Unidentified Infertility Factors
(See also Overview of Infertility.)
Unidentified factors are usually considered the explanation for infertility when semen in the man is normal and when ovulation and fallopian tubes are normal and ovulation is regular in the woman.
When no explanation for infertility is identified, an approach called controlled ovarian stimulation may be used.
Controlled ovarian stimulation may make pregnancy more likely and may help women become pregnant more quickly. This treatment may result in more than one fetus.
Controlled ovarian stimulation involves the following:
Women are given a fertility drug (clomiphene), which stimulates several eggs to mature and be released, and human chorionic gonadotropin (hCG), which triggers ovulation, for up to three menstrual cycles.
Semen is placed directly in the uterus to bypass the mucus (intrauterine insemination) within 2 days after treatment with hCG.
If pregnancy does not result after this treatment, one of the following may be done:
Another method of controlled ovarian stimulation, which involves giving women human gonadotropins (preparations containing hormones that stimulate the follicles of the ovaries to mature), followed by human chorionic gonadotropin (hCG) to trigger ovulation, then intrauterine insemination
Women have the same chance of pregnancy (about 65%) whether unsuccessful treatment with clomiphene is followed immediately by in vitro fertilization or whether clomiphene is followed by human gonadotropins, then in vitro fertilization. However, women become pregnant more quickly and are less likely to have a pregnancy with three or more fetuses when unsuccessful treatment with clomiphene is immediately followed by in vitro fertilization than when human gonadotropins are used. Thus, if clomiphene plus intrauterine insemination is unsuccessful, the next step is often in vitro fertilization.
Some evidence suggests that women who are over 38 and have unexplained infertility conceive more quickly when in vitro fertilization is done before controlled ovarian stimulation is tried.
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