Subamniotic hemorrhage, a potential fetal and neonatal alloimmune thrombocytopenia (FNAIT) complication involving bleeding between the amniotic membrane and fetal chorionic plate, poses significant diagnostic challenges, particularly when it presents before birth, as illustrated by a recently published case report in BMC Pregnancy and Childbirth.
“Subamniotic hemorrhage is defined as a hemorrhage occurring between the amniotic membrane and the fetal chorionic plate and its occurrence is relatively rare but can significantly impact fetal health,” the authors wrote.
Although most cases are diagnosed postnatally due to excessive traction on the umbilical cord during delivery, this case study documents a critical antepartum presentation. The authors noted that the rarity and nonspecific nature of its ultrasonographic findings further complicate diagnosis, underlining the need for heightened clinical vigilance.
The case involved a 35-year-old woman at 37 weeks gestation who presented with decreased fetal movements and lower abdominal discomfort. Her previous obstetrical history was unremarkable.
On admission, she exhibited a firm cervix with irregular, painless uterine contractions and a non-engaged fetal head. The fetal heart rate (FHR) tracing was categorized as Category II, indicating moderate risk. Ultrasound showed unusual floating echoes in the amniotic fluid and around the umbilical cord, and a distended fetal stomach filled with medium-strong echoes suggestive of swallowed blood.
Further investigations revealed maternal anemia and raised concern for fetal anemia, though MCA-PSV remained below the diagnostic threshold. A repeat ultrasound three hours later showed persistent abnormal findings, with an increasing volume of blood clots adherent to the umbilical cord. These changes, together with persistent Category II FHR, suggested evolving fetal compromise. Though the hemorrhage’s origin could not be definitively determined at that point, the clinical picture prompted urgent cesarean delivery.
During the procedure, approximately 400 g of clotted blood was evacuated from the intraamniotic space, and the amniotic fluid was bloody. A subamniotic hematoma near the umbilical cord insertion was identified with active bleeding, confirming the diagnosis. The newborn was delivered in stable condition. The mother required blood transfusions intraoperatively Both were discharged without complications after six days and remained well during a three-year follow-up.
“While the incidence of subamniotic hemorrhage is generally low and nonspecific, extreme values are particularly significant, as subamniotic hematoma is a rare finding typically reported at the time of delivery and is thought to result from traction on the umbilical cord,” the authors wrote.
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