Progesterone treatment to prevent preterm birth

Preterm birth is birth that happens too soon, before 37 completed weeks of pregnancy. Babies who are born preterm may need to stay in the hospital longer or have more health problems than babies born full term. Progesterone may help prevent preterm birth for some women. Talk to your provider to see if progesterone treatment may help reduce your risk of having preterm birth.

What is progesterone?

Progesterone is a hormone. It plays a key role during pregnancy.

In early pregnancy, the hormone helps your uterus grow and keeps it from contracting. (If your uterus contracts in early pregnancy, this may lead to miscarriage.) In later pregnancy, progesterone helps your breasts get ready to make breast milk. It also helps your lungs work harder to give oxygen to your growing baby.

Recent studies show that for some women, especially if they have a short cervix or if they already had a preterm birth, being given progesterone during pregnancy may help reduce the risk of having a premature baby.

There are two kinds of progesterone treatment: vaginal gel and shots. Studies to date show that gel may help reduce preterm birth for pregnant women with a short cervix. Shots are recommended for pregnant women who already had a preterm birth.

What is progesterone gel?

Progesterone gel is a treatment for women who have a short cervix. Progesterone gel comes in a tampon-like applicator that you place in your vagina. You put in one applicator of progesterone gel every day. You may begin treatment between 20 and 23 weeks of pregnancy. Treatment can last until just before 37 weeks of pregnancy.

Studies show that treatment with progesterone gel in women with a short cervix can help prevent preterm birth and some of the problems that premature babies have after birth.

What is short cervix? 

The cervix is the part of your uterus that opens and shortens during labor. These changes allow your cervix to become thinner and softer so that your baby can pass through the birth canal during childbirth.

If you have a short cervix, it may open too early, before your baby is ready to be born. Women who have a short cervix have a 1 in 2 chance of having a preterm birth. Your health care provider may find that you have a short cervix during an ultrasound. Ask your provider about having an ultrasound to check for short cervix.

If you have a short cervix during pregnancy, you’re at risk for preterm birth. Ask your provider about treatment with progesterone gel that may help reduce this risk.

Who can get progesterone gel?

You may be eligible for progesterone gel if you have a short cervix.

Is progesterone gel safe?

Research shows that progesterone gel has no side effects for you or your baby.

How can you get progesterone gel?

Talk to your provider to see if progesterone gel is right for you. If it is, you get a prescription for it from your provider.

Does progesterone gel work for all pregnant women?

So far, research shows that progesterone gel may help prevent preterm birth if you have a short cervix and if you’re pregnant with one baby.

What are progesterone shots?

The shots are a kind of progesterone called 17 alpha-hydroxyprogesterone caproate. You may have heard it called 17P. You begin the shots between 16 and 20 weeks of pregnancy. You get a shot each week until 37 weeks.

Who can get progesterone shots?

You may be eligible for progesterone shots if both of these requirements describe you:

  1. You’ve had a spontaneous preterm birth before, when you were pregnant with just one baby. Spontaneous preterm birth means labor began on its own, without drugs or other methods. Or the sac around the baby broke early, causing labor.


  2. You are currently pregnant with just one baby.

Medical experts agree that progesterone shots can help prevent preterm birth, but only for women who meet both requirements listed above.*

Are progesterone shots safe?

Talk to your provider about safety and side effects. You may have some discomfort at the site where you get the shot. Studies of babies followed through the first 4 years of life show no increase in birth defects or developmental problems. More studies are being done to follow up on both mothers and babies.

How can you get the shots?

Talk to your provider. He has to prescribe the shots for you. The shots are available in two ways:

  1. Prepared (compounded) at special pharmacies
  2. As a brand name drug called Makena™

The treatment you use depends on discussion with your provider and your insurance coverage. Insurance companies and state Medicaid programs may cover the treatment. The pharmaceutical company that makes Makena has a patient assistance program that may help pay for it.

Do progesterone shots work for all pregnant women?

No. Studies show shots can help only if you already had a spontaneous preterm birth and are pregnant again with just one baby. Even if this is true for you, the shots don’t always work to prevent another preterm birth. The shots don’t reduce your chance of preterm birth if you’re pregnant with twins, triplets or more. And the shots don’t reduce your chance of preterm birth if your previous preterm birth wasn’t spontaneous.

*American College of Obstetricians and Gynecologists (ACOG) Committee Opinion #419: Use of progesterone to reduce preterm birth, October, 2008.

Last reviewed April 2012

See also: Cervical insufficiency

Most common questions

Am I at risk for preterm labor?

No one knows for sure what causes a woman to have preterm labor. But if you have certain risk factors, you're more likely than a woman without risk factors to have preterm labor. Risk factors include: having already had a premature baby or getting pregnant again too soon after having a baby; being pregnant with twins or more; and having problems with your uterus or cervix. You're more likely to have preterm labor if you're underweight or overweight or if you have health problems, like high blood pressure, diabetes or certain infections. Things in your life like stress, smoking, drinking alcohol and using drugs also put you at risk. Talk to your provider if you have any of these risk factors. You may be able to reduce your risk and have a better chance for a healthy pregnancy.

How do I know I’m in labor?

You'll know you're in labor if:

  • You have strong and regular contractions that last 30 to 60 seconds and come 5 to 10 minutes apart.
  • Your water breaks. Your baby has been growing in amniotic fluid (bag of waters) in your uterus. When the bag of waters breaks you may feel a big rush of waters or you may feel just a trickle.
  • You bleed a little from your vagina. This is called bloody show.

If you think you're in labor, call your health care provider, no matter what time of day or night.

How early can a baby be born and live?

There is no set timeline for survival for babies born early. Babies born earlier than 23 weeks have a much smaller chance of survival than babies born after 23 weeks.

About 9 out of 10 babies born at 28 weeks survive. But many have serious health problems. Any baby born before 37 completed weeks of pregnancy is considered premature. Premature babies have less time to develop in the womb than babies who arrive on time. This puts them at greater risk of medical and developmental problems. Every extra day in the womb helps the baby develop and mature and probably improve his or her health and development later in life. Between 23 and 26 weeks, every extra day in the womb increases a baby's chance of survival by 2 to 4 percent.

©2013 March of Dimes Foundation. The March of Dimes is a non-profit organization recognized as tax-exempt under Internal Revenue Code section 501(c)(3).