Preterm birth is birth that happens before 37 completed weeks of pregnancy. This is too soon, and your baby could be born with serious health problems. Preterm labor is labor that happens before 37 completed weeks of pregnancy. If untreated, it can lead to preterm birth.
Preterm birth can happen to any pregnant woman. But it happens more often to some women than others, especially if they make certain lifestyle choices that may not be healthy for mom and baby during pregnancy.
You may be able to reduce your risk of preterm labor and early birth. Here’s what you can do:
Last reviewed September 2012
No one knows for sure what causes a woman to have preterm labor. But if you have certain risk factors, you're more likely than a woman without risk factors to have preterm labor. Risk factors include: having already had a premature baby or getting pregnant again too soon after having a baby; being pregnant with twins or more; and having problems with your uterus or cervix. You're more likely to have preterm labor if you're underweight or overweight or if you have health problems, like high blood pressure, diabetes or certain infections. Things in your life like stress, smoking, drinking alcohol and using drugs also put you at risk. Talk to your provider if you have any of these risk factors. You may be able to reduce your risk and have a better chance for a healthy pregnancy.
You'll know you're in labor if:
If you think you're in labor, call your health care provider, no matter what time of day or night.
There is no set timeline for survival for babies born early. Babies born earlier than 23 weeks have a much smaller chance of survival than babies born after 23 weeks.
About 9 out of 10 babies born at 28 weeks survive. But many have serious health problems. Any baby born before 37 completed weeks of pregnancy is considered premature. Premature babies have less time to develop in the womb than babies who arrive on time. This puts them at greater risk of medical and developmental problems. Every extra day in the womb helps the baby develop and mature and probably improve his or her health and development later in life. Between 23 and 26 weeks, every extra day in the womb increases a baby's chance of survival by 2 to 4 percent.