Significance of Low Levels of Glucose-6-Phosphate Dehydrogenase Levels in Pregnancy

To characterize the significance of Glucose-6- Phosphate Dehydrogenase (G6PD) levels measured in pregnancy.

We saw 3 patients referred to Hematology clinic over the past 1 year. The G6PD levels were measured in pregnancy by the obstetrician while working up the anemia (Table 1). They did not have any evidence of hemolysis during the time of workup and it is unclear as to why the G6PD levels were sent. The G6PD levels were found to be low and all 3 patients had iron deficiency anemia, that improved with iron supplementation. There was no evidence of pregnancy induced hypertension, urinary tract infections, or infections during pregnancy. All the pregnancies were uneventful resulting in healthy babies and the G6PD levels normalized after the delivery in all the patients. We did a literature search to see the significance of such an association and if there were any recommendations for further testing in these individuals.

G6PD deficiency is one of the most common inherited red cell disorders transmitted in an X-linked recessive fashion affecting approximately 400 million people worldwide. In the United States, black males are most commonly affected, with a prevalence of approximately 10 percent. Acute hemolysis is caused by infection, ingestion of fava beans, or exposure to an oxidative drug. G6PD catalyzes nicotinamide adenine dinucleotide phosphate (NADP) to its reduced form, NADPH, in the pentose phosphate pathway. NADPH protects cells from oxidative damage. G6pd deficiency predisposes cells to increased oxidative damage predisposing to hemolysis. G6PD deficiency in pregnancy may manifest as increased urinary tract infections, preeclamsia, neonatal jaundice, hydrops fetalis and still birth. Vergnes et al. [Lancet 1968] reported that low erythrocyte G6PD levels were found in 25% of women in early pregnancy and in up to 65% of women in late pregnancy. In their study G6PD levels normalized after delivery. The reason for this decrease is unclear. Pregnancy is shown to cause increased oxidative stress, alteration in neutrophil G6PD trafficking [ Kindzelskii et al. J Clin Invest 2002] though it is unclear if any of these mechanisms are implicated in the decreased levels of G6PD during pregnancy.

There are no clear guidelines for the subsequent testing and management of low levels of G6PD diagnosed in the setting of pregnancy. Evidence based guidelines would be helpful towards identifying the subset of patients with true G6PD deficiency.

No relevant conflicts of interest to declare.