Ovarian hyperstimulation syndrome is an exaggerated response to excess hormones. It usually occurs in women taking injectable hormone medications to stimulate the development of eggs in the ovaries. Ovarian hyperstimulation syndrome (OHSS) causes the ovaries to swell and become painful.
OHSS may occur in women undergoing in vitro fertilization (IVF) or ovulation induction with injectable medications. Less often, OHSS happens during fertility treatments using medications you take by mouth, such as clomiphene.
Treatment depends on the severity of the condition. OHSS may improve on its own in mild cases, while severe cases may require hospitalization and additional treatment.
During in vitro fertilization, eggs are removed from mature follicles within an ovary (A). An egg is fertilized by injecting a single sperm into the egg or mixing the egg with sperm in a petri dish (B). The fertilized egg (embryo) is transferred into the uterus (C).
Symptoms of ovarian hyperstimulation syndrome often begin within a week after using injectable medications to stimulate ovulation, though sometimes it can take two weeks or longer for symptoms to appear. Symptoms can range from mild to severe and may worsen or improve over time.
With mild to moderate ovarian hyperstimulation syndrome, symptoms can include:
Some women who use injectable fertility drugs get a mild form of OHSS. This usually goes away after about a week. But, if pregnancy occurs, symptoms of OHSS may worsen and last several days to weeks.
With severe ovarian hyperstimulation syndrome, you might have:
If you're having fertility treatments and you experience symptoms of ovarian hyperstimulation syndrome, tell your doctor. Even if you have a mild case of OHSS, your doctor will want to observe you for sudden weight gain or worsening symptoms.
Contact your doctor right away if you develop breathing problems or pain in your legs during your fertility treatment. This may indicate an urgent situation that needs prompt medical attention.
The cause of ovarian hyperstimulation syndrome isn't fully understood. Having a high level of human chorionic gonadotropin (HCG) — a hormone usually produced during pregnancy — introduced into your system plays a role. Ovarian blood vessels react abnormally to HCG and begin to leak fluid. This fluid swells the ovaries, and sometimes large amounts move into the abdomen.
During fertility treatments, HCG may be given as a "trigger" so that a mature follicle will release its egg. OHSS usually happens within a week after you receive an HCG injection. If you become pregnant during a treatment cycle, OHSS may worsen as your body begins producing its own HCG in response to the pregnancy.
Injectable fertility medications are more likely to cause OHSS than is treatment with clomiphene, a medication given as a pill you take by mouth. Occasionally OHSS occurs spontaneously, not related to fertility treatments.
Sometimes, OHSS happens in women with no risk factors at all. But factors that are known to increase your risk of OHSS include:
Severe ovarian hyperstimulation syndrome is uncommon, but can be life-threatening. Complications may include:
To decrease your chances of developing ovarian hyperstimulation syndrome, you'll need an individualized plan for your fertility medications. Expect your doctor to carefully monitor each treatment cycle, including frequent ultrasounds to check the development of follicles and blood tests to check your hormone levels.
Strategies to help prevent OHSS include:
For ovarian hyperstimulation syndrome, your doctor may make a diagnosis based on:
Ovarian hyperstimulation syndrome generally resolves on its own within a week or two or somewhat longer if you're pregnant. Treatment is aimed at keeping you comfortable, decreasing ovarian activity and avoiding complications.
Mild OHSS typically resolves on its own. Treatment for moderate OHSS may involve:
With severe OHSS, you may need to be admitted to the hospital for monitoring and aggressive treatment, including IV fluids. Your doctor may give you a medication called cabergoline to lessen your symptoms. Sometimes, your doctor may also give you other medications, such as gonadotropin-releasing hormone (Gn-RH) antagonist or letrozole (Femara) — to help suppress ovarian activity.
Serious complications may require additional treatments, such as surgery for a ruptured ovarian cyst or intensive care for liver or lung complications. You may also need anticoagulant medications to decrease the risk of blood clots in your legs.
If you develop mild ovarian hyperstimulation syndrome, you'll probably be able to continue your day-to-day routine. Follow your doctor's advice, which may include these recommendations:
Depending on how severe your ovarian hyperstimulation syndrome is, your first appointment may be with your primary care provider, your gynecologist or infertility specialist, or possibly with a treating doctor in the emergency room.
If you have time, it's a good idea to prepare in advance of your appointment.
Some basic questions to ask include:
Make sure that you completely understand everything that your doctor tells you. Don't hesitate to ask your doctor to repeat information or to ask follow-up questions for clarification.
Some potential questions your doctor might ask include: