Delayed prenatal care and the risk of low birth weight delivery

To determine if the timing of prenatal care is associated with low birth weight delivery after adjusting for sociodemographic and behavioral risk factors, we performed a retrospective cross-sectional study of singleton births to white (2,945,595) or African-American (552,068) women in the United States in 1996. When adjusted for race, maternal age, educational level attained, and the use of alcohol and tobacco during pregnancy, women beginning care in the 2nd (adjusted RR = 0.85; 95% CI: 0.83–0.86) and 3rd trimesters (RR = 0.87; 95% CI: 0.84–0.91) had a reduced risk of low birth weight compared to women beginning care in the 1st trimester. Our findings suggest that no benefit exists for early initiation of prenatal care for reducing the risk of low birth weight. Findings related to differences in low birth weight among women who start prenatal care later are likely due to sociodemographic differences that may influence access to early care.     

Predicting low birth weight delivery using maternal nutritional and uterine parameters

At the Institute of Medical Sciences, Banaras Hindu University in Varanasi, India, health workers took anthropometric measurements and hemoglobin level of 196 pregnant women at gestation of 37-41 weeks and of their singleton newborns to detect a combination of maternal nutritional and uterine parameters which could be used to screen mothers at high risk of delivering a low birth weight (LBW) infant ( 2500 g). The maternal anthropometric measurements included pre- and post-delivery weight, height, head and midarm circumference, fundal height, and abdominal girth. Weight, height, head and midarm circumference, and hemoglobin were significantly correlated with birth weight. Pre-delivery weight was better correlated than post-delivery weight with birth weight (r value = 0.4966 vs. 0.3494). The correlation between pre-delivery weight and birth weight remained, even when hemoglobin and one of the uterine parameters were controlled simultaneously. Hemoglobin was an independent significant predictor of birth weight, when all other variables were controlled simultaneously. Both fundal height and abdominal girth were significantly associated with birth weight, when all other variables were controlled simultaneously. Fundal height had a greater difference in means of birth weight than did abdominal girth (960 vs. 871 g). If the fundal height was less than 25 cm, all infants had a LBW. If the fundal height was greater than 35 cm, only one infant had a LBW. The multiple regression equation using pre-delivery weight, hemoglobin, fundal height, and abdominal girth (all independent significant parameters) to estimate birth weight accounted for 70.5% variation. Researchers tested the equation on 118 consecutive full-term singleton newborns. The equation predicted LBW in 32 of the 36 actual LBW deliveries. The estimated birth weights in the 4 actual but missed cases were 2620, 2600, 2566, and 2826 g. This equation can be successfully used to screen pregnant women for LBW.     

The association between low birth weight and caffeine consumption during pregnancy

In a prospective study of 3,891 antenatal patients at Yale-New Haven Hospital between 1980 and 1982, 76.7% consumed caffeine from coffee, tea, colas, and drugs. A dose response of caffeine intake to increased risk for delivering low birth weight (less than 2,500 g) singleton newborns was observed. This relation was observed in deliveries after 36 weeks gestational age. When comparison was made with women who had no caffeine exposure, the relative risks of low birth weight after adjustment for confounding factors were 1.4 (95% confidence interval (CI) 0.7-3.0) for 1-150 mg of caffeine daily; 2.3 (95% CI 1.1-5.2) for 151-300 mg; and 4.6 (95% CI 2.0-10.5) for over 300 mg. Decreases in mean birth weight were 6, 31, and 105 g, respectively. Gestational age did not appear to be related to caffeine consumption in the crude or adjusted analysis. Maternal caffeine intake seems to exert an effect on birth weight through growth retardation in term newborns.     

Obstetric factors associated with low birth weight

An analysis was made of 18,804 of 19,446 consecutive births of the number analysed 15.93% presented low birth-rate. Significant statistical association was found in relation to maternal age, pre-natal care, previous pregnancies, smoking and gestational age at birth. Measures with a view to the attenuation of the problem are proposed, among them being: educational programs for teenagers on human reproduction, programs designed to create awareness of the harm done by smoking, amplification of antenatal assistance, medical programs for the limitation of premature labor, all of these and others, in association with programs of socio-economic support.     

Delayed childbearing: no evidence for increased risk of low birth weight and preterm delivery

Prior studies of the effect of increased maternal age on reproductive outcome in primiparous women have often ignored the possible influence on this relation of more frequent histories of spontaneous abortion and infertility in older women. When these histories are taken into account, the present study of 1,382 white primiparous women who had live singleton deliveries at Yale-New Haven Hospital finds no evidence for an increased risk of low birth weight (relative risk (RR) = 1.06, 95% confidence interval (CI) = 0.38-2.94) or preterm delivery (RR = 1.07, 95% CI = 0.50-2.24) in women delivering at age 30 years or more compared with younger women. Mean birth weight (beta = -19 g, p = 0.57) and gestational age (beta = -0.16 weeks, p = 0.34) were also not significantly affected by older maternal primiparity. Women aged 35 years or more had twice the rate of preterm births compared with women under age 30, although this result was not statistically significant in this data set (RR = 2.07, 95% CI = 0.67-6.35). Other confounding variables were taken into account.     

父母地中海贫血与早产及低出生体重的关系研究

目的 探讨父母妊娠合并地中海贫血（地贫）对新生儿早产和低出生体重的影响。方法 选择2017年1－12月在广西壮族自治区靖西市、德保县人民医院或妇幼保健院进行产前检查的孕妇及其丈夫作为研究对象,从中选取经过地贫基因诊断确诊一方或双方均为地贫且有妊娠结局的父母共758对作为地贫组,选择地贫基因诊断为正常或者地贫筛查、血红蛋白电泳检测均为阴性且有妊娠结局的父母共758对作为非地贫组,并将地贫组按是否罹患地贫分为母亲地贫组、父亲地贫组以及父母双方地贫组,收集研究对象的临床、妊娠结局资料,采用独立样本t检验、χ²检验以及Cox回归分析等统计学方法对父母罹患地贫与新生儿早产和低出生体重的关系进行分析。结果 新生儿早产发生率在地贫组和非地贫组中分别约为6.5%、1.6%,低出生体重发生率分别约为7.3%、0.8%。校正可能存在的混杂因素后,Cox回归分析结果显示,母亲地贫组（aRR=3.45,95% CI：1.35～8.81,P=0.010）、父亲地贫组（aRR=4.93,95% CI：2.16～11.21,P<0.001）及父母双方地贫组（aRR=5.13,95% CI：2.62～10.04,P<0.001）均与新生儿早产风险增加相关;母亲地贫组（aRR=12.98,95% CI：4.91～34.30,P<0.001）、父亲地贫组（aRR=9.40,95% CI：3.40～25.95,P<0.001）及父母双方地贫组（aRR=10.74,95% CI：4.44～26.00,P<0.001）均与新生儿低出生体重风险增加相关;父母双方罹患地贫比父母单方罹患地贫发生新生儿早产（趋势检验χ²=22.72,P<0.001）以及低出生体重（趋势检验χ²=34.03,P<0.001）的风险更高。结论 父母双方罹患地贫或任意一方罹患地贫均可增加新生儿早产和低出生体重的风险,且父母双方罹患地贫发生早产和低出生体重的风险更高。     

Factors associated with low birth weight: a multivariate analysis

The low birth weight of infants is a major public health problem of unknown cause in Benin. We recruited 4,213 pregnant women from a maternity ward in Cotonou for a prospective study. The women were interviewed and further information was obtained from their maternity records. The women were followed until delivery. We found that 6.9% of the births occurred pre-term and there was intrauterine growth retardation in 10.9% of cases. Multiple regression analysis showed that the risks of giving birth to underweight infants were highest for women who were themselves underweight, who had complications due to bleeding or malaria or had social and psychological risk factors. For these particular women, unwanted pregnancy (ORa = 1.60; CI = 1.30-2.00) and lifting heavy loads (ORa = 1.30; CI = 1.10-1.60) were high risk factors. However, adequate prenatal care (ORa = 0.85; CI = 0.69-0.99) and having given birth before were protective factors, reducing the likelihood of a low birth weight. These results have implications for preventive care, in terms of nutrition during pregnancy and psychosociological factors.     

低出生体重儿液体配方奶对极低/超低出生体重儿生后早期生长发育的影响

目的:研究低出生体重儿液体配方奶对极低/超低出生体重早产儿生后早期生长发育的影响,进而评估其临床应用效果。方法:选择胎龄≤32周住院的极低/超低出生体重儿,分为观察组和对照组,分别给予低出生体重儿液体配方奶和普通早产儿配方奶粉喂养,观察喂养后体格发育指标、喂养相关指标、合并疾病等方面的差异,进行统计学分析。结果:应用低出生体重儿液体配方奶喂养的极低和超低出生体重早产儿体重增长速率高于对照组;体重增长所需热量、恢复至出生体重所需时间、喂养耐受时间、静脉营养应用时间均低于对照组;感染、贫血和高间接胆红素血症的发生率低于对照组,差异具有统计学意义(P<0.05)。结论:低出生体重儿液体配方奶由于可提供高热量,有效利用度高,肠道负荷小,且应用方便、能保证极低和超低出生体重儿生后早期良好的生长发育,同时可减少其并发症的发生。     

出生体重与分娩方式的变化分析

目的 探讨本院近19年来足月妊娠,头位分娩,无合并症的产妇年龄、孕周、出生体重和分娩方式的变化及意义。方法 26 479例产妇资料被输入计算机,采用SSPS软件进行相关性分析、t检验和卡方检验。结果 随年代递增,产妇年龄逐渐增大,孕周减小,出生体重增加。阴道产率下降,剖宫产率上升,产钳助产率变化无规律。男女婴比例接近,男婴出生体重高于女婴,随年代不同,两者均增长,但增长幅度呈下降趋势。结论 近十几年来,胎儿出生体重逐渐增加,剖宫产率上升,男女婴比例略高于1:1。     

Demographic correlates of low birth weight

Data from 100,277 certificates of livebirths were analyzed in an attempt to uncover independent correlates of birthweight and gestation time. Without statistical control, each of these variables was shown to be significantly related to race, trimester of obtaining prenatal care, maternal age, parity, socioeconomic status, and legitimacy status. Regression analyses indicated that maternal race and the trimester in which she obtained prenatal care were the most significant correlates of birthweight and gestation time. It was suggested that race and trimester of obtaining prenatal care were not, in themselves, causes of low birthweight. Other indicess of socioeconomic, cultural, biological, medical, and psychological factors may be correlated with mother's race and the trimester in which she obtains prenatal care.