199438 Health Library | Health and Wellness | Wellmont Health System
  • Premature Birth



    The normal gestation period for humans is about 40 weeks. Some babies are born before 40 weeks. Any birth that occurs more than three weeks before the due date, or before 37 full weeks, is defined as a premature birth.
    Amniotic Sac
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    There are many reasons why a woman would go into labor before her scheduled due date, including:
    • Having previously delivered prematurely
    • A ruptured amniotic sac (ruptured membranes)
    • Infections of the urinary tract or cervix
    • A weak cervix—especially if there have been prior surgical procedures
    • Abnormalities in the uterus, including fibroids and malformations of the uterus
    • Twins or higher number of fetuses
    • Smoking, drinking, or using drugs during pregnancy—especially cocaine
    • Poor nutrition during pregnancy
    • Too much amniotic fluid (polyhydramnios)
    • Chronic diseases like:

    Risk Factors

    A risk factor is something that increases your chance of getting a disease or condition.
    The following factors increase your chance of delivering prematurely:
    • Having had a previous premature birth
    • Having multiple births (twins, triplets, quadruplets, etc.)
    • Having a chronic disease—For example, if you have poorly controlled asthma , this may increase your risk.
    • Having poor prenatal care or poor nutrition during pregnancy
    • Abusing drugs during pregnancy (especially cocaine)
    • Taking certain medicines during pregnancy (eg, benzodiazepines)
    • Being overweight or obese


    Symptoms include:
    • Abdominal pain that feels something like menstrual cramps
    • Dull pain in the lower back
    • Pressure in the pelvis and tightening in the thighs
    • Vaginal bleeding or spotting, or watery discharge


    Your doctor will ask about your symptoms and medical history, and perform a physical exam. Your obstetrician will want to see if your cervix has dilated and if fetal membranes have ruptured. Regularity of any contractions will also be monitored, and an ultrasound may be performed.
    Sometimes special tests are done, such as an ultrasound, to measure the cervix length, or fetal fibronectin (fFN).
    The definition of preterm labor requires increase in the dilation of the cervix under the influence of uterine contractions. Prior to actual preterm labor, the phrase "threatened preterm labor" may be used. Threatened preterm labor is potentially reversible.


    Depending on how premature the pregnancy is, the doctor will talk to you about the risks associated with proceeding with the labor. If the fetus has developed enough to be able to live successfully outside of the uterus, the doctor may recommend proceeding with the labor. If it is too early and too risky to deliver, the doctor will try to stop the labor. Stopping labor is not simple. Often, the medicines are not effective in preventing a preterm birth.
    Sometimes when there is a risk of preterm deliver, the doctor will suggest giving a steroid medicine to the mother. The medicine can reach the fetus and cause maturation of the surfactant (a substance which prevents lung collapse) in the lungs.
    If you are diagnosed as likely to to deliver your baby prematurely, follow your doctor's instructions .


    To help reduce your chances of delivering your baby prematurely, take the following steps:
    • Get the proper prenatal care throughout your entire pregnancy.
    • Eat a healthy, balanced diet with plenty of fruits, vegetables and whole grain.
    • Ask your doctor if you should take a daily vitamin. Your doctor may also recommend other supplements like calcium or zinc.
    • Avoid smoking, alcohol, and drugs.
    • Keep chronic diseases under control.
    • Reduce your stress level.
    • Stay active during your pregnancy. Your doctor can give you exercise guidelines that are right for you.
    • Follow your doctor's recommendations about having sex during pregnancy.
    • If you are at high-risk for premature birth, talk to your doctor about progesterone therapy.


    The American College of Obstetricians and Gynecologists http://www.acog.org/

    Kids Health http://www.kidshealth.org/


    Health Canada http://www.hc-sc.gc.ca/index-eng.php/

    The Society of Obstetricians and Gynaecologists of Canada http://www.sogc.org/index%5Fe.asp


    The American College of Obstetricians and Gynecologists. Management of stillbirth. Practice Bulletin. March 2009;102.

    Hall R. Prevention of premature birth: do pediatricians have a role? Pediatrics . 2000;105(5): 1137-1140.

    Premature labor. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/labornbirth/prematurelabor.html. Accessed April 18, 2007.

    Prevention of preterm labor and preterm birth. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/ . Updated April 4, 2012. Accessed April 6, 2012.

    Sheridan P. Rice sociologist finds premature birth increases risk for asthma. Rice University website. Available at: http://www.media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=8305&SnID=651540035. Accessed April 18, 2007.

    10/29/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Bakhireva LN, Schatz M, Jones KL, et al. Asthma control during pregnancy and the risk of preterm delivery or impaired fetal growth. Ann Allergy Asthma Immunol. 2008;101:137-143.

    7/6/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Kumar A, Devi SG, Batra S, Singh C, Shukla DK. Calcium supplementation for the prevention of pre-eclampsia. Int J Gynaecol Obstet. 2009;104:32-36.

    1/22/2010 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Calderon-Margalit R, Qiu C, Ornoy A, Siscovick DS, Williams MA. Risk of preterm delivery and other adverse perinatal outcomes in relation to maternal use of psychotropic medications during pregnancy. Am J Obstet Gynecol. 2009;201(6):579.e1-8.

    8/23/2010 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : McDonald SD, Han Z, Mulla S, Beyene J; Knowledge Synthesis Group. Overweight and obesity in mothers and risk of preterm birth and low birth weight infants: systematic review and meta-analyses. BMJ. 2010;341:c3428.

    10/25/2012 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Mori R, Ota E, Middleton P, Tobe-Gai R, Mahomed K, Bhutta ZA. Zinc supplementation for improving pregnancy and infant outcome. Cochrane Database Syst Rev. 2012 Jul 11;7:CD000230.

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