Impact of maternal height and gestational diabetes mellitus on offspring birthweight.

Aims: To evaluate the impact of gestational diabetes mellitus (GDM) and maternal height on offspring birthweight.

Methods: This is an observational cohort study, encompassing 4 111 Finnish primiparous women from Vantaa city, Finland, with singleton deliveries between 2009 and 2015. Data were obtained from the Finnish Medical Birth Register. The study population was divided into five groups according to maternal height. Cut-offs for height levels were I ≤ 158 cm, II 159-163 cm, III 164-167 cm, IV 168-172 cm, V ≥ 173 cm. The main outcome measure was offspring birthweight, expressed as Z-scores according to sex and gestational age.

Results: Independently, both maternal height and GDM increased offspring birthweight (p < 0.001 for height and GDM). When studying the interaction, a significant increase in offspring birthweight was noted only in extreme height categories; group I ≤ 158 cm (p = 0.011), group IV 168-172 cm (p = 0.010) and group V ≥ 173 cm (p < 0.001) and the impact was similar in both sexes. Maternal height had no impact on offspring ponderal index (p = 0.20 for trend).

Conclusions: In extreme height categories, short and tall primiparous women with GDM are at risk for delivering larger offspring compared to women without GDM of similar height.