Aim: This study aims to explore fetal and maternal complications of macrosomia; and also to compare fetal characteristics of macrosomia infants of GDM and Non- GDM mothers. Methodology: This is a retrospective study, on women who delivered macrosomia infants over a two-year period (2014-2015), at the University of Lubumbashi hospital and Don Bosco Clinic in Lubumbashi/ Democratic Republic of Congo. Obstetrical parameters were taken from the labor register and all data were analyzed using SPSS 17.00 statistical software; independent and paired sample t- test, Chi-square tests were performed (__ampersandsignalpha;=0.05 level, 95 % confidence interval). Results: A total of 87 women, with a mean age of 32.73 51 (__ampersandsignplusmn; 5.16) were enrolled into the study. From these women 54 % had Gestational Diabetes Mellitus (GDM).Mean birth weight of babies from GDM mothers (4182.25 __ampersandsignplusmn; 177) was higher than those with Non-GDM mothers (4156__ampersandsignplusmn;165.662) with a p value __ampersandsignlt;0.05.This study revealed that GDM induce hypoglycemia in newborn(X2=4.252 and p=0.001) but other parameters such as Cephalohematoma and perineal mortality were not statistically associated with GDM. Conclusion: Fetal characteristics of macrosomia can be different when it occurs in infants from GDM mothers or non-GDM mothers. Hypoglycemia in infants was found to have a strong association with GDM. The main recommendation is to increase Glucose control during pregnancy in order to minimize any risk in the infants.