Does One Ectopic Pregnancy Lead to Another?

If a woman has an ectopic pregnancy, what is her risk of having another one? Does a history of ectopic pregnancy influence the outcomes of future intrauterine pregnancies?

These questions were addressed in a large, population-based cohort study that evaluated the outcomes of intrauterine pregnancies among 1,117,571 women with a previous surgically treated extrauterine pregnancy. This cohort of women, who had been pregnant between 1989 and 2013, included 15,823 women who had a surgically treated ectopic first pregnancy (exposed group) and a control group of women whose first pregnancy was intrauterine (nonexposed group).

The key findings:

• The exposed group had a higher risk for an ectopic second pregnancy, and this risk was higher after salpingostomy versus salpingectomy.

• The risk for an adverse pregnancy outcome was higher among those with surgically treated ectopic first pregnancy; adverse outcomes included preterm birth, low birth weight, and need for cesarean section.

• The risks for preeclampsia, placenta previa, ICU admission, multiple birth, gestational diabetes, and blood transfusion were also higher among women with an ectopic first pregnancy.

• Women over the age of 30 with a previously surgically treated ectopic pregnancy had a greater risk for placental abruption in a subsequent pregnancy.

Viewpoint

In about 2% of pregnancies, the developing embryo implants not in the endometrium but in an extrauterine location, such as the fallopian tubes, ovarian surface, cervix, or peritoneum. Most occur in the fallopian tubes.

Known risk factors for ectopic pregnancy include older age, smoking, previous pelvic infection, tubal surgery, hormone use, endometriosis, and use of assisted reproductive technology. Some of these factors are also associated with adverse pregnancy outcomes. Even when the analysis in this study adjusted for these risk factors, however, a surgically treated ectopic first pregnancy increased the risk for a recurrent ectopic pregnancy, as well as the risk for adverse pregnancy outcomes in a subsequent intrauterine pregnancy.

The reason for a link between adverse pregnancy outcome and previous surgically treated ectopic pregnancy is not clear, but there are multiple potential pathways. For example, surgical management of the extrauterine pregnancy could compromise uterine blood supply and endometrial function. Because all of the women in the study were surgically treated, it isn't known whether medical treatment of an ectopic pregnancy would similarly affect later birth outcomes.

It's important to be aware of a woman's history of ectopic pregnancy and the association with negative outcomes when providing prenatal care during a subsequent pregnancy. A woman with a previous surgically treated ectopic pregnancy is at higher risk for preterm birth, low birth weight, and other complications of pregnancy, and more frequent prenatal visits and monitoring in the third trimester might be warranted.