From the Guidelines
17-hydroxyprogesterone caproate (17P) is recommended for pregnant women with a history of spontaneous preterm birth to prevent recurrence, with a standard regimen of 250 mg administered by intramuscular injection once weekly, starting between 16-20 weeks of pregnancy and continuing until 36 weeks gestation or delivery, whichever comes first, as supported by the Society for Maternal-Fetal Medicine 1.
Key Points
- The medication is not effective for stopping active preterm labor and should not be used for this purpose.
- It works prophylactically by maintaining the uterus in a quiescent state, as progesterone inhibits uterine contractions by reducing the production of prostaglandins and oxytocin receptors.
- Side effects may include pain at the injection site, swelling, itching, bruising, and rarely allergic reactions.
- Patients should be counseled that weekly injections are necessary for the treatment to be effective, and that the medication is specifically for prevention in women with prior preterm birth, not for other risk factors or for active preterm labor management.
Recent Guidelines
Recent studies and guidelines have reaffirmed the use of 17P for prevention of preterm birth in women with a history of spontaneous preterm birth, while also highlighting its limitations and potential lack of efficacy in other scenarios, such as short cervix without prior preterm birth 1.
Clinical Considerations
It is essential to consider the individual patient's risk factors and medical history when deciding on the use of 17P, and to counsel patients about the potential benefits and limitations of the treatment, as well as the importance of adherence to the recommended regimen.
Evidence-Based Practice
The recommendation for 17P use is based on the most recent and highest-quality evidence available, including guidelines from the Society for Maternal-Fetal Medicine 1 and other relevant studies 1.
From the Research
17 Hydroxyprogesterone Caproate for Preterm Labor
- 17 hydroxyprogesterone caproate (17P) is used to prevent preterm delivery in women with a history of spontaneous preterm delivery 2.
- The exact mode of action of 17P therapy in preventing preterm labor and delivery is not known, but current evidence supports its use in women with a history of spontaneous preterm delivery 2.
- 17P treatment is typically begun early in the second trimester of gestation and continued weekly until 36 weeks 2, 3.
- There is no evidence to support the use of 17P to prevent preterm delivery in women with multiple gestation, a short uterine cervix, or other high-risk conditions outside of randomized trials 2.
- Vaginal progesterone is recommended for women with a short cervix, rather than 17P, as it has been shown to reduce the rate of preterm delivery in this population 4.
Efficacy of 17 Hydroxyprogesterone Caproate
- Some studies have found that 17P reduces the rate of preterm birth in women with a history of spontaneous preterm delivery 2, 5.
- However, other studies have found that 17P has no effect on preterm birth rates in certain populations, such as women with a short cervical length 5.
- A 2020 review found that there is limited evidence to support the use of 17P for the prevention of preterm birth, and that more research is needed to fully understand its efficacy 3.
Comparison to Other Treatments
- Vaginal progesterone has been shown to be effective in reducing preterm birth rates in women with a short cervix, and is recommended as the treatment of choice for this population 4.
- Cervical cerclage may be used in combination with 17P or vaginal progesterone to prevent preterm birth in women with a short cervix 5, 4.
- Other treatments, such as corticosteroids and tocolytics, may be used to reduce the risk of preterm birth and improve neonatal outcomes 6.