Knowing the Risk Factors and Signs of Preterm Labor

A full term pregnancy lasts 40 weeks. Preterm labor is when an expectant mother goes into labor before her 37th week of pregnancy. Ideally, it’s best to stay pregnant until at least 39 weeks because the last few weeks of pregnancy are an important time for the baby’s growth and development. However, about one in 10 babies born in the U.S. is considered preterm. A premature birth can put the baby at greater risk for medical and developmental problems down the road. Sometimes, there will be medical indications and health care providers may recommend delivery before 39 weeks. In the case of preterm labor, early labor typically begins unexpectedly and on its own.

While the exact cause of preterm labor is often unknown, there are some risk factors that increase a woman’s chance of having preterm labor. However, it is important to remember that preterm labor can happen to anyone and many women who experience a premature birth have no known risk factors. Some of the risk factors include:

  • Preterm labor or preterm birth in a previous pregnancy
  • Being pregnant with multiples (twins, triplets or more)
  • Certain problems with your uterus, cervix or placenta
  • Having little or no prenatal care
  • Smoking or drug use
  • Abdominal surgery during this pregnancy
  • Too much amniotic fluid
  • Bleeding or infection while pregnant
  • Being underweight or overweight


A preterm labor typically begins unexpectedly. The signs of preterm labor are often no different from regular labor, except that they happen before the 37th week of pregnancy. If you experience any of the warning signs listed below before your 37th week of pregnancy, call your doctor. Sometimes, preterm labor can be stopped. However, there are certain situations and complications that make an earlier delivery safer for the mother or baby. The warning signs for preterm labor include:

  • Contractions, where your abdomen tightens like a fist, every 10 minutes or more often
  • Change in vaginal discharge, such as a watery, mucus-like fluid leaking from the vagina, or bleeding
  • Pelvic pressure; the feeling that your baby is pushing down
  • Low, dull backache
  • Cramps that feel like your period
  • Abdominal cramps with or without diarrhea


Women who are at risk for preterm labor may be advised to take certain steps to prevent preterm birth. At Virginia Women’s Center, we have three maternal-fetal medicine specialists who collaborate with our OB-GYNs in the care of high-risk pregnancies.