Study assesses association between Gestational Weight Gain, Preterm Birth, and Metabolic Factors

The increasing rate of preterm birth (PTB) has garnered greater attention from the medical community and society as a whole. Recent study investigated the association between gestational weight gain (GWG) and preterm birth (PTB) according to pre-pregnancy body mass index (pp-BMI) and glycated hemoglobin (HbA1c) levels within the normal range. The researchers conducted a population-based retrospective cohort study involving 23,699 pregnant women.

Results on GWG and PTB Risk

The results showed that 4.7% of the women experienced PTB. The women were classified into three GWG groups: inadequate GWG (21.2%), appropriate GWG (43.2%), and excessive GWG (35.6%). The analysis revealed that women with inadequate GWG had a significantly higher risk of PTB compared to those with appropriate GWG, even after adjusting for confounding factors. In contrast, women with excessive GWG had a reduced risk of PTB.

Variations in PTB Risk based on BMI and HbA1c

Interestingly, the relationship between GWG and PTB varied based on pp-BMI and HbA1c levels. Among women with pp-BMI <18.5 kg/m2 (underweight) and 18.5-24.9 kg/m2 (normal weight), the risk of PTB increased with rising HbA1c levels when GWG was inadequate. For example, underweight women with HbA1c <5.6% and inadequate GWG had a significantly higher PTB risk compared to those with HbA1c 4.6-5.0% and appropriate GWG, and the risk increased further with higher HbA1c levels.

PTB Risk Among Overweight Women

Similar results were observed in the normal weight group - women with HbA1c >4.6% and inadequate GWG had an elevated PTB risk. However, among overweight women (pp-BMI 25-29.9 kg/m2) with inadequate GWG, the significantly increased PTB risk was only observed in the HbA1c 5.6-6.0% subgroup.

Association Between Excessive GWG and PTB Risk

In contrast, the negative association between excessive GWG and reduced PTB risk was seen in some but not all HbA1c subgroups.

Conclusion and Recommendations

In conclusion, the study found a significant association between GWG and PTB risk, but the risk varied based on pp-BMI and HbA1c levels, even when HbA1c was within the normal range. Inadequate GWG conferred a higher PTB risk, especially among underweight and normal weight women with higher HbA1c levels. The findings suggest that close monitoring of GWG, pp-BMI, and HbA1c is crucial to prevent PTB.

Key Points

Here are the 6 key points of the research paper: 1. The study investigated the association between gestational weight gain (GWG) and preterm birth (PTB) based on pre-pregnancy body mass index (pp-BMI) and glycated hemoglobin (HbA1c) levels within the normal range. 2. The results showed that women with inadequate GWG had a significantly higher risk of PTB compared to those with appropriate GWG, even after adjusting for confounding factors. In contrast, women with excessive GWG had a reduced risk of PTB. 3. The relationship between GWG and PTB varied based on pp-BMI and HbA1c levels. Among underweight and normal weight women, the risk of PTB increased with rising HbA1c levels when GWG was inadequate. 4. For overweight women with inadequate GWG, the significantly increased PTB risk was only observed in the HbA1c 5.6-6.0% subgroup. 5. The negative association between excessive GWG and reduced PTB risk was seen in some but not all HbA1c subgroups. 6. The findings suggest that close monitoring of GWG, pp-BMI, and HbA1c is crucial to prevent PTB, as the risk varies based on these factors, even when HbA1c is within the normal range.

Reference –

Xiaoxiao Zhang, Binbin Yin, Kaiqi Wu, Lei Fang & Yan Chen (2024) Association between maternal gestation weight gain and preterm birth according to pre-pregnancy body mass index and HbA1c, Journal of Obstetrics and Gynaecology, 44:1, 2359671, DOI: 10.1080/01443615.2024.2359671