The influence of sperm morphology and the number of motile sperm inseminated on the outcome of intrauterine insemination combined with mild ovarian stimulation

Objective: To determine the influence of sperm morphology and the number of motile sperm inseminated on the outcome of IUI in hMG-stimulated cycles and to establish lower limits for these variables below which the expectation of pregnancy is limited. Design: Retrospective study of data from 1990 to 1992. Setting: Tertiary referral Reproductive Medicine Unit. Patients: Couples with bilaterally patent fallopian tubes, and greater than or equal to 200,000 motile sperm recovered in a trial preparation before treatment. No other semen criteria were used to exclude couples. Women were stimulated with hMG irrespective of whether they were ovulatory or anovulatory. The study comprised 163 couples who underwent 330 cycles. Main Outcome Measures: Pregnancy rate (PR) per cycle was related to the percentage normal sperm morphology in the fresh semen sample and the number of motile sperm inseminated after sperm preparation by swim-up or Percoll gradients. Results: The overall PR was 16.1% per cycle. The PR was highest in the first cycle of treatment (21.4%) and declined in the second and third cycles. The miscarriage rate was 10.4% and the incidence of multiple pregnancies was 13.9%. Two groups of patients were defined on the basis of sperm morphology: a ''poor outcome'' group (less than or equal to 10% normal) and a ''good outcome'' group (>10% normal). The PRs in these two groups were 4.3% and 18.2%, respectively, and the cumulative PRs after three cycles were 8.3% and 40.1%, respectively. The number of motile sperm inseminated did not significantly affect the PR. Conclusions: The degree of teratozoospermia affected the PR in hMG-stimulated IUI cycles and a normal morphology value of 10% in the fresh semen distinguished couples with good and poor outcomes. In contrast, the number of motile sperm inseminated did not significantly influence IUI outcome.