Thin endometrium is associated with the risk of hypertensive disorders of pregnancy in fresh IVF/ICSI embryo transfer cycles: a retrospective cohort study of 9,266 singleton births

Abstract

Background Thin endometrial thickness (EMT) has been suggested to be associated with reduced incidence of pregnancy rate after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment, but the effect of thin endometrium on obstetric outcome is less investigated. This study aims to determine whether EMT affects the incidence of obstetric complications in fresh IVF/ICSI-embryo transfer (ET) cycles. Methods We conducted a retrospective cohort study collecting a total of 9266 women who had singleton livebirths after fresh IVF/ICSI-ET treatment cycles at the Center for Reproductive Medicine Affiliated to Shandong University between January 2014 and December 2018. The women were divided into three groups according to the EMT: 544 women with an EMT ≤8 mm, 6234 with an EMT > 8–12 mm, and 2488 with an EMT > 12 mm. The primary outcomes were the incidence of obstetric complications including hypertensive disorders of pregnancy (HDP), gestational diabetes mellitus (GDM), placental abruption, placenta previa, postpartum hemorrhage (PPH) and cesarean section. Multivariable logistic regression analysis was performed to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for associations between the EMT measured on the day of human chorionic gonadotropin (HCG) trigger and the risk of the outcomes of interest. Results The HDP incidence rate of pregnant women was highest in EMT ≤ 8 mm group and significantly higher than those in EMT from > 8–12 mm and EMT > 12 mm group, respectively (6.8% versus 3.6 and 3.5%, respectively; P = 0.001). After adjustment for confounding variables by multivariate logistic regression analysis, a thin EMT was still statistically significant associated with an increased risk of HDP. Compared with women with an EMT > 8–12 mm, women with an EMT ≤8 mm had an increased risk of HDP (aOR = 1.853, 95% CI 1.281–2.679, P = 0.001). Conclusion A thin endometrium (≤8 mm) was found to be associated with an increased risk of HDP after adjustment for confounding variables, indicating that the thin endometrium itself is a risk factor for HDP. Obstetricians should remain aware of the possibility of HDP when women with a thin EMT achieve pregnancy through fresh IVF/ICSI–ET treatment cycles.

Association of Polycystic Ovary Syndrome Phenotypes With Adverse Pregnancy Outcomes After In-Vitro Fertilization/Intracytoplasmic Sperm Injection

“…At present, advanced maternal age (38,39), high levels of BMI (40,41), and a thin endometrium (42)(43)(44) as risk factors for adverse pregnancy outcomes are well recognized in the literature. Therefore, multivariate logistic regression analyses in our study were performed to exclude the potential influences of these confounding factors, but the effect of PCOS phenotypes A and D on adverse pregnancy outcomes persists.…”

Endometrial thickness is an independent risk factor of hypertensive disorders of pregnancy: a retrospective study of 13,458 patients in frozen-thawed embryo transfers

“…As mentioned in a previous study [ 18 ], the first follow-up was performed around 14 d after FET, and biochemical pregnancy was assessed by measuring the serum HCG-beta subunit. The second follow-up was performed at 5 or 6 weeks after embryo transfer; a clinical pregnancy was confirmed by the presence of a gestational sac by transvaginal ultrasound.…”

“…EMT is a key factor influencing endometrial receptivity and is a predictor of early pregnancy outcomes in ET cycles [ 16 ]. Furthermore, our previous studies demonstrate that thin EMT is associated with small for gestational age infants and hypertensive disorders of pregnancy in fresh ET cycles [ 17 , 18 ]. Another study from our clinic shows that women with a singleton delivery after FET in artificial cycles had an elevated risk of pre-eclampsia and postpartum hemorrhage compared with those in natural cycles [ 19 ].…”

Endometrial thickness: How thin is too thin?

“…In a study conducted by Miwa et al (26), it was found that vascular endothelial growth factor was underexpressed in a thin endometrium (<8 mm), leading to poor vascularization of the endometrium and impaired placentation. Apart from pathophysiology, several studies have shown that pregnancies conceived with a thin endometrium using assisted reproductive technology (ART) are at an increased risk of pregnancy loss, hypertensive disorders of pregnancy, preterm delivery, placenta previa, and cesarean section (27)(28)(29)(30). Additionally, infants conceived in these pregnancies are at risk of intrauterine growth restriction, being small for gestational age, and a lower birth weight (28,(31)(32)(33).…”