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Observational Study
. 2025 Nov;49(6):1262-1271.
doi: 10.4093/dmj.2024.0700. Epub 2025 Jun 2.

First Trimester Mean Glucose Level on Continuous Glucose Monitoring Is Associated with Infant Birth Weight

Phaik Ling Quah  1   2 , Lay Kok Tan  3 , Serene Pei Ting Thain  3 , Ngee Lek  2   4 , Shephali Tagore  3 , Bernard Su Min Chern  5 , Seng Bin Ang  6 , Ann Wright  3 , Michelle Jong  7   8 , Kok Hian Tan  1   2
Affiliations
Observational Study

First Trimester Mean Glucose Level on Continuous Glucose Monitoring Is Associated with Infant Birth Weight

Phaik Ling Quah et al. Diabetes Metab J. 2025 Nov.

Abstract

Backgruound: Comparisons between continuous glucose monitoring (CGM) metrics during the first and second trimesters and conventional mid-pregnancy oral glucose tolerance test (OGTT) values in pregnant women without pre-existing diabetes for predicting infant birth weight are scarce.

Methods: In a longitudinal observational study, 113 participants had first and second trimester CGM data collected over a 7- to 14-day period, as well as three-point OGTT (fasting, 1-hour, and 2-hour) performed at mid-pregnancy (24 to 28 weeks). Multinomial logistic regression, adjusting for maternal ethnicity, education level, age, pre-pregnancy body mass index, parity, gestational diabetes mellitus diagnosis, gestational age at delivery, and type of CGM sensor was used to analyse the relationship between CGM metrics, OGTT glucose values and infant birth weight tertile (Clinical trial identification number: NCT05123248).

Results: In the univariate analysis, CGM-derived metrics including higher mean glucose in the first trimester, higher % time above range in the second trimester, and higher % time in range (TIR) and lower % time below range (TBR) in both the first and second trimesters were associated with infants in the highest birth weight tertile. After adjusting for confounders, a 1-standard deviation increase in mean glucose level during the first trimester was significantly associated with the likelihood of the neonatal birthweight being in the highest tertile (adjusted odds ratio, 3.11; 95% confidence interval, 1.18 to 8.21; P=0.022). No significant associations were found between OGTT glucose values and infant birth weight outcomes.

Conclusion: CGM-derived mean glucose levels in early pregnancy may be a better predictor of an infant's birth weight within the highest tertile, compared to mid-pregnancy OGTT glucose values.

Keywords: Birth weight; Continuous glucose monitoring; Glucose tolerance test; Pregnancy trimester, first.

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Conflict of interest statement

CONFLICTS OF INTEREST

No potential conflict of interest relevant to this article was reported.

Figures

Fig. 1.
Fig. 1.
Flow chart of study participants. CGM, continuous glucose monitoring; OGTT, oral glucose tolerance test.
None
See this image and copyright information in PMC

References

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