Minimal stimulation IVF
For many years there has been interest in minimal stimulation IVF. Recent reports in the popular media have made minimal stimulation IVF a topic of interest to infertile couples. IVF stimulation protocols can be divided into three broad groups:
- Standard in vitro fertilization – IVF.
Standard IVF uses a combination of two types of fertility medications. One type is used to prevent premature ovulation of the eggs. The other type is used to stimulate the development of multiple eggs within the ovaries. The idea behind standard IVF is to obtain a large number of eggs since it is known that most eggs will not produce viable embryos. A large number of eggs increase the chances for having at least some eggs that will be mature eggs. Some of those mature eggs will fertilize and some of those fertilized eggs will develop into healthy appearing embryos than can be placed into the uterus in an attempt at pregnancy.
- Natural cycle IVF.
Natural cycle IVF can only be performed if a woman is having ovulatory menstrual cycles. During a normal ovulation, one egg is selected to mature and be released into the fallopian tubes. The idea behind natural cycle IVF is to remove that egg before it is released by the ovary, fertilize it, and transfer it into the uterus. Natural cycle IVF is associated with a high cancellation rate. Since there is only one egg available, often times, the physician is unable to retrieve the egg. Sometimes, the egg is not mature or doesn’t fertilize or develop. At its best, natural cycle IVF only allows the transfer of one embryo. Therefore, pregnancy rates are much lower with standard IVF.
- Minimal stimulation IVF.
Minimal stimulation IVF uses some combination of medications to stimulate the ovaries but with the intent of retrieving fewer eggs than with standard IVF but more than with natural cycle IVF.
Minimal stimulation IVF with Clomid is less effective than standard in vitro fertilization
Clomid is an oral medication that has been used for over forty years for women with infertility. Clomid stimulates the pituitary gland to cause stimulation of the ovaries. The result is the growth and development of a few eggs. During stimulation of the ovaries, at a certain point, the pituitary gland will trigger ovulation. In order to perform IVF, this signal from the pituitary gland must be blocked or at least controlled. Otherwise, many IVF cycles would be cancelled. A group of medications known as GnRH antagonists may be used to prevent ovulation.
A few small studies have been published using clomiphene citrate for in vitro fertilization. One study, published in 2003, evaluated 33 infertile couples who used clomid and compared them to 156 couples who had standard in vitro fertilization. The group that used clomiphene citrate ended up with fewer eggs, less embryos, less embryos transferred and less embryos that could be frozen. The pregnancy rate was less than one-half of the pregnancy rate of the standard in vitro fertilization group. This was due to a much lower implantation rate. In other words, the number of pregnancies produced per embryo transferred was much lower.
The authors suggested that the lower rate of implantation and pregnancy rate might have been due to adverse effects of the clomiphene citrate on the uterine lining rather then an effect of the embryos themselves.
Although each clomiphene citrate cycle was less expensive to perform, the couples would be predicted to spend more money overall because they would require a greater number of attempts to get the same number of pregnancies.