Treatment Stops Repeated Preterm Labor

Magnesium Treatment Allows Women to Continue Pregnancy Without More Episodes of Early Labor

From the WebMD Archives

Feb. 10, 2005 -- When pregnant women go into labor too early, successful treatment can help stop preterm labor (premature labor) from returning.

Labor that occurs before the 37th week of pregnancy is called preterm. Premature babies have a greater risk of health problems and death than babies born on or near their due date. However, preterm labor doesn't always lead to early birth.

"Most babies will do just fine. They will be delivered near term or at term," says ob-gyn Brian Brost, MD, in a news release. Brost specializes in high-risk pregnancies at Minnesota's Mayo Clinic.

Preterm labor can start in any woman; it's not always clear why preterm labor starts. The problem could lie in the mother, the fetus, or both. Women at greater risk for preterm labor include those who have had preterm labor in prior pregnancies, women who are pregnant with twins or more, smokers, and women with an abnormal cervix or uterus.

The March of Dimes estimates that 1,300 babies are born prematurely in the U.S. each day, or about 11% of all U.S. pregnancies.

Symptoms of Preterm Labor

With rest and medication preterm labor can sometimes be stopped. But when symptoms appear, they can include:

  • Contractions that occur every 10 minutes or more which feel like menstrual cramps
  • Pressure or pain in your lower back, pelvic area, lower abdomen, or thighs that continues after you change position -- standing, sitting, or lying down (it may feel like your baby is pushing out)
  • Changes in your vaginal discharge, which may increase in amount or become pink or reddish

You may have one or more of these symptoms and not be in preterm labor. Consult your doctor with any questions.

Study's Findings

With Mayo clinic co-workers and colleagues from the Medical University of South Carolina, Brost analyzed the medical records of 172 women who underwent preterm labor.

When preterm labor started, the women were between 24 to 34 weeks pregnant. A typical full-term pregnancy lasts 37 to 42 weeks. If contractions start before 37 weeks but after 20 weeks of pregnancy, this is defined as preterm labor.

To try to stop preterm labor, all of the women had been treated with magnesium sulfate which is used to stop preterm labor; it slows contractions of the uterus.

By delaying preterm labor, doctors can use other medications to help speed up the baby's lung development and improve the baby's chance of survival. The extra time could also allow mothers to be transferred to a more specialized hospital, if needed.

For 154 of the women in the study, the magnesium treatment stopped preterm labor for at least seven days. Out of that group, 87.7% delivered their babies at 34 weeks or later. After treatment these women continued their pregnancy without other episodes or preterm labor.

Delaying Early Delivery Again

The other 19 women had another episode of preterm labor before reaching 34 weeks. In 11 of those cases, magnesium treatment delayed delivery for at least 48 hours. The remaining eight women gave birth less than 24 hours after being readmitted to the hospital.

For the minority of magnesium-treated women who have another round of preterm labor, magnesium treatment might help. In Brost's study, magnesium sulfate delayed recurrent preterm labor long enough for the steroid to work in about half of the cases, according to the news release.

Side Effects

Magnesium treatment can tire mothers-to-be and make them feel somewhat disoriented. Other side effects include a very dry mouth, congestion, and sensitivity to light. Serious side effects can occur, but they're rare, says Brost, in the news release.

The findings were presented in Reno/Lake Tahoe, Nev., at the Society for Maternal-Fetal Medicine's 25th annual meeting.

Show Sources

SOURCES: Society for Maternal-Fetal Medicine, Reno/Lake Tahoe, Nev., Feb. 7-12, 2005. News release, Mayo Clinic. March of Dimes, "Preterm Labor." WebMD Medical Reference from Healthwise: "Preterm Labor: Symptoms." WebMD Medical Reference from Healthwise: "Preterm Labor: Topic Overview." WebMD Medical Reference from Healthwise: "Preterm Labor: Tocolytic Medication." WebMD Medical Reference from The High-Risk Pregnancy Sourcebook: "Premature Labor."
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