Risk factors for preterm labor and birth

Preterm birth is a serious risk for both mothers and children. Children born preterm (before 39 weeks) are at an elevated risk of many negative health outcomes, including breathing problems, developmental delays, and other severe lifelong issues. The earlier a baby is born, the more likely it is that they face complications.

Healthcare professionals rely on a number of risk factors for preterm birth to know which pregnancies to monitor more closely. This way, they can keep women and their babies safe every step of the way.

Risk factors most likely to influence

There are a few major factors that healthcare professionals consider the most important in influencing a woman’s likelihood of preterm labor, but the most important factor is a prior history of preterm birth. Other important factors include:

  • Structural abnormalities of a woman’s reproductive organs such as an abnormally shaped uterus
  • Multiple gestations such as a pregnancy of twins, triplets or more
  • Having a short cervix around the 20-week mark

Data show that certain interventions may reduce the risk of preterm labor, such as progesterone supplementation for those with a short cervix.

Other risk factors likely to influence labor and birth

There are other factors that healthcare professionals look for when assessing preterm labor risk. These factors are not as likely to be an influence as the ones above, but have been associated with an increased risk of preterm labor and birth.

Some of these factors involve a specific medical problem, as opposed to ones that are caused by a certain behavior or lifestyle. It is difficult for many women to predict or treat these factors on their own. The factors involving a specific medical problem are:

  • Having an STI or a UTI
  • Going 12 months or less between pregnancies
  • Being over- or underweight before or during the pregnancy
  • Vaginal bleeding, especially in the last two trimesters
  • Chronic conditions like diabetes or hypertension
  • Conditions that indicate an abnormality in the placenta
  • Certain birth defects in the baby
  • Polyhydramnios (too much amniotic fluid)
  • Oligohydramnios (too little amniotic fluid)
  • Gum disease
  • Specific lifestyle or individual risk factors likely to influence labor and birth
  • Preeclampsia

Some of these issues can be detected at a preconception appointment, or an early prenatal visit, so it’s important to seek this care.

Finally, some risk factors are more related to certain behaviors or individual factors than they are to medical conditions. They are:

  • Alcohol or drug use before or during pregnancy
  • Smoking
  • Inadequate nutrition during pregnancy
  • Exposure to dangerous pollutants
  • The woman’s age – women who are under 18 and over 35 have a higher risk of preterm birth

If you smoke, use recreational drugs, abuse alcohol, or have an inadequate diet, it’s a good idea to work with your healthcare provider to come up with strategies to help lessen your risks.

As you can see, there are a variety of risk factors that could have an influence over whether or not women go into labor early. But healthcare professionals are quick to note that preterm labor really can affect any woman, whether or not she experiences any of these factors. It all depends on the woman’s body. Because of this, the best way to be prepared for preterm labor, besides identifying and monitoring risk factors, is to learn how to recognize it.

If you have any questions about this, if you have access to coaching, you can speak to your healthcare provider, who will be able to discuss in detail the different risks of preterm labor and how they apply to you. Women with certain risk factors should ask their provider about whether they are candidates for any medication or increased surveillance that may help some individuals reduce the risk of recurrent preterm birth.

  • “Preterm labor and premature birth.” MarchofDimes. March of Dimes Foundation, Mar 2016. Web. 
  • Mayo Clinic Staff. “Premature birth: Risk factors.” MayoClinic. Mayo Foundation for Medical Education and Research, Nov 27 2014. Web. 
  • “What are the risk factors for preterm labor and birth?” NIHCD. National Institutes of Health, Nov 6 2013. Web. 
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