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Centile charts for birthweight for gestational age for Scottish singleton births
Sandra Bonellie, James Chalmers, Ron Gray, Ian Greer, Stephen Jarvis, Claire Williams
BMC Pregnancy and Childbirth , 2008, DOI: 10.1186/1471-2393-8-5
Abstract: Routinely collected data of 100,133 singleton births occurring in Scotland from 1998–2003 were used to construct new centile charts using the LMS method.Centile charts for birthweight for sex and parity groupings were constructed for singleton birth and compared to existing charts used in Scottish hospitals.Mean birthweight has been shown to have increased over recent decades. The differences shown between the new and currently used centiles confirm the need for more up-to-date centiles for birthweight for gestational age.Birthweight is one of the important indicators used to assess the health of an infant at birth. Low birthweight has often been defined as weights less than 2500 grams with birthweights less than 1500 grams classed as very low birthweight. These definitions however do not take into account gestational age. It is important to be able to differentiate between babies who are light because they are premature and those who are small-for-gestational age since the latter may have different health problems to the former. They may be growth restricted and have an increased risk of other complications such as perinatal asphyxia, symptomatic hypoglycaemia, congenital malformations, chronic intra-uterine infection and pulmonary haemorrhage [1]. Large-for-gestational age babies also have related health problems. Identification of small or large for gestational age babies is important for the management of the individual pregnancy and neonate. It is also a valuable aid to epidemiological studies where the aim is to identify risk factors or to assess the management of pregnancies [2].Small- or large-for-gestational age babies may be identified using centile charts of birthweight by gestational age. Centile reference charts are used to monitor clinical measurements on individuals in the context of population values. Raw centiles can be calculated from appropriate data but the perturbations in these curves are unlikely to reflect the pattern of underlying growth at
Inference for Extremal Conditional Quantile Models, with an Application to Market and Birthweight Risks  [PDF]
Victor Chernozhukov,Ivan Fernandez-Val
Quantitative Finance , 2009, DOI: 10.1093/restud/rdq020
Abstract: Quantile regression is an increasingly important empirical tool in economics and other sciences for analyzing the impact of a set of regressors on the conditional distribution of an outcome. Extremal quantile regression, or quantile regression applied to the tails, is of interest in many economic and financial applications, such as conditional value-at-risk, production efficiency, and adjustment bands in (S,s) models. In this paper we provide feasible inference tools for extremal conditional quantile models that rely upon extreme value approximations to the distribution of self-normalized quantile regression statistics. The methods are simple to implement and can be of independent interest even in the non-regression case. We illustrate the results with two empirical examples analyzing extreme fluctuations of a stock return and extremely low percentiles of live infants' birthweights in the range between 250 and 1500 grams.
Prevalence of hypospadias in Italy according to severity, gestational age and birthweight: an epidemiological study
Paolo Ghirri, Rosa T Scaramuzzo, Silvano Bertelloni, Daniela Pardi, Amerigo Celandroni, Guido Cocchi, Roberto Danieli, Luisa De Santis, Maria C Di Stefano, Orietta Gerola, Mario Giuffrè, Giuseppe S Gragnani, Cinzia Magnani, Cristiano Meossi, Ilaria Merusi, Giuseppe Sabatino, Stefano Tumini, Giovanni Corsello, Antonio Boldrini
Italian Journal of Pediatrics , 2009, DOI: 10.1186/1824-7288-35-18
Abstract: We reviewed all the newborns file records (years 2001–2004) in 15 Italian Hospitals.We found an overall hypospadias prevalence rate of 3.066 ± 0.99 per 1000 live births (82.48% mild hypospadias, 17.52% moderate-severe). In newborns Small for Gestational Age (birthweight < 10th percentile) of any gestational age the prevalence rate of hypospadias was 6.25 per 1000 live births. Performing multivariate logistic regression analysis for different degrees of hypospadias according to severity, being born SGA remained the only risk factor for moderate-severe hypospadias (p = 0.00898) but not for mild forms (p > 0.1).In our sample the prevalence of hypospadias results as high as reported in previous European and American studies (3–4 per 1000 live births). Pathogenesis of isolated hypospadias is multifactorial (genetic, endocrine and environmental factors): however, the prevalence rate of hypospadias is higher in infants born small for gestational age than in newborns with normal birth weight.Hypospadias is a congenital displacement of the urethral meatus in male newborns, often associated to an incomplete development of the foreskin (prepuce) and abnormal penile curvature (recurvatum or hypospadias sine hypospadias). According to the exact localization of the meatus, hypospadias is named glandular or coronal (mild), penile (moderate), scrotal and perineal (severe). While most cases of mild forms are usually an isolated defect, the severe ones may be a symptom of a disorder of sexual differentiation [1]. According to the Chicago Consensus Conference, severe isolated hypospadias can be classified either into among 46, XY Disorders of Sexual Differentiation ("Disorders in androgen synthesis or action") when it is supposed to be due to a complex disorders as 5α reductase deficiency or defects in androgen action, or classified into the C group ("Other"), when it is considered an isolated embryological defect [2].The isolated malformation is likely caused by failed seam of the ur
Obesity and diabetes genes are associated with being born small for gestational age: Results from the Auckland Birthweight Collaborative study
Angharad R Morgan, John MD Thompson, Rinki Murphy, Peter N Black, Wen-Jiun Lam, Lynnette R Ferguson, Ed A Mitchell
BMC Medical Genetics , 2010, DOI: 10.1186/1471-2350-11-125
Abstract: In this study we tested the association between SGA and polymorphisms in genes that have previously been associated with obesity and/or diabetes. We undertook analysis of 54 single nucleotide polymorphisms (SNPs) in 546 samples from the Auckland Birthweight Collaborative (ABC) study. 227 children were born small for gestational age (SGA) and 319 were appropriate for gestational age (AGA).The results demonstrated that genetic variation in KCNJ11, BDNF, PFKP, PTER and SEC16B were associated with SGA and support the concept that genetic factors associated with obesity and/or type 2 diabetes are more prevalent in those born SGA compared to those born AGA. We have previously determined that environmental factors are associated with differences in birthweight in the ABC study and now we have demonstrated a significant genetic contribution, suggesting that the interaction between genetics and the environment are important.Small for gestational age (SGA) babies (typically defined as birthweight below the 10th centile according to gestational age [1,2]) are not only at increased risk of neonatal morbidity and mortality, but are also at increased risk of rapid postnatal weight gain, later obesity and diseases in adulthood such as type 2 diabetes, hypertension and ischemic heart disease [3-7] which are major causes of adult morbidity and mortality worldwide. Although the cause of this association is unknown, several hypotheses have been proposed. The fetal insulin hypothesis [8] proposes that common genes inherited by the fetus affect both birth size and predisposition to adult diseases. In contrast, the Barker hypothesis [4,5,9-11] suggests the association to be the result of fetal programming - permanent changes in physiology and metabolism in response to adverse maternal uterine environment in pregnancy that result in increased metabolic disease risk in adulthood. The increased risk of adult metabolic diseases in those who are born small at birth is further amplified by an
Temporal Trends in Chorioamnionitis by Maternal Race/Ethnicity and Gestational Age (1995–2010)  [PDF]
Michael J. Fassett,Deborah A. Wing,Darios Getahun
International Journal of Reproductive Medicine , 2013, DOI: 10.1155/2013/906467
Abstract: Objective. To characterize trends in chorioamnionitis (CAM) by maternal race/ethnicity and gestational age. Study Design. We examined trends in CAM from 1995–2010 among singleton births in all Kaiser Permanente Southern California hospitals ( ). Data were extracted from Perinatal Service System and clinical utilization records. Gestational age- and race/ethnicity-specific biannual diagnosis rates were estimated using the Poisson regression after adjusting for potential confounding factors. Results. Overall diagnosis rates of CAM increased from 2.7% in 1995-1996 to 6.0% in 2009-2010 with a relative increase of 126% (95% confidence intervals [CI] 113%–149%). From 1995-1996 to 2009-2010, CAM increased among the Whites (1.8% to 4.3%, -value for trend <.001), Blacks (2.2% to 3.7%, -value for trend <.001), Hispanics (2.4% to 5.8%, -value for trend <.001), and Asian/Pacific Islanders (3.6% to 9.0%, -value for trend <.001). The adjusted relative percentage change in CAM from 1995-1996 to 2009-2010 was for Whites [preterm 21% (9%–78%), term 138% (108%–173%)], for Blacks [preterm 24% (?9%–81%), term 62% (30%–101%)], for Hispanics [preterm 31% (3%–66%), term 135% (114%–159%)], and for Asian/Pacific Islanders [preterm 44% (9%–127%), term 145% (109%–188%)]. Conclusion. The findings suggest that CAM diagnosis rate has increased for all race/ethnic groups. This increase is primarily due to increased diagnosis at term gestation. 1. Introduction Chorioamnionitis, an infection and inflammation of the maternal and fetal interface, is arguably the most important cause of preterm birth and infant morbidity. Despite advancements in diagnosis and treatment, chorioamnionitis and its complications remain major public health concern in the United States. It has been estimated that about 10 percent of all pregnancies are complicated by chorioamnionitis [1, 2]. Documented immediate and long-term sequelae of chorioamnionitis include fetal mortality [3], preterm premature rupture of membranes [4], neonatal intensive care admission [5], bronchopulmonary dysplasia [6, 7], and cerebral palsy [8]. Most importantly, chorioamnionitis is responsible for approximately half of all preterm births [9–11]. Prevalence varies with race/ethnicity and is higher in non-Whites than Whites [12]. The most common route of infection is ascending microbial invasion of the amniotic cavity from upper genital tract [13, 14]. Inflammatory processes at sites remote from the female genital tracts are also described as important sources of infection [15, 16]. There is a gap in knowledge about the recent trends
Clinical Prediction in Early Pregnancy of Infants Small for Gestational Age by Customised Birthweight Centiles: Findings from a Healthy Nulliparous Cohort  [PDF]
Lesley M. E. McCowan, John M. D. Thompson, Rennae S. Taylor, Robyn A. North, Lucilla Poston, Philip N. Baker, Jenny Myers, Claire T. Roberts, Gustaaf A. Dekker, Nigel A. B. Simpson, James J. Walker, Louise C. Kenny, on behalf of the SCOPE Consortium
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070917
Abstract: Objective Small for gestational age (SGA) infants comprise up to 50% of all stillbirths and a minority are detected before birth. We aimed to develop and validate early pregnancy predictive models for SGA infants. Methods 5628 participants from SCOPE, a prospective study of nulliparous pregnant women, were interviewed at 15±1 weeks’ gestation. Fetal anthropometry, uterine and umbilical Doppler studies were performed at 20±1 weeks’. The cohort was divided into training (n = 3735) and validation datasets (n = 1871). All-SGA (birthweight <10th customised centile), Normotensive-SGA (SGA with normotensive mother) and Hypertensive-SGA (SGA with mother who developed hypertension) were the primary outcomes. Multivariable analysis was performed using stepwise logistic regression firstly using clinical variables and then with clinical and ultrasound variables. Receiver operator curves were constructed and areas under the curve (AUC) calculated. Results 633 infants (11.3%) in the whole cohort were SGA; 465 (8.3%) Normotensive-SGA and 165 (3.0%) Hypertensive-SGA. In the training dataset risk factors for All-SGA at 15±1 weeks’ included: family history of coronary heart disease, maternal birthweight <3000 g and 3000 g to 3499 g compared with ≥3500 g, >12 months to conceive, university student, cigarette smoking, proteinuria, daily vigorous exercise and diastolic blood pressure ≥80. Recreational walking ≥4 times weekly, rhesus negative blood group and increasing random glucose were protective. AUC for clinical risk factors was 0.63. Fetal abdominal or head circumference z scores <10th centile and increasing uterine artery Doppler resistance at 20±1 weeks’ were associated with increased risk. Addition of these parameters increased the AUC to 0.69. Clinical predictors of Normotensive and Hypertensive-SGA were sub-groups of All-SGA predictors and were quite different. The combined clinical and ultrasound AUC for Normotensive and Hypertensive-SGA were 0.69 and 0.82 respectively. Conclusion Predictors for SGA of relevance to clinical practice were identified. The identity and predictive potential differed in normotensive women and those who developed hypertension.
The Relationship between Birthweight and Longitudinal Changes of Blood Pressure Is Modulated by Beta-Adrenergic Receptor Genes: The Bogalusa Heart Study
Wei Chen,Sathanur R. Srinivasan,D. Michael Hallman,Gerald S. Berenson
Journal of Biomedicine and Biotechnology , 2010, DOI: 10.1155/2010/543514
Abstract: This study examines the genetic influence of -adrenergic receptor gene polymorphisms (2-AR Arg16Gly and 3-AR Trp64Arg) on the relationship of birthweight to longitudinal changes of blood pressure (BP) from childhood to adulthood in 224 black and 515 white adults, aged 21–47 years, enrolled in the Bogalusa Heart Study. Blacks showed significantly lower birthweight and frequencies of 2-AR Gly16 and 3-AR Trp64 alleles and higher BP levels and age-related trends than whites. In multivariable regression analyses using race-adjusted BP and birthweight, low birthweight was associated with greater increase in age-related trend of systolic BP (standardized regression coefficient =?0.09, =.002) and diastolic BP (=?0.07, =.037) in the combined sample of blacks and whites, adjusting for the first BP measurement in childhood, sex, age, and gestational age. Adjustment for the current body mass index strengthened the birthweight-BP association. Importantly, the strength of the association, measured as regression coefficients, was modulated by the combination of 2-AR and 3-AR genotypes for systolic (=.042 for interaction) and diastolic BP age-related trend (=.039 for interaction), with blacks and whites showing a similar trend in the interaction. These findings indicate that the intrauterine programming of BP regulation later in life depends on -AR genotypes.
Reference birthweight range for multiple birth neonates in Japan
Noriko Kato
BMC Pregnancy and Childbirth , 2004, DOI: 10.1186/1471-2393-4-2
Abstract: Pairs of multiple births were identified by birthplace, the ages of the parents, gestational age, and the year and month of birth. We studied a total of 32,232 livebirth-livebirth pairs of twins, 1894 triplet live births, and 206 quadruplet live births.The median birthweight of males, taking gestational age into account, was ca. 0.05 kg–0.1 kg heavier than that of females. Compared to singleton neonates, the median birthweight of twins was ca. 0.15 kg smaller at the gestational age of 34 weeks, increasing to ca. 0.5 kg at 42 weeks of gestation. As for birth order, the mean birthweight of the first-born twin was heavier than that of the second-born. The standard deviation of birthweight was larger for second-born twins. The birthweight of twins from multiparous mothers was greater than those from primiparous mothers. The median birthweight according to gestational age was found to be the greatest in twins, lower in triplets and the lowest in quadruplets. In triplets, the 50th percentile was 0.08 kg heavier in boys than for girls.Our results can be used for assessment of birthweight of multiple births in Japan.Since the introduction of assisted reproductive technology, the rate of multiple births has been increasing rapidly in Japan [1]. A reference range for the birthweight of multiple births neonates is necessary for the assessment for intrauterine growth. Studies on the birthweight of twins have been conducted in many countries [2-5], and some of these studies have used hospital birth records [6].The aim of this research is to present a methdologic approach to constructing birthweight reference ranges for multiples based on Japanese birth certificates, and also to clarify how the population-based data are useful for creation of birthweight reference for multiple births. Results of the research would be helpful to perinatologists for evaluating intrauterine growth of multiples, and for evaluating twin percentile rank at birth.In Japan, birth, death, and stillbirth c
Smoking in preeclamptic women is associated with higher birthweight for gestational age and lower soluble fms-like tyrosine kinase-1 levels: a nested case control study
Susan R Kahn, Nisha D Almeida, Helen McNamara, Gideon Koren, Jacques Genest, Mourad Dahhou, Robert W Platt, Michael S Kramer
BMC Pregnancy and Childbirth , 2011, DOI: 10.1186/1471-2393-11-91
Abstract: From a multicenter cohort of 5337 pregnant women, we prospectively identified 113 women who developed preeclampsia (cases) and 443 controls. Smoking exposure was assessed by self-report and maternal hair nicotine levels. Fetal growth was assessed as z-score of birthweight for gestational age (BWGA). sFlt-1 was measured in plasma samples collected at the 24-26-week visit.In linear regression, smoking and preeclampsia were each associated with lower BWGA z-scores (β = -0.29; p = 0.008, and β = -0.67; p < 0.0001), but positive interaction was observed between smoking and preeclampsia (β = +0.86; p = 0.0008) such that smoking decreased z-score by -0.29 in controls but increased it by +0.57 in preeclampsia cases. Results were robust to substituting log hair nicotine for self-reported smoking and after adjustment for confounding variables. Mean sFlt-1 levels were lower in cases with hair nicotine levels above vs. below the median (660.4 pg/ml vs. 903.5 pg/ml; p = 0.0054).Maternal smoking seems to protect against preeclampsia-associated fetal growth restriction and may account, at least partly, for the U-shaped pattern of fetal growth described in preeclamptic pregnancies. Smoking may exert this effect by reducing levels of the anti-angiogenic protein sFlt-1.Preeclampsia, a hypertensive disorder that occurs in 2-7% of pregnancies, is an important cause of fetal and maternal morbidity and mortality [1]. Paradoxically, while maternal cigarette smoking increases the risk of a number of pregnancy complications, including miscarriage, preterm birth and small-for-gestational-age (SGA) birth, smoking has consistently been shown to be associated with a ~30% reduction in the risk of preeclampsia [2,3]. The mechanism for this protective effect is unclear, but may involve direct effects of smoking byproducts nicotine or carbon monoxide in inhibiting placental cytokine production, placental vascular constriction or oxidative stress [4,5], factors that have been implicated in the patho
Quantifying Low Birth Weight, Preterm Birth and Small-for-Gestational-Age Effects of Malaria in Pregnancy: A Population Cohort Study  [PDF]
Marcus J. Rijken, Alysha M. De Livera, Sue J. Lee, Machteld E. Boel, Suthatsana Rungwilailaekhiri, Jacher Wiladphaingern, Moo Kho Paw, Mupawjay Pimanpanarak, Sasithon Pukrittayakamee, Julie A. Simpson, Fran?ois Nosten, Rose McGready
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100247
Abstract: Background The association between malaria during pregnancy and low birth weight (LBW) is well described. This manuscript aims to quantify the relative contribution of malaria to small-for-gestational-age (SGA) infants and preterm birth (PTB) in pregnancies accurately dated by ultrasound on the Thai-Myanmar border at the Shoklo Malaria Research Unit. Methods and Findings From 2001 to 2010 in a population cohort of prospectively followed pregnancies, we analyzed all singleton newborns who were live born, normal, weighed in the first hour of life and with a gestational age (GA) between 28+0 and 41+6 weeks. Fractional polynomial regression was used to determine the mean birthweight and standard deviation as functions of GA. Risk differences and factors of LBW and SGA were studied across the range of GA for malaria and non-malaria pregnancies. From 10,264 newborns records, population centiles were created. Women were screened for malaria by microscopy a median of 22 [range 1–38] times and it was detected and treated in 12.6% (1,292) of pregnancies. Malaria was associated with LBW, PTB, and SGA compared to those without malaria. Nearly two-thirds of PTB were classified as LBW (68% (539/789)), most of which 83% (447/539) were not SGA. After GA 39 weeks, 5% (298/5,966) of non-LBW births were identified as SGA. Low body mass index, primigravida, hypertension, smoking and female sex of the newborn were also significantly and independently associated with LBW and SGA consistent with previous publications. Conclusions Treated malaria in pregnancy was associated with an increased risk for LBW, PTB, and SGA, of which the latter are most important for infant survival. Using LBW as an endpoint without adjusting for GA incorrectly estimated the effects of malaria in pregnancy. Ultrasound should be used for dating pregnancies and birth weights should be expressed as a function (or adjusted for GA) of GA in future malaria in pregnancy studies.
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