IVF And OHSS
HSS is short for Ovarian Hyperstimulation Syndrome. This is a potentially harmful condition that can be caused by some of the drugs used during IVF treatment. Women trying to get pregnant through IVF should be aware of OHSS symptoms and report any signs of the condition to their fertility doctor.
What Exactly Is OHSS?
OHSS is basically a hormonal imbalance causing a woman's ovaries to become over stimulated (as the word "hyperstimulation" suggests). This results in the ovaries becoming swollen and painful. In some cases, hormonal secretions will flow into the abdomen causing inflammation and discomfort there too.
The IVF Connection
Injectable gonadotropins are drugs used in IVF to encourage mature eggs to develop in the patient's ovaries, and later to trigger ovulation. In a normal, natural ovulation cycle, only one egg is released. In IVF, however, the aim is to have as many mature eggs as possible all released in one go, so that they can be harvested from the woman's body and fertilized in a laboratory by her partner's sperm. The strong hormonal effect of the gonadotropin drugs stimulates the development of many eggs, but it's also the strong effect of these drugs that can over stimulate the ovaries and cause OHSS.
The gonadotropin drugs that may have this effect are:
FSH (follicle-stimulating hormone) - this encourages follicles to grow on the ovaries. Eggs develop inside these follicles.
LH (luteinizing hormone) - triggers the release of mature eggs from the follicles on the ovaries
hMG (human menopausal gonadotropin) - contains both FSH and LH.
HCG (human chorionic gonadotropin) - functions in the same way as LH.
All these drugs stimulate the ovaries directly. This makes them more likely than other non-injectable ovulation-inducing fertility drugs to cause OHSS. The drugs stimulate the pituitary gland in the brain, thereby having only an indirect effect on the ovaries themselves. A quarter of all women who use injectable gonadotropins will develop some form of OHSS. Less than 2% of these cases will be severe, and most women recover within a week or two.
How OHSS Begins
OHSS in IVF happens after the patient has been given drugs to kick start her ovaries into producing eggs (the follicle stimulating hormones). The first symptoms of OHSS usually appear within 10 days after this drug injection is administered. The blood vessels in the ovaries take an adverse reaction to the drugs and they begin to emit fluid. The fluid fills the ovarian follicles in which the eggs are growing. This causes the ovaries themselves to swell up. Excess fluid may also run into the abdomen in large quantities.
OHSS symptoms are mild in the majority of cases but some women do become seriously ill with the condition. If you're undergoing IVF treatment and you develop any of the following problems, contact your IVF doctor immediately:
Rapid weight gain
Shortness of breath
Mild OHSS treatment can be monitored and treated at home with over-the-counter pain medications. The patient should keep a close eye on her weight, avoid sex, and stay in regular contact with her doctor. In more serious cases, the patient may need to take prescription painkillers or medication for nausea, while attending physical and ultrasound examinations, monitoring her weight gain and urine output, and drinking plenty of fluids. Blood tests may also be necessary.
Most cases of OHSS will fade within a couple of weeks, but if not, it may be necessary to drain fluid away from the ovaries or abdomen using a needle. Only in the most severe cases will a patient require hospitalization and perhaps surgery to rectify the situation.