Are women with endometriosis more prone to pregnancy loss?

Different types of pregnancy loss are encountered more commonly in women with endometriosis.

Key Points

Highlights:

• The association between endometriosis and pregnancy loss is strengthened with an increasing number of losses.

Importance:

• Women with all types of endometriosis should be informed about the increased risk of poor obstetric outcomes including pregnancy loss.

What’s done here?

• This nationwide historical cohort study with a nested case-control analysis was conducted to determine whether there was an association between endometriosis and pregnancy loss.
• The population consisted of women diagnosed with endometriosis as the study group and those without any signs of endometriosis from the cohort of the Danish general population as the control group.
• The numbers of pregnancy losses (categorized as 0, 1, 2, and more than 3 losses) were the primary outcomes; secondary outcomes were the predefined types of pregnancy losses.
• Spontaneous loss of a pregnancy until 22 gestation weeks (spontaneous abortion, missed abortion, and gestational sac without fetus) was identified as pregnancy loss; recurrent pregnancy loss was defined as three consecutive pregnancy losses.
• If women without prior live birth or stillbirth were identified as primary recurrent pregnancy loss, whereas secondary recurrent pregnancy loss had at least 1 prior live birth or stillbirth.

Key results:

• More than 29 thousand women with endometriosis and a similar number of age-matched cohort women without endometriosis were recruited in the study.
• Women with endometriosis had a higher rate of assisted conceptions and a lower number of pregnancies and parities than women without endometriosis.
• There was an association between endometriosis and pregnancy loss.
• No association between endometriosis and more than two pregnancy losses in the second trimester or stillbirth was detected.
• In addition, there was no association between endometriosis and secondary recurrent pregnancy loss after giving birth to a girl.
• The association between endometriosis and an increasing number of pregnancy losses was strengthened.
• More women with endometriosis had any type of pregnancy loss with higher euploid probability.

Strengths and Limitations

• The strength of the study is that this is the first to assess the association between endometriosis and pregnancy losses identifying a distinction between the numbers of pregnancy losses.
• The longitudinal study design over years and large sample size including nulliparous women was another strength of the study.
• Non-identification of early or uncomplicated pregnancy losses could be accepted as the limitation of the study.

Lay Summary

Endometriosis is a gynecological disease of reproductive-aged women who may suffer from reproductive outcomes such as infertility, miscarriage, and recurrent pregnancy loss. Pregnancy loss is the spontaneous loss of a pregnancy until 22 weeks of gestation including spontaneous abortion, missed abortion, and gestational sac without a fetus; while recurrent pregnancy loss is defined as three consecutive pregnancy losses.

Dyhrberg Boje et al, and associates from Denmark, published a study titled “Endometriosis is associated with pregnancy loss: a nationwide historical cohort study” in the journal Fertility and Sterility.

The authors aimed to investigate the association between endometriosis and pregnancy loss making a distinction between the numbers of pregnancy losses. They enrolled the participants with a diagnosis of endometriosis as the study group and those without any signs of endometriosis as the control group. Women with endometriosis were found to have a higher rate of assisted conceptions and a lower number of pregnancies and parities than women without endometriosis. Although there was an association between endometriosis and pregnancy loss, no association between endometriosis and more than two pregnancy losses in the second trimester or stillbirth was detected. The association between endometriosis and an increasing number of pregnancy losses was strengthened.  

“Endometriosis was found to have an association between pregnancy loss and recurrent pregnancy loss, and the association was strengthened with an increasing number of losses.” the authors added.   

Research Source: https://pubmed.ncbi.nlm.nih.gov/36608920/