Ovarian Hyperstimulation Syndrome (OHSS) is a complication that can arise from fertility treatments, particularly those involving ovarian stimulation. It occurs when the ovaries overreact to hormonal medications, causing them to swell and leak fluid into the abdomen. While OHSS can be a concerning side effect, significant advancements in medical understanding and treatment protocols have improved patient safety and the overall success of fertility journeys.
Understanding OHSS Risk Factors
Several factors can increase an individual’s susceptibility to OHSS, influencing how their body responds to fertility medications. Polycystic Ovary Syndrome (PCOS) is a common risk factor, as individuals with PCOS often have a high number of small follicles in their ovaries. This condition is associated with an elevated ovarian reserve, indicated by a high Anti-Müllerian Hormone (AMH) level, which can predict an increased risk of OHSS. Studies suggest that an AMH level above 3.36 ng/mL may predict OHSS development.
A high antral follicle count (AFC) on ultrasound, particularly an AFC of 24 or more, also correlates with a higher risk of moderate to severe OHSS. Younger age, under 35, and a lower body mass index (BMI) are additional predispositions. A history of previous OHSS episodes significantly increases the likelihood of recurrence. Rapid or excessive ovarian response to stimulation medications, characterized by a high or rapidly increasing estradiol (estrogen) level before the trigger shot, further elevates the risk. These factors collectively indicate a heightened potential for the ovaries to overproduce eggs.
Medical Strategies for Prevention
Fertility specialists employ several medical approaches to minimize OHSS risk during ovarian stimulation. Gonadotropin-releasing hormone (GnRH) antagonist protocols are preferred over GnRH agonist protocols for patients at risk of OHSS. These antagonists, such as Cetrotide or Ganirelix, prevent premature luteinizing hormone (LH) surges, offering more flexibility in trigger shot choices and reducing the OHSS incidence by as much as 52% compared to long GnRH agonist protocols.
Another preventive measure is the choice of trigger shot. Shifting from human chorionic gonadotropin (hCG) triggers to GnRH agonist triggers (e.g., Lupron) for high-risk patients substantially reduces OHSS risk. GnRH agonists induce a shorter LH surge, leading to a rapid decrease in estrogen and progesterone levels and mitigating fluid leakage. While hCG triggers have been a traditional method, a GnRH agonist trigger has been shown to almost eliminate early OHSS.
A “freeze-all” strategy involves cryopreserving all embryos after retrieval and delaying embryo transfer to a subsequent cycle. This approach eliminates the influence of pregnancy-related hCG, which can worsen or prolong OHSS symptoms, allowing the patient’s body to recover from the stimulation before pregnancy hormones are introduced. This strategy is considered highly effective in preventing moderate and severe forms of OHSS, especially when combined with a GnRH agonist trigger.
Individualized dosing of gonadotropins is also a recognized strategy. Specialists start with lower doses of these stimulating hormones and adjust them based on the individual’s ovarian reserve and follicular response, aiming to achieve an adequate number of mature eggs without overstimulating the ovaries. Regular monitoring through ultrasound examinations to assess follicle growth and blood tests to track hormone levels, particularly estradiol, guides these dosage adjustments and helps identify patients at risk of impending OHSS.
Patient Actions for Prevention and Monitoring
Patients play an active role in minimizing their OHSS risk by maintaining open communication with their medical team. Sharing a complete medical history, including any previous diagnoses like PCOS or prior OHSS episodes, is important for tailoring personalized prevention strategies. Adherence to prescribed medication dosages and schedules is also fundamental to ensure a controlled ovarian response.
While not primary prevention, maintaining good hydration and a balanced diet supports overall health during fertility treatments. Staying well-hydrated helps regulate fluid balance, which can be disrupted by fertility medications. Patients should be aware of early signs of OHSS, such as abdominal discomfort, bloating, slight weight gain, or nausea. Recognizing these symptoms allows for timely intervention to prevent the condition from worsening.
It is important to report any concerning symptoms, even if they seem minor, to the medical team immediately. Prompt communication enables the clinic to assess the situation and adjust the treatment plan if necessary. During ovarian stimulation, light activity is recommended, while strenuous exercise should be avoided to reduce the risk of ovarian torsion or rupture, given the enlarged state of the ovaries.
Managing Early Signs to Prevent Worsening
If mild OHSS symptoms emerge, immediate contact with the fertility clinic or doctor is necessary. This allows for prompt assessment and guidance to prevent the condition from progressing. Clinics often advise home monitoring for mild OHSS, which includes daily weight checks to detect rapid fluid gain and measuring abdominal girth to track swelling. Monitoring urine output is also a common recommendation.
Managing mild symptoms at home involves resting and increasing fluid intake, particularly electrolyte-rich beverages like sports drinks, to combat dehydration. Avoiding alcohol and caffeinated beverages is also advised as they can worsen fluid retention. Over-the-counter pain relievers like acetaminophen can help with abdominal discomfort.
The clinic may intervene with measures such as adjusting medication dosages to reduce ovarian activity or, in some cases, canceling the embryo transfer. These early management strategies aim to prevent mild OHSS from escalating to moderate or severe forms, which can require more intensive medical care or even hospitalization.