O-189 The effect of endometriosis on placental histopathology and perinatal outcome in singleton live births resulting from in vitro fertilization
Authors: Volodarsky-Perel A , Ton Nu T.N , Mashiach R , Berkowitz E , Balayla J , Machado-Gedeon A , Cui Y , Shaul J , Dahan M 
Published: June 2022

Abstract

Study question
Does endometriosis have an effect on the placental histopathology patterns in singleton live births resulting from in-vitro fertilization?

Summary answer
Endometriosis is associated with acute chorioamnionitis, placenta previa, subchorionic fibrin deposition, intervillous thrombosis, fetal vascular malperfusion, as well as with failed labour induction.

What is known already
Endometriosis is a common chronic benign disease that affects reproductive age women and causes chronic pelvic pain and infertility. The effect of endometriosis on the reproduction and perinatal outcomes may be explained by the impact on the implantation decreasing the pregnancy rate and by causing abnormal placentation. Suboptimal placentation in the presence of endometriosis was previously explained by the altered uterine contractility, increased progesterone resistance, increased secretion of interleukins, and chronic inflammation. However, the spectrum of certain anatomical, inflammation, vascular, and villous maturation features of placentas introduced by the presence of endometriosis has not been previously evaluated.

Study design, size, duration
We conducted a retrospective analysis of all live births following IVF treatment during 2009-2017 from one tertiary hospital. All women with either surgically confirmed endometriosis or persistent ovarian cysts (for at least 12-weeks duration) consistent with endometriomas in ultrasound appearance were included in the endometriosis group. Placental histopathology results, obstetrical, and perinatal outcomes from pregnancies complicated by endometriosis were compared with those without signs of adenomyosis or endometriosis.

Participants/materials, setting, methods
Full gross and histopathology assessment of all placentas irrelevant of complication status was performed. The pathologic findings were categorized according to the Amsterdam Placental Workshop Group Consensus. The primary outcomes included anatomical, inflammation, vascular malperfusion, and villous maturation placental disorders. The secondary outcomes included fetal, maternal, perinatal, and delivery complications. A multivariate logistic model was used to adjust the results for confounding factors potentially associated with significant placental and perinatal characteristics.

Main results and the role of chance
A total of 1057 live births were included in the final analysis and were allocated to the group of women with endometriosis (n = 75) and without endometriosis (n = 982). Demography, obstetric history, distribution of chronic co-morbidities, the results of infertility evaluation including ovarian reserve, infertility factor, and partner’s semen parameters were similar between the groups. Placental weight, cord length as well as the prevalence of small (&lt;10 percentile) and large (&gt;90 percentile) placentas were also similarly distributed. After the adjustment for confounding factors endometriosis was found to be significantly associated with acute chorioamnionitis with moderate to severe maternal (OR 2.2; 95% CI 1.1–4.6) and fetal (OR 4.9; 95% CI 1.8–13.1) inflammatory response, placenta previa (OR 3.1; 95% CI 1.2–7.8), subchorionic fibrin deposition (OR 3.4; 95% CI 1.2–9.1), intervillous thrombosis (OR 3.4; 95% CI 1.5–8.1), fetal vascular malperfusion (OR 5.1; 95% CI 1.4–18.1), as well as with failed labour induction (OR 4.2; 95% CI 1.2–16.7).

Limitations, reasons for caution
It is possible that control group may contain some women with endometriosis who went unrecognized. However, we would expect this possibility to decrease the likelihood of significant findings when comparing the control group to women with endometriosis. This would suggest that significant findings in the endometriosis group represent real differences.

Wider implications of the findings
This was the first clinical study evaluating the effect of endometriosis on the placental pattern according to the Amsterdam Placental Workshop criteria. Our study demonstrates new insights into the pathophysiology of endometriosis which has an impact on the reproductive potential and pregnancy outcomes by causing abnormal placentation.

Trial registration number
not applicable (observation study)