The Influence of Maternal Obesity on Cell-Free Fetal DNA and Blood Pressure Regulation in Pregnancies with Hypertensive Disorders

Background and Objectives: obesity and blood pressure disorders are one of the main risk factors for antenatal, intra, postpartum, and neonatal complications. In preeclampsia (PE), the placental hypoxia leads to vascular endothelium dysfunction, cell necrosis, and apoptosis. This condition is associated with the release of free fetal DNA (cffDNA) circulating in plasma. The disturbance of the efficiency of vasodilatation and blood pressure regulation in PE can be confirmed by analyzing the apelin, salusin, and prosalusin. This study aimed to assess the influence of obesity on cffDNA, and the effectiveness of maintaining normal blood pressure in patients with preeclampsia and gestational hypertension. Material and Methods: the research material was blood serum and oral mucosa swabs, obtained from 168 patients. Pregnant women were divided into the following: a control group (C)—67 women; a gestational hypertension group (GH)—35 patients; a preeclampsia with obesity group (PE + O) (pre-gravid BMI > 30)—23 patients. The rest were lean preeclamptic women (PE)—66 patients—(pre-gravid BMI < 25 in 43 women). Results: the cffDNA was observed in 1.50% of women in the C group, in 2.45% in the GH group, but in 18.18% of lean patients with preeclampsia. The cffDNA was detected in 58% of obese pregnant women with PE. The greater the placental hypoxia was in preeclampsia, the less efficient the hypotensive mechanisms, according to an analysis of the studied adipokines. The prosalusin concentration was significantly lower in the PE group with cffDNA than in the PE group without it (p = 0.008). Apelin was higher in the PE group with cffDNA (p = 0.006) compared to other groups. The same results were also observed in the subgroup with obesity. Conclusion: in preeclamptic women, obesity seems to act as an additive factor of placental damage by means of the dysregulation of hypotensive mechanisms.