孕妇孕期适宜体质量增加范围的探讨及其与新生儿出生体质量的关系

Gestational weight gain and its relationship with the birthweight of offspring

目的探讨健康足月孕妇孕期适宜体质量增加范围及其与新生儿出生体质量的关系。方法选择2010年1—12月在首都医科大学附属北京妇产医院和北京市海淀区妇幼保健院分娩的健康足月单胎孕妇16460例，将孕妇的年龄、身高、孕前体质指数（BMI）、历次产检体质量、分娩孕周与方式、新生儿卅生体质量等指标录人统一的病例回顾调查数据库，采用回顾性分析的方法对数据进行分析。以孕前BMI〈18．5kg／m^2定义为孕前低体质量组，孕前BMI为18．5～〈24．0k∥m。定义为孕前正常体质量组；孕前BMII〉24kg／m。为孕前超重组。新生儿出生体质量〈2500g为低出生体质量儿，2500～〈4000g为正常出生体质量儿，其中2900～3499g为最适宜出生体质量儿，≥4000g为巨大儿。结果（1）3组孕妇孕期体质量增加范围及新生儿卅生体质量：16460例孕妇孕期平均体质量增加范围（17．1±4．9）k，新生儿平均出生体质量为（3406±400）g，其中低出生体质量儿发生率为0．92％（152／16460），巨大儿发生率为7．55％（1242／16460）。孕前低体质量组（3089例）、正常体质量组（11478例）、超重组（1893例）孕妇的孕期体质量增加范围[分别为（17．4±4．6）、（17．3±4．8）、（15．6±5．3）k]与新生儿出生体质量均呈正相关关系（r分别为0．276、0．256和0．170，P均〈0．01）。3组孕妇孕期体质量增加范围、新生儿出生体质量分别比较，差异均有统计学意义（P均〈0．01）；巨大儿发生率3组间分别比较，差异均有统计学意义（P均〈0．01）。（2）百分位法分析3组孕妇孕期适宜的体质量增加范围：3组出生适宜体质量新生儿共8449例，孕前低体质量组、正常体质量组及超重组孕妇孕期体质量增加范围分别为14．0～19．5kg、13．5～19．5kg及11．0～18．0kg，平均增加16．0kg最为适宜。（3）孕期体质量增加不同孕妇的妊娠结局：以结果（2）中推荐的孕期适宜体质量增加范同为标准，将16460例孕妇分为孕期体质量增加过少、增加适宜和增加过多3个类别，与体质量增加适宜孕妇比较，体质量增加过少孕妇分娩低出生体质量儿的风险增加（OR值为1．589，95％CI为1．085～2．326），分娩巨大儿的风险降低（OR值为0．500，95％CI为0．401～0．624）；而体质量增加过多并不能降低出生体质量儿的风险（OR值为1．168，95％CI为0．774～1．764），同时，分娩巨大儿的风险却会增加1倍（OR值为2．031，95％CI为1．789～2．306）。（4）受试者工作特征（ROC）曲线对孕妇孕期最佳体质量增加值的分析：将孕妇孕期体质量增加值作为预测新生儿卅生体质量〈2900g或≥3500g的指标，结果发现，对于孕前低体质量组孕妇最佳孕期增加范围是16．3～16．7kg，正常体质量组是15．6～17．8kg，超重组是14．6～15．1kg。平均最佳孕期增加范围是15．6～16．7kg。孕期体质量增加16．0k比较合适，与百分位法结论一致。结论孕妇孕期体质量增加值与新生儿出生体质量密切相关，建议孕妇孕期体质量增加控制在16．0kg左右比较合适。

Objective To explore the appropriate weight gain during pregnancy and its relationship with the birthweight of offspring. Methods A total of 16 460 healthy pregnant women who delivered in Beijing Obstetrics and Gynecology Hospital and Haidian Maternity and Child Health Care Hospital in 2010 were recruited. All are singleton pregnancies. Conditions of bahies and mothers were recorded, including maternal age, height, prepregnant weight, pregnant weight, gestational weeks on delivery, delivery mode and newborn birthweight. All the pregnant women were divided into underweight, normal weight and overweight group according to their prepregnant body mass index and the criteria of overweight and obesity for Chinese adults. Birthweight between 2500 g and 4000 g was defined as normal birthweight, and 2900 g to 3499 g was defined as appropriate birthweight. Logistic regression model and receiver operating characteristic （ROC） curve analysis were used to explore the recommended gestational weight gain （GWG）. Results （ 1 ） The average GWG of the 16 460 women was （ 17.1 ±4.9） kg, and the average birthweight of the babies was （3406 ± 400） g. Prevalence of low birthweight and maerosomia was 0. 92% （152/16 460 ） and 7.55% （1 242/16 460） , respectively. GWG of underweight （ n = 3089） , normal weight （ n = 11 478 ） and overweight group （n = 1893） was （17.4 ± 4.6） kg, （17.3 ± 4.8） kg and （15.6 ± 5.3） kg, respectively. And GWG was positively related with the birthweight of offspring （P 〈 0. 01 ）. The differences of GWG, neonatal birthweight and macrosomia prevalenee among the three groups are statistieally significant （P 〈 0. 01 ）. （2） There are 8449 appropriate birthweight babies in the three groups. For their mothers in the underweight, normal weight and overweight group, the recommended range of GWG were 14.0 - 19.5 kg, 13.5 - 19. 5 kg and 11.0 - 18.0 kg, respectively. The recommended GWG for all women was 16.0 kg. （3） According to the recommended GWG, low GWG will increase the risk of low birthweight （OR = 1. 589, 95% Cl：1. 085 - 2. 326） and reduce the risk of macrosomia （ OR = 0. 500, 95% CI： 0. 401 -0. 624）. Excessive GWG will increase the risk of maerosomia （ OR = 2.031, 95% CI： 1. 789 - 2. 306 ） , but will not lower the risk of low birthweight （ OR = 1. 168, 95% CI：0. 774 - 1. 764）. （4） For the underweight, normal weight and overweight group, the range of GWG obtained by the receiver operating characteristic （ROC） curve analysis were 16. 3 - 16.7 kg, 15.6 - 17.8 kg and 14.6 - 15.1 kg. For all the three groups, the range was 15.6 - 16. 7 kg. The ranges obtained by the ROC curve analysis were all within the recommended range. Conclusion The GWG was positively associated with the birthweight of offspring, and the appropriate GWG was around 16. 0 kg.