Observational Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. May 15, 2019; 10(5): 304-310
Published online May 15, 2019. doi: 10.4239/wjd.v10.i5.304
Association of hypoglycaemia in screening oral glucose tolerance test in pregnancy with low birth weight fetus
Ananth U Nayak, Arun M A Vijay, Radha Indusekhar, Sushuma Kalidindi, Venkata M Katreddy, Lakshminarayanan Varadhan
Ananth U Nayak, Arun M A Vijay, Radha Indusekhar, Sushuma Kalidindi, Venkata M Katreddy, Lakshminarayanan Varadhan, Combined Antenatal Diabetes Clinic, University Hospital of North Midlands NHS Trust, Stoke on Trent ST4 6QG, Staffordshire, United Kingdom
Author contributions: Nayak AU and Katreddy VM contributed to study conception and design and writing of article; Nayak AU contributed to data acquisition, data analysis and interpretation, and writing of article; all authors contributed to editing, reviewing and final approval of article.
Institutional review board statement: This study was an audit undertaken in the Joint Antenatal Diabetes clinic at University hospital of North Midlands NHS Trust (UHNM Trust) and was approved and presented at the departmental audit meeting in the UHNM Trust.
Informed consent statement: The use of relevant patient database was approved for undertaking this audit locally. There was no active patient intervention in this study and written patient consent was not needed as per the audit requirements.
Conflict-of-interest statement: There are no conflicts of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Ananth U Nayak, FRCP, MBBS, MRCP, Consultant Physician and RCP Tutor, Combined Antenatal Diabetes Clinic, University Hospital of North Midlands NHS Trust, Newcastle Road, Stoke on Trent ST4 6QG, Staffordshire, United Kingdom. ananth.nayak@nhs.net
Telephone: +44–1782–679997 Fax: +44–8436–365428
Received: March 18, 2019
Peer-review started: March 20, 2019
First decision: April 13, 2019
Revised: April 18, 2019
Accepted: May 1, 2019
Article in press: May 1, 2019
Published online: May 15, 2019
Abstract
BACKGROUND

Gestational diabetes mellitus (GDM) is a common metabolic derangement in pregnant women. In the women identified to be at high risk of GDM, a 75 g oral glucose tolerance test (OGTT) at 24-28 wk gestation is the recommended screening test in the United Kingdom as per National Institute for Health and Care Excellence (NICE). Hypoglycaemia following the glucose load is often encountered and the implication of this finding for the pregnancy, fetus and clinical care is unclear.

AIM

To determine the prevalence of hypoglycaemia at any time during the screening OGTT and explore its association with birth weight.

METHODS

All deliveries between 2009 and 2013 at the local maternity unit of the University hospital were reviewed. Of the total number of 24,154 women without pre-existing diabetes, those who had an OGTT for GDM screening based on NICE recommended risk stratification, who had a singleton delivery and had complete clinical and demographic data for analysis, were included for this study (n = 3537). Blood samples for fasting plasma glucose (FPG), 2-hour plasma glucose (2-h PG) and HbA1c had been obtained. Birth weight was categorised as low (≤ 2500 g), normal or Macrosomia (≥ 4500 g) and blood glucose ≤ 3.5 mmol/L was used to define hypoglycaemia. Binary logistic regression was used to determine the association of various independent factors with dichotomized variables; the differences between frequencies/proportions by χ2 test and comparison between group means was by one-way ANOVA.

RESULTS

Amongst the study cohort (3537 deliveries), 96 (2.7%) women had babies with LBW (< 2500 g). Women who delivered a LBW baby had significantly lower FPG (4.3 ± 0.6 mmol/L, P = 0.001). The proportion of women who had a 2-h PG ≤ 3.5 mmol/L in the LBW cohort was significantly higher compared to the cohorts with normal and macrosomic babies (8.3% vs 2.8% vs 4.2%; P = 0.007). The factors which predicted LBW were FPG, Asian ethnicity and 2-h PG ≤ 3.5 mmol/L, whereas maternal age, 2-h PG ≥ 7.8 mmol/L and HbA1c were not significant predictors.

CONCLUSION

A low FPG and 2-h PG ≤ 3.5 mmol/L on 75-gram OGTT are significantly associated with low birth weight in women identified as high risk for GDM. Women of ethnic backgrounds (Asians) appear to be more susceptible to this increased risk and may serve as a separate cohort in whom we should offer more intensive follow up and screening for complications. Cost implications and resources for follow up would need to be looked at in further detail to support these findings.

Keywords: Hypoglycemia, Glucose tolerance test, Low birth weight, Pregnancy

Core tip: Hypoglycaemia following a glucose load in a oral glucose tolerance test is often encountered whilst screening for Gestational diabetes mellitus in pregnant women categorized as high risk and our study with a large cohort, confirms an association between hypoglycaemia and low birth weight (LBW) delivery. In addition to this, our study also finds that Asian ethnicity confers a risk for LBW babies.