Diabetes Care, Vol 20, Issue 9 1368-1369, Copyright © 1997 by American Diabetes Association
Maternal serum ferritin and gestational impaired glucose tolerance
TT Lao and KF Tam
Department of Obstetrics and Gynaecology, University of Hong Kong, Tsan Yuk Hospital, Hong Kong, China.
OBJECTIVE: To determine if the reported features of decreased iron store in
the infant of diabetic mother are related to underlying maternal iron
deficiency, a prospective case-control study was performed on a group of
low-risk antenatal patients without preexisting anemia or thalassemia trait
and before the diagnosis of gestational diabetes mellitus (GDM) in the last
trimester. RESEARCH DESIGN AND METHODS: At the time of routine screening
for anemia and GDM at 28-30 weeks of gestation, an additional blood sample
was collected for the assay of serum ferritin, iron, and total iron binding
capacity (TIBC). Patients with elevated random sugar underwent a 75-g oral
glucose tolerance test (OGTT), interpreted by the World Health Organization
criteria. For each person diagnosed with GDM, a control subject matched in
maternal age and parity was identified, and their iron status and
hematological indexes were compared. RESULTS: There were 60 patients with
gestational impaired glucose tolerance (GIGT), and none had frank GDM.
There was no difference in the hematological indexes or serum iron and TIBC
values, but serum ferritin level was significantly increased in the GIGT
group, when compared with control subjects. CONCLUSIONS: The findings
indicate that there was no evidence of preexisting iron deficiency in the
third trimester before the diagnosis of GIGT, while serum ferritin was even
increased in the GIGT patients, a phenomenon that could have reflected the
glucose intolerance. Serum ferritin is probably an unreliable index for
maternal iron therapy in these patients, and the role of iron therapy in
GIGT patients remains to be established.