Human Papillomavirus (HPV)
What it is: A genital infection due to a group of viruses. There are about 100 different strains, more than 30 of which are sexually transmitted and can infect your vagina, cervix, or butt, or your partner's penis. Of these 30 strains, about 15 have been linked to cervical cancer, and two have been linked to genital warts. It's the most common STD in the U.S. About 75 percent of men and women will be infected with genital HPV at some point, but most don't know it because they have no symptoms and the infection clears up on its own.
Why it's dangerous: If you've got the type of HPV linked to cervical cancer, there's little to no risk of it passing to the baby, Dr. Duff reassures. If you have genital warts, they may grow faster in pregnancy, probably due to a slight depression in your immune system, Dr. Greene says. But the risk to your baby is small, and you can usually deliver vaginally.
Should you be tested? No, but if you've ever developed warts or had an abnormal Pap, tell your doctor so she can monitor you more closely during pregnancy, Dr. Duff advises.
Treatment: If you have a history of abnormal Paps, your ob-gyn will most likely monitor you closely with repeat smears every three to six months. If the results are abnormal, she will perform a colposcopy, examining your cervix under a microscope and doing biopsies of any suspicious areas. If you've got precancerous or low-grade cancerous cells, your doctor will probably opt to wait until after you give birth for treatment, instead of just following you carefully with colposcopies, Dr. Wilcox says. If you've got a more developed cancer, you'll need more invasive treatments such as surgery. Chances are, your doctor will wait until after your pregnancy to treat your genital warts -- unless they get really big, in which case she may remove them by laser or surgically. "Oftentimes, the warts, even if they're large, will disappear on their own after a woman gives birth and her immune system returns to normal," Dr. Greene says.