Treating Female Infertility: Recombinant FSH (rFSH)
For couples experiencing difficulty getting pregnant, finding the proper infertility treatment can often become an overwhelming task. However, for women experiencing abnormal ovulation cycles, there may be hope in recombinant follicle stimulating hormone (rFSH). This fertility drug works by stimulating ovulation using synthetic female hormones, in effect improving a woman’s overall fertility.
What is Recombinant FSH?
Follicle-stimulating hormone is a special hormone that is secreted by the pituitary gland; a small gland located in the brain. This hormone belongs to a group of hormones known as gonadotropins, which are responsible for stimulating the ovaries. In women, FSH’s job is to stimulate the development of follicles inside your ovaries so that they can mature and release eggs for fertilization.
Recombinant FSH is a synthetic form of FSH that is produced using DNA technology. It is used to help induce ovulation in preparation for fertility treatments, like IUI and in vitro fertilization (IVF). It is most often recommended for women whose ovaries produce follicles but lack sufficient hormones to stimulate their development. This often comes as a result of a preexisting reproductive health condition, such as:
In the past, FSH could only be retrieved from a woman's urine. But this procedure often made it difficult to retrieve FSH without contamination. The advantage of recombinant FSH therefore, is that it can be easily produced with little risk of contamination. Recombinant FSH now represents 98% of all FSH used in fertility treatments.
Who Should Not Take Recombinant FSH?
People with any of the following conditions may require a varied dosage of rFSH, or special monitoring:
- thyroid problem
- adrenal dysfunction
- cancer of the breast, ovary, uterus, hypothalamus or pituitary gland
- undiagnosed abnormal vaginal bleeding
- ovarian cysts or enlargement not caused by PCOS
Women who are pregnant or breastfeeding should not use rFSH.
How is Recombinant FSH Taken?
Recombinant FSH is usually given in the form of intramuscular or subcutaneous injections. It is typically started on day 2 or 3 of your menstrual cycle and is continued daily for six to ten days. Dosages vary from woman to woman, but are typically between 75 and 600 units.
Side Effects of Recombinant FSH
If you are taking recombinant FSH therapy, you may notice a few side effects during your treatment. Possible side effects include:
- ovarian enlargement manifested in abdominal or pelvic pain, tenderness or swelling
- breast tenderness
- fluid retention and swelling
- fatigue or dizziness
- fever or chills
- spotting or menstrual changes
- dry skin, rash or hair loss
- rapid pulse or heart rate
You should stop taking rFSH right away if you experience any of the following symptoms:
- an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives)
- pain, warmth, redness, numbness, or tingling in an arm or leg (which may indicate a blood clot);
- confusion, severe dizziness, severe headache; or
- difficulty breathing
It is important to be aware of the fact that FSH increases the risk multiple birth pregnancies. Because FSH stimulates follicular development, there is a chance that more than one egg will be released and fertilized.
Recombinant FSH has also been associated with ovarian hyperstimulation syndrome (OHSS), especially after the first cycle of therapy. Symptoms of OHSS include severe pelvic pain, swelling of the hands or legs, abdominal pain and swelling, shortness of breath, weight gain, low urine output, diarrhea, and nausea or vomiting. Left untreated, OHSS can be fatal. You should notify your health care professional immediately if you notice any of these symptoms.
Success Rates with Recombinant FSH
Recombinant FSH does appear to be effective in stimulating ovulation in women who are having difficulties ovulating regularly. That being said, between 70% and 90% of women taking recombinant FSH do begin to ovulate. Pregnancy rates with recombinant FSH are between 26% and 28%.
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