Effect of Endometriosis on IVF Success Rates

Endometriosis lowers the number of embryos available to transfer in IVF but not their quality.

Key Points

Highlights:

• The cumulative live birth rate in IVF for women with endometriosis is lower than for women without the disease, not because of the quality of their embryos, but because of the decreased number of embryos available for transfer.

Importance:

• This study provides information about the mechanisms affecting the outcome of assisted reproductive techniques.
• This information would help to improve the management of endometriosis as well as its treatment outcomes.  

What's done here:

• Authors retrospectively evaluated more than 1000 IVF cycles of women with and without endometriosis in terms of the number of eggs available, their quality, their implantation rate, and live birth rates.

Key results:

• Women with endometriosis had significantly lower levels of ovarian reserve markers regardless of previous ovarian surgery.
• Women with endometriosis had significantly fewer egg cells and embryos despite receiving significantly higher doses of exogenous gonadotropins.
• There was no association between endometriosis and the proportion of top-quality embryos.
• There was no difference between women with endometriosis and those without, in terms of implantation rate and live birth rate per cycle.
• The cumulative live birth rate was significantly lower for women with endometriosis compared to women without the disease.

Limitations:

• There may have been bias and limitations while assessing the quality of the embryos.
• The semen quality of the male partners may have been different between the two groups and this may have an impact on the findings.
• There may have been a selection bias as the center in which this study was conducted is an endometriosis referral center and women included in the study may have particularly severe forms of the disease, which could have an impact on the outcomes of the IVF cycles. 

Lay Summary

Endometriosis lowers the rate of cumulative live births during in vitro fertilization (IVF). However, this is due to a lower number of embryos being available for transplantation rather than their quality. This is according to a study published in the "Journal of Clinical Medicine".

Cumulative live birth rate reflects the chance of getting pregnant over many IVF cycles as opposed to each cycle. 

In this study, Dr. Boucret et al. sought to understand the impact of endometriosis on IVF success rates by retrospectively evaluating 1,124 IVF cycles with intracytoplasmic sperm injection (ICSI). ICSI is an IVF procedure where a single sperm cell is injected directly inside the egg cell to facilitate fertilization. 

Of those 1,124 cycles, 155 were performed with eggs obtained from women with endometriosis, and 969 were performed with eggs obtained from women without the disease. 

The researchers noted that women with endometriosis had significantly lower levels of ovarian reserve markers regardless of whether or not they had ovarian surgery before. Ovarian reserve markers are hormones, the levels of which can help doctors estimate the ovarian reserve, or “how many eggs a woman has left”. The hormone that was examined in this case was the anti-mullerian hormone (AMH). They also looked at the antral follicle count (AFC), or resting follicles that contain the egg cells.

The researchers reported that despite receiving significantly higher doses of exogenous gonadotropins, women with endometriosis had significantly fewer egg cells and embryos compared to women without the disease. Exogenous gonadotropins are hormones that are given to women undergoing IVF to induce ovulation or the release of mature eggs from the ovaries. 

Researchers did not find an association between endometriosis and the proportion of top-quality embryos. They saw that the implantation rate (the chance of the embryos implanting into the mother’s uterus) and the live birth rate per cycle were comparable between ICSI cycles where eggs from women with endometriosis and eggs from women without the disease were used.

However, the cumulative live birth rate was significantly lower for women with endometriosis compared to women without the disease. According to the researchers, this was a consequence of the lower number of frozen embryos rather than the quality of the embryos. (During each IVF cycle more embryos than can be implanted are obtained. Prospective parents can choose to freeze these embryos for future attempts for pregnancy). 

Research Source: https://pubmed.ncbi.nlm.nih.gov/32752267/