[Factors relevant to newborn birth weight in pregnancy complicated with abnormal glucose metabolism].

OBJECTIVE: To investigate the influencing factors of neonatal birth body mass in women with abnormal glucose metabolism during pregnancy.

METHODS: A study was conducted on 1157 singleton gravidas, who were diagnosed and treated for abnormal glucose metabolism and delivered in the Department of Obstetrics and Gynecology, First Hospital, Peking University from January 2005 to December 2009, by reviewing the medical records. Based on the pre-pregnant body mass index, the selected cases were divided into 4 groups: low body mass group [body mass index (BMI) < 18.5 kg/m(2), n = 53], ideal body mass group (BMI 18.5-23.9 kg/m(2), n = 647), over body mass group (BMI 24.0-27.9 kg/m(2), n = 323), and obese group (BMI ≥ 28.0 kg/m(2), n = 134). 1157 newborns were divided by birth body mass into 3 groups: normal birth body mass group (body mass 2500-4000 g, n = 987), of which 545 cases of birth body mass 3000-3500 g for the appropriate newborns, macrosomia group (body mass ≥ 4000 g, n = 112); low birth body mass group (body mass < 2500 g, n = 58). The following information was collected, including pre-pregnancy body mass, height, gestational age of diagnosis and body mass gain after diagnosis, maternal serum level of cholesterol, history of adverse pregnancy, and family history of diabetes, gestational age, delivering body mass, neonatal birth body mass. The influence of pre-pregnant BMI, body mass gain during pregnancy, gestational age of diagnosis, body mass gain after diagnosis, maternal serum level of cholesterol, family history of diabetes on the newborns' birth body mass was analyzed. The appropriate ranges of gestational body mass gain were calculated in women with abnormal glucose metabolism.

RESULTS: (1) The average neonatal birth body mass for each group respectively were (3142 ± 333) g for low body mass group, (3339 ± 476) g for the ideal body mass group, (3381 ± 581) g for over body mass group, and (3368 ± 644) g for obese group. The neonatal birth body mass was increasing with maternal pre-pregnant BMI, and average birth body mass of the newborns in low body mass group was lower than other 3 groups, respectively, the difference was statistically significant (P < 0.05). The difference was not statistically significant (P > 0.05), when it was compared among the obese group, ideal weight group and over body mass group. (2) The body mass gain during pregnancy in women delivered normal birth weight newborn and delivered macrosomia for each group respectively were (13.5 ± 4.5) and (17.1 ± 5.4) kg for the ideal body mass group, (11.6 ± 4.9) and (15.3 ± 6.4) kg for the over body mass group, (10.3 ± 5.0) and (14.7 ± 7.4) kg for the obese group. The difference was statistically significant in 3 groups (P < 0.05). The difference of body mass gain during pregnancy in women delivered normal birth weight newborn and delivered macrosomia for low body mass group could not be compared statistically, because of only 1 case delivered macrosomia. (3) The gestational age of diagnosis in women who delivered normal birth weight newborn and macrosomia for the ideal body mass group respectively were (27.8 ± 5.8) and (29.8 ± 5.3) weeks, the difference was statistically significant (P < 0.05). The gestational age of diagnosis in gravidas who delivered normal birth weight newborn and macrosomia for the over body mass group respectively were (26.7 ± 6.8) and (30.2 ± 4.1) weeks, the difference was statistically significant (P < 0.05). The gestational age of diagnosis in women who delivered normal birth weight newborn for obese group was (26.2 ± 7.5) weeks, less than that of pregnant women who delivered macrosomia [(25.7 ± 9.3) weeks], but the difference was not statistically significant (P > 0.05). The difference of the diagnosed gestational age for low body mass group could not be compared statistically, because of only 1 case delivered macrosomia. (4) The serum triglyceride (TG) levels of pregnant women who delivered macrosomia was (3.1 ± 1.5) mmol/L, higher than that of pregnant women who delivered normal birth weight newborn [(2.7 ± 1.2) mmol/L], and the difference was statistically significant (P < 0.01). The serum high density lipoprotein cholesterol (HDL-C) levels of pregnant women who delivered macrosomia was (1.4 ± 0.3) mmol/L, lower than that of pregnant women who delivered normal birth weight newborn [(1.7 ± 0.9) mmol/L], and the difference was statistically significant (P < 0.01). The serum low-density lipoprotein cholesterol (LDL-C) and cholesterol level of pregnant women who delivered macrosomia respectively was (2.8 ± 0.8) and (5.4 ± 1.1) mmol/L, less than those of pregnant women who delivered normal birth weight newborn [(3.0 ± 0.9) mmol/L and (5.6 ± 1.1) mmol/L], but the difference was not statistically significant (P > 0.05). (5) The final regression model of variables into the top three were pre-pregnant BMI, body mass gain during pregnancy and maternal serum level of HDL-C, when analyzing the related factors of affecting neonatal birth body mass with multiple logistic regression analysis such as age, history of adverse pregnancy, family history of diabetes, pre-pregnancy BMI, body mass gain during pregnancy and after diagnosis of abnormal glucose metabolism, maternal serum level of cholesterol, abnormal glucose metabolism categories, gestational age and other factors (P < 0.01).

CONCLUSION: Pre-pregnant BMI, body mass gain during pregnancy and maternal serum level of HDL-C may affect the neonatal birth body mass whose mothers were complicated with abnormal glucose metabolism during pregnancy.