Ovarian hyperstimulation syndrome

The high doses of gonadotrophins used in IVF or ICSI treatment can result in ovarian hyperstimulation syndrome (OHSS). OHSS is the abnormal release of cytokines from the ovaries, which increases the permeability of blood vessels and causes leakage of fluid from the vasculature into the tissues. OHSS occurs in less than 2% of cycles in IVF and uncommonly in ovulation induction. Gonadotrophin treatment must be monitored by practitioners with experience in recognising OHSS and access to facilities for treating females with OHSS.

OHSS can be a medical emergency; early detection and management is important. Serious complications can occur, such as:

  • ascites, pleural or rarely, pericardial effusions
  • acute kidney failure
  • venous and arterial thrombosis
  • cerebral oedema
  • ovarian torsion
  • ileus
  • death.
Note: Ovarian hyperstimulation syndrome can be a medical emergency.

OHSS usually occurs within 7 to 10 days of the hCG trigger injection. Symptoms range from mild abdominal discomfort or bloating, to severe abdominal pain (due to massive ovarian enlargement and ascites), vomiting and dehydration. Seek advice from an ART clinician if OHSS is suspected.

If the individual has mild abdominal discomfort, normal urine output, and no vomiting, diarrhoea, shortness of breath or biochemical evidence of volume depletion, they can be managed in the community (provided they have support at home) with advice from the treating ART clinician. Encourage fluid intake (2 L water daily) and gentle activity (but not strenuous exercise or intercourse), and organise prompt review by the ART clinician. Thromboprophylaxis may be required.

Urgent review by the treating ART clinician or referral to an emergency department is needed if any of the following occur:

  • moderate to severe abdominal pain or bloating
  • nausea or vomiting
  • shortness of breath
  • reduced urine output.

Hospital management includes:

  • immediate notification of the gynaecologist on call
  • investigations including urea, electrolytes, full blood count, coagulation profile
  • strict fluid balance and intravenous fluid replacement if significantly volume depleted
  • thromboprophylaxis
  • analgesia
  • antiemetics
  • management of complications.

For comprehensive management guidelines, see the South Australian Health Perinatal Practice Guideline on Ovarian hyperstimulation syndrome .