Amount of hemorrhage during vaginal delivery correlates with length from placental edge to external os in cases with low-lying placenta whose length between placental edge and internal os was 1-2 cm

Aim: The aim of the present studywas to investigate whether amount of hemorrhage during a vaginal delivery associates with the cervical length, length from the placental edge to the os and the sum of the two in cases with a low-lying placenta. Material and Methods: A retrospective study was performed on cases with low-lying placenta diagnosed at 35-36 weeks of gestation based on a distance of 1-2 cm from the lower placental edge to the internal os, and subject to the trial of labor. The total amount of intrapartum hemorrhage in association with the distance from the placental lowest edge to the internal os (placenta-internal os distance, A); cervical length, B; and sum of the two (placenta-external os distance; A + B) were reviewed from our medical records. Results: Twenty-Three cases of low-lying placenta that underwent trial of labor were analyzed. Twenty (87%) of 23 patients with low-lying placenta delivered transvaginally and patients underwent emergency cesarean section due to intrapartum bleeding. The length from the placental edge to the external os (length from placental edge to internal os + cervical length) was correlated significantly with the total amount of hemorrhage during delivery (r = -0.598, P = 0.004), though neither the length from the placental edge to the internal os nor the cervical lengths correlated with it. Conclusion: Our results suggest that the length from the placental lowest edge to the external os negatively correlated with the amount of hemorrhage during vaginal delivery, but did not correlate with cervical length and distance from the placental edge to the internal os.