The ovaries in women are about the size of the thumb (3 to 4 cm), but when the eggs (follicles) in them are over-stimulated, the ovaries may swell. This causes symptoms such as ascites and sometimes a pleural effusion, which is defined as OHSS (ovarian hyperstimulation syndrome).
One cause of ovarian hyperstimulation syndrome is excessive stimulation of follicles during ovulation induction. It is rarely caused by oral clomiphene therapy and is known to occur more easily with hMG-hCG therapy (gonadotropin hormone therapy).
The incidence of ovarian hyperstimulation syndrome and multiple pregnancies is high in hMG-hCG therapy for PCOS (polycystic ovary syndrome). If you develop ovarian hyperstimulation syndrome, you may not be able to continue hMG-hCG therapy.(1)
What Leads To Ovarian Hyperstimulation Syndrome?
The follicle in the ovary grows continuously, causing the ovary to enlarge, resulting in water leakage into the abdominal cavity from the blood vessels on its surface.
The leaked water is stored as ascites, causing the blood to concentrate and reduce urine output. As a result, renal dysfunction, electrolyte abnormalities, thrombosis, respiratory disorders, etc. are caused.
One of the causes of continual follicle growth is that excessive ovarian stimulation triggers a high level of E2 (estradiol), and the hCG that triggers ovulation causes follicles to grow beyond the required number.
Ovarian hyperstimulation syndrome is classified as mild, moderate, or severe. In hMG-hCG therapy, approximately 3% of the resulting severe OHSS required treatment. Ovarian hyperstimulation syndrome is rarely caused when ovulation is induced without using large amounts of hMG and hCG.
In PCOS, the LH level in the blood is high, so it is thought that the LH component contained in the hMG preparation works excessively on the follicle.(3)
Onset Of Ovarian Hyperstimulation Syndrome
Ovarian hyperstimulation syndrome is a serious complication as a side effect that can often occur when using ovulation induction. However, OHSS development depends largely on the individual constitution.
In general, it is more likely that the ovaries will be sensitive to ovulation-induced stimuli. Specifically, the age of ovarian reactivity (18-35 years old), lean type, a large number of follicles in the ovaries, high estradiol, etc. are applicable.
It is known that people with PCOS, in which a large number of follicles of about 5 to 8 mm form a necklace in the ovaries, are particularly susceptible to developing ovarian hyperstimulation syndrome. When a person with PCOS induces ovulation, 20 to 30, and sometimes more, follicles develop, and the ovaries may grow larger than your fists.(2)(4)
Treatment Of Ovarian Hyperstimulation Syndrome: Can It Be Cured?
In the case of mild or moderate ovarian hyperstimulation syndrome, it is often observed in the outpatient department. However, if the symptoms are more severe, you may be hospitalized to manage your condition.
Treatment of ovarian hyperstimulation syndrome is based on the principle that it will not make the condition worse anymore, and you will have to wait for the symptoms to subside naturally. Administration of hCG, which worsens the symptoms of OHSS, will, of course, be discontinued. Overgrown ovaries can burst; thus, you require rest and avoid stress or physical strain in everyday life.
At present, there are both active and passive measures to treat ovarian hyperstimulation syndrome, and there seems to be some pros and cons among experts. For example, there are cases in which ascites puncture (draining of water) is performed. But some opinions suggest that lowering the abdominal pressure may invite the production of new ascites from the ovarian surface that will further promote the concentration of blood.
It is believed that the balance of water in the body is very important when you are suffering from ovarian hyperstimulation syndrome. The first step to natural healing is to balance urine output with fluid intake and stop developing further ascites.
Rehydration with low urine output may promote ascites. Once the leakage of water from the ovaries is reduced, ascites may decrease and water may return to the blood, resulting in increased urine output.
When the percentage of water in the blood increases and the hematocrit (the percentage of red blood cells) drops below 40%, a large amount of urine is excreted and ascites are reduced (administration of diuretics are also effective).
In cases of severe ovarian hyperstimulation syndrome with serious stomach tension, treatment such as administration of albumin (protein) in the blood to increase the oncotic pressure and perfusion of ascites into the vein is performed.(4)(5)
Symptoms Of Ovarian Hyperstimulation Syndrome
- Getting hungry (abdominal bloating)
- Abdominal and back pain
- Rapid weight gain
- Oliguria or decreased urine output
Other Diagnostic Symptoms
- Ovarian enlargement
- Pleural effusion
- Hematocrit value of 45% or more
- Lower blood pressure
- White blood cell counts 15,000/mm3 or more.(2)
- Griesinger G, Verweij PJ, Gates D, et al. Prediction of ovarian hyperstimulation syndrome in patients treated with corifollitropin alfa or rFSH in a GnRH antagonist protocol. PloS one. 2016;11(3).
- Toftager M, Bogstad J, Bryndorf T, et al. Risk of severe ovarian hyperstimulation syndrome in GnRH antagonist versus GnRH agonist protocol: RCT including 1050 first IVF/ICSI cycles. Human Reproduction. 2016;31(6):1253-1264.
- Pellicer N, Galliano D, Pellicer A. Ovarian hyperstimulation syndrome. The Ovary: Elsevier; 2019:345-362.
- Nelson SM. Prevention and management of ovarian hyperstimulation syndrome. Thrombosis research. 2017;151:S61-S64.
- Dauod L, Schenker JG. Ovarian Hyperstimulation Syndrome (OHSS): Pathogenesis and Prevention. Reproductive Medicine for Clinical Practice: Springer; 2018:83-92.