探讨孕妇孕前体重指数(BMI)、孕期体重增加与新生儿出生体重及非选择性剖宫产的关系。

选取2000年1月1日至2010年5月1日于解放军五三七医院住院分娩的孕产妇3231例为研究对象。纳人标准：所有孕妇身体健康，无相关家族遗传疾病史和妊娠期合并症，均为初产、单胎妊娠。按照孕妇孕前BMI将其分为低BMI组(n=671)、正常BMI组(n=1845)和高BMI组(n= 715)；按照孕妇孕期体重增加值，又将其分为≤9 kg组(n=331)，(9~18)kg组(n=1755)和≥18 kg组(n=1145)，分别比较两种分组方式的三组新生儿中巨大儿及低出生体重儿发生率和非选择性剖宫产率，并分析孕妇孕期体重增加与新生儿中巨大儿及低出生体重儿发生率和非选择性剖宫产率的关系。各组受试对象年龄、相关家族遗传疾病史和妊娠期合并症、产次等比较，差异无统计学意义(P>0.05)(本研究遵循的程序符合本院人体试验委员会所制定的伦理学标准,得到该委员会批准，分组征得受试对象本人的知情同意，并与之签署临床研究知情同意书)。

三组孕前BMI不同孕妇新生儿出生体重比较，差异有统计学意义(P< 0.05)。孕前低BMI组的低出生体重儿发生率高，孕前高BMI组巨大儿发生率高，非选择性剖宫产率随孕妇孕前BMI降低而降低。三组孕妇孕期体重增加不同，新生儿出生体重比较，差异有统计学意义(P< 0.05)。孕妇孕期体重增加过多，则巨大儿发生率增加；孕妇孕期体重增加越少，非选择性剖宫产率则越低。

孕妇孕前BMI过高和孕期体重增加过多，可导致新生儿出生体重增加，非选择性剖宫产率增高。

To study the effect of maternal pre-pregnant body mass index (BMI) and gestational weight gain during pregnancy on birth weight of neonate and incidence of non-selected caesarean section.

From January 2000 to May 2010, 3231 cases of pregnancy women giving birth to a single baby for the first time were recruited into the study. Pre-pregnant BMI and weight gain during pregnancy were measured and the pregnancy outcomes were followed up. According to BMI, they were divided into low BMI group(n=671), normal BMI group(n=1845) and high BMI group(n=715). They were further divided into ≤9 kg group(n=331), (9-18) kg group(n=1755) and ≥18 kg group (n=1145) according to weight gain during pregnancy. There had no significant differences between age, relevant family history of genetic diseases, pregnancy complications and parity between two groups (P<0.05). The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Military 537 Hospital. Informed consent was obtained from all participants.

There were significant difference on birth weight of neonates in three groups of maternal pre-pregnant BMI (P<0.05). The incidence of macrosomia was significantly higher in high BMI group than that of normal BMI group and low BMI group. Pregnant women in low BMI group were more likely to give birth to babies with low birth weight than normal BMI group and high BMI group. The less maternal pre-pregnant BMI had the lower incidence of non-selected caesarean section existed. There were significant difference on birth weight of neonates in three groups of maternal weight gain during pregnancy among ≤9 kg group, (9-18) kg group, and ≥ 18 kg group (P< 0.05). The incidence of macrosomia was significantly higher in weight gain during pregnancy ≥18 kg group than (9-18)kg group and ≤9 kg group (P<0.05). The less mothers weight gain during pregnancy had, the lower incidence of non-selected caesarean section existed.

The neonates' birth weight and incidence of non-selected caesarean section increased by pre-pregnant over weight and high weight gain during pregnancy.