From the Guidelines
Vaginal progesterone is recommended for pregnant women with a short cervix (typically less than 25mm) or history of cervical insufficiency to reduce the risk of preterm birth, as it has been shown to reduce preterm birth rates by approximately 40-45% in women with a singleton pregnancy and a cervical length of less than 25mm on ultrasound 1.
Benefits of Vaginal Progesterone
The benefits of vaginal progesterone in preventing preterm birth are well-established, with studies showing a significant reduction in preterm birth rates in women with a short cervix or history of cervical insufficiency 1.
- Reduces preterm birth rates by approximately 40-45% in women with a singleton pregnancy and a cervical length of less than 25mm on ultrasound
- Maintains the structural integrity of the cervix
- Reduces inflammation
- Decreases uterine contractions
- Inhibits the production of prostaglandins that can trigger labor
- Helps stabilize the fetal membranes
Recommended Regimen
The standard regimen for vaginal progesterone is 200mg vaginal progesterone suppository or gel daily, starting between 16-24 weeks of pregnancy and continuing until 36 weeks 1.
- Alternatively, some providers use 90mg progesterone gel (Crinone) daily
- Vaginal administration is preferred over oral or intramuscular routes because it delivers the medication directly to the cervix with fewer systemic side effects
Side Effects
Common side effects of vaginal progesterone include vaginal irritation, discharge, and mild discomfort, but these are generally well-tolerated compared to the benefits of preventing preterm birth 1.
- Vaginal irritation
- Discharge
- Mild discomfort
Comparison to Other Treatments
Vaginal progesterone is preferred over other treatments such as cervical pessary or 17-alpha hydroxyprogesterone caproate (17-OHPC) for the prevention of preterm birth in women with a short cervix or history of cervical insufficiency 1.
- Cervical pessary has been shown to have potential safety concerns and is not recommended for the prevention of preterm birth in individuals with a singleton gestation and a short cervix
- 17-OHPC is not recommended for the treatment of a short cervix in individuals without a history of spontaneous preterm birth
From the Research
Benefits of Vaginal Progesterone for Cervical Insufficiency
- Vaginal progesterone is effective in reducing the rate of preterm birth in women with a short cervix 2
- Combined therapy of cervical cerclage and vaginal progesterone may result in a greater reduction in preterm birth than single therapy 3
- Vaginal progesterone is as effective as cervical cerclage in reducing the rate of preterm delivery in women with a singleton gestation, history of preterm birth, and a short cervix (<25 mm) 2
Comparison with Cervical Cerclage
- Cervical cerclage showed more benefits in maternal and neonatal outcomes than vaginal progesterone therapy for women with an asymptomatic short cervix and prior preterm birth history 4
- However, cervical cerclage and vaginal progesterone therapies showed similar effectiveness for women with an asymptomatic short cervix but without a history of preterm birth 4
Outcomes with Vaginal Progesterone
- Vaginal progesterone reduces the rate of preterm delivery at <33 weeks of gestation by 44%, along with the rate of admission to the neonatal intensive care unit, respiratory distress syndrome, requirement for mechanical ventilation, and composite neonatal morbidity/mortality score 2
- Vaginal progesterone may also decrease neonatal mortality, increase birthweight, and increase gestational age 3, 4
Specific Scenarios
- For women with a normal mid-gestation cervical length, the effectiveness of vaginal progesterone in preventing preterm birth is still being studied 5
- For women with progressive cervical shortening <10 mm while on vaginal progesterone, cerclage plus vaginal progesterone may decrease overall spontaneous preterm birth rates, prolong pregnancy latency, and improve neonatal outcomes compared to vaginal progesterone alone 6