Preterm (or premature) labor happens when a woman’s body prepares for birth before the baby is fully developed in the womb. Babies grow throughout pregnancy and are considered full term after week 37 of pregnancy. Those born before week 34 are at risk for health concerns, such as underdeveloped lungs and being underweight. At NYU Langone, our doctors aim to keep labor from starting before week 34 of pregnancy to give the baby more time to develop.
You may be at increased risk of preterm labor if you have experienced it before, are pregnant with more than one baby, have had an operation for a pelvic condition such as fibroids, or have a shortened cervix (the outlet from uterus to vagina)—measuring less than 2.5 centimeters thick—at or before week 22 of pregnancy. You may also have an increased risk if you have previously had a second-trimester miscarriage.
For some women, certain factors such as smoking, drug use, and chronic stress may also play a role in their risk of preterm labor. Women younger than age 18, women older than age 35, and African American women tend to have elevated rates of preterm labor. Certain conditions, such as systemic lupus erythematosus, can raise the risk of preterm labor.
It is not always possible to prevent preterm labor. However, NYU Langone doctors recommend the following strategies to help ensure that you have a healthy pregnancy and your baby has as much time as possible to develop before birth.
It’s important that all women receive regular prenatal care throughout a pregnancy. Your doctor follows an appointment schedule designed to meet both your and your baby’s needs during each stage of pregnancy.
To determine if you are at risk of preterm labor, your doctor performs a transvaginal ultrasound. This test is given at 20 weeks of pregnancy and involves inserting a wand in the vagina; it uses sound waves to create images of the organs and structures of the pelvis. If you are at high risk because of prior preterm labor or other factors, this test is performed at 16 weeks.
With ultrasound, your doctor measures the length of your cervix and checks the anatomy of the uterus for abnormalities that might cause preterm labor. The cervix typically shortens soon before birth; this involves effacing, or thinning, and dilating, or opening horizontally.
If your cervix measures less than 2.5 centimeters in length, your doctor may prescribe a vaginal suppository containing a hormone called progesterone. This treatment has been shown to reduce preterm births by about 40 percent.
If you are at risk for preterm labor, your doctor may monitor you for bladder, kidney, and urinary tract infections, which can lead to preterm labor early in pregnancy, even if you have no symptoms of these conditions.
Doctors at NYU Langone may recommend the following tips to prevent preterm labor.
The odds of preterm labor increase when there are six months or less between a birth and the next pregnancy. Therefore, NYU Langone doctors recommend waiting at least 12 months between birth and the next pregnancy, especially in women who have had preterm labor before.
Because being underweight or obese is linked to preterm labor, our doctors advise that you reach and maintain a healthy weight before getting pregnant. It’s also important when planning a pregnancy to limit alcohol to no more than two drinks per week, to refrain from using recreational drugs, and to quit smoking, as smoking has been linked to preterm labor and other health risks for mothers and babies.
NYU Langone doctors recommend that you drink plenty of fluids throughout the day while pregnant to prevent dehydration, which can trigger contractions. Urine that is pale yellow or nearly clear is a good indication that you are well hydrated. For most women, this requires drinking 8 glasses (8 ounces each) of water per day. Because urinary tract infections can increase the risk of preterm labor, it’s important that you report to your doctor any urinary symptoms, including burning while urinating, difficulty urinating, or a feeling that your bladder hasn’t completely emptied after urinating.
If you have a chronic health condition, such as hypertension, diabetes, or rheumatic disease, your doctor can advise you on how managing the condition promotes a healthy pregnancy and may recommend changes to your medication, diet, or lifestyle.
If you experience signs of labor, including cramping, regular and painful contractions, a heavy feeling in the pelvis, or even an overall feeling that something isn’t right with the pregnancy, call your doctor immediately.
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