A randomized trial of in vitro fertilization versus conventional treatment for infertility

OBJECTIVE: To evaluate the effectiveness of IVF in couples with infertility. DESIGN: Two hundred forty-five consecutive couples with infertility were randomized to receive one cycle of IVF treatment (experimental group) or to wait for a period of 6 months before receiving IVF treatment, during which time other infertility treatments could have been undertaken (control group). SETTING: Patients were referred to the Fertility Clinic at Chedoke-McMaster Hospitals, a university-associated institution in Hamilton, Ontario, Canada, in which IVF has been offered to couples since 1984. PATIENTS: Couples with infertility (mean duration of 65 months) not corrected by conventional treatment. They came from all socioeconomic classes, and the costs of IVF treatment, except medication, were covered by the Ontario Health Insurance Plan. MAIN OUTCOME MEASURE: Pregnancy was confirmed by ultrasound documentation of a gestational sac or histologic examination of tissue. Outcomes included livebirth, spontaneous abortion, and ectopic pregnancy. The overall pregnancy rate (PR) and the interval-to-pregnancy duration were compared in each group. RESULTS: Univariate analysis demonstrated a significant beneficial effect of IVF treatment in patients with bilateral severe tubal disease. Although in other diagnostic categories the crude and cumulative PRs in the experimental group were higher than in the control group, the differences did not reach statistical significance. Among the early IVF group, those with endometriosis had significantly more pregnancies when compared with other diagnostic categories. Although IVF increases the likelihood of pregnancy by 40% with severe tubal disease, the overall 31% increase associated with IVF was not statistically significant. CONCLUSIONS: There was a significant difference in favor of treatment in patients with severe bilateral tubal disease. For couples with other causes of infertility, the confidence limits around the treatment effect included unity. To reject the null hypothesis of no treatment effect, a larger sample size or a meta-analysis to combine the results of similar trials is required.