Association Between Paternal Age and Birth Weight in Preterm and Full-Term Birth: A Retrospective Study

Abstract

Purpose: While it is well documented that maternal adverse exposures contribute to a series defects on offspring health according to the Developmental Origins of Health and Disease (DOHaD) theory, paternal evidence is still insufficient. Advanced paternal age is associated with multiple metabolism and psychiatric disorders. Birth weight is the most direct marker to evaluate fetal growth. Therefore, we designed this study to explore the association between paternal age and birth weight among infants born at term and preterm (<37 weeks gestation).

Methods: A large retrospective study was conducted using population-based hospital data from January 2015 to December 2019 that included 69,964 cases of singleton infant births with complete paternal age data. The primary outcome was infant birth weight stratified by sex and gestational age including small for gestational age (SGA, 10th percentile) and large for gestational age (LGA, 90th percentile). Birth weight percentiles by gestational age were based on those published in the INTERGROWTH-21st neonatal weight-for gestational-age standard. Logistic regression analysis and linear regression model were used to estimate the association between paternal age and infant birth weight.

Results: Advanced paternal age was associated with a higher risk for a preterm birth [35-44 years: adjusted odds ratio (OR) = 1.13, 95%CI (1.03 to 1.24); >44 years: OR = 1.36, 95%CI (1.09 to 1.70)]. Paternal age exerted an opposite effect on birth weight with an increased risk of SGA among preterm infants (35-44years: OR = 1.85, 95%CI (1.18 to 2.89) and a decreased risk among term infant (35-44years: OR = 0.81, 95%CI (0.68 to 0.98); >44 years: OR = 0.50, 95%CI (0.26 to 0.94). U-shaped associations were found in that LGA risk among term infants was higher in both younger (<25 years) (OR = 1.32; 95%CI, 1.07 to 1.62) and older (35-44 years) (OR = 1.07; 95% CI, 1.01 to 1.14) fathers in comparison to those who were 25 to 34 years old at the time of delivery.

Conclusions: Our study found advanced paternal age increased the risk of SGA among preterm infants and for LGA among term infants. These findings likely reflect a pathophysiology etiology and have important preconception care implications and suggest the need for antenatal monitoring.

Keywords: birth weight; large for gestational age; obesity; paternal age at birth; small for gestation age.

Figure 1

Flow chart: 69,964 cases are enrolled in this study.

Figure 2

Paternal age is associated with higher risk of adverse birth weight outcomes. Linear regression model is generated for paternal age at birth with the incidence of SGA (A), LGA (B), LBW (C) and Macrosomia (D), expressed as predicted prevalence with 95% CIs. Analyses were adjusted for maternal age, BMI, ethnicity, education level and marital status.

Figure 3

Paternal age exerted an opposite effect on birthweight among preterm and term infants. Adjusted odds ratios (ORs) and 95% confidence intervals for risks of SGA (A–C) and LGA (D–F) according to paternal age in overall population, preterm birth and full-term birth infants. Analyses were adjusted for maternal age, BMI, ethnicity, education level and marital status.

Figure 4

Combined effects of maternal BMI in early pregnancy and paternal age on birth weight and LGA. Maternal BMI were categorized into three stages: underweight (BMI <18.5 kg/m²), normal (BMI 18.5 to 24.9 kg/m²), and overweight or obesity (OWO) (BMI ≥25 kg/m²). Heat map (filled contour plot) for the correlation of gestational age–adjusted birth weight (A) and paternal age in overall population (red indicates increased gestational age–adjusted birth weight; blue indicates decreased gestational age–adjusted birth weight). Heat map for the prevalence of LGA in three maternal BMI levels (B–D) (red indicates high risk, blue indicates low risk) according to their interaction with maternal BMI and paternal age are generated. Analyses were adjusted for maternal age, BMI, ethnicity, education level and marital status.