Metformin-associated lactic acidosis in a pregnant patient

Metformin-associated lactic acidosis is a rare but serious condition and potentially even more hazardous during pregnancy. We reported a case of lactic acidosis in a 28-year-old pregnant woman (gravida 3, para 0, abortion 2, ante-partum 22 weeks) after ingestion of 39.50 g (approximately 80 tablets) metformin in a suicide attempt. She had no pre-existing systemic illness. Analysis of arterial blood gases revealed a high anion gap (28.1 mEq/l) and a normal osmol gap (8 mEq/l) metabolic acidosis. Other etiologies of high anion gap and normal osmol gap metabolic acidosis were excluded by laboratory investigation. The patient was treated on an emergency basis and received aggressive fluid management, intravenous sodium bicarbonate (1 mEq/kg) and activated charcoal, orally. The fetal condition was monitored intensively. The fetus was delivered smoothly via vaginal delivery in a healthy state at the 38th gestational week. Clinical follow-up over the next 2 years confirmed no congenital abnormality. We present a case of successful management of metformin-associated lactic acidosis during pregnancy, treated simply, with intravenous sodium bicarbonate and intensive fetal monitoring. This relatively noninvasive method is an effective treatment option. However, hemodialysis still has a valuable role in the management of acidosis which proves refractory to conservative treatment, such as that described.