Many obstetrical complications are known to be related to systemic or local inflammatory actions. The most well-known complication related to inflammation is preeclampsia/hypertensive disorders in pregnancy. Elevated blood pressure, liver dysfunction, renal failure or eclampsia can occur as a result of acute inflammation following circulating placental debris, increased cytokine release, or hypoxic stress. Premature labor is another serious condition related to bacterial or nonbacterial inflammation, which can result in neonates being born with a range of disabilities. Gestational diabetes or pancreatitis are common disorders in pregnancy and can be related to or contribute to systemic inflammations.

Over recent decades, placentation failure—especially uterine spiral artery (SpA) remodeling failure in the human endometrium—has been well described and is regarded as a key process in pregnancy complications, such as preeclampsia, fetal growth restriction, or placental abruption. Reduced uteroplacental perfusion in preeclampsia was identified and discussed during the 1990s by researchers in the field; in the years since, it has become common knowledge that SpA remodeling failure can form the basis of preeclampsia and other related pregnancy complications, encouraging research into these conditions and the wider field. As a result of this, research into angiogenic factors (e.g., sFlt, PlGF) as a marker of early trophoblast debris has notably progressed, and these are now identified as danger signal promoters in maternal circulation.

However, current knowledge and research into placental inflammation which may lead directly to complications in pregnancy still have a long way to come. This special issue aims to focus on the importance of the placenta, trophoblasts, and immune cells, which may be key locations for inflammation affecting both the mother and fetus. Original research articles as well as reviews from new viewpoints are welcome, in order to stimulate the continuing efforts to understand the pathophysiology of these diseases.

Potential topics include but are not limited to the following:

• Inflammation, placental disorders, and oxidative or hypoxic stress of preeclampsia /hypertensive disorders in pregnancy/HELLP syndrome/eclampsia/renal failure
• Inflammation, placental disorders, and trophoblast cells of placental abruption/disseminated intravascular coagulation (DIC)
• Inflammation, placental disorders, and oxidative or hypoxic stress of gestational diabetes/overt diabetes in pregnancy
• Inflammation, placental disorders, and oxidative or hypoxic stress of fetal growth restriction
• Inflammation, placental disorders, trophoblast cells, and oxidative or hypoxic stress of premature labor/preterm rupture of membrane
• Inflammation, trophoblast cells, markers related to the fetomaternal interface, and oxidative or hypoxic stress of onset of labor
• Genetic research, basic study, or animal models for obstetrical inflammation and placental disorders