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Ovulation Induction, Clomiphene and Controlled Ovarian Hyperstimulation (COH)

Ovulation Induction, Clomiphene and Controlled Ovarian Hyperstimulation (COH)

Before any ovulation treatment is started, Fertility Specialists conduct a thorough assessment to identify and deal with any contributing factors/causes for a problem with ovulation. This might include completing a questionnaire to collect details such as the menstrual cycle pattern and whether there is acne and/or increased hair growth in certain areas such as the face or chest, a physical examination, and an ultrasound examination. Blood tests may also be organized to assess ovulation and to exclude hormonal problems with the thyroid, pituitary, ovary and adrenal gland(s). One example of an underlying condition that can cause problems with ovulation is polycystic ovary syndrome (PCOS). For more information on PCOS, please refer to our PCOS webpage and fact sheet.

A lifestyle assessment is also important as women who are underweight or overweight may begin to ovulate on their own once their weight changes to be within the ideal range. Furthermore, women who are overweight but are ovulating have a lower natural pregnancy rate and success rate with fertility treatment, but their chance of pregnancy increases when their weight enters the ideal range. One method of assessing whether a person's weight is in the ideal range is to calculate their body mass index. Some women who are in acutely stressful situations may stop menstruation (and ovulating), and their ovaries may begin to function normally after the stress has resolved.

Clomiphene

Clomiphene (Clomiphene Citrate) is a medicine that can be used to treat some women whose cause of infertility is a problem with ovulation (releasing an egg). Whilst the role of using clomiphene to treat ovulation problems is well documented, some doctors have used this medicine in women who already ovulate, in the hope that it will boost their pregnancy rate. This is why clomiphene is sometimes called a "fertility drug". However, a recent authoritative review of all available scientific evidence found that clomiphene does not increase the chance of pregnancy in women who already ovulate regularly. Therefore, this medication is a good treatment for certain ovulation problems, but beyond inducing ovulation it is not a fertility enhancing agent. The main risk associated with clomiphene citrate is a 10% chance of multiple pregnancy (twins or more). Before considering long-term usage of clomiphene it is important to be aware of potential concerns associated with such long-term usage including worries about an increased risk of certain cancers. Risks associated with clomiphene use are outlined in our fact sheet which can be found at the bottom of this page.

How Clomiphene Works

Clomiphene "tricks" the body into producing more of a hormone that your body produces naturally called Follicle Stimulating Hormone (FSH), which in turn stimulates the ovary to develop follicle(s) that contain egg(s) in preparation for ovulation. The technical/medical description is that clomiphene acts as a central oestrogen receptor blocker, which results in increased production and secretion of Follicle Stimulating Hormone (FSH).

Clomiphene and Unexplained Infertility

As mentioned above, some doctors have used this medicine in women who already ovulate, in the hope that it will boost their pregnancy rate, and hence why clomiphene is sometimes called a "fertility drug". However, a recent authoritative review of all available scientific evidence found that clomiphene does not increase the chance of pregnancy in women who already ovulate regularly. Consequently, the use of this medicine on its own does not appear to have any beneficial effects in treating unexplained infertility. Given the increased risk of multiple pregnancy and the potential long-term risks of using clomiphene that will be outlined below, women should think very carefully before considering using clomiphene to treat unexplained infertility.

Controlled Ovarian Hyperstimulation (COH)

Controlled ovarian hyperstimulation (COH) with clomiphene combined with intrauterine insemination (IUI) has been used as treatment for infertility which is unexplained, or where there is a male factor, ovulatory problems and/or endometriosis. A recent authoritative review of all available scientific evidence found that pregnancy rates in such couples using clomiphene and IUI were higher than the natural background pregnancy rate without treatment. However, there was only a very small increase in the monthly pregnancy rate. Treatment with injectable medicines (gonadotrophins/FSH) and IUI results in a much higher pregnancy rate than clomiphene, however there is a considerable increase in the multiple birth rate with such an approach (around 20%). As we cannot guarantee to control how many eggs are released using FSH there is a major concern about the risk of high order multiple pregnancies including triplets and quads. The latter treatment is more often used in countries where there is not universal coverage for in-vitro fertilization (IVF), but is seldom used in Australia due to worries about the risk of multiple birth and the available funding for IVF as an alternative to COH. In IVF the number of fertilized eggs (embryos) transferred into the woman's uterus is controlled and so with IVF the risk of high order multiple birth is considerably less. 


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