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• Ovarian Hyperstimulation Syndrome can occur following any form supraphysiological ovarian stimulation, including clomifene and gonadotrophin ovulation induction.

• As many as 33% of IVF cycles has been reported to be assosciated with mild forms of OHSS.

• A gain in weight of 3 kg following administration of hCG is an earliest sign of OHSS. Rapidly rasing estrogen levels or serum levels of estrogen >2500 pg/ml is suggestive of OHSS.

Classification of OHSS

• Mild OHSS

  • Abdominal bloating

  • Mild abdominal pain

  • Ovarian size usually <8 cm

• Moderate OHSS

  • Moderate abdominal pain

  • Nausea, vomiting

  • Ultrasound evidence of ascites

  • Ovarian size is usually 8 -12 cm

• Severe OHSS

  • Clinical ascites

  • Oliguria

  • Haemoconcentration haematocrit >45%

  • Hypoproteinaemia

  • Ovarian size > 12cm

• Critical OHSS

  • Tense ascites or large hydrothorax

  • Haematocrit

  • White cell count >25,000/ml

  • Oliguria/anuria

  • Thromboembolism

  • Acute respiratory distress syndrome

Monitoring of patients with OHSS

History and examination

• Pain

• Breathlessness

• Hydration

• Weight

• Cardiovascular

• Heart rate, blood pressure

• Abdominal girth, distension, ascites

• Intake & output charting

Investigation

• Full blood count

• Hb, Total count, haematocrit

• RFT & electrolytes

• LFT

• Basline clotting studies

• USG Abdomen and pelvis

• Chest xray

• ECG

Complication

• Pleural effusion, pericardial effusion, ascites

• Stroke

• Thromboembolic episode

• Ovarian torsion

Treatment

• Preventing ovulation by withholding hCG is an effective method of avoiding hyperstimulation in overestimated ovaries.

• Alternatively, aspiration of follicles 36 hrs after administration of the ovulatory dose of hCG may lower the risk of developing clinical hyperstimulation by reducing mass of luteinized granulosa cells.

Fluid resuscitation

• Initial fluid resuscitation in a patient with hypotension is done using NS 1-2 L.

• Urine output should be monitored; aim to maintain a output > 0.5ml/kg/hr

• Further resuscitation is done using volume expanders and CVP guidance.

Volume Expander

• Volume expanders like dextran, albumin can be used.

• Albumin is the preferred volume expander. 200ml of albumin is given as an infusion over 4 hrs every day.

• Hematocrit must be monitored every 4^th hrly and volume expanders to be continued until HCT <38%.

Oral Indomethacin

• They can be used as it reduces capillary permeability by blocking prostaglandin synthesis.

• Diuretics should be avoided. Tapping should be done only if there is respiratory distress.

Updated on 29/11/13

Reference

• Ovarian Hyperstimulation Syndrome ; The practice committee of the american society for reproductive medicine,2008.

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