Sexual Intercourse and Premature Labor Risk
Sexual intercourse does not increase the risk of premature labor in low-risk or high-risk pregnancies, and restrictions on sexual activity should not be routinely recommended. 1, 2
Evidence in Low-Risk Pregnancies
The most robust evidence comes from a 2019 systematic review and meta-analysis of randomized controlled trials involving 1,483 women with singleton pregnancies at term, which found that sexual intercourse had no effect on spontaneous onset of labor (relative risk 1.02,95% CI 0.98-1.07). 1 This aligns with earlier observational data showing:
- No association exists between sexual intercourse and preterm birth, premature rupture of membranes, or low birth weight in low-risk pregnancies 1
- A 1980 matched case-control study of 111 patients who delivered prematurely found no significant difference in coital frequency, sexual activity rates, or orgasm incidence compared to term deliveries 2
- Normal coital activity does not result in premature delivery and should not be discouraged during uncomplicated pregnancy 2
Evidence in High-Risk Pregnancies
Despite widespread practice of restricting sexual activity in high-risk pregnancies, there is minimal published evidence supporting these restrictions. 3 A comprehensive 2018 review examining sexual activity in high-risk conditions (history of preterm delivery, shortened cervix, cerclage, PPROM, placenta previa, multiple gestations) found insufficient data to justify routine sexual activity restrictions. 3
Important Context on Activity Restriction
The Society for Maternal-Fetal Medicine provides strong guidance against activity restriction in general for high-risk pregnancies:
- Activity restriction is NOT recommended for women at risk of preterm birth, including those with preterm labor symptoms, arrested preterm labor, or shortened cervix (Grade 1B recommendation) 4, 5
- Activity restriction is NOT recommended for multiple gestations (Grade 1A recommendation) 4, 5
- Some evidence suggests activity restriction may actually increase preterm birth risk (adjusted OR 2.37 for delivery <37 weeks; OR 2.28 for delivery <34 weeks) 4
Clinical Reality vs. Patient Concerns
Despite the evidence, many pregnant women harbor concerns about sexual activity:
- 49% of pregnant women worry that intercourse may harm the pregnancy 6
- Concerns about sexual activity causing preterm labor or PPROM increase as pregnancy progresses 6
- Only 29% of women discuss sexual activity with their physician, and 49% must raise the issue themselves 6
- 76% of women who haven't discussed these issues feel they should be addressed 6
Practical Recommendations
Sexual intercourse should not be restricted in low-risk pregnancies at any gestational age. 1, 2
For high-risk pregnancies (history of preterm birth, cervical insufficiency, multiple gestations), sexual activity restrictions lack evidence-based support and should not be routinely prescribed. 3 The broader evidence against activity restriction in these populations suggests that sexual activity restrictions are similarly unfounded. 4, 5
When to Consider Individual Assessment
The only exception where caution may be warranted based on pathophysiology (though not evidence-based):
- Active placenta previa with risk of bleeding
- Active preterm premature rupture of membranes (infection risk)
- Active vaginal bleeding from any cause
Common Pitfalls to Avoid
- Do not reflexively restrict sexual activity based on high-risk diagnosis alone - this lacks evidence and may cause unnecessary psychological distress 4, 3
- Proactively discuss sexual activity with patients - waiting for them to ask leaves 71% without guidance 6
- Distinguish between different types of activity restriction - if you wouldn't recommend bed rest or work restrictions (which you shouldn't per guidelines), sexual activity restrictions are similarly unjustified 4