Study finds IVF success negatively correlates with endometriosis severity

For in vitro fertilization (IVF), clinical and ongoing pregnancy rates deteriorated with worsening endometriosis, according to results of a retrospective study in The Journal of Minimally Invasive Gynecology.  

In addition, presence of endometriomas in patients with stage 3 and 4 endometriosis did not impact IVF outcomes.

The Canadian and Israeli study also concluded that the best time to perform IVF appears to be between 7 and 25 months after endometriosis surgery.

Study participants consisted of 216 infertile patients with endometriosis and 209 infertile patients without endometriosis on laparoscopy.

Patients with endometriosis were classified according to criteria from the American Society for Reproductive Medicine: stage 1 disease (58 patients), stage 2 (67 patients), stage 3 (63 patients) and stage 4 (28 patients).

The only patient demographic that was significantly different between the two groups was age: 35.2 years in the endometriosis group and 36.4 years in the control group.

All patients underwent both laparoscopy and an autologous IVF cycle at the CReATe Fertility Center in Toronto, Canada, between 2009 and 2014.

Compared to controls, patients with endometriosis had significantly lower estradiol on trigger day (9,986 pg/mL vs. 12,220 pg/mL) and fewer retrieved oocytes (12.7 vs. 14.0).

“We found a consistent decline in clinical and ongoing pregnancy rates with increasing stage of endometriosis,” the author wrote. 

Patients with time intervals after surgery of 7 to 12 months and 13 to 25 months achieved the more favorable outcomes. The 7- to 12-month group had a pregnancy rate of 50%, compared with 52.4% for the 13- to 25-month group. In comparison, the pregnancy rate was only 32.5% in the 25-month group, the same as for the 0- to 3-month group.

The authors note that endometriosis is more common in women presenting for infertility evaluation (25% to 50%) compared to the general fertile population (3% to 10%).

However, classification systems for endometriosis have typically been based on lesion appearance, presence of pelvic adhesions and anatomic location of disease, none of which predict clinical outcome, except more accurate fertility prediction by the endometriosis fertility index.

Laparoscopy for diagnosis and treatment of endometriosis is appealing for infertile patients as an alternative to pharmacologic intervention that is associated with ovulation suppression. But laparoscopy may damage a woman’s ovarian reserve.

IVF clinical outcomes were evaluated based on rates of fertilization, implantation and spontaneous pregnancy.

The fertilization rate among patients with endometriosis was 70% compared to 67.1% for patients who did not have the condition. Moreover, for all stages of endometriosis, the fertilization rate ranged from 66% to 74%.  The implantation rate for all cohorts was comparable, ranging from 23.6% to 30%.  Still, patients with severe endometriosis (stages 3 and 4) had significantly lower clinical and ongoing pregnancy rates per fresh embryo transfer than controls: 35% and 29% vs. 44.5% and 38.8%, respectively.

All patients with endometriosis were divided into five interval groups between laparoscopy and the IVF cycle. The 0- to 3-month group had an ongoing pregnancy rate of 32.5%. This compared to a pregnancy rate of 38.6% for the 4- to 6-month group 

For the 12 patients with bilateral endometriomas, the interval distribution was 0, 2, 1, 4 and 5 patients, respectively.

“Although the exact mechanism for impaired fertility during the first 6 months remains to be investigated, the reduced pregnancy rates after 2 years may be explained by either endometriosis recurrence and/or age factors,” the authors wrote.

Two limitations of the study are that it is retrospective, thus the lack of live birth rate evaluation, and that the surgical intervention for treating endometriosis was not uniform, although 86% of women underwent cystectomy.

Nonetheless, the authors contend that laparoscopy’s cost-effectiveness in advanced disease is still debatable, despite many published articles proposing that the procedure’s feasibility has a positive impact on pregnancy rates, especially for stages I and II disease.