Ectopic First Pregnancy Means Risk for Fewer Children Later

Larry Hand

October 19, 2012

Women whose first pregnancy is an ectopic pregnancy are likely to have fewer children in later years compared with women whose first pregnancy resulted in a delivery, miscarriage, or abortion, according to a study published online October 18 in Human Reproduction. These women are also more likely to have future ectopic pregnancies.

Line Lund Kårhus, MD, a research student in the Gynaecological Clinic at Rigshospitalet, Copenhagen, Denmark, and colleagues conducted a historical controlled study of data from Danish registries for 1977 through 2009. They matched women whose first pregnancy was ectopic from 1977 to 1982 with age-matched women whose first pregnancy resulted in a miscarriage, induced abortion, or delivery, as well as with other women who were not pregnant.

"We found that the group of women who had a first ectopic pregnancy had the lowest delivery rate and total number of pregnancies over the following 20-30 years when compared with the other groups, and also lower rates of miscarriages and abortions," Dr. Kårhus said in a news release. "They had a 4.7-10-fold increased risk of further ectopic pregnancies."

The researchers indentified 40,101 women included in the registries who had at least 1 ectopic pregnancy between January 1, 1977, and December 31, 2009; 2917 of these women whose first ectopic pregnancy occurred between 1977 and 1982 formed the study index group.

Women whose first pregnancy was ectopic had the lowest long-term delivery rate through 2009, at 69 per 100 deliveries, compared with women whose first pregnancy ended with a miscarriage, at 125.7 per 100 deliveries; induced abortion, at 77.4 per 100; delivery, at 72.7 per 100; or no first pregnancy during the index period, at 100.5 per 100.

Birth rate ratios (RRs) for the groups came to, respectively, 0.55% (95% confidence interval [CI], 0.52 - 0.58), 0.89 (95% CI, 0.84 - 0.95), 0.95 (95% CI, 0.89 - 1.01), and 0.69 (95% CI, 0.65 - 0.72). "As compared with the miscarriage group, women with a first [ectopic pregnancy] thus had a 45% reduced long-term delivery rate," the researchers write. In addition, 15% of the later pregnancies after first ectopic pregnancy were also ectopic.

About 1% of all pregnancies are ectopic, the researchers write, and they are never viable.

"We think women with a first ectopic pregnancy have to try harder to achieve the number of deliveries they wish," Dr. Kårhus said in the news release. "However, their attempts are counterbalanced by the fact they are less fertile, and, therefore, ultimately they end up with one less birth."

She added, "These results indicate that fertility is compromised in women whose first pregnancy is ectopic and even after 30 years they have significantly fewer children compared with other women. We had expected that, over time, women would compensate for their reduced fertility by making more attempts to become pregnant. However, our results demonstrate that these extra attempts at pregnancy do not result in the same number of babies for women whose first pregnancy was ectopic compared with other women."

Limitations of the study include the lack of pregnancy data before 1977 and the lack of information on whether pregnancies were intended or not. However, the strength of the study lies in the depth of information contained in the combined Danish registries on reproductive outcomes, the researchers write.

"[T]he study is further strengthened by the complete follow-up, the large number of patients in the study subgroups, and the fact that it was based on registry data, which eliminates recall bias and other detection bias during follow-up," they write.

All study expenses were covered by Gynaecological Clinic, Rigshospitalet, University of Copenhagen. One author reports receiving honoraria for speeches on pharmacoepidemiologic issues. The other authors have disclosed no relevant financial relationships.

Hum Reprod. Published online October 18, 2012. Abstract