What causes ovarian hyperstimulation syndrome?

During some fertility treatments, medicines encourage several ovarian follicles to grow. A trigger medicine can then promote egg maturation and ovulation. In an unusually strong response, the enlarged ovaries release signals that make blood vessels more leaky. Fluid can move into the abdomen and, in more serious illness, affect circulation, breathing, or kidney function.

Symptoms may start after stimulation or become more noticeable after pregnancy begins, because pregnancy hormones can sustain the process. People with many developing follicles or a previous strong response may need particularly careful monitoring, but symptoms can occur despite planned treatment.

Follow the fertility clinic's monitoring and medicine instructions, keep track of weight changes, abdominal swelling, urine output, pain, nausea, and breathing, and maintain fluids as advised. Do not change fertility medicines or start self-treatment without contacting the clinic. The team may adjust treatment, arrange scans or blood tests, and recommend observation or hospital care according to symptoms.

Contact your fertility clinic promptly for increasing abdominal swelling, persistent vomiting, worsening pain, reduced urine, dizziness, or rapid breathing. Seek emergency care for severe breathlessness, chest pain, fainting, confusion, severe abdominal pain, or inability to keep fluids down. Early assessment helps identify fluid shifts, blood clots, and other complications.

How strongly did my ovaries respond? Which symptoms should I report immediately? How will you monitor fluid balance and ovarian size? Should the treatment plan or timing of embryo transfer change?