Yeast infections during pregnancy are very common. Depending on the study, anywhere from 29% to 41% of pregnant women develop one, compared to roughly 8% to 24% of non-pregnant women. The CDC notes simply that yeast infections “occur frequently during pregnancy.” If you’re dealing with one right now, you’re far from alone, and the reasons have everything to do with the hormonal shifts your body is going through.
Why Pregnancy Makes Yeast Infections More Likely
The main driver is estrogen, which rises steadily throughout pregnancy. Estrogen does two things that tip the balance in favor of yeast overgrowth. First, it increases glycogen production in the vaginal lining. Glycogen is essentially a sugar reserve, and it creates a nutrient-rich environment where yeast can thrive. Second, estrogen helps yeast dodge your immune system. It triggers changes on the surface of yeast cells that make them harder for your body’s immune cells to recognize and destroy. Normally your immune system would tag the yeast for removal, but estrogen interferes with that tagging process.
Progesterone plays a role too. It suppresses the activity of certain white blood cells that normally fight yeast, and it weakens the protective barrier of vaginal tissue. These hormonal changes persist for the entire pregnancy, which is why yeast infections can keep coming back even after treatment.
Normal Discharge vs. a Yeast Infection
Pregnancy naturally increases vaginal discharge, so it can be hard to know whether what you’re experiencing is normal or a sign of infection. Normal pregnancy discharge is thin, white or milky, and mild smelling. A yeast infection produces discharge that is thick, white, and often described as looking like cottage cheese. The key difference is the accompanying symptoms: itching, redness, irritation, and burning point toward a yeast infection. If you have increased white discharge but none of those other symptoms, it’s likely just the normal increase that comes with pregnancy.
What About Gestational Diabetes?
You might assume that higher blood sugar levels during pregnancy would make yeast infections worse, since elevated glucose is a known risk factor for yeast infections outside of pregnancy. But a large study published in BMC Pregnancy and Childbirth found no association between gestational diabetes, blood glucose levels, and yeast infections during pregnancy. Women with gestational diabetes didn’t develop yeast infections at higher rates than those without it. The hormonal changes of pregnancy appear to be the dominant factor, regardless of blood sugar status.
How Treatment Differs During Pregnancy
Outside of pregnancy, yeast infections are often treated with a single oral pill. That approach is not recommended when you’re pregnant. The common oral antifungal has been linked to an increased risk of miscarriage at both low and high doses. At higher doses taken during the first trimester, there’s also a possible association with heart-related birth defects, though the absolute risk remains small.
The recommended treatment during pregnancy is a topical cream or suppository applied vaginally for 7 to 14 days. This is longer than the 1-day or 3-day courses often used for non-pregnant women. The reason for the extended treatment is that yeast infections are simply harder to clear during pregnancy. The same hormonal environment that caused the infection in the first place continues to suppress your body’s defenses against yeast, so a longer course is needed to fully eliminate the overgrowth. Shorter courses carry a higher risk of the infection returning.
Recurrent Infections Are Normal
Because the underlying hormonal changes last the full nine months, many pregnant women experience more than one yeast infection. This doesn’t mean something is wrong with you or that the treatment failed in some permanent way. Each infection is a fresh response to an environment that continuously favors yeast growth. After delivery, when hormone levels return to their pre-pregnancy state, the cycle typically stops.
Can Probiotics Help?
There’s early clinical evidence that certain probiotic supplements may reduce yeast overgrowth during pregnancy. In one trial, pregnant women with yeast infections who took a multi-strain probiotic containing several Lactobacillus species saw a significant decrease in yeast levels after four to eight weeks compared to baseline. The probiotics also increased levels of protective Lactobacillus bacteria in the vaginal environment, which naturally compete with yeast for space and resources. These results are promising but come from a relatively small body of research. Probiotics are not a replacement for antifungal treatment if you have an active infection, but they may help reduce the chance of recurrence.
Can a Yeast Infection Affect the Baby?
An untreated yeast infection at the time of vaginal delivery can be passed to the baby. One study found that about 45% of newborns born vaginally to mothers with an active yeast infection picked up the same yeast species. In most cases this shows up as oral thrush, a white coating inside the baby’s mouth, or as a diaper rash. Both are treatable and not dangerous, but it’s one more reason to address a yeast infection before your due date rather than waiting it out.