Longitudinal semen parameter assessments and live birth : variability and implications for treatment

Objective: To examine whether semen parameters are associated with live birth among couples seeking infertility treatment after ac-counting for semen parameter variability.Design: Folic Acid and Zinc Supplementation Trial (FAZST) prospective cohort.Setting: Four US reproductive endocrinology and infertility care study centers, 2013-2017.Patient(s): Couples (n = 2,369) seeking fertility consultations at 4 US infertility care study centers.Intervention(s): Semen volume, pH, sperm viability, morphology, progressive and total motility, concentration, count, and total and progressive motile count assessed at baseline and at 2, 4, and 6 months after enrollment.Main Outcome Measure(s): Log-binomial models stratified by fertility treatment received (in vitro fertilization [IVF], intrauterine insemination [IUI], ovulation induction [OI], or no treatment) estimated risk differences (RDs) between semen parameter quartiles and live birth and accounted for multiple semen assessments per person. We accounted for abstinence time, the biological interdepen-dence of semen parameters, and potential selection bias because of loss to follow-up.Result(s): Among couples using OI only or no treatment, 39% had a live birth, and relative to the highest quartile, the lowest quartiles of morphology (RD, -19 [95% CI, -23 to -15] per 100 couples), motility (RD, -13 [95% CI, -17 to -9]), concentration (RD, -22 [95% CI, -26 to -19]), and total motile count (RD, -18 [95% CI, -22 to -14]) were associated with fewer live births. For IUI, 26% had a live birth, and the lowest quartiles of volume (RD, -6 [95% CI, -11 to -0.4]), concentration (RD, -6 [95% CI, -11 to -0.1]), count (RD, -10 [95% CI, -15 to -4]), and total motile count (RD, -7 [95% CI, -13 to -1]) were associated with fewer live births. For IVF, 61% had a live birth, and only morphology (Q1 RD, -7 [95% CI, -14 to 0.2]; Q2 RD, -10 [95% CI, -17 to -2.2]) was associated with live birth.Conclusion(s): Semen parameters are critical in couples undergoing OI/IUI. Only low morphology was important for live birth after IVF. Although data supporting the use of semen parameters are fragmented across differing populations, current findings are generaliz-able across the range of male fertility and couple fertility treatments, providing evidence about which semen parameters are most rele-vant in which settings.

Automated summary

This study examined the association between semen parameters and live birth in couples seeking infertility treatment. The findings suggest that low morphology, motility, concentration, and total motile count are associated with fewer live births in couples undergoing ovulation induction or no treatment. For intrauterine insemination, low volume, concentration, count, and total motile count are associated with fewer live births. Only low morphology is important for live birth after in vitro fertilization.