ALEXANDRIA, Egypt, Jan. 26 - Gonadotrophin-releasing hormone (GnRH) agonists can significantly increase the pregnancy rate for women with endometriosis undergoing fertility treatment, according to an international team.
GnRH agonists can also increase the number of live births although it remains unclear by how much, reported Hassan Sallam, M.B., Ch.B., of Alexandria University here, in a systematic review published by the Cochrane Collaboration.
Women with endometriosis are often treated with in vitro fertilization or intracytoplasmic sperm injection (ICSI), but they have a lower chance of becoming pregnant than do women whose infertility has other causes, Dr. Sallam and colleagues said.
But an analysis of the most recent data, from three randomized trials, indicates that three to six months of treatment with GnRH agonists increases the rate of clinical pregnancies fourfold, the researchers reported.
The data from the three trials showed 78 pregnancies for 165 women; the pooled odds ratio was 4.28, with a 95% confidence interval from 2.00 to 9.15, in favor of the women taking a GnRH agonist.
The three studies were randomized but not blinded, and all were published in the journal Fertility and Sterility.
None of the studies reported a live birth rate, but one reported viable pregnancies -- those that included at least 24 weeks of gestation. In that study, there were nine viable pregnancies for 67 women.
Based on that information, Dr. Sallam and colleagues said, there was an odds ratio, favoring treatment with GnRH agonists, of 9.19, with a 95% confidence interval from 1.08 to 79.22.
But without data from other studies, the researchers said, it is difficult to say how accurate that number is. "The chances of having a live birth are also increased, though currently the data is not strong enough to show how great that increase is," Dr. Sallam said.
The researchers also noted:
* No significant differences in the number of follicle-stimulating hormone (FSH) or human menopausal gonadotrophin (HMG) ampules required between women who received the GnRH agonist and those who did not.
* Inconclusive data on the number of oocytes retrieved.
* An inability to say whether one type of agonist is superior to another.
The improved pregnancy rate could be due to better oocytes (and hence embryos), the researchers said, or to better endometrial receptivity, but the studies were inconclusive: "At the moment there are no data showing whether the treatment leads to better eggs or better acceptance of embryos by the lining of the womb," Dr. Sallam said.
Also, none of the studies reported the rate of complications of adverse effects of treatment on either mother or fetus; the researchers said physicians and patients planning to use GnRH agonists should bear the lack of data in mind.