What Are the Most Commonly Prescribed Ovulation-Inducing Medicines?
You're probably familiar with clomiphene citrate
). It's usually the first choice when a fertility drug
is needed. Clomiphene
indirectly stimulates the ovaries to produce an egg by increasing the production of certain reproductive hormones in the brain. Clomiphene is the first choice for several reasons -- it's relatively inexpensive, easy to take (since it comes as a tablet), has been around for many years, and works well for many women.
If clomiphene fails, injectable medicines known as gonadotropins are often the next option. These medicines act like naturally occurring hormones in the body. They bypass the brain to stimulate the ovaries directly.
Using Clomiphene for Ovulation Induction
Clomiphene works by binding to estrogen receptors in the body, primarily in the hypothalamus. The hypothalamus is a small area in the brain, but it has a big job -- it controls the release of important reproductive hormones from the pituitary gland. By binding to estrogen receptors, clomiphene prevents estrogen from also binding to the receptors, thus making it seem like estrogen levels are low.
Normally, the pituitary gland slows down its production of follicle-stimulating hormone (FSH) in response to rising estrogen levels. FSH is the hormone that stimulates the follicles, which are the sacs in the ovaries that contain an egg. When clomiphene is taken, the body thinks estrogen levels are low, so the pituitary gland continues to release FSH and the ovarian follicles grow and mature. These growing follicles release estrogen into the body, which triggers the pituitary gland to release luteinizing hormone (LH), the hormone that causes the mature egg to be released. This release of an egg is known as ovulation.
When It's Used
As mentioned, clomiphene is usually the first fertility drug tried in women who aren't ovulating normally, either because they don't menstruate or they menstruate infrequently. It is also often tried in couples who are infertile for unknown reasons. When used for such couples, clomiphene is usually combined with intrauterine insemination. Intrauterine insemination is a medical procedure in which sperm is carefully placed directly into the uterus.
How It's Taken
The usual initial dose of clomiphene is 50 mg every day for five straight days. You'll begin taking it early in your cycle, about 5 to 10 days after you start your period. If you don't have periods, your healthcare provider may give you progestin medication to trigger a period. However, some recent studies suggest this step isn't necessary.
You'll normally ovulate about a week after you take the last clomiphene tablet. You'll need some form of monitoring to make sure the medicine actually causes ovulation. Your healthcare provider will let you know the best way to monitor, but it could include ovulation prediction kits, an ultrasound, or blood tests to measure your blood progesterone levels.
If the dose you're taking results in ovulation, you'll continue that dose as you try to conceive. If you don't ovulate after at least three cycles, your healthcare provider may increase the dose or add or switch to another medicine.
You'll want to take the lowest dose that causes you to ovulate. Higher clomiphene doses may actually interfere with conception by causing changes in the cervical mucus that make it more difficult for sperm to enter the uterus. The chances of becoming pregnant at doses above 200 mg a day are very small, so most providers won't recommend doses higher than that.
Is Clomiphene Effective?
As many as 75 percent to 80 percent of women who take clomiphene will ovulate, and 30 percent to 70 percent of those women will become pregnant. Most pregnancies occur within the first six months. The chances of a successful pregnancy are quite low after six months of treatment.
Also, some studies suggest long-term use of clomiphene increases the risk for ovarian and endometrial cancer. Therefore, many experts recommend only using clomiphene for up to six months. If you've been taking this drug for six months and you still aren't pregnant, it may be time to talk to your healthcare provider about other options.
Most women tolerate clomiphene quite well. You might have hot flashes
, but these should go away once you stop taking the medicine. Some women also experience bloating, nausea, mood swings, and headaches (see Side Effects of Clomiphene)
Clomiphene also slightly increases your chance of multiple births. About 7 percent to 9 percent of women who take this medication become pregnant with twins.