RISK-FACTORS FOR FETAL MACROSOMIA - THE IMPORTANCE OF A POSITIVE ORALGLUCOSE CHALLENGE TEST

Objective: The aim of this study was to investigate whether minor abno rmalities of glucose metabolism without gestational diabetes are a ris k factor for fetal overgrowth. Design: A sample of 1883 unselected whi te mother-infant pairs were screened for gestational diabetes using a 50 g l-h oral glucose challenge test (GCT) in two periods of pregnancy : early (16-20 weeks) and late (26-30 weeks). Methods: The effects of risk factors (glucose metabolism, previous history of mothers, obesity , multiparity and age of mothers) were estimated using a multinomial l egit model. Results: The level of risk was related to gestational age at the appearance of an abnormal GCT. Patients with an abnormal GCT in the early and late periods of pregnancy (Group 1) had a risk of deliv ering a large for gestational age (LGA) infant seven times higher than the control group (normal GCT in both periods), and patients with a n ormal GCT in the early period and an abnormal GCT in the late period ( Group 2) showed a risk three times higher than the control group. Amon g the historical risk factors for LGA infants, such as maternal obesit y, multiparity, previous gestational diabetes and previous delivery of an infant weighing 4000 g or more, only the latter was associated wit h fetal overgrowth with a risk level 4.7 higher than the control group . Group 1 patients had a significantly higher incidence of pregnancy-i nduced hypertension and preterm birth. There were no differences in th e frequency of 5-min Apgar score <7 and metabolic complications among the infants of all groups. We found a significantly higher rate of sho ulder dystocia in Group 1 infants than in infants in the other groups. Conclusions: Our results suggest that a positive GCT at 26-30 weeks i s the most important risk factor for fetal overgrowth. This result was strongly enforced in patients who had also shown a positive early GCT at 16-20 weeks.