Background: This study aimed to investigate the effects
of abnormal placental location and placenta accreta spectrum (PAS)
disorder on the risk of hypertensive disorders of pregnancy (HDPs).
Methods: This retrospective study included 985 patients with
abnormal placental location and 2100 patients with normal placental location. The
incidence of HDPs in patients with abnormal placental location and in those with
concurrent abnormal placental location and PAS disorders was analyzed. The
factors affecting the incidence of HDPs and pregnancy-induced hypertension (PIH)
were analyzed using logistic regression analyses. Results: The incidence
of HDPs in patients with abnormal placental location (3.55%) was significantly
lower than those with normal location (8.23%) (p 0.001). The
incidence of HDPs in the placenta previa subgroup (2.87%) was significantly
lower than the low-lying placenta subgroup (6.48%) (p = 0.017). By
including confounding factors (maternal age, gestational age, gravidity, parity,
PAS disorders, and gestational diabetes mellitus), the incidence of HDPs (OR
(95% CI) = 0.252 (0.149, 0.426), p 0.001) or PIH (OR (95% CI) =
0.294 (0.169, 0.511), p 0.001) was negatively correlated with
abnormal placental location. Subgroup analysis revealed that the incidence of
HDPs of the PAS subgroup (2.66%) was significantly lower than that of the
non-PAS subgroup (5.22%). However, PAS disorder (OR (95% CI) = 0.551 (0.242,
1.254), p = 0.156) was not an independent factor of the incidence of
HDPs. Conclusions: Abnormal placental location could decrease the
incidence of HDPs. It was an independent protective factor of HDPs, especially
PIH, but PAS disorder was not.