Thrush is very common during pregnancy. Around 20% of pregnant women develop a vaginal yeast infection at some point, with the rate climbing to about 30% in the third trimester. That’s notably higher than in non-pregnant women, largely because the hormonal shifts of pregnancy create an environment where yeast thrives.
Why Pregnancy Increases the Risk
Vaginal yeast infections are caused by an overgrowth of Candida, a fungus that normally lives in small amounts in the vagina. During pregnancy, rising estrogen levels increase the sugar content of vaginal secretions, giving Candida more fuel to multiply. Your immune system also dials back slightly during pregnancy to protect the fetus, which makes it harder for your body to keep yeast populations in check.
These two factors together explain why thrush becomes progressively more common as pregnancy advances. The third trimester, when estrogen is at its highest, is the peak window for infections.
Symptoms and How to Tell It Apart From Other Infections
The hallmark of vaginal thrush is a thick, white, cottage cheese-like discharge paired with itching and burning around the vulva. Many women also notice pain during intercourse. The discharge typically has little to no odor.
This matters because bacterial vaginosis (BV), another common vaginal condition in pregnancy, looks and feels different. BV tends to produce a thin, grayish discharge that’s heavier in volume and has a noticeable fishy smell, especially after intercourse. BV can cause irritation but usually doesn’t cause pain. If you’re unsure which you’re dealing with, a simple swab from your midwife or doctor can tell the difference quickly, and the treatments are completely different.
Does Thrush Harm the Pregnancy?
For most women, thrush is uncomfortable but not dangerous. A large meta-analysis covering more than 34,000 women found no association between vaginal Candida colonization and preterm birth, low birth weight, or other adverse pregnancy outcomes. Even among women who carried yeast without any symptoms and received no treatment, there was no statistically significant increase in spontaneous preterm birth.
So while thrush is worth treating for comfort, it’s not a condition that puts your pregnancy at risk.
Treatment During Pregnancy
Topical antifungal creams and pessaries (vaginal tablets) are the standard treatment during pregnancy. These are applied directly to the vagina and vulva, and because very little of the medication enters the bloodstream, they’re considered safe at all stages of pregnancy.
One important difference from treating thrush outside of pregnancy: you’ll likely need a longer course. While non-pregnant women can often clear an infection with a one-night or three-night treatment, pregnant women typically need 12 to 14 days of topical treatment. Response rates are lower and relapse is more frequent during pregnancy, so the extended course helps ensure the infection actually resolves.
Oral antifungal tablets are a different story. A large population-based study published in The BMJ found that a single oral dose in the first trimester carried a small but real increase in the risk of musculoskeletal birth defects, roughly 12 additional cases per 10,000 exposed pregnancies compared to women who used topical treatments. Higher cumulative doses nearly doubled the risk. For this reason, topical treatments are strongly preferred throughout pregnancy, and oral antifungals are generally avoided unless there’s a compelling reason to use them.
Passing Thrush to Your Baby
If you have an active yeast infection at the time of delivery, there’s a chance your baby could pick up the fungus during birth. In newborns, this shows up as oral thrush: white, velvety patches on the tongue and inside the mouth that may bleed slightly when wiped. Some babies also develop a yeast-related diaper rash at the same time, since the fungus passes through the digestive tract.
Babies with oral thrush can become fussy and may refuse to nurse because their mouth is sore. The infection can also pass back and forth between mother and baby during breastfeeding. Oral thrush in newborns is treatable and generally resolves without lasting problems, but it’s one more reason to treat your own infection before delivery if possible.
Reducing Your Risk of Recurrence
Some women deal with thrush once during pregnancy and move on. Others get repeated infections, especially in the second and third trimesters. While you can’t fully override the hormonal changes driving the problem, a few practical habits lower your odds of recurrence.
- Wear cotton underwear. Synthetic fabrics trap moisture and warmth, both of which encourage yeast growth.
- Choose loose, breathable clothing. Tight leggings and jeans create the same warm, damp environment that Candida loves.
- Keep the area clean and dry. Change out of wet swimwear or sweaty workout clothes promptly, and avoid scented soaps, bubble baths, or douches that can disrupt your vaginal pH.
- Be cautious with antibiotics. Antibiotics kill off the beneficial bacteria that normally keep yeast in check. If you need a course during pregnancy, be aware that a yeast infection may follow, and mention it to your provider early.
None of these measures guarantee prevention, but together they reduce the conditions that let Candida overgrow. If you’re getting frequent infections despite these steps, your provider may recommend a longer or repeated course of topical treatment to keep symptoms under control through the rest of your pregnancy.