Genital tract
Ovarian cyst
Prevalence:
- 1 in 2,500 births.
- Most common intra-abdominal cyst in female fetuses.
Ultrasound diagnosis:
- Unilateral, unilocular cyst, sometimes containing a ‘daughter cyst’, in the abdomen of a female fetus >26 weeks’ gestation.
- If the cyst undergoes torsion (40% of cases) or hemorrhage the appearance is complex or solid. Rupture can result in ascites.
- Fetal ovarian cysts are sensitive to placental hormones and are more common in diabetic or rhesus isoimmunised mothers as a result of placental hyperplasia.
- Large ovarian cysts (>6 cm in diamater) can cause polyhydramnios due to compression of the bowel.
Associated abnormalities:
- Most cases are sporadic and there is no association with chromosomal abnormalities.
- A few cases are associated with genetic syndromes. The most common is McKusick - Kaufman syndrome (automosomal recessive; hydrometrocolpos, polydactyly, heart defects).
- Other defects, mainly genitourinary (renal agenesis, polycystic kidneys) and gastrointestinal (esophageal atresia, duodenal atresia and imperforate anus), are often found.
Investigations:
- Detailed ultrasound examination.
Follow up:
- Ultrasound scans every 4 weeks to monitor the evolution of the cyst. If the cyst is >6 cm ultrasound guided aspiration should be considered.
Delivery:
- Place: hospital with neonatal intensive care and facilities for pediatric surgery
- Time: 38 weeks.
- Method: induction of labor aiming for vaginal delivery.
Prognosis:
- The majority of cysts are benign and resolve spontaneously in the neonatal period. Surgery may be necessary if there is torsion.
Recurrence:
- Isolated: no increased risk of recurrence.