Ovarian pregnancy

Definition

• Ovarian pregnancy is one of the rarest forms of ectopic pregnancy, with implantation in the ovary.

Classification

Pregnancy in scars and on the ovary

• A caesarean scar pregnancy carries the risk of uterine rupture and a subsequent a placenta accreta spectrum.
• An ovarian pregnancy is often misdiagnosed as a a ruptured corpus luteum cyst.

Occurrence & epidemiology

Epidemiology

• It accounts for about 3% of all ectopic pregnancies; the incidence in spontaneous pregnancies ranges from 1 in 2,000 to 1 in 60,000.

Aetiopathogenesis

Aetiology and risk factors

• Frequent associations are intrauterine devices, previous ectopic pregnancy, endometriosis, tubal lesions, pelvic inflammatory disease and chlamydia infection.
• Intrauterine devices reduce intrauterine and tubal implantation but not ovarian implantation.

Clinical features

Clinical features and complications

• Clinically there is moderate to severe pelvic or abdominal pain and vaginal bleeding with a positive pregnancy test; the course is acute in 90%.
• The natural course usually ends towards the end of the first trimester with rupture and haemoperitoneum.

Histology

• The diagnosis is confirmed by the Spiegelberg criteria: ipsilateral tube including the fimbriae intact and separate from the ovary, gestational sac in the ovarian cortex, ovary in its normal position attached to the uterus by the utero-ovarian ligament, and placental villi in the ovarian cortex on histology.

Diagnosis

• On ultrasound, ovarian pregnancy is hard to distinguish from a corpus luteum, haemorrhagic cyst or ruptured tubal pregnancy; the definitive diagnosis is made by histopathological examination.

Keep learning in the app

Further reading (selection)

1. StatPearls: Ectopic Pregnancy (NCBI Bookshelf)
2. Rom J Morphol Embryol 2020: Ovarian ectopic pregnancy: the role of complex morphopathological assay. Review and case presentation (PMC, open access)
3. DocCheck Flexikon, Zervixgravidität

Cross-references