Background

United Arab Emirates (UAE) has a high prevalence of obesity in the population. Maternal weight gain is one of the risk factors for gestational diabetes mellitus (GDM) which is defined as glucose intolerance with onset or first recognition during pregnancy. GDM is associated with poor outcomes for both the mother and the fetus. Recent research suggests that epigenetic changes take place in the fetus, due to the hyperglycemic environment, well before GDM is diagnosed and that this has a lasting impact on the offspring in the form of increased risk for obesity from childhood and increased risk of diabetes in later life. Early identification of women at risk and better management of GDM is therefore very important not only to reduce obstetric complications but also to prevent its transgenerational impact.

Aim
To study association of pre-gestational Body Mass Index (BMI) with development of Gestational Diabetes Mellitus (GDM) and biochemical parameters in women of Arab ethnicity in UAE.

Method
Arab women, 11-13 weeks pregnant, visiting the obstetric clinic of Thumbay Hospital Ajman and antenatal clinics at the Primary Health Centers in Ajman were invited to participate in this prospective study. Ethics approval was obtained from the Ministry of Health, UAE and informed consent taken from the women. Demographic data, personal and family medical history, height and pre-pregnancy body weight were noted using a questionnaire. Diabetic women and those with other chronic diseases were excluded. First trimester glycated hemoglobin (HbA1c) and Pregnancy Associated Plasma protein-A (PAPP-A) levels were measured in blood. The enrolled pregnant women were then followed up as per routine in the clinics. One step screening for GDM was performed, in the second trimester, as per American Diabetes Association 2016 guidelines. Data was analyzed using statistics software SPSS 22.0. ANOVA, T-test, Mann-Whitney tests were used for significance, Pearson’s and Spearman’s test for correlations.

Results
227 pregnant women participated in the study. Age (mean±SD) of the participants was 28.4±4.8 years (range 18-42). 35.2% were primigravidae. 40.5% had a family history of diabetes mellitus and 16.4% had GDM in the previous pregnancy. 33% of the women mentioned not taking any vitamin or folate supplements. 25% of the women had hemoglobin values less than 11.2 g/dL. Based on the pre-gestational BMI, 47.6% of the women were normal (BMI 18.9-24.9 Kg/m2), 30% overweight (BMI 25-29.9 Kg/m2) and 22.6% obese (BMI ≥30 Kg/m2). Pre-gestational BMI correlated positively and significantly (p= 0.011) with first trimester HbA1c. Mean±SD HbA1c (%) in normal women was 5.37±0.35, in overweight women 5.47±0.37 and in obese women 5.60±0.38. This difference between the groups was statistically significant (p=0.001). Using HbA1c cutoff of ≥5.7%, BMI (Mean ±SD) of the group was 27.19±5.10 Kg/m2 which was significantly higher than those with HbA1c less than 5.7% (25.61±4.74, p=0.03). Similarly PAPP-A (Multiples of Median) was found to be significantly different between the groups. It was (mean ±SD) 1.50±1.12 in normal,1.23±1.01 in overweight and 0.98±0.90 in obese women (p=0.014). Blood pressure was also varied significantly (p=0.00) between the groups. Systolic mean±SD was 101.96±9.31, 106.69±14.14 and 110.73±11.83 and Diastolic mean±SD was 67.59±6.62, 70.94±7.81 and 72.59±7.79 mm Hg in normal, overweight and obese women respectively. These women were followed up prospectively in the clinics. Screening for GDM showed a prevalence of 29.2% among the enrolled participants. Fasting plasma glucose values correlated strongly and significantly (p=0.00) with 2-hour plasma glucose after load. Pre-gestational BMI (mean±SD) of women diagnosed with GDM was significantly higher (28.62±5.59) compared to the normal group (25.85 ± 4.82), p=0.02. Significantly (p= 0.006) higher number of both overweight (45%) and obese women (41%) developed GDM compared to normal weight women (13.3%). ROC analysis showed pre-gestational BMI to be a significant predictor (p=0.003) for GDM and the area under the curve was 0.651.

Discussion
52.6% of pregnant Arab women are overweight or obese before pregnancy. 1 in 3 women are not taking folate supplementation in the first trimester and are anemic as well. Women with higher pre-gestational BMI had higher HbA1c levels, lower first trimester Pregnancy Associated plasma protein-A levels, and were at increased risk for development of Gestational Diabetes Mellitus in the second trimester. Interventions are needed to address obesity in Arab women of reproductive age in the UAE since it can have long term effects on the offspring as well.

Conflict of Interest: I have no potential conflict of interest to disclose

Acknowledgements: This study was funded by the Al Jalila Foundation, UAE

Pre-gestational body mass index and development of gestational diabetes mellitus in women of Arab ethnicity