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

Abstract

Background Hypertensive disorders of pregnancy (HDP) are an important cause of maternal and fetal mortality, and its potential risk factors are still being explored. Endometrial thickness (EMT), as one of the important monitoring indicators of endometrial receptivity, has been confirmed to be related to the incidence of HDP in fresh embryo transfer. Our study was designed to investigate whether endometrial thickness is associated with the risk of hypertensive disorders of pregnancy in frozen-thawed embryo transfer (FET). Methods This respective cohort study enrolled 13,458 women who received vitrified embryo transfer and had a singleton delivery in the Reproductive Hospital affiliated to Shandong University from January 2015 to December 2019. We set strict screening criteria and obtained the information from the hospital electronic medical system. Statistical methods including logistic regression analysis, receiver operating characteristic curve and restricted cubic spline were used to evaluate the relationship between endometrial thickness and the incidence of pregnancy-induced hypertension. Results The incidences of HDP in a thin endometrial thickness group (< 0.8 cm) and a thick endometrial thickness group (> 1.2 cm) were significantly greater than in a reference group (0.8 cm–1.2 cm) (7.98 and 5.24% vs 4.59%, P < 0.001). A nonlinear relationship between endometrial thickness and risk of hypertensive disorders of pregnancy was examined by restricted cubic spline (P < 0.001). The thin endometrial thickness and thick endometrial thickness groups were significantly associated with the risk of HDP after adjusting for confounding variables by stepwise logistic regression analysis. Subsequently, subgroup logistic regression analysis based on endometrial preparation regimens showed that thin endometria were still significantly associated with a higher morbidity rate in the artificial cycle group, while in the natural cycle group, thick endometria were closely associated with increased morbidity. Conclusion Our study manifested that both the thin and thick endometria were associated with an increased risk of hypertensive disorders of pregnancy in frozen embryo transfer cycles. Reproductive clinicians should focus on adjusting endometrial thickness in different preparation regimens; and obstetricians should be mindful of the risk of hypertension during pregnancy, when women with thin (< 0.8 cm) or excessively thicker (> 1.2 cm) endometrial thickness achieve pregnancy through frozen-thawed embryo transfer.

Effect of endometrial thickness on obstetric and neonatal outcomes in assisted reproduction: a systematic review and meta-analysis

“…Finally, 19 articles were appropriate to be included in this systematic review and meta-analysis (Fig. 1 ) [ 8 – 23 , 25 , 28 , 29 ].

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“…EMT was divided into dichotomous variables in 15 studies [ 10 – 14 , 17 – 21 ], which were thus included in meta-analysis. Most studies defined thin endometrium as EMT below 8 mm [ 11 , 12 , 19 , 20 , 23 , 25 , 28 , 29 ], while different cut-off values of 7.0, 7.5, 7.6 and 9.0 mm were used in other studies [ 10 , 13 , 14 , 17 , 21 , 22 ]. Some of the data in Liu et al [ 20 ] were partially duplicated with those in Guo et al [ 10 ], and we retained the study containing a larger sample size during the analysis.…”

“…Six studies [ 14 , 17 , 20 , 23 , 28 , 29 ], including 34,908 patients, were pooled in this meta-analysis. Overall, the risk of HDP was significantly higher in the thin endometrium group than in the normal EMT group (OR = 1.72, 95% CI: 1.44–2.05, P < 0.0001; I 2 = 0%) (Fig.…”

Exploring the mechanism of Alisma orientale for the treatment of pregnancy induced hypertension and potential hepato-nephrotoxicity by using network pharmacology, network toxicology, molecular docking and molecular dynamics simulation

“…The complexity of the interactions also limits the efficacy of treatment. Currently available management consists of symptomatic treatment, including spasmolytics (magnesium sulfate), anticoagulants (aspirin), antihypertensive drugs, and termination of pregnancy as a last resort ( Zhang et al, 2022a ). Nevertheless, the clinical curative efficacy is highly heterogeneous and has been reported to cause maternal and fetal adverse effects ( Ni et al, 2022 ).…”

Network Pharmacology and Molecular Docking Approach to Reveal the Immunotherapeutic Mechanism of Cuscutae Semen in Treating Thin Endometrium

“…Thin endometrium is defined as insufficient endometrial thickness with a maximum thickness not more than 7 mm on an ultrasound in the middle luteal phase (i.e., 6-10 days after ovulation), which is considered as a leading cause of recurrent miscarriage and poor embryo implantation, thus resulting in long-term infertility [ 4 , 5 ]. More specifically, thin endometrium was found to be an independent risk factor of hypertensive disorders of pregnancy in a study based on 13,458 patients in frozen-thawed embryo transfers [ 6 ]. The pathogenesis of thin endometrium refers to low estrogen level, insufficient progesterone level, ovulation disorder, and lack of growth hormone [ 7 ].…”