Oxidative stress at the maternal-fetal interface

Abstract

Pregnancy, delivery and neonatal age are critical developmental stages that are particularly prone to the formation of excess reactive oxygen species (ROS). Oxidative stress is manifested at the maternal-fetal interface from early pregnancy on- wards. During the first trimester, the conceptus develops in a low-oxygen environment that favors organogenesis in the embryo, and may protect against teratogenesis mediated by ROS. The establishment of fetoplacental circulation at the end of the first trimester is associated with a three-fold increase in the oxygen concentration within the placenta. ROS generation is stimulated at higher rates than it was previously and can lead to oxidative stress. This physiological placental oxidative stress occurs in every normal pregnancy. It constitutes an essential part of placental remodeling. Healthy pregnant women overcome oxidative stress by upregulating the antioxidation machinery. However, the increase in antioxidants could be insufficient to offset the increase in lipid peroxidation. Given these findings, the balance favors increased oxidative stress during pregnancy. Labor and childbirth may be associated with periods of both hypoxia and oxidative stress for the newborn while neonatal plasma is relatively deficient in antioxidants.