What causes preterm birth is one of the greatest mysteries surrounding pregnancy, and science may have just discovered a surprising clue.
Every expectant mother knows the essentials for a healthy pregnancy: regular checkups, nutrient-rich foods, and prenatal vitamins. But what if one of the most important factors for your baby’s health lies in a place you usually only associate with digestion—your gut?
A groundbreaking study published in Cell Host & Microbe points to the gut microbiome—the trillions of bacteria living in your intestines—as a powerful predictor of preterm birth. While most research has focused on the vaginal microbiome, this new work shifts attention to the gut, offering fresh hope for protecting vulnerable babies.

The Gut–Preterm Birth Connection
Researchers in China discovered a striking link between a gut bacterium called Clostridium innocuum and preterm birth. Women who delivered early were more likely to have higher levels of this microbe in their intestines.
Here’s why it matters: pregnancy depends heavily on the hormone estradiol, which helps sustain a healthy environment for the baby. The study revealed that C. innocuum produces an enzyme that breaks down estradiol, potentially lowering its levels. Too much of this bacterium, the researchers suggest, could disrupt hormone balance—raising the risk of early labor.
As study co-author An Pan explained:
“For pregnant women or women preparing to become pregnant, it may be important to monitor their gut microbiome to prevent potential adverse pregnancy outcomes.”
What This Means for Moms
For a long time, the spotlight has been on the vaginal microbiome in preterm birth research. This new study broadens the picture, showing that gut health may play just as important a role in pregnancy.
It’s too early for routine prenatal screenings to test for this bacterium, and more research is needed across larger, more diverse populations. Still, the findings offer a hopeful path toward identifying risk factors earlier than ever before.
For expectant mothers, it reinforces what many of us already know: gut health is a critical component of our overall well-being. From eating fiber-rich foods to taking probiotics and making smart lifestyle choices, supporting your microbiome benefits overall health—and now, possibly pregnancy outcomes too.
This research simply adds a powerful new reason to pay attention to your gut health during pregnancy and beyond.
Source: Motherly