Ovarian hyperstimulation syndrome (OHSS) is a condition in which the ovaries respond to medications used to induce conception. It is characterized by a significant ovarian enlargement due to several ovarian cysts and a fluid shift in the tissue area. While most cases of OHSS are mild, severe cases occur, although they are rare.(1)
Who Is At Risk For Ovarian Hyperstimulation Syndrome?
The causes of ovarian hyperstimulation syndrome during IVF treatment are sometimes very diverse.
Women Under 35 Years Of Age: Some studies can now show a connection between the age of the treated patients and the occurrence of ovarian hyperstimulation syndrome. It is often women before the age of 35 who are affected by the syndrome. This is explained by the fact that the density of the gonadotropin receptors in the ovaries of younger women is higher and the response to gonadotropin administration from the outside is stronger.
Moreover, there is the fact that younger women also have a significantly higher number of ovarian follicles, which are capable of fertilization. These are considered as ovarian reserves.
Low BMI: Another risk factor could also be a low body weight (BMI below 20). In women with lower body weight, the potential to develop an overstimulation syndrome with the addition of hormones is higher.
The Presence Of PCOS: The likelihood of overstimulation is further increased by the presence of PCOS (polycystic ovary syndrome), and about 63% of the affected patients with a severe course also have a diagnosis of polycystic ovaries.(1)(2)
Higher Serum Estradiol Concentration And Other Factors
Ovarian hyperstimulation syndrome continues to occur in women who have high serum estradiol concentrations and rapidly increasing estradiol levels, high follicle numbers, hCG stimulation in the luteal phase, and IVF treatment to become pregnant. An overstimulation syndrome that has already occurred in the previous history also favors the recurrence of the next one.
If the treatment results in an estradiol value of more than 3,000pg/ml, the cycle can be saved before the termination by so-called coasting. It is important that the follicles already have a diameter of 15 to 18 millimeters. If coasting is performed, stimulation is suspended. With continued downregulation, the system then waits until the value of estradiol has dropped below 3,000pg/ml.(2)
Is There A Blood Test For Ovarian Hyperstimulation Syndrome?
Depending on the medical history and clinical symptoms, weight gain, thirst, abdominal discomfort, slight swelling of the lower abdomen, slight nausea and vomiting are possible signs of ovarian hyperstimulation syndrome. Other signs are:
Superellipse enlargement (diameter> 5 cm), there are several corpus luteum that show a small amount of effusion in the abdominal cavity.
Blood cell volume and increase in white blood cells, low sodium levels, hypoproteinemia
Severe ovarian hyperstimulation syndrome can lead to liver dysfunction (expressed as hepatocyte damage) and cholestasis, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and bilirubin increased creatine kinase.
Patients suspected of having ovarian hyperstimulation syndrome should have a complete blood count analysis, liver and kidney function tests, water and electrolyte tests, pelvic ultrasound, body weight measurement, determination of the E2 level, etc. carried out.(5)
Preventing Ovarian Hyperstimulation Syndrome
Nowadays, of course, the goal is to avoid hyperstimulation at best. The pregnancy hormone hCG plays a role here, which is necessary for the maturation of the egg cells and later for the egg cell puncture. There would be no hyperstimulation without hCG. However, if no hCG is administered, egg puncture is not possible. In the past, it was, therefore, necessary to interrupt the treatment cycle.
Today, newer stimulation programs are used. They are known as antagonist protocols – the eggs are not matured with hCG, but with a GnRH analog. Since hCG is no longer used, hyperstimulation cannot be triggered.
However, such a procedure has a disadvantage: the luteal phase is disturbed, improvement is not possible even with a higher dose of progesterone. The likelihood of pregnancy after the embryo transfer would then decrease significantly. As a rule, the process then begins to freeze fertilized egg cells and to transfer them into the uterus in the following cycle under normal and, above all, optimal conditions.(3)(4)
Treatment For Ovarian Hyperstimulation Syndrome
Mild ovarian hyperstimulation syndrome usually resolves spontaneously within a week of diagnosis. You may need an ovarian hyperstimulation syndrome diet. It is recommended to eat a high protein diet.
A moderate ovarian hyperstimulation syndrome requires close monitoring of the vital parameters. Sufficient liquids prevent dehydration.
Severe ovarian hyperstimulation syndrome usually needs hospitalization with invasive treatment. These include anticoagulants (blood thinners), blood components, electrolyte corrections, and IV fluids. You may require intensive care for cardiovascular monitoring and ovarian hyperstimulation syndrome radiology management.(5)
- Pellicer N, Galliano D, Pellicer A. Ovarian hyperstimulation syndrome. The Ovary: Elsevier; 2019:345-362.
- Peigne M, Lobert M, Tintillier V, Trillot N, Catteau-Jonard S, Dewailly D. Prevalence of ovarian hyperstimulation syndrome (OHSS) and hypercoagulability in patients triggered by GnRH agonist for excessive follicular response: a systematic follow-up. Fertility and Sterility. 2017;108(3):e227.
- Sopa N, Larsen EC, Andersen AN. A Case with Severe Endometriosis, Ovarian Hyperstimulation Syndrome, and Isolated Unilateral Pleural Effusion after IVF. Case reports in obstetrics and gynecology. 2017;2017.
- Dauod L, Schenker JG. Ovarian Hyperstimulation Syndrome (OHSS): Pathogenesis and Prevention. Reproductive Medicine for Clinical Practice: Springer; 2018:83-92.
- Nelson SM. Prevention and management of ovarian hyperstimulation syndrome. Thrombosis research. 2017;151:S61-S64.
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