
For most women, it is fine to have sex during pregnancy. The fetus is safe in the uterus, protected by amniotic fluid and strong uterine walls. A mucus plug blocks the cervix, stopping bacteria and other harmful substances from reaching the baby. And during typical pregnancies, sex is unlikely to cause miscarriage or early labor.
However, there are times when doctors advise against having sex or against certain sexual activities during pregnancy. Women should always check with their doctor if they have any questions.

When might sex be risky? Women in these situations are usually advised to avoid vaginal sex:
- Miscarriage risk. Women who have had a miscarriage in the past are at higher risk for another one. Other miscarriage risk factors include infections, uncontrolled diabetes, hormonal issues, older age, smoking, and drug use.
- Risk for preterm labor. Preterm labor is more common in women who have a history of premature labor; are carrying twins, triplets, or “multiples”; or have problems with reproductive organs, such as a short cervix. Older women are more likely to go into labor early, as are women who smoke, drink alcohol, and use illicit drugs. Domestic violence and exposure to toxic substances are other risk factors for preterm labor.

- Placenta previa. This condition occurs when the placenta forms in the lower part of the uterus and covers the cervix, either partially or completely. Women are at higher risk for placenta previa if they have had several past pregnancies, have had pregnancies with “multiples” (twins, triplets, etc.), have scarring on the uterine lining, or have undergone in vitro fertilization.
- Unexplained vaginal bleeding or cramping. This situation can occur during an ectopic pregnancy (when the fertilized egg grows outside the uterus), when there is a uterine rupture, or when there are problems with the placenta.

- Incompetent (weakened) cervix. The weight of the baby can put pressure on the cervix, making it open before it’s time for the birth. Cervical surgery, cervical trauma [such as a dilation and curettage (D & C) procedure], and exposure to DES (diethylstilbestrol) can increase a woman’s risk for an incompetent cervix.
- Leaking amniotic fluid/premature rupture of membranes. When a pregnant woman is about to start labor, the amniotic sac breaks and leaks a clear fluid. Some people call this “water breaking.” However, sometimes the sac ruptures early. This can happen when the woman is having more than one baby, if she has a urinary tract infection or sexually transmitted infection, or if she smokes, drinks alcohol, or uses drugs.
Resources
Eunice Kennedy Shriver National Institute of Child Health and Human Development
“What are the risk factors for preterm labor and birth?”
(Last reviewed: January 31, 2017)
https://www.nichd.nih.gov/health/topics/preterm/conditioninfo/who_risk
Mayo Clinic
“Incompetent cervix”
(July 25, 2019)
https://www.mayoclinic.org/diseases-conditions/incompetent-cervix/symptoms-causes/syc-20373836
“Miscarriage”
(July 16, 2019)
“Sex during pregnancy: What’s OK, what’s not”
(July 10, 2018)
Medical News Today
Barrell, Amanda
“Signs and causes of leaking amniotic fluid”
(August 24, 2018)
https://www.medicalnewstoday.com/articles/322878.php
Cadman, Bethany
“What to know about sex during pregnancy”
(Reviewed: February 22, 2019)
https://www.medicalnewstoday.com/articles/321648.php
MedlinePlus
“Placenta Previa”
(Page last updated: November 6, 2019)
https://medlineplus.gov/ency/article/000900.htm
WebMD
“Sex During and After Pregnancy”
(Reviewed: February 15, 2019)