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INTRODUCTION
Hyperglycemia in pregnancy encompasses diabetes that predates pregnancy and hyperglycemia first detected in pregnancy. Hyperglycemia first detected in pregnancy affects 15.8% of worldwide live births; affected pregnancies have an increased risk of preterm labor, caesarian section and neonatal hypoglycemia while previous hyperglycemia in pregnancy poses increased risk of adverse long term maternal and cardio metabolic diseases.
Prevalence data on Hyperglycemia in pregnancy in sub Saharan Africa is limited however; the international diabetes association estimates 9.6% of African women are affected, affecting 3.5% live births annually. True prevalence cannot be established as sub-Saharan Africa uses different screening and diagnostic approaches compared to the global estimates in their literatures and thus it is insufficient to show true prevalence in sub Saharan Africa.
Prevalence estimates from the International Association Diabetes in Pregnancy Study Group diagnostic criteria found out a prevalence of Hyperglycemia Diagnosed in pregnancy, in Nigeria to be 8.6% and 13.1% in Tanzania. The IADPSG recommends all women regardless of risk factors to undergo a single step 2 Hour 75g oral glucose tolerance test at 24-28 weeks of gestation using venous plasma glucose to establish hyperglycemia.
The objective of this study done here in Gambia was to determine the prevalence of Hyperglycemia Diagnosed in Pregnancy including gestational and diabetes in pregnancy, with a cohort of women in rural Gambia according to the current IADPSG diagnostic criteria and to compare diagnostic ability of capillary blood glucose sampling to identify Hyperglycemia diagnosed in pregnancy versus gold standard laboratory analysis of venous plasma glucose.
METHODS
This study used observational Data collected as part of the longitudinal Cohort study looking at hormonal and epigenetic regulators of growth (HERO-G). The primary focus of HERO-G was infant growth from birth to two years of age, the analyses presented here is limited to data collected during pregnancy.
This study took place between February 2014 and March 2015. All women of child bearing and reproductive age (18-45) living in West Kiang were invited to participate in this study.
Exclusive criteria for this study were specified as:
- HIV antibody positive or refusal of HIV testing
- Major congenital malformations
- Chronic diseases including sickle cell and asthma
- Already known pregnancy > 28 weeks of Gestation at recruitment
- Multiple pregnancies
Women that consented to be part of the study were visited monthly and asked about their date of last menstrual cycle, if there was no reason for missed menses they provided urine samples for pregnancy testing and sent to MRC field station Keneba for antenatal visit when pregnancy test was positive.
At booking, pregnancy status was confirmed by ultra sound gestational age ascertained, routine antenatal exams conducted and maternal weight and height collected. At 28 weeks, all women were invited to undergo a 75g OGTT following an overnight fast. Where results indicated Hyperglycemia in Pregnancy were referred to the midwife working in this study for repeat visits, monitoring of blood glucose and guidance given to the study participants on how to manage blood glucose levels.
The primary outcome assessed was the prevalence of Hyperglycemia diagnosed in Pregnancy including both Gestational Diabetes and Diabetes in Pregnancy using the IADPSG diagnostic criteria specifying GDM: Fasting blood glucose concentration >=5.1-6.9 mmol/l: >=10.0 mmol/l at 1 hour post load and >= 8.5 mmol/l at 2-hour post load while Diabetes in Pregnancy is specified as fasting glucose concentration >7.0 mmol/l.
Ethical approval for this study was given by the joint Gambia Government/MRC Unit the Gambia Ethics Committee (SCC 1313V3), with additional approval from the university of Colorado institutional Research board (Protocol number 13-0441). Prior to the beginning of the study community approval was sought from each participating village and written informed consent obtained from each participant.
RESULTS
1669 women across the west kiang region were eligible for the HERO-G study. 1392 consented to take part in the study, from this 1392 women 398 had positive urine pregnancy test, of these 314 went for antenatal visit (N=63 were withdrawn or excluded) and from that number 251 were eligible to take part in the study.
199 and 244 women had venous and capillary glucose concentration recorded for 28 weeks of antenatal visits, 198 women had both venous and capillary measurement. 247 women were recorded to have delivered.
38 women were identified with Hyperglycemia in pregnancy by venous sampling for both Gestational Diabetes and Diabetes in Pregnancy giving an estimate prevalence of 16.1%. Most women were diagnosed using fasting blood glucose thresholds. 29 women 14.6% had Gestational Diabetes whilst a further 3 women 1.5% had significant glucose intolerance to warrant diagnosis of Diabetes in Pregnancy.
38 women were identified with Hyperglycemia Diagnosed in Pregnancy using Capillary Samples producing a prevalence of 15.5%. Of these 34 women were diagnosed with Gestational Diabetes Mellitus 13.9% and 4 women diagnosed with Diabetes in Pregnancy 1.6%. The greatest number of women were diagnosed on the basis of their Fating Capillary blood glucose levels perhaps owing to the fact that Capillary blood sampling showed more sensitivity and specificity compared to Venous plasma blood Sampling .(80.7% and 62.3% and 27% in Southern India, 91% and 57% in Western Kenya 89% and 27% in South Africa). In this study, capillary sampling had a specificity and sensitivity of 95.2% and 68.8%.
Presence of Hyperglycemia Diagnosed in Pregnancy was not associated to maternal age, parity or BMI at enrollment into this study.
CONCLUSION
The prevalence of Hyperglycemia diagnosed in pregnancy accounts for 16.1% within this population of women in rural kiang was higher than anticipated. Measuring fasting venous plasma glucose sampling alone may be of Diagnostic potential where conducting a full OGTT is not feasible, such as in resource limited setting. There was a strong agreement between capillary blood glucose and venous plasma glucose concentration, although the diagnostic accuracy of capillary sampling versus venous sampling could not be established because of laboratory conditions for handling venous samples are not optimized.
Capillary Sampling may be a value for excluding diseases and limiting costly laboratory based investigations
REFERENCE OF ARTICLE FOR FURTHER READING AND AUTHORS.
Doel, A.M., Bernstein, R.M. and Moore, S.E. (2020) “Prevalence estimates of diabetes in pregnancy in a rural, sub-saharan population,” Diabetes Research and Clinical Practice, 169, p. 108455. Available at: https://doi.org/10.1016/j.diabres.2020.108455.
