Cesarean section (C-section) deliveries prevent infants from receiving initial exposure to the maternal vaginal microbiome, unlike vaginally born infants. Consequently, the microbiome of C-section babies is more influenced by the maternal skin and the hospital environment. This difference further complicates assessing the impact of pregnancy antibiotics on postnatal offspring infection, as the baseline microbiome composition differs significantly.

What exactly is dysbiosis, and how is it connected to taking antibiotics during pregnancy?

Dysbiosis, or an imbalance in the gut bacteria, arises when antibiotics disrupt the maternal microbiome. This disruption can influence the infant's developing immune system, potentially increasing their susceptibility to infections. The 'International Journal of Epidemiology' study emphasizes that both pre-pregnancy and pregnancy antibiotic use can contribute to dysbiosis, with implications for offspring health.

What are the main factors that influence a baby's risk of infection when the mother takes antibiotics during pregnancy, and what should parents consider?

Maternal antibiotic exposure, maternal microbiome composition, and the infant's mode of delivery (C-section vs. vaginal birth) all interact to influence the risk of infant infection. While antibiotics are sometimes necessary during pregnancy, understanding the potential impact on the child's gut health and immune system is crucial. Parents should discuss concerns about antibiotic use with their healthcare provider to make informed decisions that balance the benefits and risks.