Treatment-independent pregnancy rate in patients with severe reproductive disorders.

A long waiting list for in-vitro fertilization (IVF) offers the possibility to study treatment-independent pregnancy rates in patients with severe reproductive disorders. We performed a retrospective cohort study with a nested case-control design in which the cases achieved a spontaneous pregnancy while on the waiting list for IVF, or for IVF with intracytoplasmic sperm injection (ICSI), and the controls did not become pregnant while on the waiting list. Spontaneous pregnancies occurred in 76 of 1391 patients on the waiting list. Significant differences between pregnant and non-pregnant patients were found for duration of subfertility (couples on the IVF waiting list), and for progressive sperm motility and basal 17beta-oestradiol (couples on the ICSI waiting list). The 12 months cumulative pregnancy rate for patients on the waiting list was 2.4% (95% CI 1.2-3.9%) for tubal subfertility patients, 5.9 % (3.7-8.7%) for longstanding unexplained subfertility patients, and 6.6% (4.5-9.3%) for male subfertility patients. Of the 76 control patients, 21% of tubal subfertility patients, 18% of unexplained subfertility patients, and 17% of male subfertility patients achieved a pregnancy in their first IVF or ICSI treatment cycle. We confirm that the treatment-independent pregnancy rate in patients with severe reproductive disorders is low. More than 75% of the spontaneous pregnancies in the tubal subfertility and unexplained subfertility couples occurred during their first three months on the waiting list, whereas spontaneous pregnancy rate in male subfertility couples showed a more gradual but persisting increase. We conclude that one cycle of IVF or ICSI is superior to 12 months of expectant management in patients with severely impaired fertility due to tubal, unexplained or male factors.