Checkmark fetal heart rate pattern associated with severe fetal hypoxia. A case report.

A 31-year-old nulliparous woman developed vaginal bleeding after spontaneous rupture of the membranes at 40 weeks of gestation. Fetal heart rate monitoring showed checkmark and sinusoidal patterns. A 3,281 g male neonate was delivered by emergency cesarean section, with Apgar scores of 1 and 3 at 1 and 5 min, respectively. The neonate exhibited severe acidosis with arterial blood gas pH of 6.96, and was diagnosed to have severe hypoxic-ischemic encephalopathy. An umbilical artery branch was noted in the membrane near the cervical os and found to be torn, representing hemorrhagic vasa previa. Severe fetal hypoxia resulting from hemorrhagic vasa previa might be associated with checkmark fetal heart rate pattern.