top of page

Individuals with PCOS are at 2.0-2.4x the risk of pre-term birth,[1],[2] defined as babies born alive before 37 weeks of pregnancy.[3]  In this article we explore the link between PCOS and pre-term birth.


PCOS is associated with elevated levels of androgens[4], sex hormones that are produced in the ovaries, start at puberty and play a key role in reproductive health.[5]  Find out more about PCOS and Androgen Excess.

  • High androgen levels lead to elevated cytokine levels, the small molecules that control the growth an activity of other immune cells;[6],[7]

  • Elevated cytokine levels result in higher pro-inflammatory signals, an increased immune response that normally works to protect your body from viruses, bacteria, allergens and other harmful substances;[8],[9]

  • Higher inflammatory signals lead to endothelial dysfunction, where the single cell layer that lines the blood vessels constricts or narrows when they should be dilating or opening;[10],[11] and

  • This endothelial dysfunction affects the lining of maternal and placental blood vessels and, through an as yet unknown mechanism, can lead to pre-term birth, as well as other pregnancy complications such as preeclampsia, fetal growth restriction and diabetes.[12],[13]


There are a variety of other risk factors associated with pre-term birth, including:[14],[15],[16]

  • Urinary tract infections (UTIs) and sexually transmitted infections (STIs);

  • Certain vaginal infections, such as bacterial vaginosis and trichomoniasis;

  • High blood pressure;

  • Bleeding from the vagina;

  • Certain developmental anomalies in the fetus;

  • Pregnancy resulting from in vitro fertilization (IVF);

  • Being underweight or obese before pregnancy;

  • Being a younger (<18 years) or older (>35 years) mother;[17]

  • Short time period (<6 months) between pregnancies;

  • Having African American or indigenous ethnicity;[18]

  • Inadequate or no prenatal care;

  • Being subject to physical, sexual or emotional abuse;

  • Long working hours, especially if they include extended periods of standing;

  • High levels of stress or lack of social support;

  • Use of tobacco, alcohol or illegal drugs;

  • Placenta previa, where the placenta grows in the lowest part of the uterus and covers all or part of the opening to the cervix;

  • Risk of uterine rupture due to prior cesarean delivery or previous removal of a uterine fibroid;

  • Diabetes or gestational diabetes;

  • Blood clotting problems; and

  • Exposure to “forever chemicals” through food packaging.[19]


Reviewed by Sandra Multiva PhD, EMBA, CHE, CRM, BHSc RM(Ret)

Sources
[1] https://www.mdpi.com/1660-4601/19/9/5470
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103656/
[3] https://www.who.int/news-room/fact-sheets/detail/preterm-birth
[4] https://www.uptodate.com/contents/polycystic-ovary-syndrome-pcos-beyond-the-basics/
[5] https://my.clevelandclinic.org/health/articles/22002-androgens
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103656/
[7] https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-023-04116-4
[8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103656/
[9] https://my.clevelandclinic.org/health/body/24585-cytokines
[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103656/
[11] https://stanfordhealthcare.org/medical-conditions/blood-heart-circulation/endothelial-dysfunction.html
[12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9103656/
[13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8698592/
[14] https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk
[15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791955/
[16] https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk
[17] https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0191002
[18] https://www.cmaj.ca/content/188/1/E19
[19] https://www.medscape.com/s/viewarticle/chemicals-common-food-packaging-linked-preterm-birth-2024a10002

Want to learn more about pregnancy complications and PCOS?  Check out our articles on gestational diabetes, low birth weight, miscarriage, and recurrent pregnancy loss.

Complications - Pregnancy & Birth

PCOS and Pre-Term Birth

bottom of page