Human papillomavirus (HPV) is a type of sexually transmitted infection (STI). You can get HPV if you have sex with a partner who has it.

HPV is very common. About 20 million Americans have the virus. Up to 75 percent of sexually active people get HPV at some point in their lives. Few people find out they have it.

Over 150 different types of HPV exist. Most types don’t cause any problems. About 40 virus strains can infect the genital tract and may cause genital warts and cancer of the:

  • cervix
  • vagina
  • vulva
  • penis
  • anus

HPV usually doesn’t cause problems during pregnancy. However, you should know about a few rare complications if you’re pregnant and have HPV.

HPV can cause warts. Warts are flesh-colored bumps on the skin that grow alone or form into clusters that look like cauliflower.

The type of HPV you have will determine where on your body the warts grow:

  • Genital warts grow on the vagina, vulva, cervix, or anus in women, and on the penis, scrotum, or anus in men.
  • Common warts form on the hands or elbows.
  • Plantar warts appear on the balls or heels of the feet.
  • Flat warts usually occur on the face in children and men, and on the legs in women.

You probably you won’t feel the warts, but sometimes they can itch or burn.

During pregnancy, changing hormone levels can make warts grow faster than usual. A pregnant woman’s body also produces an increased amount of vaginal discharge, which gives warts a warm, moist place to thrive.

Having certain types of HPV can also increase your risk for cervical cancer. This kind of cancer often doesn’t produce symptoms until it starts to spread. Then, it can cause:

  • abnormal bleeding from the vagina, or bleeding that isn’t due to your menstrual period
  • discharge from the vagina, which may contain blood
  • pain during sex

Most OB-GYNs don’t normally test for HPV during pregnancy. Your doctor might discover the virus if you have warts or when you have a routine Pap test. During a Pap test, your doctor uses a swab to remove a small number of cells from your cervix. They send the sample to a lab and test it for precancerous cells. The presence of precancerous cells may indicate that you have HPV.

If you’re over the age of 30 and have HPV, your OB-GYN will also give you an HPV DNA test along with the Pap test. This test can detect whether you have a type of HPV that can cause cervical cancer.

You probably won’t need any treatment during pregnancy. Your HPV shouldn’t pose a risk to your baby. No drug is available to treat the virus itself.

Warts also don’t need treatment, unless they’re especially large or they bother you. Then, your doctor can safely remove them by:

  • freezing them off with liquid nitrogen, which is called cryotherapy.
  • using a laser
  • using a heated needle
  • performing surgery

How will HPV affect delivery?

Having genital warts shouldn’t affect your delivery. Rarely, warts can grow large enough during pregnancy to block the birth canal. If that happens, your doctor will recommend that you have a Cesarean delivery.

How is HPV treated after delivery?

If a Pap test shows that you have precancerous cells in your cervix, your doctor may wait to treat you until after you deliver. Once your baby is born, you’ll likely have another Pap test. Precancerous cells often clear up without treatment. If you still have abnormal cells after delivery, your doctor may treat you by removing the abnormal tissue with one of these procedures:

  • an electrosurgical procedure that removes tissue with an electrically heated loop
  • a cone biopsy, which involves using a knife to remove a cone-shaped wedge of tissue
  • cryosurgery, which involves freezing off the abnormal cells

Having HPV during your pregnancy shouldn’t affect your baby’s health. You can pass the virus to your unborn baby during pregnancy or delivery, but it’s unlikely. Studies have differed on the rate of HPV transmission from mother to baby, but a 2013 study found that about 5 percent of babies born to HPV-positive mothers also have the virus.

Most babies who have HPV in the womb will clear the virus on their own without having any long-term problems. In rare cases, babies of HPV-infected mothers can develop warts on their larynx, or vocal cords. This condition is called recurrent respiratory papillomatosis. These babies may need surgery to remove the growths.

Having HPV shouldn’t stop you from breast-feeding. Although the virus can pass from mother to baby in breast milk, this kind of transmission is very rare.

Two of the best ways to avoid getting HPV are to limit the number of sexual partners you have and to get vaccinated. Guidelines recommend the HPV vaccine for girls and young women between the ages of 11 and 26. The complete series involves three vaccines. You’ll need to get all three vaccines to be fully protected.

If you didn’t get vaccinated before your pregnancy or you started the vaccine series but didn’t finish it, you’ll need to wait to get or complete the vaccine until after the birth of your baby. Guidelines don’t recommend HPV vaccines for pregnant women.

If you’re over age 30, see your OB-GYN to get HPV tests in addition to Pap tests. That way, if you are infected with HPV, you can talk to your doctor about any special monitoring you might need during your pregnancy.