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 anyone 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 have sex during pregnancy. They worry, for instance, whether the penetration of the penis into the vagina might accidentally 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 concerns.

Although research is sparse on first trimester miscarriages, there is no known association between sexual activity and miscarriage. Additionally, scientists have found no association between sexual activity and preterm birth. Many people believe that having intercourse later in pregnancy can bring on labor, but the evidence does not support this.

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. 

It's possible that sex during pregnancy may sometimes feel painful or uncomfortable due to the hormonal and bodily changes you're experiencing. In most cases, you may be able to remedy the situation by figuring out which positions are more comfortable for you and by making sure to have lubricant on hand if you're experiencing vaginal dryness. Additionally, if you're not in a monogamous relationship and it's possible that your partner has a sexually transmitted infection, you'll want to protect yourself (and your baby) by using condoms.

There are two main scenarios in which a doctor is more likely to tell you to skip sex during pregnancy—and they are fairly rare. If you have been diagnosed with one of these conditions, your doctor may advise you not to have intercourse during pregnancy.

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. Placenta previa is 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 or 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.

In cervical insufficiency (also known as incompetent cervix), the cervix is weak and starts dilating, or opening, too early during pregnancy. The condition increases the odds of pregnancy loss and preterm birth.

For the most part, sex during pregnancy isn't a concern for most doctors. But If you're worried that having sex may hurt your developing baby or lead to miscarriage, discuss your concerns with your doctor. If you're feeling embarrassed, remember that midwives and doctors—especially OB/GYNs—see patients who have similar concerns every day. They will not think it's weird for you to ask questions about sex in general, let alone during pregnancy.