The miscarriage rate in women with endometriosis undergoing IVF fresh cycles

There is no statistically significant increase regarding the risk of miscarriage in women with endometriosis who achieved pregnancy through IVF fresh cycles.

Key Points

Highlights:

• Miscarriage, which is the most common obstetric complication in the first trimester has been examined to see whether it is increased in women with endometriosis resulting in IVF failure.  

Importance:

• The risk of miscarriage does not increase in endometriosis in women with endometriosis independent of the presence and size of endometrioma.

What’s done here?

• This retrospective cohort study evaluates the effect of the presence of endometriosis on the risk of miscarriage in women undergoing fresh IVF cycles in a tertiary university hospital reproductive medical center.
• Women with endometriosis diagnosed by the laparoscopy or laparotomy were accepted as the study group. The control group included women with tubal or male factor. All of these women underwent first IVF cycle and achieved singleton pregnancies after fresh embryo transfer.
• The ovarian endometrioma was diagnosed on at least two pelvic ultrasound scans before IVF and this ultrasonography was repeated after 3 months to confirm its presence.
• Women older than 42 years old and who had hydrosalpinx, abnormal uterine cavity, excessive uterine volume and uterine malformations, having comorbid conditions such as diabetes, hypertension, ..were excluded.
• Standardized clinical protocol was applied to all women during IVF cycle.
• Clinical pregnancy was confirmed by transvaginal ultrasonography at 30 days after embryo transfer.
• The loss of clinical pregnancy before 24 weeks of gestation divided by the number of clinical pregnancy defined the miscarriage rate.

Key results:

• A total of 1006 women with endometriosis in the study group and 2012 age-matched women in the control group studied.
• There was no significant difference regarding the miscarriage rate between women in the study and control groups.
• After adjustment for the risk factors for miscarriage, the odds ratio was calculated as 1.14.
• When the study group was evaluated based on the presence of endometrioma, the miscarriage rate was also found to be similar in this subgroup analysis.
• The miscarriage rate did not differ according to the size of endometrioma.  

Strengths and Limitations

• The larger number of patients comparing with other studies represents the strengths of this study.
• The retrospective design, impossibility to find the exact surgical classification of endometriosis in analysis, unreliability of sonographic diagnosis of ovarian endometrioma and relatively small size of ovarian endometrioma were the limitations of this study.  

Lay Summary

Endometriosis is a chronic estrogen-dependent disease diagnosed in 25-40% of women with infertility. There are several mechanisms explaining the negative impacts of endometriosis on fertility through the entire reproductive process such as sperm-oocyte interaction, ovarian reserve, and implantation.

Endometriosis is also associated with poor obstetric outcomes including preterm birth, intrauterine growth restriction, and babies’ small for gestational age. Miscarriage is the most common obstetric complication in the first trimester.

In the literature, there are controversial studies about the association between the risk of miscarriage and endometriosis. Some studies argued that endometriosis increases the risk of miscarriage and others did not. Yang et al, a group of scientists from China, published a randomized clinical study titled as “Risk of miscarriage in women with endometriosis undergoing IVF fresh cycles: a retrospective cohort study” in the journal named as Reproductive Biology and Endocrinology.

The authors sought to evaluate this association in women with endometriosis undergoing IVF fresh cycles. They found that endometriosis is not a disease that increased the risk of miscarriage. There was no significant difference regarding the miscarriage rate in between women with and without endometriosis. When women with endometriosis was evaluated based on the presence of endometrioma, the miscarriage rate was also found as similar in this subgroup analysis. The miscarriage rate did not also differ according to the size of endometrioma.

“It is also necessary to perform basic research to better define the relationship between miscarriage and endometriosis in the future.” they added.

Research Source: https://www.ncbi.nlm.nih.gov/pubmed/30755216