【Objective】 To investigate the morbidity of macrosomia and to explore its risk factors in Guangdong. 【Methods】A total of 222 cases of macrosomia (≥4000 g) were collected as the study group from 13 large hospitals such as First Affiliated Hospital of Sun Yat-sen University in Guangdong during Oct 2010 to Nov 2010. Meanwhile

414 neonates of normal birth weight (2500-3999 g) were gathered as the control group. To calculate the morbidity of macrosomia and to compare their mothers age

gravidity

parity

height

pregestational weight

prepartum weight

weight gain

geatational weeks

mode of delivery

neonatal body index and complication; To analyze the related factors and risk factors of macrosomia. 【Results】 There were 222 cases of macrosomia and its morbidity was 2.78 %; Weight gain were different between the control group and the study group [(14.59 ± 4.47) kg vs (17.73 ± 5.08) kg

P < 0.05]; In the study group

incidence of gestational diabetes mellitus (16.9 % vs 5.6 %

P < 0.01) and polyhydramnios (7.8 % vs 1.2 %

P < 0.01) was higher; Incidence of vaginal spontanese delivery (20.1% vs 47.5%

P < 0.05) was lower and incidence of c-section was higher (78.5 % vs 51.0 %

P < 0.01); There was significant difference in gender distribution between the study group and the control group (146/76 vs 229/185

P < 0.01); So was head circumstance [(35.75 ± 1.07) cm vs (33.70 ± 1.53) cm

P<0.01]. Related factors of macrosomia were gestational weeks

gravidity

height

pregestational weight

pregestational BMI

prepartum weight

prepartum BMI and weight gain; Risk factors of macrosomia were age

geatational weeks

prepartum weight and gestational diabetes mellitus. 【Conclusion】 The morbidity of macrosomia is 2.78 % in Guangdong and its risk factors were age

gestational weeks

prepartum weight and gestational diabetes mellitus; Macrosomia should be paid enough attention to and estimated by four maneuvers of Leopold and ultrasound in those pregnant women of risk factors.