Effect of Ramadan Fasting on Blood Glucose Level in Pregnant Women with Gestational and Type 2 Diabetes

Background: Pregnant women with diabetes are strongly advised against Ramadan fasting and have religious exemption, but a large proportion still choose to fast. Unfortunately, there is little information about glycemic control in these patients. This study aims to determine the fasting and postprandial blood glucose levels and to predict the risk factors for hypoglycemia in pregnant women with type 2 diabetes mellitus (DM) and gestational DM (GDM) who fast during Ramadan. Methods: A prospective cohort research was conducted at a single tertiary hospital between 2021 and 2023 on 70 pregnant women with GDM (n = 53) and type 2 DM (n = 17) in their second and third trimester. Their fasting and postprandial blood glucose levels during Ramadan were compared to those of the previous month, and hypoglycemia was defined as blood glucose levels less than 60 mg/dl. Binary regression was used to predict the risk variables for hypoglycemia. Results: The GDM and type 2 DM groups were similar in terms of age, parity, number of fasting days, and number of daily fasting hours. Only 26.9% of the women who were permitted to fast were given special instructions for Ramadan fasting. Dietary intervention was more common in the GDM group, whereas insulin and metformin treatment were more common in the type 2 DM group. The fasting glucose level decreased significantly after Ramadan fasting in both groups, from 92.5 (17.4) mg/dl to 90 (17.13) mg/dl (p = 0.033). However, there were a significantly higher number of hypoglycemia events in the type 2 DM group. Further, type 2 DM was identified as a risk factor for hypoglycemia (OR = 6.23; 95% CI = 1.04-37.54; P = 0.046. Conclusion: The present findings indicate that Ramadan fasting may improve fasting glucose control. In addition, type 2 DM was identified as a risk factor for hypoglycemia. Keywords: gestational diabetes, type 2 diabetes, pregnant women, cohort study, Ramadan fasting