Development of Thai-Specific Gestational Weight Gain Targets Using Asian BMI Cut-Points: Implications for Nursing and Midwifery Practice in Preventing Gestational Diabetes Mellitus.

Background

Thai obstetric nurses follow WHO gestational weight gain (GWG) guidelines to prevent gestational diabetes mellitus (GDM). However, these Western-derived guidelines misclassify approximately 16% of Thai pregnant women, who carry excess metabolic risk at lower BMI values than Western populations.

Objectives

To derive and validate Thai-specific GWG targets using Thai BMI cut-points across five BMI subgroups and assess implications for nursing practice in GDM prevention.

Methods

Retrospective cohort study of 1396 Thai singleton pregnancies at a maternal and child hospital (2023-2025). GWG targets were derived as interquartile ranges (P25-P75) from a healthy-outcomes subgroup (n = 706), with validity confirmed by multivariable logistic regression and a 70:30 derivation/validation split.

Results

GDM prevalence was 15.8%, with a rising crude trend that was attenuated after accounting for a mid-study change in screening protocol. Provisional Thai-specific GWG targets were underweight/normal weight 11.5-18.0 kg, overweight 9.7-18.0 kg, obesity class I 9.1-16.0 kg, and obesity class II+ 5.8-12.1 kg. Inadequate GWG in obesity class I was associated with a 3.92-fold GDM risk increase (aOR 3.92, 95% CI 2.12-7.24, p < 0.001). Adherence improved from 34.7% (IOM 2009) to 50.2% with Thai-specific targets.

Conclusions

These Thai-specific GWG targets are provisional, single-centre pilot estimates. They appear clinically safe and are substantially more achievable than IOM 2009 criteria and are offered to inform BMI-appropriate antenatal counselling and to justify a multi-centre validation study, rather than as ranges that are ready for immediate national adoption.