Reactivity of the human fetal pulmonary circulation to maternal hyperoxygenation increases with advancing gestation; this suggests that fetal pulmonary circulation is under acquired vasoconstriction at least after 31 to 36 weeks of gestation.
Second trimester pregnancy loss and preterm delivery may be considered an obstetrical syndrome. A multifactorial approach to the diagnosis of true cervical insufficiency is paramount. Surgical modification of the cervix benefits those with at least 3 second trimester losses or preterm deliveries, those with 2 early second trimester losses when no other cause for loss is identified, and those with a previous second trimester loss or preterm birth with ultrasound findings of a short cervix defined as less than 25 mm. Multifetal pregnancies do not benefit from cerclage and causes harm in those with ultrasound or physical examination identified cervical changes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.