SAN FRANCISCO — Metformin treatment before and during in vitro fertilization does not improve the chance of pregnancy in women with ovaries of polycystic morphology who do not have anovulation or hyperandrogenism, according to a study of 134 women.
Study participants treated with metformin before oocyte collection were no more likely to become pregnant or have a clinical pregnancy than were patients given placebo, Dr. Alex G. Swanton of John Radcliffe Hospital in Oxford, England said at the annual meeting of the American Society for Reproductive Medicine.
In the multicenter study, women with ovaries of polycystic morphology but no other manifestations of polycystic ovary syndrome (PCOS), such as anovulation or hyperandrogenism, were randomized to receive 1.5 g metformin (62 patients) or placebo (62 patients) starting 7 weeks before oocyte retrieval. The women were younger than 39 years and undergoing their first or second cycle of IVF (with or without intracytoplasmic sperm injection). IVF was performed using the long protocol. One 500-mg capsule of metformin was taken every morning for 1 week, increasing to two capsules daily and then three daily until the day of oocyte collection.
Polycystic ovaries were diagnosed by the ultrasound presence of at least 12 follicles measuring 2-9 mm in diameter and/or increased ovarian volume greater than 10 mL in at least one ovary. Severe ovarian hyperstimulation syndrome was defined as the presence of clinical ascites and hemoconcentration requiring hospital admission.
There were no statistically significant differences between the two groups in baseline characteristics.
The study was prompted by several factors. “Firstly, polycystic ovaries are very common, affecting about 33% of patients attending fertility clinics,” Dr. Swanton said in an interview. “Secondly, women with polycystic ovaries, who have regular cycles and no symptoms of acne or hirsutism (that is, no features of polycystic ovary syndrome) may have underlying biochemical abnormalities similar to [those of] women with polycystic ovary syndrome. Thirdly, there is good evidence that women with polycystic ovary syndrome undergoing IVF treatment benefit from metformin treatment, as it increases pregnancy rates and decreases ovarian hyperstimulation syndrome rates.”
The study relates to 33% of fertility clinic patients, Dr. Alex G. Swanton noted.