Maternal and fetal consequences of increased gestational weight gain in women of normal prepregnant weight

OBJECTIVE: To study the effects of increased gestational weight gain in women of normal prepregnant weight. PATIENTS AND METHODS: We compared 174 patients gaining more than 18 kg to 174 patients gaining between 9 and 15 kg. Body mass index was normal for every woman included in the study. RESULTS: Weight gain > or =18 kg was associated with increased risk of vascular complications (5.2% vs. 1.1%, P < 0.05) but not with increased risk of mellitus diabetes (5.2% vs. 4.0%, NS). Weight gain > or =18 kg prolonged labor length (414.4 +/- 147 min vs. 376.5 +/- 166.4 min, P < 0.05) and increased the rate of cesarean section (19.5% vs. 10.3%, P < 0.05). Neonatal outcome was similar in both groups, mean birth weight was greater (3413.6 +/- 427.0 g vs. 3163.4 +/- 495.1 g, P < 0.05) and the frequency of infants weighing more than 4000 g at birth was increased (8.0% vs. 4.0%, P < 0.05) among women gaining more than 18 kg. CONCLUSION: Excess weight gain in pregnancy affects gestational and delivery outcomes and results in higher frequency of fetal macrosomia. These results confirm recommendations on weight gain in pregnancy as guidelines for pregnant women.     

Maternal weight, pregnancy weight gain, and the risk of antepartum stillbirth

OBJECTIVE: This study investigated whether the risk of antepartum stillbirth increases with body mass index during early pregnancy and also investigated the association between weight gain during pregnancy and the risk of antepartum stillbirth.Study Design: This population-based case-control study included 649 women with antepartum stillbirths and 690 control subjects among Swedish nulliparous women. RESULTS: Compared with lean mothers (body mass index < or = 19.9 kg/m2), the odds ratios for risk of antepartum deaths were as follows: normal weight (body mass index, 20.0-24.9 kg/m2) odds ratio, 1.2 (95% confidence interval, 0.8-1.7); overweight (body mass index 25.0-29.9 kg/m2), odds ratio, 1.9 (95% confidence interval, 1.2-2.9); and obese (body mass index > or = 30.0 kg/m2) odds ratio, 2.1 (95% confidence interval, 1.2-3.6). For term antepartum death corresponding risks were even higher, with odds ratios of 1.6 (95% confidence interval, 0.9-2.6) for normal weight, 2.7 (95% confidence interval, 1.5-5.0) for overweight, and 2.8 (95% confidence interval, 1.3-6.0) for obese women, respectively. Maternal weight gain during pregnancy was not associated with risk of antepartum stillbirth. CONCLUSION: Maternal overweight condition increased the risk of antepartum stillbirth, especially term antepartum stillbirth, whereas weight gain during pregnancy was not associated with risk.     

孕前体重孕期增重与新生儿出生体重的关系

目的 分析孕前体重、孕期增重与新生儿出生体重的关系,为降低低出生体重儿及巨大儿发生率提供科学依据。方法 根据孕前体重指数（Ｂｏｄｙ Ｍａｓｓ Ｉｎｄｅｘ,ＢＭＩ）将研究对象分为高体重、理想体重和低体重三组,分别计算平均出生体重和巨大儿、低出生体重儿发生率;进一步分组分析妇女的孕期不同增重与低出生体重儿及巨大儿发生的关系。结果 与理想休重组相比,高体重组巨大儿发生率较高（９．１％）,低体重组的低出生     

The Relationship Between Weight Gain in Pregnancy, Birth-Weight and Postpartum Weight Retention

Summary: A total of 292 middle class, nonsmoking Chinese patients with known prepregnant weight who subsequently had uncomplicated singleton pregnancies delivering after 36 weeks' gestation were recruited to assess their serial antenatal weight gain, weight at 6 weeks and 3 months postpartum. The average prepregnant body mass index in the whole group was 20.4 kg/m² (SD 2.19), and the total pregnancy weight gain was 14 kg (SD 3.75). Those with weight gain over 17.83 kg (one SD above the mean) (n=58) had higher weight gain in all 3 trimesters taken separately, as well as higher weight retention at 6 weeks and 3 months postpartum (p <0.001). Similar differences were noted for those with total weight gain over 2 standard deviations above the mean. The average weight retained at 3 months postpartum was 3.64 kg (SD 2.75). Those with weight retention over 9.14 kg (2 SD above the mean) (n=8) had a significantly higher second and third trimester weight gain (p <0.01) compared to the rest. These data suggest that excessive weight gain during pregnancy for women with prepregnant BMI in the normal range occurred most significantly after the mid-trimester, and was associated with higher postpartum weight retention without significant increase in birth-weight.     

妊娠合并糖代谢异常孕妇的体重适宜增长

目的 探讨适合糖代谢异常孕妇妊娠期适宜体重增长范围.方法 对2005年1月至2007年12月在北京大学第一医院分娩的妊娠合并糖代谢异常的足月单胎且病历资料完整的孕产妇661例进行回顾性分析.根据孕前体重指数(BMI)将研究对象分为低体重组(BMI<18.5)40例(Ⅰ组);正常体重组(BMI 18.5～23.9)400例(Ⅱ组);超重组(BMI 24～27.9)162例(Ⅲ组);肥胖组(BMI≥28.0)59例(Ⅳ组).分析孕前不同BMI组正常出生体重儿和巨大儿母亲的孕期增重,并计算出新生儿出生体重在3000～3500 g产妇的孕期平均增重,作为各孕前BMI组孕期适宜的体重增长.结果 孕前不同BMI组分娩巨大儿者孕期增重明显大于分娩正常体重儿者的孕期增重,Ⅱ组孕期平均增重分别为(17.0±5.2)kg和(14.1±4.7)kg,m组孕期平均增重分别为(16.8±7.3)kg和(11.9±5.1)kg,Ⅳ组孕期平均增重分别为(18.3±6.7)kg和(11.2±5.4)kg,差异有统计学意义(P<0.05).各组孕妇孕期平均体重增长和适宜增重范围:Ⅰ组(15.6±3.3)kg,(14.0～18.O)kg,Ⅱ组(13.9±4.6)kg,(11.0～16.5)kg,Ⅲ组(11.5±5.2)kg,(9.0～15.0)ks,Ⅳ组(10.1±2.9)kg,(7.0～12.7)kg.结论 对孕前不同体重的糖代谢异常孕妇进行血糖监测的同时,使其妊娠期体重增长在各自适宜的范围,有助于获得理想出生体重的新生儿.     

Urinary incontinence during pregnancy

OBJECTIVE: To investigate incidence and prevalence of urinary incontinence during pregnancy and associated risk factors. METHODS: The data collection was conducted as part of the Norwegian Mother and Child Cohort Study at the Norwegian Institute of Public Health. We present questionnaire data about urinary incontinence obtained from 43,279 women (response rate 45%) by week 30. We report data on any incontinence, in addition to type, frequency, and amount of incontinence. Potential risk factors were investigated by logistic regression analyses. RESULTS: The prevalence of incontinence increased from 26% before pregnancy to 58% in week 30. The corresponding figures for nulliparous women were 15% and 48%, and for parous women 35% and 67%. The cumulative incidence was 46%. Stress urinary incontinence was the most common type of incontinence in week 30 of pregnancy, experienced by 31% of nulliparous and 42% of parous women. The majority of pregnant women had leakage less than once per week and droplets only, both before and during pregnancy. Parity was a strong and significant risk factor for incontinence in adjusted analyses both before pregnancy (odds ratio [OR] 2.5, 95% confidence interval [CI] 2.4-2.7 for primiparous and OR 3.3, 95% CI 3.1-3.5 for multiparous women) and during pregnancy (ORs 2.0, 95% CI 1.9-2.1 and 2.1, 95% CI 2.0-2.2, respectively). Age and body mass index were weaker, but still statistically significant, risk factors. CONCLUSION: The prevalence of urinary incontinence increases substantially during pregnancy. Incontinence both before and during pregnancy seems to be associated with parity, age, and body mass index. LEVEL OF EVIDENCE: II.     

Efficacy of an intervention to prevent excessive gestational weight gain

OBJECTIVE: This study was undertaken to evaluate the efficacy of an intervention directed at preventing excessive gestational weight gain. STUDY DESIGN: Healthy pregnant women with normal and overweight early pregnancy body mass index were monitored from early pregnancy until 1-year postpartum. One hundred seventy-nine women in the intervention group had their gestational weight gains monitored by health care providers and also received by-mail patient education. Three hundred eighty-one women formed an historical control group. The proportions in each group gaining more weight in pregnancy than is recommended and retaining more than 2.27 kg at 1-year postpartum were compared using logistic regression analysis. RESULTS: Low-income women who received the intervention had a significantly reduced risk of excessive gestational weight gain (odds ratio [OR]=0.41, 95% CI=0.20-0.81). Overweight women within this income subgroup were at significantly reduced risk of retaining more than 2.27 kg (OR=0.24, 95% CI=0.07-0.89). CONCLUSION: The intervention appeared to reduce the risk of excessive gestational weight gain only in the low-income subgroup.     

正常孕妇体重增加的监测模式

目的确定正常孕妇孕期体重增加的模式,为孕期保健提供参考。方法收集１９９５年１月１日至１９９５年１２月３１日１５６２例孕产妇的资料,并对无妊娠合并症及新生儿出生体重在２５００～３９９９ｇ的１１０５９例次产前检查资料进行分析。结果产妇平均年龄２６．４９±３．０２岁;平均身高１５８．６９±４．８５ｃｍ。根据孕前体质指数（ＢＭＩ）可将孕妇分为低ＢＭＩ（＜１６．７５）、正常ＢＭＩ（１６．７５～２３．７１）及高ＢＭＩ（＞２３．７１）３类。各类孕妇的ＢＭＩ随孕周增加而递增,尤以正常ＢＭＩ孕妇最为明显;３类孕妇孕期ＢＭＩ增加分别为８．０７、５．３７、３．８２。结论ＢＭＩ较单纯体重增加更能反映孕妇体重改变的情况     

Factors that are associated with cesarean delivery in a large private practice: the importance of prepregnancy body mass index and weight gain

OBJECTIVE: The purpose of this study was to examine body mass index and pregnancy weight gain as risk factors for primary cesarean delivery in nulliparous women in a middle-class private practice. STUDY DESIGN: Primiparous women who delivered in a private practice setting between February 1993 and July 13, 2001, were included. CIs along with Z statistics for paired count data were used to assess the statistical significance and relative importance of the relationships of body mass index and maternal weight gain to cesarean delivery. The effect of body mass index was examined as related to known confounders such as gestational age, birth weight, maternal age, and maternal height. RESULTS: The overall cesarean delivery rate for primiparous women was 21.76%. Risk of cesarean delivery increased consistently and significantly (P <.0001) with increasing body mass index. This effect was primarily mediated through an increase in cesarean delivery carried out for cephalopelvic disproportion/failure to progress. In our practice, the primiparous woman whose body mass index is >30 kg/m(2) is six times more likely to have a cesarean delivery for the diagnosis of cephalopelvic disproportion/failure to progress than the primiparous woman whose body mass index is <20 kg/m(2). This differential in cesarean delivery rate persisted when controlled for birth weight and gestational age and continues to persist when maternal age and height are also controlled. Excessive pregnancy weight gain exerted a statistically significant effect on cesarean delivery rate. This increase was primarily related to cephalopelvic disproportion/failure to progress among the nonobese women. CONCLUSION: Maternal body mass index is related strongly to the ability of primiparous women to be delivered vaginally without great difficulty. In fact, lean patients are excellent labor performers, particularly in contrast with obese patients. The relationship of increased body mass index to increased cesarean delivery is due to an increased rate of cephalopelvic disproportion/failure to progress. Excessive pregnancy weight gain is associated with a doubling of cephalopelvic disproportion/failure to progress rate in nonobese patients.     

Weight gain restriction for obese pregnant women: a case-control intervention study

Objective  To minimise obese women's total weight gain during pregnancy to less than 7 kg and to investigate the delivery and neonatal outcome.
Design  A prospective case–control intervention study.
Setting  Antenatal care clinics in the southeast region of Sweden.
Population  One hundred fifty-five pregnant women in an index group and one hundred ninety-three women in a control group.
Methods  An intervention programme with weekly motivational talks and aqua aerobic classes for obese pregnant women.
Main outcome measures  Weight gain in kilograms, delivery and neonatal outcome.
Results  The index group had a significantly lower weight gain during pregnancy compared with the control group ( P < 0.001). The women in the index group weighed less at the postnatal check-up compared with the weight registered in early pregnancy ( P < 0.001). The percentage of women in the index group who gained less than 7 kg was greater than that of women in the control group who gained less than 7 kg ( P = 0.003). The percentage of nulliparous women in this group was greater than that in the control group ( P = 0.018). In addition, the women in the index group had a significantly lower body mass index at the postnatal check-up, compared with the control group ( P < 0.001). There were no differences between the index group and the control group regarding birthweight, gestational age and mode of delivery.
Conclusion  The intervention programme was effective in controlling weight gain during pregnancy and did not affect delivery or neonatal outcome.     

Beginning regular exercise in early pregnancy: effect on fetoplacental growth

OBJECTIVE: Our purpose was to test the null hypothesis that beginning regular, moderate-intensity exercise in early pregnancy has no effect on fetoplacental growth.Study Design: Forty-six women who did not exercise regularly were randomly assigned at 8 weeks either to no exercise (n = 24) or to weight-bearing exercise (n = 22) 3 to 5 times a week for the remainder of pregnancy. Outcome variables included antenatal placental growth rate and neonatal and placental morphometric measurements. RESULTS: The offspring of the exercising women were significantly heavier (corrected birth weight: 3.75 +/- 0.08 kg vs 3.49 +/- 0.07 kg) and longer (51.8 +/- 0.3 cm vs 50.6 +/- 0.3 cm) than those born to control women. The difference in birth weight was the result of an increase in both lean body mass and fat mass. In addition, midtrimester placental growth rate was faster (26 +/- 2 cm(3)/wk vs 21 +/- 1 cm(3)/wk) and morphometric indexes of placental function were greater in the exercise group. There were no significant differences in neonatal percentage body fat, head circumference, ponderal index, or maternal weight gain. CONCLUSIONS: These data indicate that beginning a moderate regimen of weight-bearing exercise in early pregnancy enhances fetoplacental growth.     

A Case for Revising the ''Weight Gain During Pregnancy'' Guidelines for Australian Women

In 1989, an average weight gain during pregnancy of 14 kg was determined for a sample of 1,253 public patients at the Royal Women's Hospital, Brisbane. This greatly exceeded the weight gain of 10 to 12 kg which was recommended by the hospital and which is based on United States of America (US) data. The finding prompted a comparison of characteristics of Brisbane mothers (weight gain during pregnancy, age, prepregnant weight, height, birth-weight of infant, etc) with the characteristics of mothers in two large US studies. Significant differences were found to exist with Brisbane women being taller, heavier in body mass, more overweight and gaining less weight during pregnancy than the US women. Unexpectedly, the birth-weight of infants was neither more nor less than reported for the American studies. Further studies to gain more information about Australian women during their pregnancies should be undertaken.     

Prepregnant Weight and Weight Gain During Pregnancy: Relationship to Functional Status, Symptoms, and Energy

Objective: To examine the relationship of prepregnancy weight and pregnancy weight gain to functional status, physical symptoms, and physical energy.
Design: Longitudinal panel, with data collected at the end of each trimester. Functional status was measured by the Inventory of Functional Status–Antepartum Period; physical symptoms, by the Symptoms Checklist; and physical energy, by a one-item question. Self-reported weight and height were used to calculate body mass index (BMI), using the formula weight[kg]/height[m²].
Setting: Women's homes.
Participants: Two hundred twenty-two women, whose pregnancies were low-risk, drawn from a larger study.
Results: Women were classified by prepregnancy BMI as underweight (BMI < 19.8), normal weight (BMI = 19.8–26.0), or overweight (BMI > 26.0). The groups did not differ in weight gain by trimester, for an average total weight gain of 30.56 lb ( SD = 10.18, range = 1–64) (p > .05), with overweight women therefore gaining less weight on a percentage basis (M = 16.87%) than women who were of normal weight (M = 23.58%) or were underweight (M = 26.02%) ( p < .00005). The groups did not differ in functional status, physical energy, or number or type of physical symptoms. Women who gained more than the recommended amount of weight for their prepregnant weight group had a lower level of 3rd trimester functional status than those who did not.
Conclusions: Individual counseling of women regarding food intake and excessive weight gain during pregnancy needs to be reconsidered in light of these findings.     

Body mass index, midwifery intrapartum care, and childbirth lacerations

Weight status is an important determinant of many health indices. Data from a clinical trial on measures to lower genital tract trauma in vaginal birth were used for a secondary analysis. The goal was to describe the relationship of body mass index and pregnancy weight gain to clinical intrapartum care, infant birthweight, and genital tract trauma with vaginal birth. Intrapartum care measures and labor events did not vary by maternal weight status. Overweight and obese women were more likely to be parous, and Hispanic or American Indian. Total pregnancy weight gain decreased, and infant birthweight increased as body mass index category increased. Obese women who gained 40 or more pounds during pregnancy had elevated rates of macrosomia and genital tract lacerations.     

Relation of parity to pregnancy outcome in a rural community in Zimbabwe

This population-based cohort study was conducted to compare pregnancy complications and outcome among nulliparous, low (1-5) and high (> or = 6) parity women. Women who registered for antenatal care and gave birth in Guru District, Zimbabwe, between January 1995 and June 1998 were classified into groups by parity. The women were compared for baseline characteristics, utilisation of health facilities and occurrence of pregnancy complications such as hypertensive disorders of pregnancy, haemorrhage, pre-term delivery, operative delivery, low birth weight and perinatal death. In estimating risk, primiparous (parity = 1) women were used as referents. Pregnancy records for 10,569 women were analysed. Mean ages of nulliparous and high parity (> or = 6) women were 20.1 and 37.7 years respectively (p < 0.001). Prevalence of anaemia at booking (haemoglobin < or =10.5 g/dl) was reduced in nulliparous compared to multiparous women (11.7% vs 16.8%; p > or = 0.001). Nulliparous women were likely to book early (< or = 20 weeks) for antenatal care, have a higher number of visits (> or = 6) and fewer home births. Nulliparous women had higher risk for low birth weight (RR 1.70; 95% CI 1.36 - 2.13). Compared to low parity women, nulliparous and high parity women had an elevated risk of hypertensive complications RR 1.62 (95% CI 1.37-1.92) and RR 1.64 (95% CI 1.29 - 2.07) respectively. The risk of developing any pregnancy complications was highest in nulliparous women (RR 1.48; 95% 1.31- 1.67). In conclusion, nulliparous women had an increased risk of pregnancy complications. High parity women with no previous complicated pregnancy were at low risk of complications.     

Low midpregnancy placental volume in rural Indian women: A cause for low birth weight?

OBJECTIVE: We sought to study midpregnancy placental volume in rural Indian women, its maternal determinants, and its relationship to neonatal size. STUDY DESIGN: We performed a prospective community-based study of maternal nutrition and fetal growth in 6 villages near the city of Pune. Measurements included midpregnancy placental volume determined by means of ultrasonography at 15 to 18 weeks' gestation, maternal anthropometric measurements before and during pregnancy, and maternal blood pressure and biochemical parameters during pregnancy. Neonatal size and placental weight were measured at birth. RESULTS: The mothers were short and underweight (mean height, 1.52 m; weight, 42 kg; body mass index, 18 kg/m(2)) and produced small babies (mean birth weight, 2648 g). Midpregnancy placental volume (median, 144 mL) was related to the mother's prepregnancy weight (r = 0.15; P <.001) but not to weight gain during pregnancy, blood pressure, or circulating hemoglobin, ferritin, red blood cell folate, or glucose concentrations. Midpregnancy placental volume was related to placental weight at birth (r = 0.29; P <.001) and birth weight (r = 0.25; P <.001) independent of maternal size. CONCLUSION: In Indian mothers midpregnancy placental volume is significantly associated with prepregnant maternal weight and is an independent predictor of birth weight. Our findings may provide clues to the high prevalence of low-birth-weight infants in India.     

糖代谢异常孕妇体质量及相关因素对新生儿出生体质量的影响

目的 探讨影响糖代谢异常孕妇新生儿出生体质量的相关因素.方法 选择2005年1月-2009年12月在北京大学第一医院分娩的临床资料齐全的妊娠合并糖代谢异常足月单胎孕妇1157例,根据孕前体质指数(BMI)分成4组:53例BMI＜18.5 kg/m2为低体质量组,647例BMI18.5～23.9 kg/m2为理想体质量组,323例BMI 24.0～27.9 kg/m2为超体质量组,134例BMI≥28.0 kg/m2为肥胖组.1157例新生儿按出生体质量分为:出生体质量2500～4000 g为正常体质量儿(987例),其中545例出生体质量3000～3500 g为适宜体质量儿;出生体质量≥4000 g为巨大儿(112例);出生体质量＜2500 g为低体质量儿(58例).记录其孕前体质量、身高、糖代谢异常诊断时间及诊断时体质量、孕期血脂水平、不良产史、糖尿病家族史、分娩孕周、分娩时体质量、新生儿出生体质量.分析孕前BMI、孕期体质量增长(分娩时体质量-孕前体质量)、诊断糖代谢异常的孕周、诊断后孕妇体质量增长(分娩时体质量-诊断糖代谢异常时体质量)、孕期血脂水平、不良产史及糖尿病家族史对新生儿出生体质量的影响及计算孕前不同BMI孕妇分娩适宜体质量儿的孕期体质量适宜增长范围.结果 (1)新生儿平均出生体质量:低体质量组为(3142±333)g,理想体质量组为(3339±476)g,超体质量组为(3381±581)g,肥胖组为(3368±644)g.新生儿出生体质量随孕前BMI增加而增加,低体质量组新生儿平均出生体质量低于其他3组,分别比较,差异均有统计学意义(P＜0.05);但理想体质量组、超体质量组、肥胖组间分别比较,差异均无统计学意义(P＞0.05).(2)分娩正常体质量儿和巨大儿孕妇的孕期体质量增长:分娩正常体质量儿及分娩巨大儿的各组孕妇孕期体质量增长为,理想体质量组分别为(13.5±4.5)及(17.1±5.4)kg,超体质量组分别为(11.6±4.9)及(15.3±6.4)kg,肥胖组分别为(10.3±5.0)及(14.7±7.4)kg,3组分别比较,差异均有统计学意义(P＜0.05);低体质量组分娩巨大儿的孕妇仅1例,无法进行统计学分析.(3)分娩正常体质量儿和巨大儿孕妇的糖代谢异常诊断孕周:理想体质量组分别为(27.8±5.8)及(29.8±5.3)周,超体质量组分别为(26.7±6.8)及(30.2±4.1)周,两者分别组内比较,差异均有统计学意义(P＜0.05);肥胖组分别为(26.2±7.5)及(25.7±9.3)周,差异无统计学意义(P＞0.01);低体质量组分娩巨大儿孕妇例数仅1例,无法进行统计学分析.(4)分娩正常体质量儿与巨大儿孕妇的血脂水平:分娩巨大儿孕妇血清甘油三酯水平[(3.1±1.5)mmol/L]明显高于分娩正常体质量儿的孕妇[(2.7±1.2)mmol/L,P＜0.01];分娩巨大儿孕妇血清高密度脂蛋白胆固醇水平[(1.4±0.3)mmol/L]明显低于分娩正常体质量儿的孕妇[(1.7±0.9)mmol/L,P＜0.05];分娩巨大儿孕妇血清低密度脂蛋白胆固醇及总胆固醇水平[分别为(2.8±0.8)及(5.4±1.1)mmol/L]均低于分娩正常体质量儿的孕妇[分别为(3.0±0.9)及(5.6±1.1)mmol/L],但差异无统计学意义(P＞0.05).(5)影响新生儿出生体质量的相关因素:将年龄、不良产史、糖尿病家族史、孕前BMI、孕期体质量增长、诊断糖代谢异常后孕妇体质量增长、孕期血脂水平、糖代谢异常分类、诊断孕周等因素进行logistic多元回归模型分析,最终进入回归模型的变量中排在前3位的是孕前BMI、孕期体质量增长及高密度脂蛋白胆固醇水平(P＜0.01).结论 妊娠合并糖代谢异常孕妇新生儿出生体质量与孕前BMI、孕期体质量增长、孕期血浆高密度脂蛋白胆固醇水平相关.     

Prenatal risk indicators of a prolonged pregnancy. The Danish Birth Cohort 1998-2001

BACKGROUND: Few prenatal risk factors of prolonged pregnancy, a pregnancy of 42 weeks or more, are known. The objective was to examine whether sociodemographic, reproductive, toxicologic, or medical health conditions were associated with the risk of prolonged pregnancy. METHODS: Data from the Danish Birth Cohort in Denmark were used. Interview data from 53,392 participants with live-born singleton deliveries in the period 1998-2001 were available at the time of this study. The participants were interviewed by telephone at 12 and 30 weeks' gestation, and 6 and 18 months after delivery. Statistical analyses were done using logistic regression. RESULTS: Women with a pre-pregnancy body mass index of 25 kg/m2 or more had a high risk of prolonged pregnancy. If the pre-pregnancy body mass index was 35 kg/m2 or more the odds ratio was 1.52 (95% CI 1.28-1.82). Nulliparity also increased the risk of prolonged pregnancy (OR (95% CI) = 1.35 (1.27-1.44)). CONCLUSIONS: The risk of post-term delivery was high in women with a pre-pregnancy body mass index of 25 kg/m2 or more, and in nulliparous women.     

双胎妊娠孕期不同阶段体质量增长速度与母婴结局的关系

目的:分析双胎妊娠孕期不同阶段体质量增长情况与母婴结局的关系。方法:对2013年1月至2015年10月在上海交通大学医学院附属国际和平妇幼保健院住院分娩的472例双胎妊娠产妇的临床资料进行回顾性分析,比较不同孕前BMI孕妇孕期体质量增长情况,在校正年龄和孕前BMI后,使用二元Logistic回归分析孕期不同阶段体质量增长速度与孕期并发症、早产、胎膜早破和新生儿出生体质量的关系。结果:(1)孕早中期平均体质量增长速度0.41±0.15 kg/w,孕晚期平均体质量增长速度0.64±0.30 kg/w,整个孕期平均体质量增长速度0.49±0.15 kg/w。(2)孕晚期和整个孕期体质量增长过快是妊娠期高血压疾病和发生早产的高危因素(P0.05),孕早中期、孕晚期及整个孕期体质量增长过快是发生胎膜早破的高危因素(P0.05),孕早中期及整个孕期的体质量增长过慢是新生儿低出生体质量的高危因素(P0.05)。(3)在校正年龄、孕前BMI、孕周等因素后,孕期体质量每增加1 kg,双胎出生体质量之和增加25.21 g(P0.001);孕早中期每增加1 kg,双胎出生体质量之和增加30.89 g(P0.001);孕晚期每增加1 kg,双胎出生体质量之和增加21.46 g(P=0.001)。结论:双胎妊娠孕期体质量增长与母婴不良结局密切相关,妊娠不同阶段的体质量增长速度对母婴结局有一定的预测价值,应进一步探讨适合中国人群的双胎妊娠孕期体质量增长适宜范围。     

PRACTICAL APPROACHES FOR ESTIMATING PREPREGNANT BODY WEIGHT

Measurements of prepregnant body weight have important research and clinical applications. In practice, however, they are not always recorded; even when they are, this information is not always readily available. For this reason, researchers and clinicians have to rely on retrospective estimates of prepregnant weight, which can be estimated using: 1) maternal self-reports, 2) retrospective extrapolation, or 3) standardized estimates that correct for weight gained during early pregnancy. The aim of the present study was to examine the relative merits of these three approaches. Maternal self-reports tend to be unreliable and biased, being influenced by a variety of sociodemographic characteristics that generally underestimate true prepregnant body weight. Estimates of prepregnant weight based on retrospective extrapolation are vulnerable to measurement error, transient fluctuations in body weight, and incorrectly assume that the rate of weight gain is constant throughout pregnancy. Standardized estimates that correct for weight gained during early pregnancy incorrectly presume that there is little interindividual variation in gestational weight gain and that weight gain is similar for each woman in consecutive pregnancies. Because none of these techniques can provide a precise measure of prepregnant weight, researchers have little alternative but to recruit and weigh women before they become pregnant, although measurements of body weight recorded during the first trimester of pregnancy may provide a reasonable indication of prepregnant weight. For clinicians, self-reports of prepregnant weight or measurements recorded early in pregnancy are probably sufficiently accurate for practical purposes whenever recent, accurate measurements of prepregnant weight are unavailable.