New standards for birth weight by gestational age using family data

OBJECTIVE: This study was undertaken to provide new standards for birth weight according to gestational age through the addition of family data on maternal birth weight and birth weights of previous siblings. STUDY DESIGN: The analyses were based on 1.7 million births in Norway from 1967 through 1998. These population data were arranged into sibships and mother-offspring units through unique personal numbers. We categorized first births by sex and maternal birth weight and second births by sex and birth weight of the older sibling. RESULTS: Standards for birth weight per gestational age percentiles differed by >1100 g when the birth weight of an older sibling was considered and by almost 700 g when maternal birth weight was considered. The value of these new standards for birth weight according to gestational age was demonstrated through variation in perinatal mortality. CONCLUSION: Maternal birth weight and birth weights of previous siblings allow improved predictions of birth weight according to gestational age and should be used for classification of small-for-gestational-age births.     

Birth weight, gestational age and medications during pregnancy

Objective: To determine the effect of medication on birth weight and gestational age in 29 004 healthy newborn infants born to mothers with or without treatment of drugs. Method: Birth weight and gestational age were evaluated in healthy control newborn infants in the population-based dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities (1980–1991) using multiple regression analysis. Results: Of 114 drugs used in more than 100 pregnant women, 19 had a positive or negative impact. Conclusions: Further studies should be carried out to identify the possible mechanisms of medication and/or the maternal disorder for which this medication was given.     

Birth weight by gestational age in twin pregnancies: analysis of 661 pairs.

The mortality of twin infants is four to five times higher than that of singletons, and one-half to two-thirds of all twins weigh < 2,500 g at birth. The appropriate interpretation of fetal growth throughout pregnancy is dependent upon the availability of adequate standards. We reviewed 661 pairs of live twin infants born at Chang Gung Memorial Hospital from 1979 to 1990. The frequency of twin births was 1.17% (1:86), and the ratio of males to females was 1.03. The frequency of preterm births (< 37 weeks) was 36.9%, the frequency of low birth weight (< 2,500 g) was 47.9% and very low birth weight (< 1,500 g) was 6.7%. A fetus grows most rapidly from the 32nd to the 35th week of gestation (200 g per week). The growth was 145 g per week from the 28th to the 32nd week and from the 35th to the 38th week of gestation. After the 38th week, the mean birth weight increased by only 35 g per week. Compared with a singleton birth, the mean birth weight of twins was about 100 g lighter during the 28th to the 32nd week, then the difference increased gradually to about 500 g at term.     

Birth weight and gestational age of newborns from Wielkopolski and Lubuski regions

OBJECTIVES: The correlation between the gestational age and the birth body weight are among others the basis of the estimation of newborn's maturity. Because of the acceleration of development and the decrease in the gestational age and birth body weight regarded as a limitation to newborn's survivalship there is a necessity of bringing up to date the existing reference systems. DESIGN: The main goal of this work is to modernize the reference system of birth body weight in relation to gestational age. MATERIALS AND METHODS: The data of the birth body weight of 48,443 (25,225 boys and 23,218 girls) newborn, singleton children with a gestational age of 24-43 weeks were examined. Data was collected in 2001 and 2002 in Wielkopolski and Lubuski region. Values of the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentile were calculated. The analysis was carried out separately for both sexes. Additionally, because of lack of dimorphic differences until the 33rd week of gestation, percentile values were calculated for both sexes together in the partition of 24 to 33 weeks of gestation. CONCLUSIONS: In comparison to previous reference systems, the obtained results showed a tendency for the birth body weight to increase.     

A comparative analysis of birthweight for gestational age standards

Summary. The possible consequences of the use of various birthweight for-gestational age standards in a local population were investigated. Birthweight-for-gestational age standards based on the analysis of 55 387 births occurring to women resident in the area of the Greater Glasgow Health Board (GGHB) between 1975 and 1979 were estimated. The Glasgow based standard was then compared with a number of growth standards reported for other populations, including the widely adopted standards of Thomson et al . (1968). The relative performance of each standard when applied to the Glasgow population was assessed by calculating the sensitivity, specificity and predictive value of the various standards vis-å-vis the distribution of light-for-dates infants defined according to the Glasgow standard. The results suggest that both the accurate assessment of fetal growth at birth and the evaluation of screening procedures for antenatal detection of growth retardation require growth standards reflecting the pattern of fetal growth and development in the population at risk.     

Intrauterine growth retardation: characteristics, risk factors and gestational age

Maternal, obstetrical, and neonatal factors were studied in 1604 pregnancies complicated by intrauterine growth retardation and 1604 non-IUGR controls. These were examined in the overall IUGR group and at various gestational ages. Eighty-six percent of perinatal deaths were found in the IUGR group with 57.4% occurring prior to labor. Maternal smoking, low weight gain, low prepregnancy weight, and hypertension were found more frequently in the IUGR population. In addition, maternal hypertension was found to be significant in the IUGR infants delivered prematurely.     

Risk factors and perinatal outcomes associated with idiopathic small for gestational age Taiwanese newborns

Objective

To determine risk factors and perinatal outcomes associated with small for gestational age (SGA) neonates among healthy pregnant women.

Methods

A retrospective cohort study was conducted of 49 945 women who gave birth at Chang Gung Memorial Hospital, Taipei, Taiwan, after 24 weeks of pregnancy. Idiopathic SGA newborns (n = 3398) were characterized by a birth weight below the 10th percentile for mean weight corrected for GA and fetal sex.

Results

Risk factors for idiopathic SGA newborns included hypercoiling of the umbilical cord (adjusted odds ratio [aOR], 3.3; 95% confidence interval [CI], 1.6–7.0); prior fetal death (aOR, 2.8; 95% CI, 2.0–3.9); primiparity (aOR, 1.5; 95% CI, 1.4–1.7); adolescent pregnancy (aOR, 1.5; 95% CI, 1.2–2.0), low prepregnancy weight (aOR, 1.6; 95% CI, 1.5–1.8), low prepregnancy body mass index (aOR, 1.1; 95% CI, 1.0–1.3); short stature (aOR, 1.3; 95% CI, 1.1–1.4); and entangled umbilical cord (aOR, 1.1; 95% CI, 1.0–1.3). Idiopathic SGA newborns correlated with increased risk of adverse perinatal outcomes, including fetal death, low Apgar scores, oligohydramnios, placental abruption, and admission to the neonatal intensive care unit.

Conclusion

Some risk factors for idiopathic SGA newborns were modifiable, suggesting potential implications for public health.     

儿童肥胖与出生体重、胎龄及宫内营养的关系

目的 了解不同出生体重、胎龄及宫内营养状况与儿童期肥胖之间的关系,为围产期干预提供依据.方法 对上海市东北区域10所小学6～10岁共2395名儿童进行体格检查.收集每位儿童的出生资料,分析出生体重、胎龄以及宫内营养状况与儿童期肥胖的关系.结果 出生时巨大儿(出生体重≥4000 g)儿童期发生肥胖的危险是正常出生体重儿的1.55倍(OR=1.55,95%CI:1.17～2.05,x2=9.380,P=0.002);与足月儿相比,早产儿和过期儿的儿童期肥胖检出率有升高趋势,但差异无统计学意义(OR=1.38,95%CI;0.82～2.3,x2=1.448,P=0.229;OR:1.34,95%CI:0.71～2.51,x2=0.834,P=0.361);大于胎龄儿(LGA)儿童期发生肥胖的危险是适于胎龄儿(AGA)的1.38倍(OR=1.38,95%CI:1.05～1.82,x2=5.206,P=0.023).结论 巨大儿、大于胎龄儿均为发生儿童期肥胖的高危因素.     

Placental abruption: critical analysis of risk factors and perinatal outcomes

Objective.?To investigate risk factors and pregnancy outcome of patients with placental abruption.

Methods.?A population-based study comparing all pregnancies of women with and without placental abruption was conducted. Stratified analysis using multiple logistic regression models was performed to control for confounders.

Results.?During the study period there were 185,476 deliveries, of which 0.7% (1365) occurred in patients with placental abruption. The incidence of placental abruption increased between the years 1998 to 2006 from 0.6 to 0.8%. Placental abruption was more common at earlier gestational age. The following conditions were significantly associated with placental abruption, using a multivariable analysis with backward elimination: hypertensive disorders, prior cesarean section, maternal age, and gestational age. Placental abruption was significantly associated with adverse perinatal outcomes such as Apgar scores?<7 at 1 and 5?min and perinatal mortality. Patients with placental abruption were more likely to have cesarean deliveries, as well as cesarean hysterectomy.Using another multivariate analysis, with perinatal mortality as the outcome variable, controlling for gestational age, hypertensive disorders, etc., placental abruption was noted as an independent risk factor for perinatal mortality.

Conclusions.?Placental abruption is an independent risk factor for perinatal mortality. Since the incidence of placental abruption has increased during the last decade, risk factors should be carefully evaluated in an attempt to improve surveillance and outcome.     

Birth weight for gestational age of Mexican American infants born in the United States.

OBJECTIVE: To develop a reference for birth weight for gestational age to identify Mexican American infants born in the United States who are small or large for gestational age. METHODS: Reference percentiles were developed for Mexican American and non-Hispanic white births, using national vital statistics from 1992-1994 for Mexican Americans (n = 1,197,916) and 1994 for non-Hispanic whites (n = 2,238,457). Birth weights and gestation from the last menstrual period were taken from birth certificates. Smoothed curves were fit, using unweighted fourth-degree polynomial equations, for the tenth, 50th, and 90th percentiles by gender and parity. RESULTS: Mexican American infants were heavier than non-Hispanic white infants between 30 and 37 weeks' gestation for all parities and both genders. However, at term there was consistent crossover. Non-Hispanic white infants were heavier at or after 37 through 42 weeks' gestation, whereas the growth of Mexican American infants appeared to slow. Beginning at 37 weeks, the differences in weights of infants of primiparas increased to more than 100 g by 40 weeks; the differences were only slightly less for infants of multiparas. CONCLUSION: Given differences in distribution of birth weights for gestational age between Mexican Americans and non-Hispanic whites, the ability to recognize fetal growth restriction (FGR) or excessive growth is questionable. These data provide a reference for Mexican Americans for clinical use and for future studies in identifying infants at risk for FGR or overgrowth.     

Recurrent small for gestational age birth: perinatal risks and outcomes

The risk of recurrent small for gestational age birth, as well as maternal and fetal-neonatal characteristics associated with recurrence, was examined in 174 mothers of consecutively delivered small for gestational age infants followed through an additional 240 livebirths. There was a twofold and fourfold increase in the risk for small for gestational age birth after one and two small for gestational age births, respectively. Although an intervening average for gestational age birth decreased the risk of recurrence, these women remained at increased risk over the general population. Given the history of a previous small for gestational age birth, perinatal risks and outcomes considered individually would not improve the prediction of recurrence. However, the significantly higher frequency of these variables, considered as a group, among mothers with recurrent small for gestational age birth suggests an association with underlying maternal disease, for example, chronic hypertension, substance use and abuse, more severe fetal-neonatal compromise, and recurrent small for gestational age birth. Recurrent small for gestational age birth should initiate a search for persistent, underlying maternal disease.     

Birth weight percentile and perinatal outcome: recurrence of intrauterine growth retardation

In 9596 patients followed throughout two pregnancies, recurrence of intrauterine growth retardation (IUGR) was evaluated as a function of previous birth weight percentile and attendant complications of pregnancy. Among 4623 patients with two uncomplicated pregnancies, the prevalence of recurrent IUGR was significantly related to the severity of growth retardation in the first pregnancy (P less than .0001). Those patients with both medical complications and IUGR in the first pregnancy remained at significantly increased risk for recurrent IUGR, even when the second pregnancy was uncomplicated. In second pregnancies, the combination of a previous history of an IUGR neonate and an additional current complication of pregnancy acted synergistically to increase the risk of recurrent IUGR to a level higher than that attributable to either risk factor alone.     

Birth weight centiles,risk of intrapartum compromise,and adverse perinatal outcomes in term infants

Objective: The objective of this study is to evaluate the association between birth weight centiles and the risk of intrapartum compromise and adverse neonatal outcomes in term pregnancies.

Methods: Retrospective study of 32?468 term singleton births at a major tertiary maternity hospital in Australia. Data comprised gestation, mode, and indication for delivery and adverse perinatal outcomes. Fetal sex and gestational age-specific birth weight centiles were the main exposure variable.

Results: Neonates?<21st birth weight centile had an increased risk of intrapartum compromise, the highest risk was in babies?<3rd centile (OR 4.04, 95% CI 3.34–4.89). The risk of adverse perinatal outcomes was increased in neonates?<21st and?>91st birth weight centiles. The highest risk was in those?<3rd centile (OR 2.35, 95% CI 2.00–2.75).

Conclusions: Fetal size measurements near term may be used as part of screening test for identifying fetuses at an increased risk of intrapartum compromise and adverse perinatal outcomes.     

Birth weight in twins: an analysis of discordancy and growth retardation

Sonographic estimation of fetal weight offers the potential of antenatal diagnosis of discordancy and growth retardation in twins. Although standards for intertwin birth weight percent differences in infants over 2500 g are available, similar norms are not available at lower weights. Intertwin birth weight percent differences in live-born twins above 500 g in 500-g increments were analyzed. Intertwin birth weight differences, expressed as a percentage of the weight of the larger twin, were relatively uniform across a wide range of birth weights. Differences above 15% were increasingly more likely to be associated with growth retardation in one of the infants.     

Pre-eclampsia: maternal risk factors and perinatal outcome

OBJECTIVE: The aim of this study was to throw light on the incidence of pre-eclampsia (PE) in women attending for care and delivery at a hospital in Saudi Arabia, and analyze the maternal risk factors and outcome of mothers and neonates in pregnancies complicated by PE. METHODS: This retrospective study involved almost all women (n = 27,787) who delivered at King Fahad Hospital of the University in a 10-year period (1992-2001). The maternal records were reviewed for age, parity, gestational age, mode of delivery, antenatal care, onset of PE, severity of proteinuria, and the frequency of antenatal and intrapartum complications. The neonatal records were reviewed for perinatal outcome including birth weight, frequency of stillbirths, and neonatal deaths. RESULTS: Among the study cohort of pregnancies, 685 women, i.e. 2.47%, were diagnosed as having PE among whom a high proportion (42.0%) were nulliparous women. Similarly, PE was encountered at a high percentage (40.0%) in women at the extreme of their reproductive age (< 20 and >40 years), and more women with PE delivered prematurely (30.2%) as compared to healthy controls (13.5%). Spontaneous vaginal deliveries were less frequent in women with PE (69.2%) as compared with healthy controls (86.2%). Instrumental deliveries, with spontaneous labor, amounted to 15.9% in women with PE, but they comprised only 2.9% in healthy women. The deliveries were more likely to be induced (22.8%) or be performed by cesarean section (14.9%) in women with PE than in healthy controls (6.8% and 9.6%). Placental abruption was the most common maternal complication (12.6%) in women with PE, followed by oligouria (7.9%), coagulopathy (6.0%), and renal failure (4.1%). The perinatal outcome of pregnancies with PE shows that stillbirths (2.34%) and early neonatal deaths (1.02%) comprised an overall mortality rate of 33.6 per 1,000. More stillbirths and neonatal deaths showed a tendency to be associated with the severe form of PE (diastolic BP > or =120), as compared with the mild form (diastolic BP 90-110). Stillbirths and neonatal deaths appear to be associated with women who had no or irregular antenatal care and whose proteinuria amounted to or exceeded 3 g per 24 h, when delivery occurred at 28th gestational week or less, and when the birth-weight of the neonates was between 500 and 1,000 g. CONCLUSION: We document a hospital-based incidence rate of PE of 2.47%, with a high proportion of PE cases occurring among nulliparous women and those at the extreme ends of the reproductive age. More maternal and neonatal complications were encountered in women with PE when the PE was severe, when the pregnancy had to be terminated early, when there was no regular antenatal care, the birth-weight was low, or the proteinuria was severe.