Management of Anembryonic Pregnancy

Diagnosis and Terminology

The American College of Obstetricians and Gynecologists recommends using the term "anembryonic pregnancy" instead of "blighted ovum", defined as a gestational sac measuring ≥25 mm without an embryo, or absence of an embryo on serial examinations obtained at discriminatory time intervals 1, 2, 3
Diagnosis of anembryonic pregnancy is made via transvaginal ultrasound using specific criteria, including a mean sac diameter ≥25 mm with no embryo, with a diagnostic accuracy supported by the American Journal of Obstetrics and Gynecology 2, 4

The American College of Obstetricians and Gynecologists suggests that expectant management involves waiting for spontaneous passage of pregnancy tissue, with success rates varying depending on gestational age and time from diagnosis 4, 1
Medical management with misoprostol is recommended for patients who wish to avoid surgery but desire faster resolution than expectant management, according to the American College of Obstetricians and Gynecologists 4
Surgical management with suction dilation and curettage (D&C) is indicated for patients with hemodynamic instability, significant bleeding, or signs of infection, as recommended by the American Journal of Obstetrics and Gynecology 5, 4

The American College of Obstetricians and Gynecologists recommends serial hCG monitoring until levels return to non-pregnant state, and ultrasound evaluation to confirm complete evacuation of products of conception 4
Histopathologic examination of tissue is recommended to confirm intrauterine pregnancy and rule out gestational trophoblastic disease, according to the American College of Obstetricians and Gynecologists 4

The risk of infection increases with time after diagnosis, particularly after 18 hours, and hemorrhage is a potential complication, especially with incomplete evacuation, as reported by the American Journal of Obstetrics and Gynecology 6, 4

Using outdated terminology like "blighted ovum" or "nonviable pregnancy" can be hurtful to patients, and failing to confirm complete evacuation of products of conception can lead to complications, as noted by the American Journal of Obstetrics and Gynecology 2, 3, 4

An anembryonic (blighted ovum) pregnancy is characterized by a fluid‑filled gestational sac measuring ≥ 25 mm in diameter that is surrounded by trophoblastic (early placental) tissue but lacks an embryo. 7

On transvaginal ultrasound, a trophoblastic reaction appears as a well‑defined, continuous echogenic rim encircling the gestational sac, representing the developing placental (chorionic) tissue despite the absence of an embryo. 7

Early complete molar pregnancies (≤ 12 weeks gestation) may mimic an anembryonic pregnancy on imaging; however, they typically display hyperechoic areas with multiple cystic spaces rather than a simple empty sac. 8

Following spontaneous or medically induced evacuation of an anembryonic pregnancy, residual chorionic or placental tissue can persist within the uterine cavity and is visualized on Doppler ultrasound as intracavitary vascularized tissue. [7][8]