The impact of glycosylated hemoglobin and 75-g oral glucose tolerance test glucose levels on birthweight percentile.

Objective: Our research objective was to validate and contribute further evidence to the studies regarding large for gestational age and birthweight percentile by examining oral glucose tolerance test and glycosylated hemoglobin levels in both healthy women and those with gestational diabetes mellitus.

Methods: This retrospective cohort study was conducted at a tertiary care hospital involving 106 women who delivered at gestational week 36 or later between February 2022 and February 2023. Maternal, obstetric, and neonatal data were collected from the participant's medical records. Large for gestational age and non-large for gestational age groups were compared. Correlation analysis was used to determine associations among oral glucose tolerance test, glycosylated hemoglobin levels, and the birthweight percentile.

Results: Mothers of neonates in the large for gestational age category had higher body mass indexes before pregnancy (p=0.002) and delivery (p=0.003), as well as a higher incidence of gestational diabetes mellitus (p=0.027). Mothers of male large for gestational age infants had higher fasting plasma glucose and glycosylated hemoglobin levels compared to male non-large for gestational age infants (p=0.007 and p=0.004, respectively). There was a weak positive correlation between fasting plasma glucose levels and birthweight percentile in the overall group (r=0.342, p<0.006). Further analysis by gender showed a weak positive correlation between birthweight percentile and fasting plasma glucose and glycosylated hemoglobin values in male newborns (r=0.393, p=0.004 and r=0.373, p=0.006, respectively).

Conclusion: Our study has established a clear association between the birthweight percentile in male infants and the levels of glycosylated hemoglobin and fasting plasma glucose measured during oral glucose tolerance test. It is imperative to devise potential strategies aimed at achieving optimal glycosylated hemoglobin and fasting plasma glucose parameters to effectively reduce the frequency of large for gestational age in male infants.