Effect of Adding Metformin to Insulin in Uncontrolled Diabetic Patients During the 3rd Trimester of Pregnancy

Background Diabetes mellitus (DM) is a significant contributor to adverse obstetric and perinatal outcome. There is now clear and unequivocal evidence that adverse pregnancy outcomes are strongly linked to maternal hyperglycemia, both in the peri-conception period and throughout gestation. Although strict glycemic control does improve outcomes, there is still a higher rate of complications in women with DM and poorer perinatal outcomes .

The incidence of type 2 diabetes is rising worldwide at a remarkable rate IDF When receiving large doses of insulin, patients complain of pain at the site of injection leading to compliance issues and poor glycemic control. This can be explained as when taking large doses of insulin it leads to alter absorption kinetics because very large doses are delivered to one site, resulting in a failure to reduce postprandial hyperglycemia, but with later hypoglycemia once the insulin is absorbed. This poor glycemic control in mothers with diabetes leads to an increased risk of severe respiratory distress syndrome, low Apgar scores, neonatal hypoglycemia and neonatal intensive care unit (NICU) admissions .

Infants of mothers with diabetes have high rates of being born large for gestational age (LGA) and macrosomic (>4 or 4.5 kg). Macrosomia is associated with increased rates of perinatal asphyxia, meconium aspiration, hypoglycemia, shoulder dystocia, brachial plexus injury, skeletal injuries, and fetal death .

Metformin is among the oldest and most well studied oral anti hyperglycemic agents. Its efficacy has been demonstrated both in the primary prevention of disease and secondary prevention of diabetes-related morbidity and mortality. Because of metformin's proven efficacy, low cost, and minimal side effect profile, it is largely recommended as the first line, initial monotherapy and as part of any combination therapy (included with insulin) for the treatment and prevention of type II diabetes .

Metformin produces euglycemia by reducing insulin resistance, improving insulin sensitivity, reducing hepatic gluconeogenesis, and increasing peripheral glucose uptake and utilization.