Modulation off birthweight through gestational age and fetal growth

Summary Several factors are known to affect birthweight and their effects are variously mediated through gestational duration or through fetal growth conditional on this gestation, in order to quantify independent associations of birthweight conditional and unconditional on gestational age, all 2538 mothers of singleton babies delivered during 1993 in two Maternity Hospitals in Athens were interviewed and their obstetric records abstracted. Birthweight was modelled as outcome variable through multiple regression including 32 potentially predictive factors. The regression model was fitted with and without gestational age as an additional independent variable in order to apportion birthweight associations into those independent of, or mediated through, gestational length. The factors studied were found to be classifiable into the following categories: factors associated with birthweight mostly through increases in gestational duration, either positively (age at menarche, long menstrual cycles, parity 4 or higher), or negatively (single motherhood, maternal age, tobacco smoking); those associated with birthweight mostly through increase of birthweight conditional on gestational duration, either positively (male gender, short menstrual cycles, maternal pre-pregnancy weight, anaemia, oedema) or inversely (employment during pregnancy, stillbirth, primiparity, pregnancy induced hypertension, coffee drinking); and those associated with birthweight through apparently dual effects, either positively (maternal education) or inversely (perceived stress, bleeding during pregnancy). The other studied factors were not demonstrably related to birthweight in this data set. Identification and quantification of these relations is useful for understanding underlying physiological and pathophysiological processes and for increasing specificity in exploring the association of birthweight with adult onset diseases, like coronary heart disease or cancer.     

Perinatal mortality in relation to birthweight and gestational age: a registry-based comparison of Northern Norway and Murmansk County, Russia

The objective was to explore how perinatal mortality relates to birthweight, gestational age and optimal perinatal survival weight for two Arctic populations employing an existing and a newly established birth registry. A medical birth registry for all births in Murmansk County of North-West Russia became operational on 1st January 2006. Its primary function is to provide useful information for health care officials pertinent to improving perinatal care. The cohort studied consisted of 17,302 births in 2006-07 (Murmansk County) and 16,006 in 2004-06 (Northern Norway). Birthweight probability density functions were analysed, and logistic regression models were employed to calculate gestational-age-specific mortality ratios. The perinatal mortality rate was 10.7/1000 in Murmansk County and 5.7/1000 in Northern Norway. Murmansk County had a higher proportion of preterm deliveries (8.7%) compared to Northern Norway (6.6%). The odds ratio (OR) of risk of mortality (Northern Norway as the reference group) was higher for all gestational ages in Murmansk County, but the largest risk difference occurred among term deliveries (OR 2.45, 95% confidence interval 1.45, 4.14) which hardly changed on adjustment for maternal age, parity and gestation. Proportionately, more babies were born near (± 500 g) the optimal perinatal survival weight in Murmansk County (67.2%) than in Northern Norway (47.6%). The observed perinatal mortality was higher in Murmansk County at all birthweight strata and at gestational ages between weeks 25 and 42, but the adjusted risk difference was most significant for term deliveries.     

Mothers' and fathers' birth characteristics and perinatal mortality in their offspring: a population‐based cohort study

Nordtveit TI, Melve KK, Skjaerven R. Mothers' and fathers' birth characteristics and perinatal mortality in their offspring: a population‐based cohort study. Paediatric and Perinatal Epidemiology 2010; 24: 282–292. There is increasing interest in the associations between parental birthweight and gestational age with their perinatal outcomes. We investigated perinatal mortality risk in offspring in relation to maternal and paternal gestational age and birthweight. We used population‐based generational data from the Medical Birth Registry of Norway, 1967–2006. Singletons in both generations were included, forming 520 794 mother–offspring and 376 924 father–offspring units. Perinatal mortality in offspring was not significantly associated with paternal gestational age or birthweight, whereas it was inversely associated with maternal gestational age. A threefold increased risk in perinatal mortality was found among offspring of mothers born at 28–30 weeks of gestation relative to offspring of mothers born at term (37–43 weeks) (relative risk: 2.9, 95% CI 1.9, 4.6). There was also an overall association between maternal birthweight and offspring perinatal mortality. Relative risk for mothers whose birthweight was <2000 g was 1.5 (95% CI 1.1, 1.9), relative to mothers whose birthweight was 3500–3999 g. However, confined to mothers born at ≥34 weeks of gestation, the birthweight association was not significant. Weight‐specific perinatal mortality in offspring was dependent on the birthweight of the mother and the father, that is, offspring who were small relative to their mother's or father's birthweight had increased perinatal mortality. In conclusion, a mother's gestational age, and not her birthweight, was significantly associated with perinatal mortality in the offspring, while there was no such association for the father.     

5 012名单胎活产儿小于胎龄儿和大于胎龄儿发生率及其影响因素研究

目的 了解湖南省两市小于胎龄儿(SGA)和大于胎龄儿(LGA)的发生率,并分析其影响因素,为预防SGA和LGA的发生提供理论依据。方法 采用分层整群抽样方法,选择2016年1-6月在湖南省株洲市和湘潭市当地助产机构住院分娩的孕妇作为研究对象,收集孕妇及其丈夫的社会人口学特征、家庭经济情况和妊娠情况,记录新生儿出生结局。运用χ²检验和Fisher确切概率法进行单因素的SGA和LGA发生率比较,采用无序多分类Logistic回归模型进行多因素SGA和LGA的影响因素分析。结果 SGA发生率为6.5%(328/5 012),LGA发生率为7.9%(394/5 012)。无序多分类Logistic回归模型显示,孕妇孕期进行规范产前检查为SGA和LGA共同的保护因素,孕期贫血和妊娠期高血压疾病是SGA的危险因素,妊娠糖尿病、孕妇年龄≥35岁、丈夫年龄≥30岁是LGA的危险因素。结论 孕妇孕期进行规范产前检查可降低SGA和LGA的发生风险,孕期贫血和妊娠期高血压疾病会增加SGA的发生风险,妊娠糖尿病、孕妇高龄和丈夫高龄会增加LGA的发生风险。     

Psychosocial work stress during pregnancy and birthweight

Although there is a growing interest in the health effects of psychosocial work stress, studies on the relationships between job stress and adverse reproductive outcome are limited. We, therefore, investigated the associations between prenatal maternal occupational stress and birthweight using 310 mother-infant pairs included in the Mothers and Children's Environmental Health (MOCEH) study. Information on job stress was collected by interviewing women at enrollment during the first trimester of pregnancy using standardised questionnaires, namely, the Job Content Questionnaire (JCQ) of job strain and effort-reward imbalance (ERI) questionnaires. Regression analyses were carried out. Decision latitude scores of the JCQ were found to be positively related to birthweight, while ERI ratios determined using the ERI model were found to be inversely related to gestational age. In addition, a passive job as defined by the job strain model was found to be associated with a lower birthweight, compared with a relaxed job. These results suggest that work-related psychosocial stress in pregnant women appears to affect birth outcomes, such as birthweight and gestational age.     

Using mixture models with linear predictors to identify incorrect gestational age in state birth records

Background: Birthweight distributions for early last-menstrual-period-based gestational ages are bimodal, and some birthweights in the right-side distribution are implausible for the specified gestational age. Mixture models can be used to identify births in the right-side distribution. The objective of this study was to determine which maternal and infant factors to include in the mixture models to obtain the best fitting models for New Jersey state birth records. Methods: We included covariates in the models as linear predictors of the means of the component distributions and the proportion of births in each component. This allowed both the means and the proportions to vary across levels of the covariates. Results: The final model included maternal age and timing of entry into prenatal care. The proportion of births in the right-side distribution was lowest for older mothers who entered prenatal care early, higher for teen mothers who entered prenatal care early, higher still for older mothers who entered prenatal care late, and highest for teens who entered prenatal care late. Over 44% of births were classified as incorrect reported gestational age. Conclusion: These results suggest that (1) including these two covariates as linear predictors of the means and mixing proportions gives the best model for identifying births with incorrect reported gestational age, (2) late entry into prenatal care is a mechanism by which erroneously short last-menstrual-period-based gestational ages are generated, and (3) including linear predictors of the mixing proportions in the model increases the validity of the classification of incorrect reported gestational age.     

小于胎龄儿健康状况及其影响因素的流行病学调查

【目的】 分析小于胎龄儿(small-for-gestational-age infants,SGA)的出生、健康状况、并发症发生、死亡及其影响因素,以期为产科、儿科、儿保等科学护理SGA提供临床依据。 【方法】 回顾性分析2006年1月1日-2007年12月31日在北京市海淀区妇幼保健院出生的全部新生儿资料,选择其中的217例SGA为病例组,每月1日出生的240例适于胎龄儿儿(appropriate gestational age infants,AGA)为对照组。详细分析两组并发症发生情况及母亲孕期感染、妊高症、糖尿病、贫血、胎膜早破、羊水异常、脐带异常、双胎等情况。 【结果】 2006-2007年北京市海淀区妇幼保健院共分娩新生儿22 752名,其中SGA儿217例,SGA出生率为0.95%;SGA并发症发生率依次为高胆红素血症(31.3%)、呼吸系统并发症(10.6%)、贫血(5.5%)、低血糖(5.1%)、消化系统并发症(4.6%),SGA并发症发生率高于AGA,差异有统计学意义(P＜0.05);母亲妊高症、脐带异常、胎膜早破、双胎妊娠是导致SGA的主要因素;小于胎龄儿死亡率为1.4%,明显高于AGA死亡率(0.14%)及新生儿总死亡率(0.15%),差异有统计学意义(P＜0.05)。 【结论】 SGA发生与母亲妊高症等因素有关,SGA容易发生并发症,死亡率高,应该加强预防和科学护理。     

极低出生体重儿适于胎龄儿与小于胎龄儿危险因素及并发症的比较

目的:探讨极低出生体重适于胎龄儿(AGA)与小于胎龄儿(SGA)的危险因素及并发症的特点及差异。方法:将125例极低出生体重儿分为两组,其中AGA组95例,SGA组30例,比较两组的危险因素及并发症的差异是否有统计学意义。结果:极低出生体重儿中AGA组和SGA组母亲妊娠期高血压疾病发生率的差异有统计学意义,其余危险因素两组间差异均无统计学意义,AGA组和SGA组新生儿并发症中新生儿呼吸窘迫综合征(RDS)和低血糖症发生率的差异有统计学意义,其余并发症发生率两组间差异均无统计学意义。结论:母亲妊娠期高血压疾病是极低出生体重SGA患儿发病的高危因素,极低出生体重SGA患儿RDS发生率低于AGA患儿,而低血糖症的发生率高于AGA患儿。     

Stillbirth and infant mortality in singletons by cause of death,birthweight, gestational age and birthweight‐for‐gestation,Newcastle upon Tyne 1961–2000

Glinianaia SV, Rankin J, Pearce MS, Parker L, Pless‐Mulloli T. Stillbirth and infant mortality in singletons by cause of death, birthweight, gestational age and birthweight‐for‐gestation, Newcastle upon Tyne 1961–2000. Paediatric and Perinatal Epidemiology 2010. The dramatic reduction observed in stillbirth and infant mortality over the last few decades has not been assessed by both birthweight and gestation. We have explored temporal changes in stillbirth and infant mortality in Newcastle upon Tyne, UK, by cause of death, birthweight, gestational age, birthweight standardised for gestation and infant sex during 1961–2000. We included 131 044 singleton births to mothers resident in Newcastle, including 1342 stillbirths and 1620 infant deaths. Cause‐, birthweight‐, gestational age‐ and birthweight‐for‐gestation‐specific stillbirth (per 1000 total births) and infant mortality (per 1000 livebirths) rates were compared between 1961–80 and 1981–2000 and between individual consecutive decades. Between 1961 and 2000, total stillbirth and infant mortality rates declined dramatically from 23.4 to 4.7 per 1000 total births and from 25.7 to 5.9 per 1000 livebirths, respectively. Rates fell continuously during the first two study decades; however, from 1981–90 to 1991–2000 the decline was not statistically significant. Between 1961–80 and 1981–2000, both stillbirth and infant mortality significantly declined in all birthweight and gestational age categories and for most leading causes of death. Although the population mean birthweight during 1981–2000 [3304 g (SD ± 569)] was significantly higher than during 1961–80 [3255 g (SD ± 572)] (P < 0.0001), the lowest stillbirth and infant mortality rates in 1981–2000 were consistently at about 1 SD above the mean birthweight, with mortality rates increasing for babies with lower or higher weight‐for‐gestation. Declines in stillbirth and infant mortality in Newcastle were associated with reductions in birthweight‐ and gestational age‐specific mortality rates and occurred in most cause‐specific groups of death.     

出生胎龄与小于胎龄儿智能发育的相关性分析

目的 分析出生胎龄与小于胎龄儿(SGA)智能发育的相关性,为SGA的管理和早期干预提供参考。方法 采用回顾性病例对照方式将纳入研究的SGA按出生胎龄分为早期早产儿(<32周)、中期早产儿(32~33^+6周)、晚期早产儿(34~36^+6周)、早期儿(37~38^+6周)和足月儿(≥39周)5个组,应用0~6岁小儿神经心理发育量表对纳入研究的SGA进行智能发育评估。组间比较采用方差分析、Kruskal-Wallis检验、卡方检验和Fisher精确检验,胎龄与智能发育水平的相关性采用多元回归模型、曲线拟合以及阈值效应分析。结果 本研究共纳入研究对象203例。调整了可能的混杂因素后,早期儿组SGA较早期早产儿组SGA发育商得分高23.06分(95%置信区间[confidence interval,CI],12.58-33.55;P<0.01),较中期早产儿组SGA高7.03分(95%CI:0.74-13.32;P<0.05),较晚期早产儿组SGA高5.2分(95%CI:0.91-9.49;P<0.05),较足月儿组SGA高6.08分(95%CI:1.19-10.98;P<0.05)。阈值效应分析发现出生胎龄的关键时间点为37周,当出生胎龄<37周时,胎龄每增加1周SGA的发育商得分提高2.29分(95%CI:1.07-3.52,P<0.01);当出生胎龄>37周时,胎龄每增加1周SGA的发育商得分降低2.14分(95%CI:0.11-4.17,P<0.05)。结论 SGA智能发育水平与出生胎龄呈"U"型相关,在SGA的随访管理中应当将早产和足月SGA作为重点监测人群。     

An investigation into the disparity between Australian Aboriginal and Caucasian perinatal mortality rates

The babies of Australian Aboriginal mothers have higher overall perinatal mortality rates than the babies of Caucasian mothers. They are also more likely to be preterm and of low birth weight. This study used Poisson regression models to adjust the perinatal mortality rates for differences in the gestational age and birth weight distributions of Aborigines and Caucasians. The intriguing finding was that full-term Aboriginal neonates (the group at lowest absolute risk) fare particularly poorly in comparison with Caucasian (adjusted relative risk: 2.9; 95% confidence interval: 1.5 to 5.5). Possible explanations for this phenomenon are explored.     

母亲孕前体质指数和孕期体重增加及其交互作用对新生儿出生体重的影响

目的 研究孕妇孕前BMI和孕期增重对新生儿出生体重的影响及其交互作用。方法 应用队列研究方法,选取2014年1月至2015年3月在安徽省安庆市立医院住院分娩的孕妇进行问卷调查,收集孕妇基本情况,并通过医院电子病历信息系统获取孕妇及新生儿信息。采用χ²检验、多分类logistic回归、相乘模型和相加模型分析孕妇孕前BMI、孕期增重及其交互作用与新生儿出生体重的关系。结果 共纳入单胎活产孕妇2 881例,其中小于胎龄儿359例（12.46%）,大于胎龄儿273例（9.48%）。多分类logistic回归分析显示,控制可能的混杂因素后,孕前体重过低（aRR=1.33,95%CI：1.02~1.73）与孕期增重不足（aRR=1.64,95%CI：1.23~2.19）可增加小于胎龄儿发生风险,孕前超重/肥胖（aRR=1.86,95%CI：1.33~2.60）与孕期增重过多（aRR=2.03,95%CI：1.49~2.78）可增加大于胎龄儿发生风险;交互作用分析显示,未发现二者对新生儿出生体重存在交互作用。结论 母亲孕前体重和孕期增重与新生儿出生体重相关,但未发现二者之间的交互作用。     

孕妇分娩年龄和初潮年龄间隔年数与大于胎龄儿的相关性

目的  探讨孕妇分娩年龄和初潮年龄间隔年数与大于胎龄儿(large for gestational age, LGA)的相关性。方法  选取2015年6月—2018年4月在广西壮族自治区百色市5个县孕早期建卡产检2 032名孕妇为研究对象。分析孕妇间隔年龄与LGA发生的相关性,接收者操作特征(receiver operating characteristic, ROC)曲线分析孕妇间隔年龄在预测LGA发生中的作用。结果  队列随访至2 032名孕妇分娩,其中发生LGA 67例,发生率为3.3%。LGA组孕妇分娩年龄、间隔年龄和BMI较非LGA组大(均有P < 0.05)。相关性分析中,校正混杂因素后,孕妇间隔年龄与出生体重无相关(P=0.178),但间隔年龄≥30岁的孕妇LGA发生风险是间隔年龄 < 10岁的29.214倍(P=0.018)。ROC曲线分析显示,孕妇间隔年龄预测总体、分娩女婴的AUC分别为0.585、0.644,孕妇间隔年龄预测LGA的最佳截断点均为13岁。结论  孕妇分娩年龄和初潮年龄间隔年数与LGA发生有关,间隔年数越大则LGA发生风险越大。分娩年龄和初潮年龄间隔在女婴LGA发生预测中效果更好。     

Perinatal Outcomes in Large Infants Using Customised Birthweight Centiles and Conventional Measures of High Birthweight

Background: Large‐for‐gestational‐age (LGA) or macrosomic infants are associated with adverse maternal and neonatal outcomes. It is unclear if these associations are stronger using customised birthweight centiles. We compared outcomes between term infants defined macrosomic by birthweight >4000 g (Macro₄₀₀₀) or LGA by population centiles (LGA_pop) with those defined LGA by customised centiles (LGA_cust). Methods: This is a prospective cohort study of 2668 term nulliparous women recruited into the Screening for Pregnancy Endpoints (SCOPE) study centres in Auckland, New Zealand and Adelaide, Australia. Maternal (caesarean delivery, postpartum haemorrhage) and infant (severe neonatal morbidity/mortality and admission to neonatal intensive care) outcomes in Macro₄₀₀₀ and LGA groups were compared with appropriate‐for‐gestational‐age infants by customised centiles using logistic regression. Results: Customised centiles defined fewer infants as LGA (10.3% LGA_cust, 14.8% Macro₄₀₀₀, 11.2% LGA_pop). However customised centiles showed stronger association with adverse outcomes. Pre‐labour and intrapartum caesarean section were increased twofold in LGA_cust pregnancies, including those that were not Macro₄₀₀₀ or LGA_pop. Postpartum haemorrhage was increased twofold in mothers of LGA_cust infants only when infants were also LGA_pop. Severe neonatal morbidity/mortality or admission to neonatal intensive care was increased twofold in LGA_cust who were also either Macro₄₀₀₀ or LGA_pop. Importantly 52.3% of Macro₄₀₀₀ and 25.5% of LGA_pop infants were AGA_cust and not at increased risk of most adverse maternal or neonatal outcomes. Conclusions: The use of customised centiles are more strongly associated with adverse birth outcomes and its use should be considered in the definition of LGA.     

胎龄和日龄对早产儿甲状腺功能指标的影响

目的 分析胎龄和日龄对早产儿甲状腺功能的影响,为进一步研究基于胎龄和日龄制定适用于早产儿的甲状腺功能参考区间。方法 收集2017年5月—2020年5月在深圳市龙岗中心医院新生儿科住院早产儿的甲状腺功能指标[促甲状腺激素(TSH)、甲状腺素(T₄)、游离甲状腺素(FT₄)和三碘甲状腺原氨酸(T₃)]结果。按照胎龄和生后日龄分组,对比各组早产儿甲状腺功能指标水平,并分析各检测指标随胎龄和生后日龄的变化。结果 共纳入符合条件的早产儿497例,其中早期早产儿组206例、中期早产儿组128例和晚期早产儿组163例。1)早期早产儿组甲状腺功能指标分别与中期、晚期早产儿组比较,差异有统计学意义(P＜0.05);中期早产儿组甲状腺功能指标与晚期早产儿组比较,差异无统计学意义(P＞0.05)。2)各胎龄组早期早产儿T₄、FT₄和T₃水平比较,差异有统计学意义(H=36.588、32.381、43.021,P＜0.01),TSH水平差异无统计学意义(P＞0.05)。3)生后日龄7~14 d组与14~28 d组早产儿T₄、FT₄和T₃水平比较,差异有统计学意义(Z＝8.706、6.904、9.497,P＜0.05),而血清TSH比较,差异无统计学意义(P＞0.05)。4)早产儿T₄、FT₄、T₃水平与胎龄、日龄呈正相关性,而TSH 水平与胎龄、日龄之间均无相关性。结论 早期早产儿T₄、FT₄、T₃水平与胎龄、日龄呈正相关,需基于胎龄和日龄制定适用于早产儿的甲状腺功能参考区间。     

巨大儿与单纯性肥胖症的相关性分析

[目的 ]　探讨巨大儿与婴幼儿、青少年单纯性肥胖的关系。　 [方法 ]　对 6～ 14岁的 132例巨大儿、5 0 0例正常对照儿及其双亲作了身高和体重的人体测量学检查 ,并对以往超重肥胖情况采用了回顾性问卷调查 ;对婴儿期 5 0例巨大儿 ,15 0例对照儿于 1岁内作了身长体重测量的定期随访。　 [结果 ]　 6～ 14岁时巨大儿组肥胖率 16 .3% ,高于对照组的 8.6 % (P <0 .0 5 ) ,巨大儿组超重率 10 .9% ,略高于对照组的 9.8% ,且与遗传因素无明显的相关性。肥胖和超重在婴儿期最多 ,在学龄前期 ,随着年龄的增加 ,人数逐渐减少 ,但在各年龄段巨大儿组和对照组的肥胖和超重率差异均有显著性。　 [结论 ]　胎儿期肥胖易导致婴幼儿期肥胖 ,与青少年肥胖有一定的相关性