Men becoming fathers by intracytoplasmic sperm injection were more often born small for gestational age

Being born with nonoptimal birth characteristics decreases the chance of becoming a father. Urogenital malformations as well as metabolic syndrome are more common in men born small for gestational age (SGA) and could be contributing factors to the reduced fertility rate seen in these men. It could imply that men becoming fathers by assisted reproductive technology (ART) more often are born with low birth weight (LBW), preterm, and/or SGA than men conceiving without treatment and also that men where intracytoplasmic sperm injection (ICSI) had to be performed more often are born with nonoptimal birth characteristics than men where conventional in vitro fertilization (IVF) successfully could be used. In this retrospective, case–control study using Swedish national registers, we compared the birth characteristics of 1206 men who have become fathers by ART with a control group consisting of age-matched men who became fathers without treatment. The differences in birth characteristics between men becoming fathers by IVF and ICSI were also assessed. For men becoming fathers by ART, OR of being born with LBW was 1.66 (95% CI = 1.17–2.36) compared with fathers who conceived without treatment. OR of being born prematurely was 1.32 (95% CI = 1.00–1.77). Men becoming fathers via ICSI had a doubled increased likelihood of being born SGA compared with men who became fathers via IVF (OR = 2.12; 95% CI = 1.17–3.83). In conclusion, we have found that men becoming fathers by ICSI treatments had more often been born SGA than men becoming fathers by conventional IVF.