Congenital methaemoglobinaemia in pregnancy

When methaemoglobin (MetHb) levels exceed 1.5% in the bloodstream, patients typically manifest cyanosis, the hallmark feature of this condition. Arterial blood takes on a dark brown hue, despite maintaining a normal partial pressure of oxygen. Suspicion of methaemoglobinaemia arises in individuals presenting with cyanosis and reduced oxygen saturation in the absence of notable cardiopulmonary symptoms. Co-oximetry with arterial blood gas is the definitive method for diagnosis, offering precise identification and quantification of MetHb levels in the blood. While acquired methaemoglobinemia has been commonly described, there are only a few reported cases of congenital methaemoglobinemia. We report a case of a pregnancy with congenital methaemoglobinaemia. A multidisciplinary team, comprising the obstetrician, physicians and haematologists, closely monitored this case. Despite her medical condition, she remained symptom-free throughout her pregnancy and underwent an uncomplicated delivery by caesarean section. We highlight the challenges in the management of such cases during the antenatal, labour, childbirth and postpartum period.