Each year, more than 4 million babies are born in the United States. We all want to welcome them into a safe and healthy world, and part of that involves ensuring pregnancies reach full term. A baby born before reaching at least 37 weeks of pregnancy is considered “preterm.” Sadly, this happens in about 12% of births in the U.S. While the idea of delivering early might seem appealing—especially if the pregnancy has been challenging—it’s worth hanging in there because full-term pregnancies give babies the best start. Preterm babies are more likely to face health issues, require longer hospital stays, and encounter more complications the earlier they are born. If you’re expecting twins or triplets, the chances of delivering early are significantly higher. Fortunately, there’s some good news: a hormone called progesterone might help lower the risk of preterm births.
Progesterone is a key hormone during pregnancy. From the start, it helps your uterus grow so there’s enough space for your baby, and it keeps the uterus from contracting too soon. Early uterine contractions can lead to miscarriages. As your pregnancy progresses, progesterone supports your lungs to provide enough oxygen for your baby and preps your breasts for breastfeeding.
So, what causes preterm birth? One common factor is having a short cervix—measuring 25 mm or less. The cervix is the part of your uterus that opens during labor to allow your baby to pass through. For most women, this is a gradual process as the cervix shortens and thins in preparation for birth. However, if your cervix is naturally short, it may open too early and lead to a preterm birth. Thankfully, short cervixes can often be detected during an ultrasound. If you’re concerned about this, you can request an ultrasound focused on checking the length of your cervix to catch any potential issues early.
Here’s how progesterone can help: It’s available either as a shot or a vaginal gel. Studies have shown that women who received progesterone were less likely to have preterm births compared to those who received a placebo. Notably, a study on the vaginal gel found it reduced the risk of both “early” and “late” preterm births, which is crucial since early preterm births tend to involve more severe complications.
Progesterone shots are typically recommended for women who have a history of preterm birth with a single baby. These shots are usually started between 16 and 20 weeks of pregnancy and continue until 37 weeks. The shots have no known side effects aside from the mild discomfort of the injection itself, and they’ve shown to be effective in reducing the risk of delivering preterm.
For women without a history of preterm birth, the gel is often the preferred option. The gel comes with an applicator similar to a tampon. You insert one gel pack into your vagina each day, starting between 20 and 23 weeks of pregnancy and continuing until just before 37 weeks. Both the gel and the shots are safe and effective for women carrying a single baby. However, these treatments are not recommended for women expecting twins, triplets, or more, as progesterone has been linked to increased risks in those cases.
If you think progesterone treatment might be right for you, it’s important to talk to your doctor. They are the best resource for understanding your specific situation and guiding you through any concerns. If any complications arise during your treatment, don’t hesitate to contact your doctor to ensure everything is on track with your pregnancy.
Keeping your hormones balanced and your uterus healthy are key to a successful pregnancy and ensuring your baby is born at the right time. The ultimate goal is a healthy baby, and doctors are here to support you in every way possible. Progesterone might be a useful tool for moms at risk, so being informed and proactive can make all the difference.