Dietary restraint and weight gain during pregnancy

OBJECTIVES: To explore dietary intake and weight gain during pregnancy in relation to dietary restraint. DESIGN: Longitudinal prospective study. Attitudes to weight gain during pregnancy were assessed using self-administered questionnaires and dietary intake by 7-d weighed diet records in early and late pregnancy. SETTING: South West London 1995-1996. SUBJECTS: 74 Caucasian pregnant women expecting their first or second baby were recruited through a London hospital and data from 62 women were analysed. RESULTS: Restrained eaters were significantly less likely to experience weight gains within the recommended range for their pre-pregnancy body mass index (BMI) (P=0.026). They gained either more or less weight than recommended. CONCLUSIONS: Dietary restraint appears to have undesirable influences on eating and weight gain during pregnancy which require further attention.     

孕期增重及总增重与妊娠期糖尿病关系的队列研究

目的 探讨孕期增重及其总增重与妊娠期糖尿病（GDM）的关系。方法 采用前瞻性队列研究,于2013年3-9月选取成都市妇幼医疗机构产前门诊829名单胎健康孕妇作为基线调查对象,通过问卷调查于首次纳入时收集孕妇孕前等基线资料,于孕第（12±1）、（28±1）、（36±1）周及分娩前分别收集孕妇锻炼习惯、膳食摄入情况等信息和测量孕妇体重,分娩后收集分娩孕周等分娩信息。GDM诊断按中国妊娠合并糖尿病防治指南（2014）,采用多因素logistic回归分析孕早、中、晚期增重和孕期总增重与GDM的关系。结果 共682名孕妇纳入数据分析。控制生育年龄、孕前BMI、糖尿病家族史、高血压家族史、孕早期锻炼、产次、文化程度、家庭人均月收入及膳食能量等混杂因素后,多因素logistic回归分析显示：与孕早期增重适宜组相比,孕早期增重不足组和增重过多组GDM发生风险均增加（分别为OR=1.23,95% CI：0.63～2.38和OR=2.20,95% CI：1.12～4.35）;与孕中期增重适宜组相比,孕中期增重不足组和过多组GDM发生风险均降低（OR=0.47,95% CI：0.18～1.19和OR=0.78,95% CI：0.43～1.42）;与孕晚期增重适宜组相比,孕晚期增重不足组GDM发生风险增加（OR=1.48,95% CI：0.77～2.84）,增重过多组GDM发生风险降低（OR=0.53,95% CI：0.28～0.99）;与孕期总增重适宜组相比,总增重不足组GDM发生风险增加（OR=2.16,95% CI：1.04～4.46）,总增重过多组GDM发生风险降低（OR=0.74,95% CI：0.38～1.46）。结论 孕早期增重不足和过多均可能增加GDM发生风险,孕早期可能是影响GDM发生的关键时期,孕中晚期增重对GDM的影响还有待进一步论证。     

Dietary restraint and self-esteem as predictors of weight gain over an 8-year time period

The study aimed to assess dietary restraint and self-esteem as predictors of weight change over a time period of 8 years. Questionnaires assessing self-reported weight, body dissatisfaction, dietary restraint, and self-esteem were completed by 77 young adults (19 men and 58 women) on two occasions separated by 8 years. On average, participants gained approximately 6 kg over the 8 years. Although neither dietary restraint nor self-esteem predicted weight change on its own, their interaction did. Furthermore, the relationship between restraint and weight change was best described as curvilinear. It was concluded that dietary restraint is predictive of subsequent weight gain, but in a more complex way than previously assumed.     

Dietary energy density but not glycemic load is associated with gestational weight gain

BACKGROUND: Most pregnant women gain more weight than the ranges recommended. Excessive weight gain is linked to pregnancy complications and to long-term maternal and child health outcomes. OBJECTIVE: The objective was to examine the impact of dietary glycemic load and energy density on total gestational weight gain and the weight gain ratio (observed weight gain/expected weight gain). DESIGN: Data are from 1231 women with singleton pregnancies who participated in the Pregnancy, Infection, and Nutrition Cohort Study. Dietary information was collected at 26-29 wk of gestation with the use of a semiquantified food-frequency questionnaire. Linear regression models were used to estimate the associations between quartiles of glycemic load and energy density with total gestational weight gain and weight gain ratio. RESULTS: Dietary patterns of pregnant women significantly differed across many sociodemographic and behavioral characteristics, with the greatest contrasts seen for glycemic load. After adjustment for covariates, compared with women in the first quartile consuming a mean dietary energy density of 0.71 kcal/g (reference), women in the third quartile consuming a mean energy density of 0.98 kcal/g gained an excess of 1.13 kg (95% CI: 0.24, 2.01), and women in the fourth quartile consuming a mean energy density of 1.21 kcal/g gained an excess of 1.08 kg (95% CI: 0.20, 1.97) and had an increase of 0.13 (95% CI: 0.006, 0.24) units in the weight gain ratio. All other comparisons of energy intakes were not statistically significant. Glycemic load was not associated with total gestational weight gain or weight gain ratio. CONCLUSION: Dietary energy density is a modifiable factor that may assist pregnant women in managing gestational weight gains.     

Racial differences in gestational weight gain and pregnancy-related hypertension

PurposeThe aim of the study was to examine racial differences in gestational weight gain (GWG) and pregnancy-related hypertension.MethodsLogistic regression models tested racial differences in adequacy of GWG and pregnancy-induced hypertension in all singleton live births from the South Carolina 2004–2006 birth certificates.ResultsCompared with white women, black and Hispanic women had 16%–46% lower odds of gaining weight above the recommendations. However, the odds of inadequate GWG was ∼50% higher in black and Hispanic women with a pregnancy body mass index (BMI) less than 25 kg/m². Furthermore, compared with women with adequate GWG, women with excessive GWG had higher odds of pregnancy-related hypertension (underweight: 2.35, 95% confidence interval [CI; 1.66, 3.32]; normal: 2.05, 95% CI [1.84, 2.27]; overweight: 1.93, 95% CI [1.64, 2.27]; obese: 1.46, 95% CI [1.30, 1.63]). Among women with a BMI less than 25 kg/m², black women had higher odds of pregnancy-related hypertension than white women (underweight: 1.64, 95% CI [1.14, 2.36]; normal weight: 1.28, 95% CI [1.15, 1.42]), whereas among women with a BMI less than 25 kg/m², Hispanic women had 40% lower odds.ConclusionsPrograms are needed to curb excessive GWG in all racial groups and to help some sub-groups ensure adequate GWG. Maternal obesity and GWG are two factors that should be used in combination to reduce racial differences in pregnancy-related hypertension.     

中国城区妇女孕期增重适宜值研究

目的探讨中国妇女孕期体重增长适宜值。方法选取2013年1月—2016年5月于武汉市加入同济母婴健康队列(TMCHC)的单胎足月产孕妇6998人,于孕8～16周问卷调查了解其社会人口学、既往病史等资料并测量体重及身高。分娩前测量产前体重;分娩后通过医院记录收集分娩孕周、分娩方式、妊娠合并症、新生儿性别、出生体重及身长等信息。采用限制性三次样条回归模型分别拟合孕期增重与小于胎龄儿、大于胎龄儿、低出生体重、巨大儿、剖宫产、妊娠高血压及妊娠期糖尿病发生率关系曲线,寻找各妊娠结局发生率均较低的增重范围作为同济推荐值。将孕期增重的P25～P75作为百分位数法孕期增重推荐值。采用Logistic回归模型,分别以同济和百分位数法推荐孕期增重适宜值为参照,分析孕期增重过多或不足对不良妊娠结局的影响。结果 (1)不同孕前体质指数组各种不良妊娠结局发生率较低的孕期增重范围分别为:低体重组12.0～17.0 kg、正常体重组9.0～14.0 kg、超重组7.0～11.0 kg,以此作为孕期增重的同济推荐值。百分位数法孕期增重推荐值分别为:孕前低体重组14.0～19.0 kg、正常体重组13.0～19.0 kg、超重组10.8～18.0 kg及肥胖组9.0～15.8 kg。(2)与同济增重适宜组相比,增重过多组发生不良妊娠结局的风险分别为大于胎龄儿(OR=2.94,95%CI 2.31～3.73)、巨大儿(OR=3.13,95%CI 2.38～4.13)、剖宫产(OR=1.53,95%CI 1.38～1.71)及妊娠高血压(OR=2.18,95%CI 1.50～3.17);增重不足组发生的风险为小于胎龄儿(OR=1.82,95%CI 1.32～2.53)。按百分位数法推荐值分组,相应的风险值分别为大于胎龄儿(OR=2.11,95%CI 1.76～2.54)、巨大儿(OR=2.16,95%CI 1.76～2.65)、剖宫产(OR=1.53,95%CI 1.36～1.72)、妊娠高血压(OR=1.39,95%CI 1.02～1.90)及小于胎龄儿(OR=1.60,95%CI 1.29～1.98)。结论推荐中国孕妇孕期增重分别为:孕前低体重者12.0～17.0 kg、正常体重者9.0～14.0 kg及超重者7.0～11.0 kg。     

Effects of gestational weight gain on pregnancy complications

Introduction and objective

Gestational weight gain (GWG) has been reported to be associated with pregnancy outcomes. The aim of this study was to evaluate the effects of GWG on maternal and birth complications.

孕前体质指数及妊娠期体重增长与妊娠期糖尿病及高血压的关系

目的 研究孕前体质指数(pBMI)及妊娠期体重增长(GWG)与产妇患妊娠期糖尿病及高血压的关系.方法 回顾性分析2011年2月至2012年2月行常规产前检查并住院分娩的产妇1240例,记录pBMI、GWG、第24～ 28孕周的空腹血糖及血压水平.采用相关性分析及Logistic回归分析的方法研究pBMI及GWG与妊娠期糖尿病及高血压的关系.结果 根据pBMI分组,轻体重组260例,正常体重组917例,超重组36例,肥胖组27例.根据GWG分组,低度增长组104例,正常增长组758例,中度增长组249例,高度增长组129例.pBMI与GWG呈负相关(r=-0.646,P＜0.01).以正常体重组为参照,超重组妊娠期糖尿病发病率为11.11％(4/36),OR值为4.120,P＜0.05;肥胖组妊娠期糖尿病发病率为18.52％(5/27),OR值为7.492,P＜0.05;肥胖组妊娠期高血压发病率为11.11％(3/27),OR值为6.243,P＜0.05.以正常增长组为参照,低度增长组妊娠期糖尿病发病率为15.38％(16/104),OR值为9.006,P＜0.05;低度增长组妊娠期高血压发病率为4.81％(5/104),OR值为3.140,P＜0.05;高度增长组妊娠期高血压发病率为4.65％(6/129),OR值为3.033,P＜0.05.各组空腹血糖及血压水平比较差异无统计学意义(P＞0.05).结论 pBMI与GWG呈负相关,pBMI偏高及GWG偏低均是患妊娠期糖尿病及高血压的危险因素.     

妊娠20周前体重增长与妊娠期高血压关系的研究

目的：探讨妊娠20周前的体重增长与妊娠期高血压发生风险的关系。方法对自2013年1月至2013年4月在北京妇产医院进行常规产前检查并在本院分娩的1263例孕妇进行前瞻性巢式病例对照研究,病例组为发生妊娠期高血压的孕妇,对照组为血压正常的孕妇。收集年龄、身高、孕前体重、分娩前体重、妊娠期体重记录、高血压家族史、孕次、产次等资料,统计学方法采用t检验、χ2检验及多因素logistic回归分析。结果病例组的孕期总增重（17．94．5kg）高于对照组（16．44．4kg）,t＝2．54,P＝0．01;病例组的妊娠20周前体重增长（6．12．8 kg）也高于对照组（5．03．1kg）,t＝2．72, P＝0．01。按孕前体质量指数（BMI）分组后,对于BMI＜24 kg／m2的孕妇,病例组的孕期总增重和妊娠20周前的体重增长仍明显高于对照组（P＜0．05）;对于BMI≥24 kg／m2的孕妇,病例组的孕期总增重明显高于对照组（P＜0．05）,而妊娠20周前的体重增长与对照组相比虽然有增高趋势,但差异无统计学意义（P＞0．05）。控制年龄、孕前BMI、孕次、产次、高血压家族史、测量体重时的孕周等混杂因素后,妊娠20周前的体重增长每增加1kg,发生妊娠期高血压的风险增加12．5％（95％可信区间为1．038～1．220,P＝0．004）。结论妊娠20周前的体重增长是妊娠期高血压的危险因素,控制妊娠20周前的体重增长对于预防妊娠期高血压可能具有重要意义,尤其是对于孕前BMI＜24 kg／m2的孕妇。     

Excess gestational weight gain amplifies risks among obese mothers

In this issue of Epidemiology, Chen et al report that obese mothers who gained the most weight during pregnancy had elevated risk for infant mortality. Other outcomes related to excess maternal weight or weight gain not only cause complications around the time of birth but also confer elevated chronic disease risk for both mother and child. There is good reason to believe that constraining gestational weight gain within an optimal range will minimize adverse outcomes. Revised gestational weight gain guidelines are needed, especially for obese women.     

The bias in current measures of gestational weight gain

Conventional measures of gestational weight gain (GWG), such as average rate of weight gain, are likely to be correlated with gestational duration. Such a correlation could introduce bias to epidemiological studies of GWG and adverse perinatal outcomes because many perinatal outcomes are also correlated with gestational duration. This study aimed to quantify the extent to which currently used GWG measures may bias the apparent relationship between maternal weight gain and risk of preterm birth. For each woman in a provincial perinatal database registry (British Columbia, Canada, 2000-2009), a total GWG was simulated such that it was uncorrelated with risk of preterm birth. The simulation was based on serial antenatal GWG measurements from a sample of term pregnancies. Simulated GWGs were classified using three approaches: total weight gain (kg), average rate of weight gain (kg/week) or adequacy of GWG in relation to Institute of Medicine recommendations. Their association with preterm birth ≤32 weeks was explored using logistic regression. All measures of GWG induced an apparent association between GWG and preterm birth ≤32 weeks even when, by design, none existed. Odds ratios in the lowest fifths of each GWG measure compared with the middle fifths ranged from 4.4 [95% confidence interval (CI) 3.6, 5.4] (total weight gain) to 1.6 [95% CI 1.3, 2.0] (Institute of Medicine adequacy ratio). Conventional measures of GWG introduce serious bias to the study of maternal weight gain and preterm birth. A new measure of GWG that is uncorrelated with gestational duration is needed.     

Obesity and gestational weight gain: cesarean delivery and labor complications

OBJECTIVE: To assess the association between pre-gestational obesity and weight gain with cesarean delivery and labor complications. METHODS: A total of 4,486 women 20-28 weeks pregnant attending general prenatal care clinics of the national health system in Brazil from 1991 to 1995 were enrolled and followed up through birth. Body mass index categories based on prepregnancy weight and total weight gain were calculated. Associations between body mass index categories and labor complications were adjusted through logistic regression analysis. RESULTS: Obesity was present in 308 (6.9%) patients. Cesarean delivery was performed in 164 (53.2%) obese, 407 (43.1%) pre-obese, 1,045 (35.1%) normal weight and 64 (24.5%) underweight women. The relative risk for cesarean delivery in obese women was 1.8 (95% CI: 1.5-2.0) compared to normal weight women. Greater weight gain was particularly associated with cesarean among the obese (RR 4th vs 2nd weight gain quartile 2.2; 95% CI: 1.4-3.2). Increased weight at the beginning of pregnancy was associated with a significantly higher adjusted risk of meconium with vaginal delivery and perinatal death and infection in women submitted to cesarean section. Similarly, greater weight gain during pregnancy increased the risk for meconium and hemorrhage in women submitted to vaginal delivery and for prematurity with cesarean. CONCLUSIONS: Pre-gestational obesity and greater weight gain independently increase the risk of cesarean delivery, as well as of several adverse outcomes with vaginal delivery. These findings provide further evidence of the negative effects of prepregnancy obesity and greater gestational weight gain on pregnancy outcomes.