Controlled Ovarian Hyperstimulation (COH) is the process in which eggs are grown within the ovary during IVF, egg freezing, or egg donation. Occasionally, an individual's ovarian reserve is so robust that, without careful monitoring, the number of eggs growing may be significant enough to cause a host of negative side effects called Ovarian Hyperstimulation Syndrome (OHSS).
We want you to understand the risks associated with OHSS during the consultation before beginning stimulation medications.
With the advancements in technology surrounding IVF and the increased use of embryo cryopreservation, severe cases of OHSS are now rare. The severity of symptoms is related to the number of follicles—the greater the number, the more likely symptoms are to occur.
The culmination of the stimulation cycle is the "trigger shot," which starts the process of ovulation as well as the cascade of events causing extreme bloating, fluid collection within the abdomen and lungs, and potentially blood clots. The type of trigger medication—HcG vs Lupron—used in the cycle can affect the severity of symptoms.
The hormone HcG potentiates these symptoms, and if given for a trigger shot, it stays in the system for only a short period, ultimately limiting the duration of symptoms, usually 7 days. In patients at greater risk of OHSS, we typically use the Lupron trigger as opposed to the HcG; this shortens the length of time patients are symptomatic post-retrieval and doesn’t have the same potentiated effects of HcG.
Additionally, the introduction of "freeze all" cycles has helped reduce the incidence of OHSS. If you were to get pregnant from a fresh transfer immediately following your retrieval, the HcG hormone produced from the pregnancy will prolong the symptoms, and could slowly worsen and become more severe during the early parts of the first trimester. If no transfer is performed, the patient’s symptoms only last a few days and in the subsequent cycle, a transfer is performed.
Aside from limiting fresh transfers and using Lupron triggers, careful monitoring and thoughtful IVF stimulation medication dosage are key to limiting the risks of OHSS. In some cases, despite considerations of the patient’s age, ovarian reserve, BMI, and medical history, the stimulation dosage might result in too many follicles growing. In this case, the medication dosage could be lowered or the stimulation can be paused and restarted in the subsequent cycle. Stopping a stimulation mid-cycle is never the goal, but ultimately, the patient’s health, safety, and well-being are always a top priority regardless of the indication for treatment; infertility, fertility preservation, or egg donation. The goal for a successful outcome is often focused solely on the eggs, sperm, and resulting embryos, however, the physical discomfort and any severe mental and/or emotional symptoms from the patient undergoing the stimulation and procedure are equally important contributors to a successful cycle.
Understanding your risks for OHSS is an important part of the consultation prior to starting stimulation medications. Ask questions and make sure you feel comfortable with your treatment and care plan prior to starting to optimize your experience!
