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Female Reproductive System ORGAN SYSTEMS

Anembryonic pregnancy

A blighted ovum, also known as an anembryonic pregnancy, occurs when a fertilized egg implants and a gestational (embryonic) sac forms and grows, but the embryo fails to develop.

A blighted ovum, also known as an anembryonic pregnancy, occurs when a fertilized egg implants and a gestational (embryonic) sac forms and grows, but the embryo fails to develop.

  • Blighted ovum is the single leading cause of miscarriage
  • Miscarriage (loss of a pregnancy before 20 weeks of gestation or ejection/removal of embryo/fetus ≤ 500 g)

Etiology

Early pregnancy loss (EPL) risk factors:

Etiological factors for anembryonic pregnancies are generally understood and studied in the broader context of early pregnancy loss (EPL) which includes both embryonic and anembryonic pregnancies
  • Morphological abnormalities of embryo that prevents implantation or prevents long term survival of the embryo after implantation
  • Chromosomal abnormalities: Autosomal trisomy, polyploidy, sex chromosomal polysomy, and monosomy X
  • Obesity and advanced maternal age
  • Reproductive tract infections
  • Uterine malformation: Didelphic, bicornuate, and septate uteri
  • Immunologic disorders: NK cell dysfunction, autoantibodies, hereditary, and acquired thrombophilia
  • Hormonal factors (low progesterone) and endocrinological disorders (thyroid autoimmunity and thyroid dysfunction)
  • Polycystic ovarian syndrome (PCOS)
  • Alcohol consumption

Presentation

Signs and symptoms can potentially mirror those of an ectopic pregnancy. Anembryonic pregnancy is often incidentally noted on an initial first-trimester pregnancy sonogram.

Early pregnancy loss (EPL):

Early pregnancy loss in the setting of an anembryonic pregnancy can be clinically silent.
  • Abdominal cramping 
  • Vaginal bleeding

Diagnosis

Pregnancy test (done via urine/serum hCG levels) is usually positive.

Ultrasound exam (transabdominal or transvaginal):

  • CLASSICAL finding: Absence of fetal pole in a gestational sac of diameter 20mm
Single sonographic image demonstrating a gestational sac with a yolk sac. No fetal pole is seen. This is representative of a blighted ovum. | Contributed by Dr.Dawood Tafti, MD

Management

Expectant management: “Watchful waiting” approach:

Patient closely followed without intervention for spontaneous and complete passage of tissue
  • Repeat sonograms and trending hCG levels to confirm complete passage of tissue

Medical management:

  • Vaginal misoprostol (prostaglandin analog)

Surgical management:

Employed in patients with hemodynamic instability
  • Uterine aspiration/evacuation with a manual vacuum

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