Progesterone treatment to prevent preterm birth
Premature birth is birth that happens too early, before 37 weeks of pregnancy. Premature babies may need to stay in the hospital longer or may have more health problems than babies born full term. Full term means your baby is born between 39 weeks and 40 weeks, 6 days of pregnancy.
Progesterone may help prevent premature birth for some women. Talk to your provider to see if progesterone treatment may help reduce your risk of having your baby early.
What is progesterone?
Progesterone is a hormone. Hormones are chemicals made by the body.
Progesterone plays a key role during pregnancy. In early pregnancy, it helps your uterus (womb) grow and keeps it from having contractions. If you have contractions in early pregnancy, it may lead to miscarriage. This is the death of a baby in the womb before 20 weeks of pregnancy. 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.
There are two kinds of progesterone treatment:
- Vaginal progesterone may help reduce your risk for premature birth if you have a short cervix and are pregnant with just one baby.
- Progesterone shots may help reduce your risk for premature birth if you’ve had a premature birth in the past and you’re pregnant with just one baby.
If you’re pregnant with multiples (twins, triplets or more), progesterone treatment isn’t for you. It’s only for women who are pregnant with just one baby.
Talk to your health care provider to find out if progesterone treatment is right for you.
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 your baby can pass through the birth canal during childbirth.
Your cervix is short if it's less than 2 centimeters (20 millimeters) long. If you have a short cervix, it may open too early, before you baby is ready to be born. When your cervix opens too early, it’s called cervical insufficiency or incompetent cervix. If you have a short cervix, you have a 1-in-2 chance (50 percent) of having a premature 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.
What is vaginal progesterone?
Vaginal progesterone may help prevent premature birth, but only if both of these describe you:
- You have a short cervix.
- You’re pregnant with just one baby.
If both of these describe you, your provider may give you a prescription for vaginal progesterone. It comes as a gel, a suppository or a capsule. You use an applicator that looks kind of like a tampon to put the progesterone in your vagina every day. You may begin treatment before or up to 24 weeks of pregnancy, and you keep taking it until just before 37 weeks. Vaginal progesterone has no known side effects for you or your baby.
Even if you use vaginal progesterone, it doesn't always work to prevent premature birth. It doesn't work if you're pregnant with multiples. If you have a short cervix and are pregnant with just one baby, talk to your provider about vaginal progesterone.
What are progesterone shots?
Progesterone shots are a kind of progesterone called 17 alpha-hydroxyprogesterone caproate (also called 17P). The shots may help prevent premature birth if both of these describe you:
- You had a spontaneous premature birth before when you were pregnant with just one baby. Spontaneous means labor began on its own, without drugs or other methods. Or the sac around your baby broke early, causing labor.
- You’re pregnant with just one baby.
If both of these describe you, your provider may prescribe progesterone shots. You begin the shots between 16 and 24 weeks of pregnancy, and you get a shot each week until 37 weeks. The shots are available in two ways:
- As a brand-name drug called Makena™
- Prepared (also called compounded) at special pharmacies. You can get this kind of shot only if you have certain health conditions, like an allergy to something in Makena.
Insurance companies and state Medicaid programs may help pay for the shots.
Even if you get progesterone shots, they don’t always work to prevent another premature birth. They don’t reduce your chances of giving birth early if you’re pregnant with multiples. And they don’t reduce your chances of giving birth early if your previous premature birth wasn’t spontaneous.
Talk to your provider about safety and side effects of progesterone shots. You may have some discomfort at the injection site (the place on your body where you get the shot). Research on babies of moms who took the shots shows no increase in birth defects or developmental problems in the first 4 years of life. More studies are being done to follow up on both mothers and babies.
Last reviewed August 2014
Frequently Asked 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 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.