A 36-year-old woman, gravida 2 para 1, at 38 weeks gestation comes to the hospital in active labor, dilated to 10 cm. She has received no prenatal care this pregnancy. Her prior pregnancy resulted in an uncomplicated cesarean delivery. On admission, temperature is 36.7 C (98.1 F), blood pressure is 132/84 mm Hg, and pulse is 94/min. The patient precipitously delivers an infant weighing 4.1 kg (9 lb 2 oz). After delivery of the infant, small placental fragments are removed in pieces via manual extraction. Profuse vaginal bleeding occurs, and intravenous lines are placed. Uterotonic medications are administered and vigorous uterine massage is performed. The uterine fundus is firm, but the bleeding continues. Which of the following is the most likely cause of this patient's ongoing vaginal bleeding?

Question

A 36-year-old woman, gravida 2 para 1, at 38 weeks gestation comes to the hospital in active labor, dilated to 10 cm.  She has received no prenatal care this pregnancy.  Her prior pregnancy resulted in an uncomplicated cesarean delivery.  On admission, temperature is 36.7 C (98.1 F), blood pressure is 132/84 mm Hg, and pulse is 94/min.  The patient precipitously delivers an infant weighing 4.1 kg (9 lb 2 oz).  After delivery of the infant, small placental fragments are removed in pieces via manual extraction.  Profuse vaginal bleeding occurs, and intravenous lines are placed.  Uterotonic medications are administered and vigorous uterine massage is performed.  The uterine fundus is firm, but the bleeding continues.  Which of the following is the most likely cause of this patient's ongoing vaginal bleeding?

Quizplus · Accepted Answer

11ec160b_39ff_a7fe_9249_bfe23244049b_MD0001_00 This patient's postpartum hemorrhage (PPH) is likely due to placental invasion into the myometrium, which characterizes placenta accreta spectrum. The disease range is defined by depth of placental invasion: placenta accreta (attachment to the myometrium), placenta increta (invasion into the myometrium), and placenta percreta (invasion through the myometrium and serosa). Placenta accreta disorders occur due to placental invasion through defects in the decidua basalis of the endometrium, which are commonly caused by uterine scarring from prior uterine surgery (eg, cesarean delivery, dilation and curettage). The absence of an intact decidual layer and subsequent direct placental attachment to the myometrium makes for a difficult placental delivery. Usually, manual placental extraction is attempted but yields only small placental fragments due to dense adhesions between the placenta and the uterus that bleed profusely if injured. (Choice A) Uterine rupture, a full-thickness myometrial disruption, can cause vaginal bleeding; however, patients typically have antepartum (not postpartum) bleeding and intense abdominal pain. It would not cause difficulty with placental detachment. (Choice B) Abruptio placentae is premature placental separation from the uterus; it can occur secondary to hypertension-induced placental vessel rupture. Unlike placenta accreta, abruptio placentae causes antepartum bleeding and promotes, rather than delays, placental detachment. (Choice C) Uterine atony (ie, poor uterine contractility) is the most common cause of PPH and typically presents with a soft, boggy uterine fundus. This patient's firm uterine fundus and unresponsiveness to uterotonic medications (which contract the uterus) make this diagnosis less likely. (Choice D) Intraamniotic infection can cause vaginal bleeding and an inflamed, adherent placenta. However, the anatomic plane between the placenta and uterus remains intact and therefore does not cause placental fragmentation. In addition, this patient has no fever or purulent amniotic fluid, making this diagnosis unlikely. Educational objective: Placenta accreta spectrum occurs due to placental invasion into the myometrium through defects in the decidua basalis. This creates a morbidly adherent placenta that does not detach after fetal delivery, leading to postpartum hemorrhage. Manual placental extraction typically yields small placental fragments and increases bleeding. __________ References: Epidemiology, etiology, diagnosis, and management of placenta accreta. (http://www.ncbi.nlm.nih.gov/pubmed/22645616) Placenta accreta: diagnosis, management and the molecular biology of the morbidly adherent placenta. (http://www.ncbi.nlm.nih.gov/pubmed/26135782)

A 36-Year-Old Woman, Gravida 2 Para 1, at 38 Weeks