The performance of primary and secondary unexplained infertility in an in vitro fertilization-embryo transfer program

The term "unexplained infertility" is applied to a couple in whom after an elaborate workup no apparent reason for infertility is found. Between August 1985 and May 1987, 435 patients underwent 720 treatment cycles in an in vitro fertilization-embryo transfer (IVF -ET) unit. Eighty-three of the patients had unexplained infertility as their indication for IVF-ET. Fifty-two (group A) had primary unexplained infertility and 31 (group B) had secondary unexplained infertility. Group A underwent 87 and group B underwent 50 treatment cycles. Forty-six ET were performed in group A and 34 in group B. Clinical pregnancies were achieved in 20 patients of group A (11.5% per treatment cycle) and 13 of group B (26.0%), for a combined rate of 16.8% per cycle. Patients with tubal infertility treated in the program had a pregnancy rate of 18.8% per treatment cycle. The performance of the secondary unexplained infertility group is significantly better than that of the primary unexplained infertility group. However, the overall results with patients with unexplained infertility are similar to those patients treated for tubal infertility.