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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)


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

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