This is a condition where ovaries over respond to the hormone injections used to stimulate the growth of the follicles that contain the eggs. This is characterized by:
- Ovarian enlargement with more than the average number of follicles
- Fluid accumulation – most commonly in abdomen and rarely around the lungs and heart
- Thrombosis: This means development of blood clots in large blood vessels. This is due to leakage of fluid from with in your blood vessels into the tissues (see point 2 above).
- Embolism: There is the risk of the blood clot dislodging and travelling to another part of your body.
- Both thrombosis and embolism can have their own complications.
How common is OHSS?
This can occur in 1% – 10% of patients undergoing IVF treatment. Approximately 1 in 100 to 1 in 200 patients will need short stay in the hospital because of hyperstimulation.
Who is at risk?
- Anyone undergoing treatment with fertility drugs is ‘at risk’
- This complication occurs most commonly:
- In those patients who have had IVF or ICSI treatment.
- Patients with polycystic ovaries (PCO)
- Very young patients (less than 30 years).
- Occurrence is related to the total number of follicles present in the treatment cycle.
- Risk is increased in patients with increased number of follicles who subsequently become pregnant.