The current research employed a cross-sectional descriptive design to capture a ‘snapshot’ of gestational diabetes in Mopani district. Questionnaire adapted from Michigan Diabetes Research and Training Centre DCP 2.0 which has been piloted signifies reliability of the present study findings.
A systematic review conducted in sub-Saharan Africa reported the prevalence of GDM ranging between 0 and 9% [5]. Almost 6% of pregnancies in the United States (US) are affected by GDM with prevalence ranging from 1–25% depending on the population and diagnostic criteria used [18]. In Nigeria, one study found the prevalence of GDM to be 3.8%, 8.1%, 7.5%, and 8.6% in accordance with 1999 WHO, new 2013 WHO modified IADPSG and IADPSG criteria [19]. A recent prospective cohort study conducted at a level 1 clinic in Gauteng province of South Africa reported the prevalence of GDM to be 7%, 17% and 26% in accordance with 1999 WHO, National Institute for health and Care Excellence (NICE) and IADPSG [7]. In this study, the prevalence of GDM was 1.9%.
Moreover, the reason for low prevalence of GDM in this study is not documented; however, small sample size might have contributed. Another contributing reason could be that studies used different diagnostic criteria in determining the prevalence of GDM. International uniformity for ascertainment and diagnosis of GDM has not been reached and has remained an argumentative issue [20]. WHO has recognized and adopted the IADPSG diagnostic criteria, however the implementation of this new criterion in screening for GDM remains debatable due to lack of evidence from prospective randomised studies to show improved maternal and foetal outcome with this adoption [20].
There are three screening approaches of GDM and these are one-step approach, two-step approach and clinical risk factors approach. With one-step approach, 75 g two-hour fasting oral glucose test is done; this approach is commonly [18]. Regarding the two-step approach, it involves firstly administering a 50 g non-fasting Oral Glucose Challenge Test at 24 to 28 weeks of gestation followed by a 100 g fasting test for women who had a positive screening test from first administration of glucose [18]. Furthermore, this approach has been found to be easy to perform and generally well tolerated in comparison with one-step approach [18].
This abovementioned finding resonates with a study conducted which demonstrated that a modified two-step screening strategy with a Glucose Challenge Test (GCT) and clinical risk factors might be a practical and alternative to the universal one-step approach with a 75 g OGTT to reduce the workload and the need for a fasting test in about 50% of women [21].
Several studies have reported various risk factors associated with GDM. In contrast, in the present study, maternal age and BMI were not statistically associated with GDM. This can be attributed to a small sample size and less cases of GDM identified in this study (2 cases from n = 101). In this study, women with GDM were not significantly more obese or overweight than those without gestational diabetes (P = 1.000). Moreover, this is not in line with other studies which showed that diabetes is highly correlated with obesity [22]. The reason for high BMI being as risk factor for GMD is because of weight gain in pregnancy which is more likely to promote hyperglycaemia.
In agreement with previous studies conducted, family history of diabetes mellitus was significantly associated with GDM. Family history of diabetes in first degree relatives have been found to be the most significant risk factors for gestational diabetes which further emphasizes the role of genetics in susceptibility toward this condition [1, 6, 24, 25]. In addition, a study proposed that screening and early identification of this possible risk factor in pregnant women would be helpful and cost-effective in planning maternal health services and providing high quality prenatal care to women who may develop gestational diabetes mellitus [26].
A prospective study conducted in China among Chinese women found that higher educational level was related to reduce risk of gestational diabetes after adjustment for potential confounders [27]. A cross-sectional study conducted amongst pregnant women attending their first prenatal clinic at Korle-Bu Teaching hospital in Accra, found higher level of education positively associated with the development of GDM [28]. A study conducted in Italy found that high levels of maternal education were associated with reduced risks of gestational diabetes compared to less educated women. The reason for this might be that higher educational level provides pregnant women with more knowledge for understanding the risk factors associated with GDM [27].
Similarly, a matched pair case-control study conducted with 276 GDM women and 276 non-GDM women in two hospitals in Beijing China was done and it was found that the number of women who developed GDM was significantly higher in those who received more than 12 years of education when compared to those who received less than 9 years of education with p-value of 0.001 [29]. The reason for this might be lifestyle change and diet i.e. consumption of fast food. Education, income and place of residence showed no correlation with GDM diagnosis [30]. Similar to this, the finding of the present study, showed no significant association between level of education and GDM, however, pregnant women with secondary education were more likely to have shown signed of GDM. In Netherlands, one study found that low maternal education level was associated with GDM [31]. This might be because lower education status is related to a traditional diet which is inexpensive but has high concentration of fat and carbohydrate contents.
In this study, marital status was not significantly associated with the development of gestational diabetes. a study conducted in Beijing, China showed that more pregnant women in control group were married compared to those with GDM and that was no statistical significant association between marital status and GDM with p-value of 0.069 [29]. The present study did though highlight that married pregnant women were more likely to be above 35 years of age (P = 0.052). A population-based prospective study conducted in Netherlands showed that maternal lower income was associated with increased the risk of GDM [31]. In contrast to this study, there was no significant association between employment status and GDM (P = 0.535). This finding is in line with previous studies which found no significant relationship between household income and GDM [27, 32].
Regarding the limitations of this study, the sample size in this study was small which in turn affected the generalizability of this research study findings to the overall population of pregnant women. One of this study objective was to describe the maternal and infant outcomes associated with gestational diabetes mellitus. As a result of poor documentation on participant’s antenatal medical records (maternity casebook and hospital), there was no information about infant and maternal adverse health outcomes specifically those on those who were diagnosed with gestational diabetes. This information was important because it could have demonstrated the association between the infant and maternal health outcomes with GDM. Furthermore, information on the participants’ medical records was insufficient to be captured on data entry form which resulted in missing data.