Objective: This study investigates whether maternal socio-demographic and clinical characteristics influence the site of placental implantation so that placental localization and associated abnormalities can be predicted.
Methods: This study reviews 500 healthy women with singleton pregnancy that were consecutively admitted to the study center and eventually delivered healthy newborns.
Results: The most frequently observed sites of placentation were anterior uterine wall (53.2%), posterior uterine wall (28.8%), lateral uterine walls (10.0%) and uterine fundus (8.0%), respectively. The women with fundal placentation had significantly higher systolic and diastolic blood pressures (p = 0.044 and p = 0.040, respectively). Supine sleeping position was more frequent in women with anterior placenta and (OR: 11.568, 95% CI: 2.720-49.193) and prone sleeping position was more frequent in women with posterior placenta (OR: 15.449, 95% CI: 2.151-52.978) (p = 0.001). The women who favored to sleep in right lateral position were more likely to have lateral placentation, while the women who used to sleep in left lateral position were more likely to have fundal placentation (p = 0.001).
Conclusions: Sleeping position in early pregnancy may influence placental implantation site. The probable mechanism may refer to the alterations in uterine perfusion which is induced by the change in systemic blood pressure and dominant sleeping position.
Keywords: Blood pressure; placenta; placenta previa; pregnancy; sleep.