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Pre-Pregnancy Impaired Fasting Glucose Increases the Risk of Preterm Birth and Large for Gestational Age: Evidence from Large Cohort Study in Southern China
36 Pages Posted: 15 Jun 2019
More...Abstract
Background: The associations of maternal pre-pregnancy impaired fasting glucose (IFG) with preterm birth (PTB) and/or large for gestational age (LGA) are unclear. Using a large cohort data, we aimed to estimate the associations of pre-pregnancy IFG defined by the WHO cut-point with the risk of PTB and LGA. We also investigated whether the WHO cut-point of IFG was appropriate for identifying women at the risk of PTB and LGA in China.
Methods: This was a retrospective cohort study of women from the National Free Preconception Health Examination Project with singleton birth from 121 counties/districts in 21 cities of Guangdong Province, China, from 1st Jan 2013 to 31st Dec 2017. Women were included if the fasting glucose was less than 7·0mmol/L. The primary outcomes were PTB (gestation age <37 weeks), LGA (birth weight by gestation age >90th percentile) and severe LGA (birth weight by gestation age >97th percentile). We calculated adjusted incidence risk ratio (aIRR) for IFG, and a 1 SD increase in fasting glucose.
Findings: We included 640,469 women. Of these, 31,006 (4·84%) met the WHO cutpoint for IFG, 32,640 (5·08%) had PTB, 45,532 (7·11%) had LGA neonates and 16,231 (2·53%) had severe LGA neonates. Compared with women with normoglycaemia, women with pre-pregnancy IFG had a 6·0% higher risk of PTB (aIRR 1·06, 95%CI 1·01- 1·12), 10·0% higher risk of LGA (1·10, 1·06-1·14) and 17·0% higher risk of severe LGA (1·17, 1·10-1·25), these associations were similar in subgroups of women with various baseline characteristics. The aIRR for PTB per SD fasting glucose (0·7mmol/L) was 0·99 (95% CI 0·98-1·00), for LGA 1·04 (1·03-1·05) and for severe LGA 1·03 (1·01-1·04).
Interpretation: Our data support that maternal pre-pregnancy IFG is independently associated with higher risk of PTB, LGA and severe LGA. Early detection of IFG before pregnancy and appropriate interventions are warranted to improve pregnancy outcomes. Data also support that the WHO cut-point for IFG is too restrictive and lesser levels of fasting glucose also increase the risk of LGA and severe LGA.
Funding Statement: This work was partly supported by a grant National Natural Science Foundation of China (81773457 to JJT). The funder had no role in study design, data collection, data analysis, data interpretation, or writing the report.
Declaration of Interests: The authors declare no competing interests.
Ethics Approval Statement: The NFPHEP was approved by the Institutional Review Board of the Chinese Association of Maternal and Child Health Studies, Written informed consent was obtained from the participants before recruitment. The present study was executed jointly by Guangdong Institute of Family Planning Science and Technology and Guangzhou Medical University, in which the review boards determined that this study was exempt for ethical approval owing to the use of de-identified data.
Keywords: Pre-pregnancy healthcare; Impaired fasting glucose; Preterm birth; Larger for gestational age; Cohort study
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