Preterm Labor: Prevention

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Prevention

Even if you have a healthy pregnancy, you may go into preterm labor. It is difficult to prevent preterm labor because it is usually not anticipated, and it is often due to causes that are not completely understood. However, following some general guidelines for a healthy pregnancy may help prevent preterm labor and will optimize your fetus's health and ability to thrive, whether at full term or preterm.

Being pregnant with twins, triplets, or more puts you at high risk for preterm labor and infant complications. If you are planning to use assisted reproductive technology or superovulation to conceive, talk to your doctor about reducing your risk of conceiving more than one baby. For more information, see the topics Fertility Problems and Multiple Pregnancy: Twins or More.

If contractions start

Contractions are a normal part of all pregnancies. Most contractions do not thin and open the cervix. Rather, they are simply a brief stimulation of the uterine muscle. This can happen when your fetus is moving a lot, when your bladder or bowel is full, or when you are dehydrated. These non-labor contractions are irregularly timed and uncomfortable rather than painful.

Preterm labor contractions tend to be regularly timed, becoming more frequent, painful, and prolonged (30 to 60 seconds) as they progress. You may also notice low back pain, thigh pain, or increased vaginal discharge or bleeding.

If you are less than 37 weeks pregnant and your uterus is contracting more than usual (about 4 or more in 20 minutes or about 8 or more within 1 hour), the following steps may stop your contractions:

• Drink 2 or 3 glasses of water or juice (not having enough liquids can cause contractions).
• Stop what you are doing, empty your bladder, and lie down on your left side for at least an hour.

If your symptoms get worse during the hour, call your doctor or nurse-midwife or go to the hospital.

If you are at risk for preterm labor

If you have had a spontaneous preterm birth before, you are probably at high risk for another preterm labor. This might make you a candidate for weekly progesterone injections for preventing preterm labor and delivery. This is a promising new approach, though it isn't yet widely used in all areas of the country. No fetal or newborn harm has been observed, though ongoing research is needed to rule out long-term side effects.¹⁶

You may be able to help prevent preterm labor if you are at risk (see the What Increases Your Risk section of this topic). Avoid activities that can start contractions.

• Avoid using drugs such as cocaine and methamphetamines.
• Don't smoke.
• Eat a healthy diet that is low in saturated fat. Use olive or canola oil in place of other fats or oils. Get lots of whole grains, low-fat dairy, fruits, and vegetables.

The U.S. Food and Drug Administration (FDA) and the U.S. Environmental Protection Agency (EPA) have issued the following advisory for pregnant women, women of childbearing age, nursing mothers, and young children:¹⁷

• Do not eat shark, swordfish, king mackerel, or tilefish, because these all contain high levels of mercury.
• Eat up to a week (two average meals) of a variety of fish and shellfish that are lower in mercury.
  • Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
  • Another commonly eaten fish, albacore ("white") tuna, has more mercury than canned light tuna. So, when choosing your two meals of fish and shellfish, you may eat up to a week (one average meal) of albacore tuna.

Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to a week (one average meal) of fish caught from local waters, but don't eat any other fish during that week. Also check the U.S. Environmental Protection Agency (EPA) Web site for mercury advisory updates at www.epa.gov/ost/fish.

Ineffective preventive treatments

• Bed rest. Until the recent past, long-term bed rest (expectant management) was commonly used to prevent preterm labor during the last half of pregnancy. However, recent research suggests that strict bed rest for 3 days or more increases your risk of developing a blood clot in the legs or lungs (from 1 in 1,000 to 16 in 1,000).¹² No studies have shown that bed rest is effective in delaying labor.^{13 11}
• Cervical cerclage. Cervical cerclage is the placement of stitches in the cervix to hold it closed. It is rarely done. Cerclage is meant to stop the cervix from opening early, which could lead to miscarriage or preterm birth. Cerclage has helped some high-risk pregnancies last longer, but it also has risks—it can cause infection or miscarriage. Studies suggest that cerclage makes twin pregnancies more likely to deliver early. Experts do not yet know when cerclage is more likely to work and when it isn't.¹⁴
• Home fetal monitoring. Research has shown that home monitoring is expensive and has no proven effect on delaying early birth.^{15 11}

Last updated:	January 19, 2007
Author:	Kathe Gallagher, MSW
Reviewed By:	Kathleen Romito, MD - Family Medicine, William Gilbert, MD - Perinatology
Editors:	Kathleen M. Ariss, MS, Pat Truman, MATC