Fetal Malpresentation in Pregnancy

Fetal presentation refers to that anatomical part of the fetus that presents at the maternal pelvic inlet. The most common and most desirable fetal presentation is cephalic (head first). Any presentation other than cephalic is referred to as a malpresentation. Breech is the most common fetal malpresentation. The prevalence of breech presentation varies with gestational age (25% at 28 weeks and 3-5% of at term). Ultrasound evaluation is the gold standard for the diagnosis of fetal presentation. External cephalic version (ECV) refers to a series of manual manipulations designed to convert a malpresenting fetus to cephalic to promote vaginal delivery. There are two strategies around the timing of ECV; at 36-37 weeks and/or at or shortly after 39 weeks’ gestation. Each has advantages and disadvantages. Currently, most breech pregnancies at term are delivered by cesarean at 39 weeks prior to the onset of labor. Malpresentation is the second most common indication for planned cesarean (behind elective repeat cesarean). Vaginal delivery for a breech fetus at term should only be attempted if the mother is strongly motivated, if the obstetric care provider is experienced, and if the medical center has the requisite facilities to manage any and all complications. This review contains 3 figures, 2 tables, and 66 references. Keywords: fetal presentation, malpresentation, breech presentation, ultrasound evaluation, external cephalic version (ECV), cesarean delivery, vaginal breech delivery