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Preterm Labor Warning Signs

Know the signs of premature labor and what to do if you are at risk.

pregnant woman holding her belly.

Preterm labor is when contractions cause changes in the cervix before 37 weeks gestation (full term is 38 to 42 weeks). If your baby is born before 37 weeks, he or she is premature. Every year, about one out of 10 babies born in the U.S. is born preterm. It’s important to recognize the signs and symptoms of preterm labor. If preterm labor is diagnosed early, your doctor may be able to postpone birth to give your baby extra time to grow and mature inside the uterus. Even a few more days in the womb can mean a healthier baby, so early detection of preterm labor is essential.

Why is preterm birth a problem?

A baby born before 37 weeks is likely to have one or more health problems, including:

  • Underdeveloped lungs leading to breathing problems and respiratory distress
  • Problems with digestion, regulation of temperature and feeding
  • Vision problems
  • Hearing impairment
  • Risk of learning and developmental disabilities

Risks for preterm labor

There is no way to know for sure who will go into preterm labor. But awareness of risks can alert your doctor so you receive the care you need. For example, women who are at a significant risk of preterm labor may be given corticosteroids between 24 and 34 weeks gestation to help decrease the risk of lung problems.

Some health risks for preterm labor include:

  • Vaginal bleeding
  • Being overweight or underweight before pregnancy and/or not gaining enough weight during pregnancy
  • Premature rupturing of membranes
  • Infections of the vagina, cervix, uterus or fallopian tubes
  • Kidney or bladder infections
  • Having chronic health problems, such as high blood pressure, heart problems or diabetes

Some lifestyle and situational risks for preterm labor include:

  • Lack of prenatal care
  • Smoking
  • Drinking alcohol
  • Abusing illicit drugs
  • Extreme stress in your daily life
  • Not enough support from family and friends
  • In a violent or abusive relationship, including physical, sexual and emotional abuse
  • Exposure to pollutants, like air pollution

What risks make you most likely to have preterm labor?

  • If you have already had a preterm birth that was spontaneous
  • If you have had problems with your cervix or uterus
  • If you are having twins, triplets or more

Does having sex increase the chance of preterm labor?

Sex is safe during all stages of a normal pregnancy, meaning a pregnancy considered low-risk for complications (such as miscarriage or pre-term labor). Talk to your doctor about your preterm labor risk and how that may relate to your sexual activity during your pregnancy.

Symptoms of preterm labor?

Contractions feel like your abdomen is tightening like a fist. False labor or Braxton Hicks contractions are common during the third trimester. Braxton Hicks contractions can be painful, are irregular when timed and usually go away if you rest. They are called false contractions because they do not change the cervix like real labor pains.

If you notice contractions — painful or painless — that occur four times every 20 minutes or if you have six or more contractions in an hour, call your doctor's office immediately or seek immediate medical care. Also, call your doctor right away if you notice even one of these symptoms:

  • Vaginal discharge has changed to become watery, bloody, or include mucous
  • An increased amount of vaginal discharge
  • Pelvic or lower stomach pressure that feels like the baby is pushing down
  • Constant, low, dull back ache
  • Cramping that feels like your period and may or may not include diarrhea
  • Your water breaking; can be a gush or a trickle of fluid

Generally, real labor happens when contractions get closer together, last longer and become stronger as time goes by. Don't be embarrassed if your symptoms turn out to be a false alarm. You and everyone else will be relieved.

By Mary Small, Contributing Writer

American College of Obstetricians and Gynecologists (ACOG). ACOG’s Your Pregnancy and Childbirth: Month to Month. 6th edition. Washington, DC: ACOG; 2015.
American College of Obsetricians and Gynecologiest. Preterm (premature) labor and birth. FAQ 087. Accessed: July 6, 2016.
Uptodate. Preterm labor. Accessed: July 6, 2016.
March of Dimes. Preterm labor and premature birth. Accessed: July 6, 2016.

Last Updated: July 7, 2016