Sex During Pregnancy and the Risk of Miscarriage

A miscarriage is a spontaneous pregnancy loss that occurs within the first 20 weeks of gestation, usually in the first trimester. It's most often caused by a random chromosomal abnormality. The experience can be painful, both physically and emotionally, for any woman who has to go through it. 

As a result, many couples—especially those who have had previous miscarriages—often worry about whether it is safe to engage in sexual intercourse during pregnancy. They worry, for instance, whether the penetration of the penis into the vagina might accidentally poke or harm the fetus. They may also be concerned about whether uterine contractions during orgasms might cause problems with the pregnancy. It's totally normal to have these types of worries.

But you can breathe a sigh of relief, because, for the vast majority of women, there is no evidence that sex during pregnancy causes anything bad, such as a miscarriage. There are only two scenarios in which a doctor is likely to tell you to skip sex during pregnancy—and those scenarios are fairly rare. For more details, read on. 

Although research is sparse on first trimester miscarriages, there is no known association between sexual activity and miscarriage. In addition, scientists have found no association between sexual activity and preterm birth. There's an old wives' tale that having intercourse later in pregnancy can bring on labor, but the evidence does not support it. For example, one study looking at women who had full-term pregnancies (those who had reached at least 37 weeks of gestation) and were scheduled for inductions found that couples who increased their sexual activity did not improve the odds of spontaneous labor. 

Doctors do sometimes recommend that certain patients who have specific medical issues avoid intercourse during pregnancy, such as patients with placenta previa or cervical insufficiency.

• Placenta previa is a condition in which the placenta is low-lying in the uterus and either partially or completely covers the cervix. A pregnant woman's placenta is often low-lying early in pregnancy and then rises higher. It's diagnosed via ultrasound and causes problems only if it occurs later in the pregnancy. Usually, painless bleeding in the third trimester is the main symptom. Other warning signs can include premature contractions, an abnormal lie (transverse, breech), and the uterus measuring larger than normal. Placenta previa is serious because it can lead to complications including growth restriction in the baby and fatal hemorrhaging (blood loss) in the mother. Many women with this condition must be put on bed rest. Placenta previa occurs in roughly one out of 200 pregnancies.
• Cervical insufficiency (also known as incompetent cervix) means that your cervix is weak and starts dilating (opening) too early during pregnancy. The condition increases the odds of pregnancy loss and preterm birth. Women with this condition may have to avoid strenuous activities, in addition to sex. Cervical insufficiency occurs in about one out of every 100 pregnancies.

If you're concerned that having sexual intercourse may hurt your developing baby or lead to miscarriage, discuss your concerns with your doctor. It can be hard to talk about these types of topics with a doctor sometimes. If you're feeling embarrassed, remember that doctors — especially OB/GYNs — see patients who have similar concerns every day and they will not think it's weird for you to ask questions about sex.