About Ovarian Hyperstimulation Syndrome (OHSS)
OHSS overview
- OHSS can occur when the ovaries are over stimulated with fertility medication used in IVF or other fertility treatments.
- Typically, OHSS symptoms are minor, with mild to moderate pain, loss of appetite and feeling bloated.
- Careful monitoring, decreased activity, pain medicine and drinking lots of water are recommended for patients diagnosed with OHSS.
- In infrequent cases where OHSS does not improve with outpatient care, treatment may involve occasional hospitalization for intravenous fluid hydration or, in rare circumstances, inserting a needle in the abdomen to remove excess fluid.
What is ovarian hyperstimulation syndrome?
Ovarian hyperstimulation syndrome (OHSS) can occur when the ovaries are over stimulated by fertility medications and hormones. Too many stimulant hormones in a woman’s system can lead to OHSS, characterized by swollen, painful ovaries.
OHSS may occur from the injectable hormone medications used during in vitro fertilization (IVF). Fertility medications used in IVF stimulate a woman’s ovaries to produce more oocytes (eggs) than during normal ovulation (often 12-15 eggs, compared to the normal one). How much medication is needed to achieve the correct stimulation requires careful monitoring and is not an exact process.
Less often, OHSS can occur from milder fertility medications taken by mouth, such as clomiphene, or occurs spontaneously.
Causes of ovarian hyperstimulation syndrome
The cause of OHSS isn’t fully understood. Human chorionic gonadotropin (HCG) is a hormone produced during pregnancy and a high level of this hormone may play a role in ovarian hyperstimulation. HCG makes the blood vessels in the ovaries react abnormally and leak fluid. This fluid causes the ovaries to swell.
Fertility treatments sometimes use HCG as a “trigger” to make a mature follicle release its egg. OHSS happens within a week after a patient receives this trigger injection and undergoes egg retrieval.
Symptoms of ovarian hyperstimulation syndrome
Typically, OHSS symptoms are minor, with mild to moderate pain, loss of appetite, nausea, diarrhea and feeling bloated.
In rare cases, worse symptoms can include severe abdominal pain, severe nausea or vomiting, decreased urination, dark-colored urine, shortness of breath, low blood pressure and excessive weight gain.
Approximately 10 percent of patients undergoing IVF have mild OHSS, and less than 1 percent of patients need to be admitted to the hospital for severe symptoms.
Symptoms usually appear four to five days after a woman’s eggs are collected in the IVF retrieval process. However, symptoms usually resolve spontaneously with the onset of the next period or shortly thereafter.
If a patient is pregnant when OHSS hits, the symptoms may worsen and last approximately two to three weeks.
For more information, make an appointment with one of our reproductive endocrinologists.
Treatment of ovarian hyperstimulation syndrome
If after receiving a hormone injection you develop any of the symptoms described above, you should notify our center immediately.
Careful monitoring, decreased stimulation medication, taking pain medicine and drinking lots of fluids are recommended. There is also some increased risk of developing a blood clot if you have OHSS, so your doctor may recommend taking a baby aspirin.
Although very uncommon, severe OHSS symptoms can be treated through hospitalization for intravenous fluid hydration or, in rare circumstances, inserting a needle in the abdomen to remove excess fluid.
Since symptoms are usually resolved within two weeks, if you do not achieve pregnancy through fertility treatment, the doctor may advise that all embryos be frozen so they can be transferred after recovery.
If severe OHSS occurs after conceiving, it can last up to the tenth week of pregnancy and then resolve.