Guideline No. 398: Progesterone for Prevention of Spontaneous Preterm Birth

To assess the benefits and risks of progesterone therapy for women at increased risk of spontaneous preterm birth (SPB) and to make recommendations for the use of progesterone to reduce the risk of SPB and improve postnatal outcomes. To administer or withhold progesterone therapy for women deemed to be at high risk of SPB. Preterm birth, neonatal morbidity and mortality, and postnatal outcomes including neurodevelopmental outcomes. Maternity care providers, including midwives, family physicians, and obstetricians. Pregnant women at increased risk of SPB. Medline, PubMed, EMBASE, and the Cochrane Library were searched from inception to October 2018 for medical subject heading (MeSH) terms and keywords related to pregnancy, preterm birth, previous preterm birth, short cervix, uterine anomalies, cervical conization, neonatal morbidity and mortality, and postnatal outcomes. This document represents an abstraction of the evidence rather than a methodological review. This guideline was reviewed by the Maternal–Fetal Medicine Committee of the Society of Obstetricians and Gynaecologists of Canada (SOGC) and approved by the SOGC Board of Directors. Therapy with progesterone significantly reduces the risk of SPB in a subpopulation of women at increased risk. Although this therapy entails a cost to the woman in addition to the discomfort associated with its use, no other adverse effects to the mother or the baby have been identified. 1Progesterone therapy reduces the risk of spontaneous preterm birth in women at an increased risk based on history of previous spontaneous preterm birth or in women with a short cervical length (moderate).2There is insufficient evidence to support the use of progesterone for prevention of spontaneous preterm birth in women with a pregnancy in the absence of cervical shortening (moderate).3There is insufficient evidence to support the use of progesterone for prevention of spontaneous preterm birth in women with a normal cervical length and a prior conization procedure on the cervix or abnormal uterine anatomy (low).4Use of progesterone in women with arrested preterm labour is not associated with a reduced risk of spontaneous preterm birth or with improved postnatal outcomes (moderate).5Use of vaginal progesterone for prevention of spontaneous preterm birth has not been associated with an increase in congenital malformations or with a worsening of postnatal neurodevelopmental outcomes (moderate). 1In women with a singleton pregnancy and a