[The relationship between the timing of gestational diabetes screening and HbA1c level and neonatal outcome]

The aim of this study was to observe clinical outcomes of the mother and her infant who were possibly exposed to high blood glucose at least 2-3 months in the early and midterm pregnancy by checking gestational weeks (GW) and the first HbA1c level at initial diagnosis of gestational diabetes (GDM).

A total of 107 GDM patients and their newborns were subject of this study. GDM patients were newly diagnosed at the Holy Family Hospital of Catholic University from January 2003 until December 2007 and continuously managed in the diabetes center. Patients medical records were retrospectively reviewed to evaluate GW and HbA1c level at the time of diagnosis, and clinical outcomes of mother and newborn baby.

The proportion of subjects who had been diagnosed of having GDM according to GW was 7.5%, in less than 24th week of pregnancy; 55.1% in the 24-28th week; 28.0% in the 29-32nd week; and 9.4% 33rd week or more. There were 39 out of 107 subjects (36.4%) with HbA1c levels >or=6.5% and 26 out of 39 subjects (24.3%) with HbA1c levels >or=7.0%. In clinical outcomes of newborn by HbA1c levels, the frequency of delivery of large for gestational age (LGA) infant was higher in mothers diagnosed with GDM after 29th week of pregnancy or with HbA1c levels 7.0% or more (P<0.001).

If the screening test for gestational DM was delayed, HbA1c level and the risk for LGA seemed to be higher, so it may be necessary to screen GDM no later than 24th week of pregnancy.