Oral glucose tolerance outcomes among pregnant women receiving antenatal care in Calabar and environs – A pilot study

Abstract

Objectives: Dysglycemia is a common metabolic alteration during pregnancy with adverse effects on both mother and fetus. This is related to the fact that pregnancy is associated with insulin resistance which is a harbinger for hyperglycemia. This study was carried out to find out the prevalence of gestational diabetes mellitus (GDM) among pregnant women in Calabar area using International Association of Diabetes and Pregnancy Study Group (IADPSG) diagnostic values. Material and Methods: This was a prospective, observational, cross-sectional study among pregnant women attending antenatal care in four health facilities in Calabar and adjoining areas conducted from September 2018 to August 2019. All consenting pregnant women were given 75 g glucose in 250–300 mL of water after 8–10 h overnight fast, without regard to the presence or absence of GDM risk factors. GDM diagnosis was made if any of the following glucose values were met or exceeded: (1) Fasting >92 mg/dl, (2) 1 h post-glucose load >180 mg/ dl, and (3) 2 h post-glucose load >153 mg/dl. Data were analyzed using IBM Statistical Package for the Social Sciences version 20.0 and results were presented using tables and a Venn diagram. Results: There were 345 pregnant women aged 18–50 (28.7 ± 6.3) years at 24–41 (29.6 ± 4.1) completed weeks of gestation. GDM was diagnosed in 48 (13.9%) women. Fasting plasma glucose cutoff diagnosed 81% while 37.5% and 50.0% met the diagnostic cutoff for 1 h and 2 h, respectively, and 15 (31.3%) women were positive for all three diagnostic cutoffs. Diabetes mellitus in a first-degree relative was the most common risk factor identified while hypertension in a first-degree relative and history of GDM was the least. Some 36.5% of women had no identifiable risk factors. Those who had positive fasting plasma glucose only (6.1%) were more than twice those diagnosed by 1 and 2 h only (2.6%) combined. The number of women with glucose values in the diabetic range was 6 (1.72%) but was classified as GDM since they were not previously known diabetics. Conclusion: This study has shown that the prevalence of GDM is 13.9% among women in Calabar and environs using the IADPSG criteria. Fasting plasma glucose can identify more than twice GDM patients than 1 and 2 h values combined. GDM still remains a major health issue among pregnant women hence there should be a national policy on routine screening for GDM with more studies being encouraged to determine the preferred glucose cutoff among Nigerians.