Association between maternal age and low birth weight and small for gestational age in Japanese women with gestational diabetes mellitus: Hamamatsu GRACE Study 2.

AIM: The association between maternal age and low birth weight (LBW) or small for gestational age (SGA) has been variably reported in previous epidemiological studies. In gestational diabetes mellitus (GDM), evidence on this issue remains limited and mixed. To date, no study has investigated these associations in Japanese women with GDM. The aim of this study was to address this gap by examining the association between maternal age and LBW/SGA in Japanese women with GDM.

MATERIALS AND

METHODS

We enrolled 641 women with GDM in this study. Following exclusion of 94 cases with incomplete data, the final analytic sample comprised 547 women. Logistic regression analysis was performed to calculate crude odds ratios (ORs) and 95% confidence intervals (CIs) for the association between maternal age and LBW and SGA. Maternal age was categorized into tertiles (younger: <32 years, middle-aged: 32-35 years, and older: ≥36 years), and further evaluated in 5-year intervals (<30 years, 30-34 years, 35-39 years, and ≥40 years) for a more detailed analysis.

RESULTS

The mean maternal age was 33.3 years. The prevalence of LBW and SGA was 12.8% and 9.0%, respectively. The younger group was independently and positively associated with LBW (adjusted OR, 2.43 [95% CI, 1.08-5.68]) and SGA (adjusted OR, 2.30 [95% CI, 1.19-4.65]). Compared with women aged 30-34 years old, those under 30 years old had significantly higher risks of both LBW (adjusted OR 3.63 [95% CI, 1.49-9.07], p for trend = 0.001) and SGA (adjusted OR 3.15 [95% CI, 1.50-6.77], p for trend = 0.001).

CONCLUSIONS

In Japanese patients with GDM, younger maternal age was independently associated with LBW and SGA.