Metformin versus insulin in the management of diabetes mellitus in pregnancy

Arm 1: metformin only; starting dose 500mg taken orally twice daily and increased gradually every 2 weeks to a maximum dose of 2500mg or till optimum glycaemic control is attained. Treatment begins from enrolment till delivery. Arm 2: insulin only; starting total daily dose of insulin is 0.3-1.0 i.u/kg body weight depending on glycaemic profile at diagnosis. This is titrated up to achieve optimum glycaemic control. Total daily dose of premixed insulin is divided into 2: 2/3 administered 30 min before breakfast and 1/3 administered 30 minutes before supper. insulin is administered subcutaneously in the deltoid region. Insulin is administered from enrolment till delivery. Arm 3: metformin +insulin for failures on arm 1 Failures on arm 1 means worsening glycaemic profile on OGTT i.e. fasting blood glucose greater 7.0 mmol/l or 2-hour post glucose greater 11.0 mmol/l after maximum dose adjustment. Dose and duration of metformin and insulin in this arm is the same as their respective doses and durations in arms 1 and 2. Titration to higher doses is more aggressives to ensure strict control of glycaemic profile. Adherence is monitored tablet and drug return on review visit