Joint and Independent Associations of Gestational Weight Gain and Pre-Pregnancy Body Mass Index with Outcomes of Pregnancy in Chinese Women: A Retrospective Cohort Study

Objective

To explore the joint and independent effects of gestational weight gain (GWG) and pre-pregnancy body mass index (BMI) on pregnancy outcomes in a population of Chinese Han women and to evaluate pregnant women’s adherence to the 2009 Institute of Medicine (IOM) gestational weight gain guidelines.

Methods

This was a multicenter, retrospective cohort study of 48,867 primiparous women from mainland China who had a full-term singleton birth between January 1, 2011 and December 30, 2011. The independent associations of pre-pregnancy BMI, GWG and categories of combined pre-pregnancy BMI and GWG with outcomes of interest were examined using an adjusted multivariate regression model. In addition, women with pre-pregnancy hypertension were excluded from the analysis of the relationship between GWG and delivery of small-for-gestational-age (SGA) infants, and women with gestational diabetes (GDM) were excluded from the analysis of the relationship between GWG and delivery of large-for-gestational-age (LGA) infants.

Results

Only 36.8% of the women had a weight gain that was within the recommended range; 25% and 38.2% had weight gains that were below and above the recommended range, respectively. The contribution of GWG to the risk of adverse maternal and fetal outcomes was modest. Women with excessive GWG had an increased likelihood of gestational hypertension (adjusted OR 2.55; 95% CI = 1.92–2.80), postpartum hemorrhage (adjusted OR 1.30; 95% CI = 1.17–1.45), cesarean section (adjusted OR 1.31; 95% CI = 1.18–1.36) and delivery of an LGA infant (adjusted OR 2.1; 95% CI = 1.76–2.26) compared with women with normal weight gain. Conversely, the incidence of GDM (adjusted OR 1.64; 95% CI = 1.20–1.85) and SGA infants (adjusted OR 1.51; 95% CI = 1.32–1.72) was increased in the group of women with inadequate GWG. Moreover, in the obese women, excessive GWG was associated with an apparent increased risk of delivering an LGA infant. In the women who were underweight, poor weight gain was associated with an increased likelihood of delivering an SGA infant. After excluding the mothers with GDM or gestational hypertension, the ORs for delivery of LGA and SGA infants decreased for women with high GWG and increased for women with low GWG.

Conclusions

GWG above the recommended range is common in this population and is associated with multiple unfavorable outcomes independent of pre-pregnancy BMI. Obese women may benefit from avoiding weight gain above the range recommended by the 2009 IOM. Underweight women should avoid low GWG to prevent delivering an SGA infant. Pregnant women should therefore be monitored to comply with the IOM recommendations and should have a balanced weight gain that is within a range based on their pre-pregnancy BMI.     

Maternal Prepregnancy Body Mass Index and Gestational Weight Gain on Pregnancy Outcomes

Objective

The aim of the present study was to evaluate the single and joint associations of maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) with pregnancy outcomes in Tianjin, China.

Methods

Between June 2009 and May 2011, health care records of 33,973 pregnant women were collected and their children were measured for birth weight and birth length. The independent and joint associations of prepregnancy BMI and GWG based on the Institute of Medicine (IOM) guidelines with the risks of pregnancy and neonatal outcomes were examined by using Logistic Regression.

Results

After adjustment for all confounding factors, maternal prepregnancy BMI was positively associated with risks of gestational diabetes mellitus (GDM), pregnancy-induced hypertension, caesarean delivery, preterm delivery, large-for-gestational age infant (LGA), and macrosomia, and inversely associated with risks of small-for-gestational age infant (SGA) and low birth weight. Maternal excessive GWG was associated with increased risks of pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia, and decreased risks of preterm delivery, SGA, and low birth weight. Maternal inadequate GWG was associated with increased risks of preterm delivery and SGA, and decreased risks of LGA and macrosomia, compared with maternal adequate GWG. Women with both prepregnancy obesity and excessive GWG had 2.2–5.9 folds higher risks of GDM, pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia compared with women with normal prepregnancy BMI and adequate GWG.

Conclusions

Maternal prepregnancy obesity and excessive GWG were associated with greater risks of pregnancy-induced hypertension, caesarean delivery, and greater infant size at birth. Health care providers should inform women to start the pregnancy with a BMI in the normal weight category and limit their GWG to the range specified for their prepregnancy BMI.     

The Effects of Implementing the International Association of Diabetes and Pregnancy Study Groups Criteria for Diagnosing Gestational Diabetes on Maternal and Neonatal Outcomes

Background

In 2010, the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) recommended a new strategy for the screening and diagnosis of gestational diabetes mellitus (GDM). However, no study has indicated that adopting the IADPSG recommendations improves perinatal outcomes. The objective of this study was to evaluate the effects of implementing the IADPSG criteria for diagnosing GDM on maternal and neonatal outcomes.

Methodology/Principal Findings

Previously, we used a two-step approach (a 1-h, 50-g glucose challenge test followed by a 3-h, 100-g glucose tolerance test when indicated) to screen for and diagnose GDM. In July 2011, we adopted the IADPSG recommendations in our routine obstetric care. In this study, we retrospectively compared the rates of various maternal and neonatal outcomes in all women who delivered after 24 weeks of gestation during the periods before (P1, between January 1, 2009 and December 31, 2010) and after (P2, between January 1, 2012 and December 31, 2013) the IADPSG criteria were implemented. Pregnancies complicated by multiple gestations, fetal chromosomal or structural anomalies, and pre-pregnancy diabetes mellitus were excluded. Our results showed that the incidence of GDM increased from 4.6% using the two-step method to 12.4% using the IADPSG criteria. Compared to the women in P1, the women in P2 experienced less weight gain during pregnancy, lower birth weights, shorter labor courses, and lower rates of macrosomia (<4000 g) and large-for-gestational age (LGA) infants. P2 was a significant independent factor against macrosomia (adjusted odds ratio [OR] 0.63, 95% confidence interval [CI] 0.43–0.90) and LGA (adjusted OR 0.74, 95% CI 0.61–0.89) after multivariable logistic regression analysis.

Conclusions/Significance

The adoption of the IADPSG criteria for diagnosis of GDM was associated with significant reductions in maternal weight gain during pregnancy, birth weights, and the rates of macrosomia and LGA.     

The Impact of Exposure Misclassification on Associations Between Prepregnancy BMI and Adverse Pregnancy Outcomes

Prepregnancy BMI is a widely used marker of maternal nutritional status that relies on maternal self‐report of prepregnancy weight and height. Pregravid BMI has been associated with adverse health outcomes for the mother and infant, but the impact of BMI misclassification on measures of effect has not been quantified. The authors applied published probabilistic bias analysis methods to quantify the impact of exposure misclassification bias on well‐established associations between self‐reported prepregnancy BMI category and five pregnancy outcomes (small for gestational age (SGA) and large for gestational age (LGA) birth, spontaneous preterm birth (sPTB), gestational diabetes mellitus (GDM), and preeclampsia) derived from a hospital‐based delivery database in Pittsburgh, PA (2003–2005; n = 18,362). The bias analysis method recreates the data that would have been observed had BMI been correctly classified, assuming given classification parameters. The point estimates derived from the bias analysis account for random error as well as systematic error caused by exposure misclassification bias and additional uncertainty contributed by classification errors. In conventional multivariable logistic regression models, underweight women were at increased risk of SGA and sPTB, and reduced risk of LGA, whereas overweight, obese, and severely obese women had elevated risks of LGA, GDM, and preeclampsia compared with normal‐weight women. After applying the probabilistic bias analysis method, adjusted point estimates were attenuated, indicating the conventional estimates were biased away from the null. However, the majority of relations remained readily apparent. This analysis suggests that in this population, associations between self‐reported prepregnancy BMI and pregnancy outcomes are slightly overestimated.     

The Association of Gestational Weight Gain and Adverse Pregnancy Outcomes in Women with Gestational Diabetes Mellitus

Objective: To explore the association of excessive gestational weight gain (GWG) defined by the Institute of Medicine (IOM) targets and adverse perinatal outcomes in gestational diabetes mellitus (GDM) pregnancies, and whether a modified target might be related to a lower rate of adverse perinatal outcomes for GDM.Methods: This retrospective cohort study involved 1,138 women of normal glucose tolerance (NGT) and 1,200 women with GDM. Based on the IOM target, pregnancies were classified to appropriate GWG (aGWG), inadequate GWG, and excessive GWG (eGWG). Modified GWG targets included: upper limit of IOM target minus 1 kg (IOM-1) or 2 kg (IOM-2), both upper and lower targets minus 1 kg (IOM-1-1) or 2 kg (IOM-2-2).Results: The proportions of women achieving eGWG were 26.3% in NGT and 31.2% in GDM (P = .036); in comparison, for aGWG NGT, the risks of large for gestational age (LGA) were significantly higher in eGWG NGT (adjusted odds ratio &lsqb;OR] 1.47; 95% confidence interval &lsqb;CI] 1.02 to 2.13), aGWG GDM (adjusted OR 1.42; 95% CI 1.03 to 1.95), and eGWG GDM (adjusted OR 2.70; 95% CI 1.92 to 3.70). GDM pregnancies gaining aGWG based on the modified GWG targets (IOM-2, IOM-1-1, and IOM-2-2) had a lower prevalence of LGA and macrosomia delivery than that for similar pregnancies using the original IOM target (all P<.05).Conclusion: For aGWG GDM according to the IOM target, adhering to a more stringent weight control was associated with decreased adverse outcomes. A tighter IOM target might help to reduce the prevalence of adverse pregnancy outcomes.Abbreviations: aGWG = appropriate gestational weight gain; BG = blood glucose; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; GDM = gestational diabetes mellitus; GW = gestational weeks; GWG = gestational weight gain; HbA1c = hemoglobin A1c; iGWG = inadequate gestational weight gain; IOM = Institute of Medicine; LGA = large for gestational age; NGT = normal glucose tolerance; NICU = neonatal intensive care unit; OGTT = oral glucose tolerance test; OR = odds ratio; PARp = partial population attributable risks; SGA = small for gestational age     

Maternal Gestational Diabetes Mellitus and Offspring Body Mass Index from 1 to 4 Years

ObjectiveUsing the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria to diagnose gestational diabetes mellitus (GDM), the association between GDM and offspring body mass index (BMI) gains in early childhood in China remains unclear. We aimed to assess the association between GDM diagnosed by the IADPSG criteria and BMI gain and the risk for overweight/obesity in offspring from 1 to 4 years.MethodsThis prospective cohort study was based on the healthcare records data from the Medical Birth Registry in Xiamen, China. We included 10,412 mother-child pairs tested for GDM using IADPSG criteria.ResultsA total of 1,786 (17.2%) offspring were exposed to GDM. The offspring exposed to GDM had higher mean BMI Z-score (difference, 0.07; 95% confidence interval [CI], 0.02 to 0.12) and risk for overweight/obesity (odds ratio [OR], 1.22; 95% CI, 1.06 to 1.40) compared to those unexposed to GDM from 1 to 4 years of age. However, after adjustment for maternal pre-pregnancy BMI (Model 2), these associations attenuated towards the null (difference in BMI Z-score, 0.02; 95% CI, -0.03 to 0.07; OR for overweight/obesity, 1.09; 95% CI, 0.95 to 1.25).ConclusionThe associations between GDM diagnosed using IADPSG criteria and BMI Z-score and the risk for overweight/obesity in offspring at the age of 1 to 4 years were largely explained by maternal pre-pregnancy BMI. Reducing the prevalence of childhood overweight and obesity in China should focus on maternal weight status before pregnancy, in addition to glycemia during pregnancy.     

Association of Second and Third Trimester Weight Gain in Pregnancy with Maternal and Fetal Outcomes

Objective

To investigate the association between weekly weight gain, during the second and third trimesters, classified according to the 2009 Institute of Medicine (IOM/NRC) recommendations, and maternal and fetal outcomes.

Methods

Gestational weight gain was evaluated in 2,244 pregnant women of the Brazilian Study of Gestational Diabetes (Estudo Brasileiro do Diabetes Gestacional – EBDG). Outcomes were cesarean delivery, preterm birth and small or large for gestational age birth (SGA, LGA). Associations between inadequate weight gain and outcomes were estimated using robust Poisson regression adjusting for pre-pregnancy body mass index, trimester-specific weight gain, age, height, skin color, parity, education, smoking, alcohol consumption, gestational diabetes and hypertensive disorders in pregnancy.

Results

In fully adjusted models, in the second trimester, insufficient weight gain was associated with SGA (relative risk [RR] 1.72, 95% confidence interval [CI] 1.26–2.33), and excessive weight gain with LGA (RR 1.64, 95% CI 1.16–2.31); in third trimester, excessive weight gain with preterm birth (RR 1.70, 95% CI 1.08–2.70) and cesarean delivery (RR 1.21, 95% CI 1.03–1.44). Women with less than recommended gestational weight gain in the 2^nd trimester had a lesser risk of cesarean deliveries (RR 0.82, 95% CI 0.71–0.96) than women with adequate gestational weight gain in this trimester.

Conclusion

Though insufficient weight gain in the 3^rd trimester was not associated with adverse outcomes, other deviations from recommended weight gain during second and third trimester were associated with adverse pregnancy outcomes. These findings support, in part, the 2009 IOM/NRC recommendations for nutritional monitoring during pregnancy.     

孕妇孕前体重指数与妊娠期糖代谢异常发病相关性的研究

目的：探讨孕前体重指数与妊娠期糖代谢异常发病及其临床特点的关系。方法：采用病例一对照研究的方法,对孕期在我院进行健康保健确诊为糖代谢异常并已完成分娩的孕妇130例作为病例组,同时随机抽取同期分娩的260例糖代谢正常孕妇作为对照组。用Logistic回归模型对孕前体重指数进行单因素分析;计算其相对危险度。结果：病例组孕妇孕前BMI指数大于25者占80．77％,明显高于对照组的（19．23％）,差别有统计学意义（X2=30．469,P〈0．05）。logistic回归结果显示相对于BMI小于25者。BMI〉25组发生糖代谢异常的相对危险度是3．90,95％CI为2．23—6．41。结论：孕妇孕前体重指数是妊娠期糖代谢异常的独立危险因素,因此孕前控制体重指数是降低孕期糖代谢异常发生的关键因素。     

新诊断标准下妊娠期糖尿病高危因素研究

目的:调查新诊断标准下国内妊娠期糖尿病(Gestational diabetes mellitus GDM)的发病情况,分析影响GDM发生的高危因素,为新标准下国内GDM孕妇临床早期管理、诊断和干预提供理论依据。方法:对2011年1月至2011年9月我院接受产前建卡检查的所有孕妇1152例进行临床资料的收集及回顾性研究,排除孕前糖尿病患者16例,采用GDM诊断新标准进行"一步法"诊断,收集包括年龄、孕产次、体质指数(body mass index BMI)、糖尿病家族史、多囊卵巢综合征等13种影响GDM发生的危险因素,并综合分析。结果:新标准下GDM检出率为10.39%(118/1136)2)单因素分析结果发现年龄≥35岁(X2=10.2814,P=0.0013)、肥胖(孕前BMI≥28kg/m2()X2=36.2384,P<0.0001)、多囊卵巢综合征(X2=20.6725,P<0.0001)、糖尿病家族史(X2=7.8783,P=0.0050)在GDM组与非GDM组有统计学差异,多因素逐步Logistic回归分析肥胖(OR=7.546 95%CI=2.356~20.129 P=0.0002)、多囊卵巢综合征(OR=6.342 95%CI=1.783~16.329,P=0.0019)、年龄(OR=3.021 95%CI=0.983~6.459 P=0.0108)、糖尿病家族史(OR=2.43895%CI=0.612~5.231 P=0.0256)为GDM的高危因素。结论:新标准下报告GDM检出率为10.39%。肥胖、多囊卵巢综合征、年龄、糖尿病家族史为影响GDM发生的高危因素。加强GDM筛查并对具有高危因素的妊娠期妇女早期诊断,早期干预、早期管理可改善妊娠结局,提高人口素质。     

Altered maternal metabolism during mild gestational hyperglycemia as a predictor of adverse perinatal outcomes: A comprehensive analysis

Mild gestational hyperglycemia (MGH), as assessed using the normal oral glucose tolerance test (OGTT) and detection of an altered glycemic profile, is associated with adverse perinatal outcome. This study described the results of 40 years of research conducted at the Perinatal Diabetes Research Centre at São Paulo State University (UNESP), Brazil, on the maternal MGH environment and placental markers. This study also described the unidirectional relationship between MGH and excessive fetal growth, also supplying moderator analysis. In addition to hyperglycemia, MGH is associated with an increased incidence of hypertension, metabolic syndrome, persistent insulin resistance after pregnancy, and high risk of developing type 2 diabetes mellitus (T2DM) after pregnancy. Structural changes and functional abnormalities resulting from MGH were observed in placenta. The fully adjusted model concluded that the predictor variable (MGH), which creates a complex environment for the fetus, has a direct effect on excessive birth weight and produces a z-score for ratios of birth weight to gestational age of ≥2. Maternal age, pre-pregnancy BMI, number of previous pregnancies, numbers of prenatal visits, and 1 h OGTT are moderator variables that impact MGH and excessive fetal growth. These results show that maternal MGH has some characteristics associated with similar long-term T2DM development and similar adverse perinatal results to those of gestational diabetes mellitus (GDM) mothers, making it an intermediate maternal and placental marker between normoglycemic and GDM mothers.     

妊娠期糖尿病患者氧化应激水平变化及临床意义*

目的:研究GDM孕妇与正常孕妇血清MDA、SOD及GSH水平变化,探索它们与GDM之间的相互关系,追踪各组妊娠结局研究其临床意义。方法:选取175例孕妇为研究对象,分为GDM组(93例)和对照组(82例)。采用微量法测定血清丙二醛(MDA)、谷胱甘肽(GSH)及超氧化物歧化酶(SOD)水平,并对妊娠结局进行相关性分析。结果:(1) GDM组年龄、孕前体重、BMI值均高于对照组,GSH和SOD水平均低于对照组,MDA水平高于对照组,差异有统计学意义(P0.05);(2) GDM组MDA水平与孕前体重呈负相关(r=-0.3547,P0.05),SOD水平与新生儿出生体重呈正相关(r=0.3292,P0.05),SOD值与早产之间有密切联系(足月产12.68±0.85 vs.早产8.08±1.18, P 0.05),GSH、SOD水平与孕前体重之间,MDA、GSH水平与新生儿出生体重之间,MDA、GSH水平与早产之间均无明显相关性(P0.05),MDA、GSH和SOD水平与剖宫产及胎膜早破均无明显相关性(P0.05)。结论:GDM存在明显的氧化应激反应,GSH、MDA与SOD可以作为评估GDM氧化应激的有效标志物,其与不良妊娠结局有关。     

Maternal Snoring May Predict Adverse Pregnancy Outcomes: A Cohort Study in China

Objective

To examine the prevalence of snoring during pregnancy and its effects on key pregnancy outcomes.

Methods

Pregnant women were consecutively recruited in their first trimester. Habitual snoring was screened by using a questionnaire in the 1^st and 3^rd trimester, respectively. According to the time of snoring, participants were divided into pregnancy onset snorers, chronic snorers and non-snorers. Logistic regressions were performed to examine the associations between snoring and pregnancy outcomes.

Results

Of 3 079 pregnant women, 16.6% were habitual snorers, with 11.7% were pregnancy onset snorers and 4.9% were chronic snorers. After adjusting for potential confounders, chronic snorers were independently associated with gestational diabetes mellitus (GDM) (RR 1.66, 95%CI 1.09–2.53). Both pregnancy onset and chronic snorers were independently associated with placental adhesion (RR 1.96, 95%CI 1.17–3.27, and RR 2.33, 95%CI 1.22–4.46, respectively). Pregnancy onset snorers were at higher risk of caesarean delivery (RR 1.37, 95%CI 1.09–1.73) and having macrosomia (RR 1.54, 95%CI 1.05–2.27) and large for gestational age (LGA) (RR 1.71, 95%CI 1.31–2.24) infants. In addition, being overweight or obese before pregnancy plays an important role in mediating snoring and adverse pregnancy outcomes.

Conclusions

Maternal snoring may increase the risk of adverse pregnancy outcomes, and being overweight or obese before pregnancy with snoring is remarkable for researchers. Further studies are still needed to confirm our results.     

Predictive parameters of gestational diabetes mellitus

Gestational diabetes mellitus is a carbohydrate intolerance recognized in pregnancy. The objective of this study was to determine the prevalence of gestational diabetes mellitus (GDM) of all deliveries at the University Hospital Rijeka, Croatia (34 997 deliveries over 10-year period) using 2-hour 75 g oral glucose tolerant test and to evaluate the impact of GDM on neonatal outcomes and mother's health. Gestational diabetes was diagnosed in 55 of 128 pregnant women with suspected glucose intolerance. Logistic regression analysis was used to examine the relationship between fasting plasma glucose, age, family history, body mass index, maternal weight gain, neonatal weight, neonatal head diameter and Apgar score in the gestational diabetes group and in the non-diabetes group. The results indicate that fasting plasma glucose greater than 7.0 mmol/L and maternal overweight are strong predictors for GDM and macrosomia. There was no difference in the mode of delivery, and vitality and metabolic complications among the infants of all analyzed mothers. We concluded that to prevent GDM as well as to reduce the rate of macrosomic infants good glycemic control should be initiated as soon as possible. The 2-hour 75 g OGTT is worth enough to evaluate GDM. Women should be counseled and encouraged to lose weight before or at the beginning of the conception period.     

Pre-Pregnancy Body Mass Index in Relation to Infant Birth Weight and Offspring Overweight/Obesity: A Systematic Review and Meta-Analysis

Background

Overweight/obesity in women of childbearing age is a serious public-health problem. In China, the incidence of maternal overweight/obesity has been increasing. However, there is not a meta-analysis to determine if pre-pregnancy body mass index (BMI) is related to infant birth weight (BW) and offspring overweight/obesity.

Methods

Three electronic bibliographic databases (MEDLINE, EMBASE and CINAHL) were searched systematically from January 1970 to November 2012. The dichotomous data on pre-pregnancy overweight/obesity and BW or offspring overweight/obesity were extracted. Summary statistics (odds ratios, ORs) were used by Review Manager, version 5.1.7.

Results

After screening 665 citations from three electronic databases, we included 45 studies (most of high or medium quality). Compared with normal-weight mothers, pre-pregnancy underweight increased the risk of small for gestational age (SGA) (odds ratios [OR], 1.81; 95% confidence interval [CI], 1.76–1.87); low BW (OR, 1.47; 95% CI, 1.27–1.71). Pre-pregnancy overweight/obesity increased the risk of being large for gestational age (LGA) (OR, 1.53; 95% CI, 1.44–1.63; and OR, 2.08; 95% CI; 1.95–2.23), high BW (OR, 1.53; 95% CI, 1.44–1.63; and OR, 2.00; 95% CI; 1.84–2.18), macrosomia (OR, 1.67; 95% CI, 1.42–1.97; and OR, 3.23; 95% CI, 2.39–4.37), and subsequent offspring overweight/obesity (OR, 1.95; 95% CI, 1.77–2.13; and OR, 3.06; 95% CI, 2.68–3.49), respectively. Sensitivity analyses revealed that sample size, study method, quality grade of study, source of pre-pregnancy BMI or BW had a strong impact on the association between pre-pregnancy obesity and LGA. No significant evidence of publication bias was observed.

Conclusions

Pre-pregnancy underweight increases the risk of SGA and LBW; pre-pregnancy overweight/obesity increases the risk of LGA, HBW, macrosomia, and subsequent offspring overweight/obesity. A potential effect modification by maternal age, ethnicity, gestational weight gain, as well as the role of gestational diseases should be addressed in future studies.     

Quantifying the Impact of Gestational Diabetes Mellitus,Maternal Weight and Race on Birthweight via Quantile Regression

Background

Quantile regression, a robust semi-parametric approach, was used to examine the impact of gestational diabetes mellitus (GDM) across birthweight quantiles with a focus on maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG).

Methods

Using linked birth certificate, inpatient hospital and prenatal claims data we examined live singleton births to non-Hispanic white (NHW, 135,119) and non-Hispanic black (NHB, 76,675) women in South Carolina who delivered 28–44 weeks gestation in 2004–2008.

Results

At a maternal BMI of 30 kg/m² at the 90^th quantile of birthweight, exposure to GDM was associated with birthweights 84 grams (95% CI 57, 112) higher in NHW and 132 grams (95% CI: 104, 161) higher in NHB. Results at the 50^th quantile were 34 grams (95% CI: 17, 51) and 78 grams (95% CI: 56, 100), respectively. At a maternal GWG of 13.5 kg at the 90^th quantile of birthweight, exposure to GDM was associated with birthweights 83 grams (95% CI: 57, 109) higher in NHW and 135 grams (95% CI: 103, 167) higher in NHB. Results at the 50^th quantile were 55 grams (95% CI: 40, 71) and 69 grams (95% CI: 46, 92), respectively.

Summary

Our findings indicate that GDM, maternal prepregnancy BMI and GWG increase birthweight more in NHW and NHB infants who are already at the greatest risk of macrosomia or being large for gestational age (LGA), that is those at the 90^th rather than the median of the birthweight distribution.     

Pre-Pregnancy Body Mass Index,Gestational Weight Gain,and Birth Weight: A Cohort Study in China

Objective

To assess whether pre-pregnancy body mass index (BMI) modify the relationship between gestational weight gain (GWG) and child birth weight (specifically, presence or absence of low birth weight (LBW) or presence of absence of macrosomia), and estimates of the relative risk of macrosomia and LBW based on pre-pregnancy BMI were controlled in Wuhan, China.

Methods

From June 30, 2011 to June 30, 2013. All data was collected and available from the perinatal health care system. Logistic regression models were used to estimate the independent association among pregnancy weight gain, LBW, normal birth weight, and macrosomia within different pre-pregnancy BMI groups. We built different logistic models for the 2009 Institute of Medicine (IOM) Guidelines and Chinese-recommended GWG which was made from this sample. The Chinese-recommended GWG was derived from the quartile values (25th-75th percentiles) of weight gain at the time of delivery in the subjects which comprised our sample.

Results

For LBW children, using the recommended weight gain of the IOM and Chinese women as a reference, the OR for a pregnancy weight gain below recommendations resulted in a positive relationship for lean and normal weight women, but not for overweight and obese women. For macrosomia, considering the IOM’s recommended weight gain as a reference, the OR magnitude for pregnancy weight gain above recommendations resulted in a positive correlation for all women. The OR for a pregnancy weight gain below recommendations resulted in a negative relationship for normal BMI and lean women, but not for overweight and obese women based on the IOM recommendations, significant based on the recommended pregnancy weight gain for Chinese women. Of normal weight children, 56.6% were above the GWG based on IOM recommendations, but 26.97% of normal weight children were above the GWG based on Chinese recommendations.

Conclusions

A GWG above IOM recommendations might not be helpful for Chinese women. We need unified criteria to classify adult BMI and to expand the sample size to improve representation and to elucidate the relationship between GWG and related outcomes for developing a Chinese GWG recommendation.     

Effect of Iodine Nutrition on Pregnancy Outcomes in an Iodine-Sufficient Area in China

Many studies focused on the association between thyroid disease and pregnancy outcomes. The present study explored the effect of iodine nutrition during the first trimester on pregnancy outcomes. One thousand five hundred sixty-nine pregnant, euthyroid women at ≤12 weeks of gestation in an iodine-sufficient area in China were recruited. According to the World Health Organization (WHO) criteria for iodine nutrition during pregnancy, participants were divided into four groups: adequate iodine (median urinary iodine concentration (UIC), 150–249 μg/L), mild deficiency (UIC, 100–150 μg/L), moderate and severe deficiency (UIC, <100 μg/L), and more than adequate and excessive (UIC, ≥250 μg/L) groups. Pregnancy outcomes, including abortion, gestational hypertension, pre-eclampsia, gestational diabetes mellitus (GDM), placenta previa, placental abruption, preterm labor, low birth weight infants, macrosomia, breech presentation, and cord entanglement, were obtained during follow-up. The results showed that there was no significant difference in general characteristics, including age, body mass index, abdominal circumference, systolic blood pressure, diastolic blood pressure, heart rate, smoking rate, and drinking rate, among the four groups. In the more than adequate and excessive group, thyroid-stimulating hormone (TSH) was greater and free thyroxine (FT4) was lower than any other groups but still within normal range. The thyroglobulin (Tg) level was greater in the moderate and severe deficiency group. The incidence of GDM was significantly greater in women with mild iodine deficiency than in women with adequate iodine nutriture (18.38 vs. 13.70%, p < 0.05). Compared with the adequate group, incidence of macrosomia was significantly greater in the more than adequate and excessive group (12.42 vs. 9.79%, p < 0.05). Mild iodine deficiency was an independent risk factor for GDM (odds ratio = 1.566, 95% confidence interval = 1.060–2.313, p = 0.024); more than adequate and excessive iodine was an independent risk factor for macrosomia (OR = 1.917, CI = 1.128–3.256, p = 0.016). In summary, during 1st trimester, both mild iodine deficiency and excessive iodine intake had adverse impacts on pregnancy outcomes in an iodine-sufficient area.     

Mitochondrial DNA depletion in small- and large-for-gestational-age newborns

Objective: To investigate whether mitochondrial DNA (mtDNA) content may be associated with clinical features, anthropometric variables, and laboratory findings in both extremes of abnormal fetal growth: small and large size for gestational age. Research Methods and Procedures: Eighty‐eight pregnant women and their infants were included in a cross‐sectional study. According to the offspring birthweight, normalized by sex and gestational age, there were 57 newborns with appropriate weight for gestational age (AGA) and 31 with abnormal weight for gestational age: 17 small for gestational age (SGA) and 14 large for gestational age (LGA). mtDNA quantification using nuclear DNA as a reference was measured by a real‐time quantitative polymerase chain reaction method. Results: The mothers’ pregestational BMI was associated with the weight of their offspring: SGA infants had lean mothers (BMI, 21.4 ± 0.7), and LGA infants had overweight mothers (BMI, 26.7 ± 1.4) in comparison with AGA infants (BMI, 23.0 ± 0.7) (p < 0.003). Newborn leptin levels were associated with birthweight after adjustment for sex and gestational age (SGA, 7.0 ± 1.1 ng/mL; AGA, 15.2 ± 1.6 ng/mL; and LGA, 25.6 ± 4.1 ng/mL) (p < 0.002). Conversely, mtDNA/nuclear DNA ratio was significantly lower in both extremes of abnormal fetal growth, SGA (18 ± 6) and LGA (9 ± 2), at birth in comparison to AGA‐weight infants (28 ± 4) (p < 0.03). Discussion: Our findings show that mtDNA content is decreased in newborns with abnormal weight in comparison with AGA infants. On the basis of a cumulative body of evidence, we speculate that mtDNA depletion is one of the putative links between abnormal fetal growth and metabolic and cardiovascular complications in later life.     

Gestational Weight Gain as an Independent Risk Factor for Macrosomia in Women with Intermediate State Gestational Blood Glucose

Objective: Macrosomia is closely associated with gestational diabetes mellitus (GDM) but its relationship with maternal intermediate state gestational blood glucose (ISGBG; normal fasting blood glucose and 7.8 mmol/L <1 hour blood glucose &lsqb;BG] <10 mmol/L or 6.7 mmol/L <2 hour BG <8.5 mmol/L) is unclear. Here, we analyzed the clinical characteristics and pregnancy outcomes and explored risk factors for macrosomia in women with ISGBG.Methods: A total of 847 women with normal glucose tolerance gestation, 330 with ISGBG, and 99 with GDM were included. Maternal and fetal clinical data were collected and 3-point BG following oral glucose tolerance test, fasting insulin, glycated hemoglobin, and blood lipids profile were measured.Results: The incidence rate of macrosomia among the neonates of women with ISGBG was as high as 10.9%. In the ISGBG group, prepregnancy body mass index (BMI), gestational weight gain (GWG) and the proportion of women with excessive GWG (eGWG) were significantly higher in women with macrosomia compared with those who delivered a normal weight neonate. In women with ISGBG, neonate weight was positively correlated with maternal prepregnancy weight (r = 0.183, P<.01), prepregnancy BMI (r = 0.135, P<.01), and GWG (r = 0.255, P<.01), and negatively correlated with high-density lipoprotein cholesterol (r = -0.172, P<.01). Nonetheless, only eGWG was an independent risk factor (odds ratio = 3.18, 95% confidence interval = 1.26 to 7.88, P<.05) for macrosomia. The risk of macrosomia in pregnant women with prepregnancy BMI <25 kg/m² or BMI ≥25 kg/m² and eGWG was 3.39 and 3.27 times, respectively.Conclusion: The incidence rate of macrosomia is increased in women with ISGBG and eGWG is the strongest independent risk factor. In order to reduce the risk for macrosomia, timely lifestyle intervention to promote appropriate weight gain during pregnancy deserves evaluation.Abbreviations: AUC = area under the curve; BG = blood glucose; 1 hour BG = 1 hour blood glucose after OGTT; 2 hour BG = 2 hour blood glucose after OGTT; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; FBG = fasting blood glucose; FINS = fasting insulin; GDM = gestational diabetes mellitus; HbA1c = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance index; ISGBG = intermediate state gestation blood glucose; LDL-C = low-density lipoprotein cholesterol; Ln = natural logarithm; MLBW = mature low birth weight; NGTG = normal glucose tolerance gestation; OGTT = oral glucose tolerance test; OR = odds ratio; SD = standard deviation     

Association of variations in TPH1 and HTR2B with gestational weight gain and measures of obesity

Serotonin is involved in appetite regulation and energy homeostasis. Recently, it has been reported that 5-hydroxytryptamine receptor 2B (Htr2b) and tryptophan hydroxylase 1 (Tph1) play major role in β-cell proliferation in mouse during pregnancy. We investigated the genetic association of HTR2B and TPH1 with risk of gestational diabetes mellitus (GDM) and measures of obesity, in 869 Korean GDM women and carefully selected 632 nondiabetic control subjects. Six single-nucleotide polymorphisms (SNPs) in HTR2B and ten SNPs in TPH1 were selected for genotyping according to their tagging status. Genetic variants in HTR2B and TPH1 were not associated with the risk of GDM. In GDM women, SNPs of TPH1 were significantly associated with weight gain during pregnancy. In nondiabetic controls, SNPs of TPH1 were associated with waist circumference and BMI. We also found that a variant of TPH1 (rs623580) was associated with BMI in a genome-wide association study comprised of 8,842 subjects. Although genetic variants in HTR2B and TPH1 were not associated with risk of GDM, we found significant association of these variants with measures of obesity. However, further replication studies in a different population are required to confirm our findings.