bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergent trends in maternal cigarette smoking during pregnancy: United States 1990–99
Authors: Ananth Cande V. , Kirby Russell S. , Kinzler Wendy L. 
Published: January 2005

SummaryWhile examination of causes for trends in smoking have largely focused on how changes have occurred with maternal age and, less commonly, time period, little is known as to how age, period and birth cohort interact on trends in the prevalence of smoking during pregnancy. We performed a population‐based, retrospective cohort study based on the vital statistics records comprised of White (n = 24 499 629) and Black (n = 5 096 625) women delivering in the United States in 1990–99. Smoking prevalence rates were derived by seven 5‐year maternal age groups (15–19 to 45–49 years), two time periods (1990–94 and 1995–99), and eight 5‐year maternal birth cohorts (1945–49 to 1980–84) after adjusting for the confounding effects of gravidity, education, marital status, and lack of prenatal care through multivariable logistic regression models. The prevalence of smoking was 17.3% among Whites, and 13.5% among Blacks, with substantial variations by age, time period, and birth cohort. The rate declined with increasing age among Whites during the 1990–94 and 1995–99 periods. Among Blacks, the rates increased steeply with advancing age up to 25–29 years and began to decline thereafter. Smoking rates declined among both Whites and Blacks with increasing birth cohort within each age strata. These rates were highest among multigravid women (gravida ≥ 2), and lowest among primigravid women. The rates among Whites declined with increasing maternal age for each gravida. Among Blacks, smoking rates for each gravida increased with advancing age up to 25–29 years, and plateaued among older women. Variation in smoking prevalence by age, time period, and birth cohort provides impetus for designing interventions to reduce smoking. Such studies should not only consider cross‐sectional trends, but also the divergent patterns by age and cohort among women of different race/ethnic groups and gravidity.
Early life influences on serum 1,25 (OH)2 vitamin D
Authors: Arden Nigel K. , Syddall Holly E. , Javaid Muhammad K. , Dennison Elaine M. , Swaminathan R. , Fall Caroline , Cooper Cyrus 
Published: January 2005

SummaryThere is increasing evidence to support the role of the intrauterine and early postnatal environment in determining adult bone mass and risk of fracture. The mechanisms by which this occurs are uncertain but include perturbations in several endocrine axes. Vitamin D is integrally involved in bone metabolism and is therefore an ideal candidate. This study assesses whether birthweight and weight at 1 year of age are associated with the calcium vitamin D axis in elderly women.Vitamin D metabolites, parathyroid hormone, bone mineral density and biochemical markers of bone turnover were measured in 129 healthy women (mean age 65.5 years) from the MRC Hertfordshire Cohort Study whose birthweight and weight at 1 year were available from records.Serum 1,25 (OH)2 vitamin D concentrations were reduced with increasing weight at 1 year (19.1% reduction between the lowest and highest tertiles, P < 0.01). A similar, but weaker trend was seen for birthweight. These associations were not explained by serum levels of serum calcium, phosphate, PTH, creatinine or sex hormones. The association of serum calcium with 1,25 (OH)2 vitamin D was greatest in the lowest tertile with little association in the highest tertile suggesting an increased sensitivity of renal 1‐α hydroxylase in the lowest tertile. Highest levels of 1,25 (OH)2 vitamin D were associated with low BMD and high levels of urinary N‐telopeptide suggesting that vitamin D metabolism may mediate the intrauterine and early postnatal environmental effects on adult BMD.
Effects of carbon monoxide air pollution in pregnancy on neonatal nucleated red blood cells
Authors: Ziaei Saeideh , Nouri Kobra , Kazemnejad Anoshirvan 
Published: January 2005

SummaryIn an analytical cross‐sectional study, the effects of carbon monoxide air pollution on carboxyhaemoglobin (COHb) and absolute nucleated red blood cells (nRBC) of the cord venous blood, were evaluated in 41 newborns delivered by caesarean section at term to mothers who had lived in an air‐polluted area in the centre of Tehran during their pregnancies (study group). The parameters used were compared with 32 cord venous bloods of term caesarean‐delivered newborns of mothers living in a healthy air area outside the city during their pregnancies.A significant difference was observed between the two groups in the cord COHb levels (mean ± SD 10.51 ± 4.79 vs. 1.58 ± 0.96, P < 0.001), cord nRBC (723.87 ± 275.23 × 106/L vs. 248.44 ± 160.79 × 106/L, P < 0.001). A significant correlation was found between ambient carbon monoxide and cord COHb in the study and control groups, respectively (r = 0.863, P = 0.0001; r = 0.691, P = 0.0001), and also cord COHb and cord nRBC in the study group (r = 0.360, P = 0.01).Neonates born to mothers exposed to carbon monoxide air pollution had increased circulating absolute nRBC counts compared with those of the control group. We speculate that air pollution exposure in pregnancy should be avoided, because it may have negative effects on fetal oxygenation.
Influence of prenatal diagnosis and pregnancy termination of fetuses with birth defects on the perinatal mortality rate in Victoria, Australia
Authors: Davidson Natasha , Halliday Jane , Riley Merilyn , King James 
Published: January 2005

SummaryHistorical data show that in Victoria birth defects have accounted for approximately 25% of all perinatal deaths. Terminations of pregnancies (TOPs) for birth defects occurring at ≥20 weeks gestation are included in the population‐based perinatal data collection. These are classified as stillbirths or neonatal deaths. Some would have survived the perinatal period if no termination had taken place, and as a result they have the effect of increasing the perinatal mortality rate (PMR). Conversely, TOPs <20 weeks gestation, of fetuses with lethal birth defects that would have resulted in a perinatal death, are not included in the statistics and therefore reduce the PMR.The aim of this study was to examine the effect on the PMR of TOPs following the prenatal detection of birth defects, taking into account the severity or ‘lethality’ of the birth defects. Data on live births, stillbirths, neonatal deaths and TOPs carried out because of a birth defect were collected from the Victorian Birth Defects Register (BDR) for 1989–2000. Birth defects were categorised into three groups, according to the estimated likelihood of a baby with that condition dying in the perinatal period: a ‘lethal’ birth defect was one where there was >50% likelihood of death, ‘possibly lethal’ 15–50% and ‘non‐lethal’ less than 15%. Based on these ‘lethality’ groups and associated assumptions about average survival rates beyond the neonatal period, the PMR was recalculated. TOPs for ‘non‐lethal’ birth defects at ≥20 weeks gestation increased the PMR by 3.8%. TOPs for ‘lethal’ birth defects <20 weeks decreased the PMR by 14.4%. The net effect on the overall PMR from TOPs for birth defects was a 10.6% decrease.
Neonatal serum p,p’‐DDE concentrations in Germany: chronological changes during the past 20 years and proposed tolerance level
Authors: Lackmann Gerd M. 
Published: January 2005

Summary p,p’‐DDE, the main metabolite of the insecticide DDT, is prenatally transmitted from mother to fetus. Many potential effects of low‐level exposure have been reported, including preterm delivery, growth retardation and neurological impairment, although scientific evidence is still lacking. We present p,p’‐DDE concentrations in full‐term human neonates over a time period of 20 years in Germany. Peripheral venous blood samples were taken from neonates born in 1984–85 (n = 80) and 1994–95 (n = 80), as well as cord blood samples from neonates born in 1998 (n = 199), and peripheral venous blood samples from neonates born in 2002 (n = 20). Blood specimens were immediately centrifuged, and serum was stored at −20°C until analysis. Serum p,p’‐DDE concentrations were determined with capillary gas chromatography followed by electron capture detection. Differences between study groups were tested for mean differences with the Kruskal‐Wallis test.There were no differences between the study groups with regard to sex distribution, birthweight, gestational age, age of the mother, and smoking behaviour of the parents. We found a significant (P < 0.0001) chronological decline of neonatal serum p,p’‐DDE concentrations, with the highest values in 1984–85 (mean = 1.49 µg/L; range: 0.30–5.58) and the lowest in 2002 [mean = 0.18 µg/L; range: 0.07–0.54; tolerance level (95th percentile by rank) = 0.30 µg/L]. Neonatal p,p’‐DDE concentrations today are significantly lower than in the mid‐1990s, when many studies of adverse side effects of p,p’‐DDE were performed. The present results suggest that the neonatal burden of p,p’‐DDE now is so low that there may be no attendant health risks for newborns and children, however, further studies are warranted to elucidate possible long‐term health effects even of low‐level organochlorine pollution.
A dose‐response relationship between maternal smoking during late pregnancy and adult intelligence in male offspring
Authors: Mortensen Erik Lykke , Michaelsen Kim Fleischer , Sanders Stephanie A. , Reinisch June Machover 
Published: January 2005

SummaryAn association between maternal smoking during pregnancy and cognitive and behavioural development has been observed in several studies, but potential effects of maternal smoking on offspring adult intelligence have not been investigated. The objective of the present study was to investigate a potential association between maternal smoking during pregnancy and offspring intelligence in young adulthood. Adult intelligence was assessed at the mean age of 18.7 years by a military draft board intelligence test (Børge Priens Prøve) for 3044 singleton males from the Copenhagen Perinatal Cohort with information regarding maternal smoking during the third trimester coded into five categories (about 50% of the mothers were smokers). The following potential confounders were included as covariates in multivariable analyses: parental social status and education, single mother status, mother's height and age, number of pregnancies, and gestational age. In separate analyses, birthweight and length were also included as covariates.Maternal cigarette smoking during the third trimester, adjusted for the seven covariates, showed a negative association with offspring adult intelligence (P = 0.0001). The mean difference between the no‐smoking and the heaviest smoking category amounted to 0.41 standard deviation, corresponding to an IQ difference of 6.2 points [95% confidence interval 0.14, 0.68]. The association remained significant when further adjusted for birthweight and length (P = 0.007). Both unadjusted and adjusted means suggested a dose‐response relationship between maternal smoking during pregnancy and offspring adult intelligence. When subjects with missing data were excluded, essentially the same results were obtained in the reduced sample (n = 1829). These results suggest that smoking during pregnancy may have long‐term negative consequences on offspring adult intelligence.
Risk factors for pre‐eclampsia in nulliparous and parous women: the Jerusalem Perinatal Study
Authors: Funai E. F. , Paltiel O. B. , Malaspina D. , Friedlander Y. , Deutsch L. , Harlap S. 
Published: January 2005

SummaryPre‐eclampsia has been described as a ‘disease of first pregnancies’ and many believe that its occurrence in a later pregnancy signals a fundamentally different entity. We sought to compare risk factors in first and subsequent pregnancies. We studied 1319 cases of pre‐eclampsia recorded in a historical cohort of 82 436 deliveries in Jerusalem in 1964–76. Logistic regression was used to control for covariates. The adjusted odds ratio (OR) for pre‐eclampsia in first births was 2.58 (95% confidence interval[CI] 2.23, 2.97), compared with all later birth order groups, between which there were no detectable differences in risk. Other risk factors included increasing maternal age, diabetes (OR 5.64, 95% CI 4.33, 7.35), multiple gestations (OR 3.38, 95% CI 2.54, 4.49), fetal haemolytic disease (OR 2.24, 95% CI 1.43, 3.50) and lower maternal education. The risk of pre‐eclampsia was not associated with the mother's employment outside the home and did not differ between immigrants vs. Israeli‐born mothers or between groups of women whose fathers had been born in Western Asia, North Africa or Europe. Effects of each risk factor were similar within first and subsequent births. These results lend no support to the hypothesis that there is a fundamental difference between pre‐eclampsia in a first pregnancy compared with that occurring in a later pregnancy; conclusions may be moderated, however, by the knowledge that the incidence of pre‐eclampsia was low in this historical cohort.
Perinatal mortality rates: adjusting for risk factor profile is essential
Authors: Rankin Judith , Pearce Mark S. , Bell Ruth , Glinianaia Svetlana V. , Parker Louise 
Published: January 2005

SummaryPerinatal mortality has long been used as a comparative measure of health and health care across regions, countries and over time. Recently, the validity of the measure has been questioned. Using data from a population‐based survey of late fetal losses, stillbirths and infant deaths, the Northern Perinatal Mortality Survey, we demonstrate the potential for inaccuracy of crude measures of perinatal mortality. Such measures are generally not adjusted for characteristics of the population (e.g. birthweight, maternal age, plurality, gender) which are known to affect risk of adverse pregnancy outcome when comparing temporal or geographical trends. We also show the effect of standardising for these factors on the most frequent causes of perinatal death. We recommend the construction of a ‘standard birth population’ for calculating standardised perinatal mortality rates that would improve direct comparisons between populations.
The twin placenta: framework for gross analysis in fetal origins of adult disease initiatives
Authors: Salafia Carolyn M. , Maas Elizabeth 
Published: January 2005

SummaryCurrent data strongly support that a wide variety of adult health risks are influenced by intrauterine life events. Twins may have the same (identical, monozygous) or different (fraternal, dizygous) genes, but their relationship to their outside world, via their placentas, is rarely equal. Monochorionic twins and dichorionic twins both resemble and differ from singletons. In the balance between the similarities and the differences, we may find the answer to the interpretation of twin studies, and appropriately apply them to the ‘fetal origins’ hypothesis.
Can we generalise from findings in twins?
Authors: Morley Ruth 
Published: January 2005

SummaryA number of recent studies have used data from twins to shed light on the causal pathways underlying the observed association between birthweight and cardiovascular risk factors or coronary heart disease. The issue of whether findings from twin studies are generally informative, or whether factors associated with twinning preclude generalisation, is considered here. It is concluded that the association between birthweight and later health may differ quantitatively between twins and singletons, but evidence regarding blood pressure suggests it may not differ qualitatively. However, more information is needed on a number of gestational and maternal factors, and on measures of health other than blood pressure. Placentation and issues relating to infertility and its treatment need to be recorded and, together with gestation length, may need to be taken into account in analyses.
Determinants of birthweight and intrauterine growth in liveborn twins
Authors: Loos Ruth J. F. , Derom Catherine , Derom Robert , Vlietinck Robert 
Published: January 2005

SummaryWe explored the relationship of umbilical cord insertion and fusion of placentas with birthweight in monozygotic monochorionic (MZ MC), monozygotic dichorionic (MZ DC), and dizygotic (DZ) twins. In addition, we evaluated some of the possible factors responsible for the restricted intrauterine growth of twins compared with singletons. The birthweight of 4529 liveborn twin pairs of the East Flanders Prospective Twin Survey was prospectively recorded, placentas were examined, and site of umbilical cord insertion was determined after delivery. Birthweight of 76 490 liveborn singletons was obtained from the Study Centre for Perinatal Epidemiology (SPE). Infants with a peripheral cord insertion weighed 150 g less (P < 0.001) than infants with a central cord insertion. DZ infants had a significantly (P < 0.001) higher incidence of central cord insertion than MZ DC and MZ MC infants. MZ DC infants with fused placentas and a peripheral cord insertion weighed on average 300 g less (P < 0.01) than infants with separate placentas and a central cord insertion. In DZ infants, fusion of the placentas did not affect birthweight. Twins gain less weight per week of gestation than singletons from 32 weeks onwards (twins: 128 g, 156 g, 75 g and singletons: 118 g, 251 g, 149 g, weeks 27–31,32–36, 37–42 respectively). From week 32 onwards, parity, birth rank, cord insertion and number of placentas also influenced birthweight of twins. We conclude that the difference between the birthweights of DZ, MZ DC, and MZ MC infants may originate from the least favourable antenatal situation, namely fused placentas with a peripheral cord insertion, which occurs most frequently in MZ twins. Gestation is the main determinant of birthweight. Other placental and maternal factors have a modest but significant influence on prenatal growth.
Twin‐to‐twin transfusion syndrome: a model for the fetal origins of adult health
Authors: Chescheir Nancy C. 
Published: January 2005

SummaryTwin‐to‐twin transfusion syndrome (TTTS) is a complication of monochorionic, diamniotic twins that results from unbalanced blood flow from one to the other in utero. The increased rate of functional heart disease among the recipient twins in these pregnancies is a model for the theory of fetal origins of adult health. Potential mechanisms for heart disease include alterations in the hormonal environment within the fetal bodies, blood pressure‐driven alterations in blood flow and blood vessel distensibility, abnormal differentiation of fetal myocardial cells and changes in coronary artery growth. Although there are no large studies showing adult consequences of this fetal physiological disturbance, paediatric problems certainly exist and predict an increased risk of adult disease.
Gender mix: does it modify birthweight – outcome association?
Authors: Derom Robert , Derom Catherine , Loos Ruth J. F. , Thiery Evert , Vlietinck Robert , Fryns Jean‐Pierre 
Published: January 2005

SummaryGender mix, especially the supposed hormone transfer in utero of the male fetus to his female co‐twin, is a highly debated controversial subject. It occurs in animals (free‐martin syndrome in the cow) but its existence in man has not been convincingly demonstrated. Two aspects of gender mix effects in man, birthweight and cognitive development, were studied in the Belgian East Flanders Prospective Twin Survey, a large population‐based registry of multiple maternities, characterised by accurate data on pregnancy, placental structure and zygosity. The birthweight of the female member of the pair is not influenced by the male co‐twin but, unexpectedly, the female twin enhances to a slight degree the birthweight of her male co‐twin by prolonging the gestation for a few days. Also unexpectedly, in an opposite direction, the cognitive development, as measured by the IQ (WISC‐R) of the female twin rises as compared with controls if her birthweight exceeds that of her male co‐twin.
Intrauterine environmental and genetic influences on the association between birthweight and cardiovascular risk factors: studies in twins as a means of testing the fetal origins hypothesis
Authors: IJzerman Richard G. , Boomsma Dorret I. , Stehouwer Coen D. A. 
Published: January 2005

SummaryEvidence has accumulated that low birthweight is associated with several risk factors for cardiovascular disease. However, it is not known whether or not these associations are due to a programmed response to intrauterine malnutrition or genetic factors influencing both birthweight and cardiovascular risk factors. Twin studies offer a unique opportunity to distinguish between intrauterine and genetic origins of the association between birthweight and cardiovascular risk. In our twin cohort, low birthweight was associated with insulin resistance, lower HDL and shorter height within both dizygotic and monozygotic twin pairs, suggesting that these associations are, at least in part, independent of genetic factors. In contrast, low birthweight was associated with blood pressure, total and LDL cholesterol, fibrinogen and sympathetic activation within dizygotic twin pairs, but not within monozygotic twin pairs. These differences between dizygotic and monozygotic twins suggest that these associations are, at least in part, due to genetic factors. Therefore, both intrauterine environmental and genetic factors appear to play a role in the association between birthweight and cardiovascular risk factors. In the future, strategies may be developed targeted at improving or preventing impaired intrauterine growth. However, the effects of interventions that comprise changes in environment within the normal range may be limited due to the possible important role of genetic factors.
Gender mix in twins and fetal growth, length of gestation and adult cancer risk
Authors: Luke Barbara , Hediger Mary , Min Sung‐Joon , Brown Morton B. , Misiunas Ruta B. , Gonzalez‐Quintero Victor Hugo , Nugent Clark , Witter Frank R. , Newman Roger B. , Hankins Gary D. V. , Grainger David A. , Macones George A. 
Published: January 2005

SummaryThis study evaluated the effect of gender mix (the gender combinations of twin pairs) on fetal growth and length of gestation, and reviewed the literature on the long‐term effects of this altered fetal milieu on cancer risk. In singletons, it is well established that females weigh less than males at all gestations, averaging 125–135 g less at full term. This gender difference is generally believed to be the result of the effect of androgens on fetal growth. The gender difference in fetal growth is greater before the third trimester and less towards term, with males growing not only more, but also earlier than females. Plurality is a known risk factor for reduced fetal growth and birthweight. Compared with singletons, the mean birthweight percentiles of twins fall substantially (by 10% or more) below the singleton 10th percentile by 28 weeks, below the singleton 50th percentile by 30 weeks, and below the singleton 90th percentile by 34 weeks. In unlike‐gender twin pairs, it has been reported that the female prolongs gestation for her brother, resulting in a higher birthweight for the male twin than that of like‐gender male twins. Other researchers have demonstrated that females in unlike‐gender pairs had higher birthweights than females in like‐gender pairs.Analyses from our consortium on 2491 twin pregnancies with known chorionicity showed longer gestations and faster rates of fetal growth in both males and females in unlike‐gender pairs compared with like‐gender male or female pairs, although these differences were not statistically significant. The post‐natal effects for females growing in an androgenic‐anabolic environment include increased sensation‐seeking behaviour and aggression, lowered visual acuity, more masculine attitudes and masculinising effects of the auditory system and craniofacial growth. In contrast, there is no evidence to suggest that there might be a similar feminising effect on males from unlike‐gender pairs. This hormonal exposure in utero may influence adult body size and susceptability to breast cancer.