Association between paternal age and singleton birthweight in frozen embryo transfer cycles

Abstract

Background Many studies have considered maternal age as a determinant factor for success in assisted reproductive technologies (ART), but the potential role of paternal age on neonatal outcomes has been overlooked. This study aimed to explore the association between paternal age and birthweight in frozen embryo transfer (FET) cycles. Methods This retrospective study involved singleton live births born to women undergoing frozen embryo transfer from January 2013 to December 2017 at a tertiary care center in Shanghai, China. The paternal age was classified into four categories: ≤ 30, 31–35, 36–40, and ≥ 41 years. The group consisting of respondents with paternal age of 31–35 was set as the reference group. Singleton birthweight was the primary outcome measure. Z-scores were calculated according to gestational age and newborn gender on birthweight based on the national birthweight reference. Multivariable linear regression analysis was performed to reveal the relationship between paternal age and newborns’ birthweight after considering several potential confounders. Results Exactly 9765 women who fulfilled the inclusion criteria were enrolled. No significant difference was found on mean birthweight (P = 0.082) and gestation-adjusted Z-scores (P = 0.569) among paternal age categories. The reference group and the group with aged 36–40 years had the highest mean birthweight and Z-scores, respectively (3350.2 ± 467.8 g, 0.36 ± 1.00). A decline in mean birthweight with paternal age was observed, and the group over 40 years had the lowest value of 3309.4 ± 474.3 g, but the difference was not statistically significant. In multivariate analyses, the adjusted odds of very low birthweight (LBW), LBW, and high birthweight in the reference group did not significantly differ with the three other groups. After correcting several potential confounders, no significant correlation was observed between paternal age and neonatal birthweight (P = 0.289). Conclusion Paternal age was not associated with mean birthweight and gestational age- and gender-adjusted birthweight (Z-scores) of singletons among women who became pregnant in FET cycles.

Association between gestational weight gain and adverse neonatal outcomes in women conceiving with assisted reproductive technology: Evidence from the NVSS 2019–2021

“…years, which necessitates more evidence to assess the effect of paternal age on these abnormal conditions. On the other hand, the research by Basso et al [23] and Ni et al [24] showed no association of paternal age with the risk of early preterm delivery and average birthweight, which supported the similar relationships between insufficient and excessive GWG and the risks of premature birth, LGA, SGA, macrosomia, and LBW for paternal age � 35 and > 35 years to some extent. For the similar associations between GWG and adverse neonatal outcomes in different maternal and paternal age subpopulations, one explanation is that with the improvement of socioeconomic, cultural and educational environments, couples may develop healthy living habits and have more access to medical assistance and health services for ART pregnancies, which may result in no significant difference among different subgroups.…”

Risk Factors of Preterm Birth and Low Birth Weight in Singletons Conceived Through Frozen Embryo Transfer: A Retrospective Study

“…Maternal age is a determinant factor for success in ART. 23 Maternal age at natural-cycle frozen embryo transfers (NC-FET) independently impact pregnancy outcomes, such as odds of pregnancy and live birth. 24 However, studies have showed that maternal age was not associated with birth weight of singletons resulting from FET.…”