Couples in which the man has abnormal sperm morphology are often counseled that natural conception and intrauterine insemination are ineffective and that in vitro fertilization is the only option. Our objective is to determine the effect of sperm morphology on pregnancy success using intrauterine insemination (IUI).METHODS:
We systematically searched for studies published prior to January 2017 that 1) reported ultrasound-verified clinical pregnancies per IUI cycle; 2) assessed sperm morphology using the Kruger Strict Criteria; and 3) reported morphology at the >4% and ≤4% and/or ≥1% and <1% thresholds. For all studies, mean female age was between 25 and 40 years and mean total motile sperm count (TMC) was greater than 10 million. Estimates were pooled using random effects meta-analysis.RESULTS:
Data were extracted from 20 observational studies involving 41,018 cycles of IUI. Comparing men with >4% and ≤4%, the rate of ultrasound-verified pregnancy per cycle of IUI was not statistically or clinically different (14.2% vs. 12.1%, p=0.06) and the risk difference was 3.0% (95% CI 1.4–4.6%), indicating three additional pregnancies per 100 IUI cycles. Comparing men with ≥1% and <1%, there were no statistical or clinical differences in the rate of ultrasound-verified pregnancy per cycle of IUI (14.0% vs. 13.9%, p=0.97) or in the risk difference (1.6%, 95% CI -4.5–7.6%).CONCLUSION:
There appears to be no clinical difference in IUI pregnancy success among those with normal and abnormal sperm morphology, when accounting for total motile sperm count and female age. Abnormal sperm morphology alone should not exclude couples from attempting IUI.