Association between placental implantation abnormalities and hypertensive disorders of pregnancy.

Aim: This study aimed to investigate the association between placental implantation abnormalities (PIAs) and gestational hypertension‐preeclampsia (GH‐PE) in pregnant women. Methods: Patients were recruited from 2010 to 2019 into this retrospective study at the International Peace Maternity & Child Health Hospital. PIAs were classified as follows: placenta previa (PP), low‐lying placenta (LP), placenta accreta, and placenta adherence (PA). Logistic regression models were constructed to analyze the associations between placental abnormalities and GH‐PE. Propensity score matching (PSM) was conducted to reduce confounders. The relationship between PP with placenta accreta spectrum (PAS) and GH‐PE were assessed. Results: In total, 5527 women were recruited, and 2614 women had an abnormal placenta (992 with LP; 749 with PP 839 and PA; and 34 with placenta accreta). There were 296 patients with GH‐PE in those groups. After adjustments for confounding factors, women with PP had a lower risk of PE (odds ratio [OR]: 0.43; 95% confidence interval [CI]: 0.19–0.86, p = 0.025) than those in the control group. Women with PA had a higher risk of GH‐PE (OR: 1.45; 95% CI: 1.05–1.99, p = 0.022). In addition, we categorized PP into marginal, complete, and partial PP and investigated these associations. We found a lower risk of PE in complete PP (OR: 0.09, 95% CI: 0.01–0.44, p = 0.020) than in marginal or partial PP. There was no significant difference regarding GH‐PE in the PP with PAS group (OR = 0.67, 95% CI: 0.82–2.34, p = 0.525). Conclusion: PP, especially complete PP, is associated with a lower risk of PE. PA is associated with higher risks of GH‐PE. [ABSTRACT FROM AUTHOR]