Ovarian hyperstimulation syndrome (OHSS) is a side-effect of infertility treatment in which a large number of follicles develop due to the ovulation induction method used in infertility treatment, causing ovarian enlargement and ascites or pleural effusion.
The hCG preparation enhances vascular permeability, leaks plasma components, causes ascites and pleural effusion, abnormalities in the blood condensed coagulation system, abnormal electrolytes, and decreased renal blood flow.(1)
Coping Methods For Ovarian Hyperstimulation Syndrome
Management is essentially supportive until the condition resolves itself. This often involves an interdisciplinary approach and should follow agreed protocols.
Current risks are monitored by blood estrogen and ultrasound scans, but scan-only monitoring is often sufficient.
If in the blood estrogen and ultrasound scan a high risk of severe ovarian hyperstimulation syndrome is revealed, you must refrain from hCG treatment. Egg collection and insemination may occur, but live embryos should be frozen.
Fresh embryo transfer should not be done in that cycle, but frozen embryo transfer may be carried out during a subsequent treatment cycle. Regular freezing, rather than fresh transfers, as a matter of routine, was not supported in most cases.
Coasting is a term used to stop gonadotropin stimulation and continue agonist suppression until estrogen levels drop to an acceptable value before preceding egg collection. Coasting might reduce the incidence of severe ovarian hyperstimulation syndrome.(3)
Management Of Mild To Moderate Ovarian Hyperstimulation Syndrome Cases
In mild to moderate cases, the administration of analgesics should be in the form of paracetamol or opiates or combination. Nonsteroidal anti-inflammatory drugs (NSAIDs) should be avoided. Antiemetic drugs considered safe during early pregnancy should be used with caution as needed.
- Women are encouraged to increase their oral fluid intake and drink adequate water when they feel thirsty.
- If managed in the community, women should be monitored every 1-2 days and be aware of symptoms that prompt an immediate assessment.
- In moderate cases, hospitalization for thrombus prevention and continuous monitoring may be a wise decision.(1)(4)
Management Of Critically Ill Patients
An intensive care unit may need to be set up. Careful monitoring of liquid balance is required. If hydration cannot be maintained orally, intravenous (IV) fluids must be used. Colloids such as albumin are given the patient remains fluid depleted despite intensive infusion.
- Electrolytes require careful monitoring as hyponatremia is common.
- Diuretics should be avoided.
- Aspiration of ascites or pleural effusion may relieve symptoms.
To ensure early diagnosis and proper management of complications such as acute kidney injury, ARDS, pericardial effusion and thromboembolism, thorough monitoring is required.
Possible Complications Of Ovarian Hyperstimulation Syndrome
Ovarian hyperstimulation syndrome may have the following complications:
- ARDS (Acute respiratory distress syndrome)
- Ovarian torsion.
- Death may occur but is rare.(5)
Prevention Of Ovarian Hyperstimulation Syndrome
Ovarian hyperstimulation syndrome is an iatrogenic disease and several strategies have been considered to reduce its incidence. Techniques that can reduce risk include:
Gonadotropin pressor therapy is effective with individual stimulation depending on risk stratification.
Use of gonadotropin-releasing hormone (GnRH) agonists rather than hCG as an ovulation inducer. This has been shown to lower ovarian hyperstimulation syndrome but also reduces the birth rate. If the embryo is frozen and not used in that cycle or the donor-recipient IVF cycle, the chance of fertility does not decrease.
The embryos are frozen and transferred in another cycle. While it does not by itself significantly reduce the risk, it effectively eliminates it when combined with the use of GnRH agonists.
It is important to use progesterone rather than hCG to support the luteal phase. This greatly reduces the risk.
The use of metformin in PCOS women has been shown to reduce the risk of ovarian hyperstimulation syndrome but does not improve fertility.
The use of cabergoline in high-risk women from the day of hCG administration that reduces the risk of increased vascular permeability has been shown to protect against moderate ovarian hyperstimulation syndrome in higher-risk women. It is a type of dopamine antagonist.
The use of a GnRH antagonist to reduce endogenous gonadotropin release in high-risk women is a good option. When used with the long GnRH agonist protocol, ovarian hyperstimulation syndrome has been shown to decrease without affecting birth rates.
Another preventive measure is to use the injection of hydroxyethyl starch as a prophylactic plasma expander in women with high-risk (HES)(3)
Symptoms Of Ovarian Hyperstimulation Syndrome
In severe cases, cerebral infarction due to thrombosis, stalk torsion due to enlarged ovaries, acute hepatic failure, acute renal failure, acute respiratory distress syndrome, disseminated intravascular coagulation, etc. may occur.(2)
- Medicine PCotASfR. Prevention and treatment of moderate and severe ovarian hyperstimulation syndrome: a guideline. Fertility and sterility. 2016;106(7):1634-1647.
- Pellicer N, Galliano D, Pellicer A. Ovarian hyperstimulation syndrome. The Ovary: Elsevier; 2019:345-362.
- Dauod L, Schenker JG. Ovarian Hyperstimulation Syndrome (OHSS): Pathogenesis and Prevention. Reproductive Medicine for Clinical Practice: Springer; 2018:83-92.
- Abbara A, Islam R, Clarke S, et al. Clinical parameters of ovarian hyperstimulation syndrome (OHSS) following different hormonal triggers of oocyte maturation in IVF treatment’. 2018.
- Nelson SM. Prevention and management of ovarian hyperstimulation syndrome. Thrombosis research. 2017;151:S61-S64.