Risk Factors for Preterm Birth: What You Should Know Even Now

Reviewed by: Dr. Ashan

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5 min read

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Apr 16, 2025

A preterm birth is one which takes place before 37 weeks of pregnancy (a full-term pregnancy lasts forty weeks). It is a main factor causing newborn death and morbidity all over. Prematurely born babies run more danger for problems including developmental delays, infections, and respiratory problems. Early detection and prevention depend on a knowledge of the preterm birth risk factors. Although not all preterm births are avoidable, understanding the risks will assist to more properly manage pregnancies.

What Is Preterm Birth?

Preterm birth is the condition whereby a baby is born before 37 weeks of gestation. There are some known and some less understood reasons for this as well. Preterm birth can have several causes, combining environmental elements, pregnancy problems, and mother health. Although many risk factors are inevitable, appropriate prenatal care and lifestyle changes can help to reduce some others.

Major Risk Factors for Preterm Birth

1. Previous Preterm Birth

Women who have had a previous preterm birth are at a significantly higher risk of having another preterm delivery. The risk increases with the number of previous preterm births, though the exact reasons for this are still under study. If you’ve had a preterm birth in the past, your healthcare provider may monitor your pregnancy more closely for signs of early labor.

2. Multiple Pregnancies

Carrying twins, triplets, or higher-order multiples increases the likelihood of preterm labor. The presence of multiple fetuses puts additional stress on the uterus, leading to early contractions and sometimes preterm birth. Multiple pregnancies account for a significant portion of all preterm births, and extra care and monitoring are often required for women carrying multiples.

3. Age and Reproductive Health

  • Teenagers (under 17) and women over 35 are more likely to experience preterm labor. Teens’ bodies may not be fully developed for pregnancy, while older women may face higher risks of conditions such as hypertension and gestational diabetes, which can increase the chances of preterm birth.
  • Infections in the reproductive organs, including sexually transmitted infections (STIs) or urinary tract infections (UTIs), also increase the risk of preterm labor.

4. Pregnancy Complications

Certain complications during pregnancy can also elevate the risk of preterm birth:

  • Pre-eclampsia (high blood pressure and organ damage) is a leading cause of preterm birth.
  • Placental abruption (early separation of the placenta) can cause bleeding and lead to preterm labor.
  • Intrauterine growth restriction (IUGR) can trigger early delivery to protect the baby.

5. Maternal Health Conditions

Several underlying maternal health conditions increase the risk of preterm birth, including:

  • Chronic hypertension (high blood pressure) or preeclampsia
  • Diabetes (pre-existing or gestational)
  • Obesity or being overweight increases the strain on the body and can lead to complications during pregnancy, including preterm birth.
  • Autoimmune disorders, such as lupus or rheumatoid arthritis, can affect the pregnancy and increase the risk of preterm birth.

Lifestyle and Environmental Factors

1. Smoking, Alcohol, and Drug Use

Using tobacco, alcohol, or illicit drugs during pregnancy significantly increases the risk of preterm birth. These substances interfere with the development of the placenta and the fetus, leading to complications such as low birth weight and premature labor.

2. Stress and Mental Health

High levels of stress during pregnancy, whether due to emotional, financial, or physical factors, can contribute to preterm birth. Stress activates hormonal changes that may trigger early labor. Conditions like depression and anxiety can also increase the likelihood of preterm delivery, particularly if they are untreated.

3. Lack of Prenatal Care

Not seeking early and regular prenatal care increases the risk of preterm birth. Regular checkups allow your healthcare provider to identify and manage potential risks such as infections, high blood pressure, or insufficient weight gain. Early screening for conditions like gestational diabetes and STIs can help prevent preterm labor.

Other Risk Factors to Consider

1. Short Interval Between Pregnancies

Having less than 6 months between pregnancies (also known as short birth spacing) increases the likelihood of a preterm birth. It doesn’t give the body enough time to fully recover from the previous pregnancy, potentially leading to complications in the next one.

2. Physical Trauma or Injury

Trauma to the abdomen or complications from previous surgeries (such as cervical surgery) can lead to an increased risk of preterm labor. Women with a history of cervical insufficiency, where the cervix weakens prematurely, are at a higher risk for preterm birth.

3. Underlying Uterine or Cervical Abnormalities

Abnormalities in the uterus or cervix, such as a short cervix or fibroids, can increase the risk of preterm labor. These conditions can limit the ability of the cervix to stay closed until the pregnancy reaches full term.

Reducing the Risk of Preterm Birth

Early Prenatal Care and Monitoring

One of the best ways to reduce the risk of preterm birth is by attending regular prenatal checkups. Early detection of high-risk factors such as high blood pressure, infections, or growth restrictions can help healthcare providers manage and intervene when necessary.

Lifestyle Modifications

Maintaining a healthy weight, avoiding tobacco, alcohol, and drug use, and managing stress are crucial for reducing the likelihood of preterm birth. Regular exercise, eating a balanced diet, and ensuring adequate rest can also help improve pregnancy outcomes.

Managing Health Conditions

If you have chronic conditions such as hypertension, diabetes, or thyroid disease, it’s essential to follow a treatment plan recommended by your healthcare provider to keep these conditions under control throughout pregnancy.

Conclusion

While preterm birth is not always preventable, understanding the risk factors and addressing them with proper prenatal care, lifestyle adjustments, and early interventions can significantly reduce the chances of a premature delivery. It is important for expectant mothers to stay informed about the warning signs and risk factors associated with preterm birth, as early recognition and action can greatly improve both maternal and neonatal health outcomes.

References

  1. Ye, C.-X., Chen, S.-B., Wang, T.-T., Zhang, S.-M., Qin, J.-B., & Chen, L.-Z. (2021). Risk factors for preterm birth: a prospective cohort study. PubMed, 23(12), 1242–1249. https://doi.org/10.7499/j.issn.1008-8830.2108015
  2. Goldenberg, R. L., Culhane, J. F., Iams, J. D., & Romero, R. (2008). Epidemiology and causes of preterm birth. The Lancet, 371(9606), 75–84. https://doi.org/10.1016/s0140-6736(08)60074-4
  3. What are the risk factors for preterm labor and birth? (2023, May 9). Https://Www.nichd.nih.gov/. https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk