What You need to know about OHSS (Ovarian Hyperstimulation Syndrome)
Fertility treatments like IVF have revolutionised the approach to parenthood, offering hope to those experiencing challenges. However, these treatments can sometimes come with side effects, one of the most concerning being Ovarian Hyperstimulation Syndrome (OHSS). Whether you’re starting your fertility treatment or just researching your options, understanding OHSS is crucial for a safe and empowered fertility journey.
This article will help you understand OHSS, its causes, symptoms, risks, prevention strategies, and how to seek care if needed.
What Is OHSS?
Ovarian Hyperstimulation Syndrome (OHSS) is a condition that affects individuals undergoing ovulation induction or superovulation as part of assisted reproductive treatments, such as in vitro fertilisation (IVF). It occurs due to how the body responds to fertility medications, specifically gonadotrophins (hormones used to stimulate the ovaries to produce multiple eggs during treatments).
While mild cases of OHSS are common and often manageable, severe forms, though rare, can lead to significant health complications if left untreated. Approximately 10–20% of individuals undergoing fertility treatments experience mild to moderate OHSS, while the severe form affects fewer than 1%.
What Causes OHSS?
OHSS results from the use of gonadotrophins, such as Gonal-F or Puregon, which stimulate the ovaries to release several eggs rather than the single egg seen in a natural menstrual cycle. This heightened ovarian activity can lead to excessive hormone levels, particularly oestradiol (E2), and the production of too many follicles.
Certain factors increase the likelihood of developing OHSS:
Producing a high number of follicles.
Elevated oestradiol levels during ovulation induction.
Receiving an hCG injection to trigger ovulation (OHSS does not develop if the hCG injection is skipped).
Being under the age of 35 or having conditions such as polycystic ovary syndrome (PCOS).
Symptoms of OHSS
Symptoms of OHSS vary from mild to severe, depending on how strongly the ovaries respond to fertility medications. Recognising these symptoms early is key to effective management.
Mild Symptoms
Mild abdominal discomfort or bloating.
Slight ovarian enlargement.
Temporary weight gain.
Moderate Symptoms
Noticeable abdominal swelling.
Nausea and occasional vomiting.
Increased abdominal pain.
Severe Symptoms (Rare)
Severe abdominal pain.
Excessive bloating due to fluid accumulation in the abdomen.
Difficulty breathing caused by fluid in the lungs.
Rapid weight gain (over 1 kg per day).
Decreased urine output or dark urine, a sign of hydration imbalance.
Rare complications such as blood clots, kidney failure, or stroke.
It’s important to understand that severe OHSS can be life-threatening without medical attention. Always contact your fertility specialist immediately if you suspect your symptoms are escalating.
Potential Complications of OHSS
Severe cases of OHSS can result in serious health risks, including:
Thrombosis (blood clots): Can lead to life-threatening conditions like stroke or pulmonary embolism.
Dehydration and electrolyte imbalances: Caused by fluid leaving the bloodstream.
Organ damage: Such as temporary kidney shut-down.
Respiratory distress: From fluid build-up in the chest cavity.
While these complications are rare, severe OHSS requires hospitalisation and active treatment, such as IV fluids or fluid drainage.
How to Prevent OHSS
Fortunately, fertility clinics are well aware of the risks associated with OHSS and take proactive measures to minimise them.
Close Monitoring During Treatment
Regular ultrasound scans and blood tests are critical in tracking the number of follicles and oestradiol levels during ovulation induction. Fertility specialists adjust medication to prevent overstimulation.
Trigger Adjustment
If tests suggest a high risk of OHSS, alternatives to hCG (the hormone injection that triggers ovulation) may be used. Some options include smaller doses of hCG or using GnRH agonists instead.
Freezing Embryos
At-risk IVF patients may undergo egg collection, but instead of immediate embryo transfer, embryos can be frozen to be implanted during a future cycle. This allows the body to normalise before pregnancy begins.
Reduce Medication Dosage
Adjusting the dosage of fertility medications can lower the risk of overstimulating the ovaries.
Cycle Cancellation
For cases where severe OHSS seems imminent, clinicians may cancel the treatment cycle to prevent ovulation altogether.
Seeking Medical Attention for OHSS
If you’re experiencing troubling symptoms of OHSS during or after your fertility treatments, don’t wait to seek help. Contact your fertility clinic or fertility specialist immediately, particularly if you develop:
Persistent vomiting.
Breathing difficulties.
Rapid or extreme abdominal swelling.
Sharp, increasing abdominal pain.
Signs of dehydration (dizziness, dark urine).
For severe cases, hospitalisation ensures you receive advanced care, such as fluid management and close monitoring.
Empowering Your Fertility Journey
While OHSS is a concern for some individuals undergoing fertility treatments, it’s important to remember that prevention and management strategies are highly effective at reducing risk. By working closely with your medical team, you can safely and confidently proceed with your fertility treatments.
Your fertility team is here to support and guide you. Your specialists will closely monitor your progress, personalise your treatment plan, and ensure your safety every step of the way.
If you have questions or would like to learn more about OHSS prevention and fertility treatment safety, speak to your specialist: they’re here to help you achieve your dream of parenthood, safely and confidently.