RESUMO
OBJECTIVE: To characterise inflammatory bowel disease (IBD) trends and associated risk during delivery hospitalisations. DESIGN: Cross-sectional. SETTING: US delivery hospitalisations. POPULATION: Delivery hospitalisations in the 2000-2018 National Inpatient Sample. METHODS: This study analysed a nationally representative hospital discharge database based on the presence of IBD. Temporal trends in IBD were analysed using joinpoint regression to estimate the average annual percent change (AAPC). IBD severity was characterised by the presence of diagnoses such as penetrating and stricturing disease and history of bowel resection. Risks for adverse outcomes were analysed based on presence of IBD. Poisson regression models were performed with unadjusted and adjusted risk ratios (aRR) as measures of effect. MAIN OUTCOME MEASURE: Prevalence of IBD and associated adverse outcomes. RESULTS: Of 73 109 790 delivery hospitalisations, 89 965 had a diagnosis of IBD. IBD rose from 0.06% in 2000 to 0.21% in 2018 (AAPC 7.3%, 95% CI 6.7-7.9%). Among deliveries with IBD, IBD severity diagnoses increased from 4.1% to 8.1% from 2000 to 2018. In adjusted analysis, IBD was associated with increased risk for preterm delivery (aRR 1.50, 95% CI 1.47-1.53), severe maternal morbidity (aRR 1.93, 95% CI 1.83-2.04), venous thrombo-embolism (aRR 2.76, 95% CI 2.39-3.18) and surgical injury during caesarean delivery hospitalisation (aRR 5.03, 95% CI 4.76-5.31). In the presence of a severe IBD diagnosis, risk was further increased for all adverse outcomes. CONCLUSION: IBD is increasing in the obstetric population and is associated with adverse outcomes. Risk is increased in the presence of a severe IBD diagnosis. TWEETABLE ABSTRACT: Deliveries among women with inflammatory bowel disease are increasing. Disease severity is associated with adverse outcomes.
Assuntos
Doenças Inflamatórias Intestinais , Nascimento Prematuro , Cesárea/efeitos adversos , Doença Crônica , Estudos Transversais , Feminino , Hospitalização , Humanos , Recém-Nascido , Doenças Inflamatórias Intestinais/complicações , Doenças Inflamatórias Intestinais/epidemiologia , Gravidez , Nascimento Prematuro/epidemiologiaRESUMO
OBJECTIVE: To characterise medical, obstetric and demographic risk factors associated with nulliparous, term, singleton, vertex (NTSV) caesarean birth. STUDY DESIGN: Cross-sectional study. SETTING: United States delivery hospitalisations. POPULATION: NTSV births in 2016-18 US natality data. METHODS: This study analysed a national sample of natality data generated by the United States National Vital Statistics System. NTSV deliveries were identified. The primary outcome was caesarean birth. Risk factors including maternal age, body mass index (BMI) and pregestational diabetes were analysed. Multivariable log-linear regression models analysed factors associated with NTSV caesarean with adjusted risk ratios (aRR) as measures of effect. RESULTS: Of 11 622 400 deliveries, 3 764 707 met NTSV criteria, and their caesarean section rate was 25.9%. Maternal age 35-39 years (aRR 1.51, 95% CI 1.50-1.52) and 40-54 years (aRR 2.03, 95% 2.00-2.05) compared with age 19-34 years; BMI 25 to <30 kg/m2 (aRR 1.32, 95% CI 1.31-1.33), 30 to <35 kg/m2 (aRR 1.57 95% CI 1.56-1.58), 35 to <40 kg/m2 (aRR 1.82, 95% CI 1.80-1.83) and ≥40 kg/m2 (aRR 2.17, 95% CI 2.15-2.19) compared with BMI 18.5-24.9 kg/m2; and pregestational diabetes (aRR 1.54, 95% CI 1.51-1.57) were all associated with increased risk. Risk factors allowed stratification of patients into high-risk versus low-risk groups. The NTSV caesarean rate was 37.9% in women who had one or more of the following characteristics: age ≥35 years, BMI ≥30 kg/m2 or pregestational diabetes. In comparison, the NTSV caesarean rate was 20.8% among women without any of these three risk factors (P < 0.01). CONCLUSION: Among NTSV births, BMI, maternal age and medical conditions are important risk factors for caesarean delivery.
Assuntos
Cesárea/estatística & dados numéricos , Nascido Vivo/epidemiologia , Adolescente , Adulto , Índice de Massa Corporal , Estudos Transversais , Feminino , Humanos , Idade Materna , Pessoa de Meia-Idade , Paridade , Gravidez , Indicadores de Qualidade em Assistência à Saúde , Fatores de Risco , Nascimento a Termo , Estados Unidos/epidemiologia , Adulto JovemRESUMO
BACKGROUND: As more women are presenting with three previous caesarean deliveries (CD), providers may suggest early term delivery as a means to avoid the risk of spontaneous labour and associated maternal morbidity. OBJECTIVE: To determine whether early term delivery is associated with lower maternal and neonatal morbidity for women with three previous CD. STUDY DESIGN: Secondary analysis of a prospective registry of CD at 19 US academic centres from 1999 to 2002. POPULATION: Women with three previous CD undergoing scheduled or emergent delivery with live, singleton gestations 37-41+ weeks of gestation were included. Women with non-low transverse incisions, antepartum stillbirth, previous myomectomy, fetal anomalies, more or fewer than three previous CD or attempting trial of labour after caesarean section were excluded. METHODS: Gestational age was categorised by week. We fitted logistic regression models to adjust for clinically relevant or statistically significant confounders. MAIN OUTCOME MEASURES: The primary and secondary outcomes were composites, respectively, of maternal and neonatal morbidity. RESULTS: In all, 821 women met the inclusion criteria; maternal morbidity composite occurred in 9.86% and neonatal morbidity occurred in 10.5%. After adjusting for confounding variables, maternal and neonatal morbidity occurred least frequently at 39 weeks. CONCLUSIONS: In women with three previous CDs, adverse maternal outcomes do not increase with increasing gestational age beyond 37 weeks but early term elective repeat CDs are associated with higher neonatal morbidity. Elective delivery of women with three previous CD at 39 weeks of gestation is safe in the absence of maternal or fetal indications for early term delivery. TWEETABLE ABSTRACT: Delivery of women with three previous caesarean deliveries at 39 weeks, in the absence of maternal or fetal indications for early term delivery, is associated with decreased maternal morbidity.
Assuntos
Recesariana/efeitos adversos , Procedimentos Cirúrgicos Eletivos/efeitos adversos , Doenças do Recém-Nascido/etiologia , Complicações na Gravidez/etiologia , Fatores de Tempo , Adulto , Parto Obstétrico/efeitos adversos , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Modelos Logísticos , Gravidez , Estudos Prospectivos , Sistema de Registros , Estados UnidosRESUMO
OBJECTIVE: To examine age-period-cohort effects on trends in gestational diabetes mellitus (GDM) prevalence in the US, and to evaluate how these trends have affected the rates of stillbirth and large for gestational age (LGA)/macrosomia. DESIGN: Retrospective cohort study. SETTING: USA, 1979-2010. POPULATION: Over 125 million pregnancies (3 337 284 GDM cases) associated with hospitalisations. METHODS: Trends in GDM prevalence were examined via weighted Poisson models to parse out the extent to which GDM trends can be attributed to maternal age, period of delivery, and maternal birth cohort. Multilevel models were used to assess the contribution of population effects to the rate of GDM. Log-linear Poisson regression models were used to estimate the contributions of the increasing GDM rates to changes in the rates of LGA and stillbirth between 1979-81 and 2008-10. MAIN OUTCOME MEASURES: Rates and rate ratios (RRs). RESULTS: Compared with 1979-1980 (0.3%), the rate of GDM has increased to 5.8% in 2008-10, indicating a strong period effect. Substantial age and modest cohort effects were evident. The period effect is partly explained by period trends in body mass index (BMI), race, and maternal smoking. The increasing prevalence of GDM is associated with a 184% (95% CI 180-188%) decline in the rate of LGA/macrosomia and a 0.75% (95% CI 0.74-0.76) increase in the rate of stillbirths for 2008-10, compared with 1979-81. CONCLUSIONS: The temporal increase in GDM can be attributed to period of pregnancy and age. Increasing BMI appears to partially contribute to the GDM increase in the US. TWEETABLE ABSTRACT: The increasing prevalence of GDM can be attributed to period of delivery and increasing maternal age.
Assuntos
Diabetes Gestacional/epidemiologia , Macrossomia Fetal/epidemiologia , Natimorto/epidemiologia , Adolescente , Adulto , Estudos de Coortes , Feminino , Humanos , Recém-Nascido , Modelos Logísticos , Idade Materna , Pessoa de Meia-Idade , Gravidez , Prevalência , Estudos Retrospectivos , Fatores de Risco , Estados Unidos/epidemiologia , Adulto JovemRESUMO
OBJECTIVE: Placental abruption has a profound impact on perinatal mortality, but implications for neurodevelopment during childhood remain unknown. We examined the association between abruption and neurodevelopment at 8 months and 4 and 7 years and evaluated the extent to which these associations were mediated through preterm delivery. DESIGN: Secondary analysis of a multicenter prospective cohort study. SETTING: Multicenter US National Collaborative Perinatal Project (1959-76). POPULATION: Women that delivered singleton live births. METHODS: Analyses of IQ scores were based on marginal structural models (MSM) to account for losses to follow-up. We also carried out a causal mediation analysis to evaluate if the association between abruption and cognitive deficits was mediated through preterm delivery, and performed a sensitivity analysis for unobserved confounding. MAIN OUTCOME MEASURES: We evaluated cognitive development based on the Bayley scale at 8 months (Mental and Motor Scores), and intelligent quotient (IQ) based on the Stanford-Binet scale at 4 years and the Wechsler Intelligence Scale for Children at 7 years. RESULTS: The confounder and selection-bias adjusted risk ratio (RR) of abnormal 8-month Motor and Mental assessments were 2.35 (95%CI 1.39, 3.98) and 2.03 (95%CI 1.13, 3.64), respectively, in relation to abruption. The associations at 4 years were attenuated and resolved at 7 years. The proportion of children with abruption-associated neurological deficits mediated through preterm delivery ranged from 27 to 75%. Following adjustment for unobserved confounding the proportion mediated through preterm delivery was attenuated. CONCLUSION: The effect of abruption on neurodevelopmental outcomes appears restricted to an effect that is largely mediated through preterm delivery. TWEETABLE ABSTRACT: Increased risk of cognitive deficits in relation to abruption appears to be mediated through preterm delivery.
Assuntos
Descolamento Prematuro da Placenta/epidemiologia , Transtornos do Neurodesenvolvimento/epidemiologia , Trabalho de Parto Prematuro/epidemiologia , Criança , Desenvolvimento Infantil , Pré-Escolar , Cognição , Estudos de Coortes , Feminino , Humanos , Lactente , Recém-Nascido , Transtornos do Neurodesenvolvimento/etiologia , Gravidez , Nascimento Prematuro , Estudos Prospectivos , Fatores de Risco , Estados Unidos/epidemiologiaRESUMO
OBJECTIVE: We examined rates of serious maternal complications in relation to severe pre-eclampsia based on the delivering hospital's annualised volume. DESIGN: Retrospective cohort study. POPULATION AND SETTING: Singleton deliveries (n = 25 782 235) in 439 hospitals in the USA. METHODS: Annualised hospital volume was categorised as 25-500, 501-1000, 1001-2000 and >2000. MAIN OUTCOME MEASURES: Rates of in-hospital maternal death and serious maternal complications, including puerperal cerebrovascular disorders, pulmonary oedema, disseminated intravascular coagulation, acute renal, heart and liver failure, sepsis, haemorrhage and intubation in relation to severe pre-eclampsia. We derived adjusted risk ratio (RR) and 95% confidence interval (CI), from hierarchical Poisson regression models. RESULTS: Severe pre-eclampsia was associated with an 8.7-fold (95% CI 7.6, 10.1) risk of composite maternal complications, with similar RRs across levels of hospital volumes. However, compared with hospitals with low annual volume (<2000), maternal mortality rates in relation to severe pre-eclampsia were lower in high volume hospitals. The rates of serious maternal complications were 410.7 per 10 000 to women who delivered in hospitals with a high rate of severe pre-eclampsia (≥2.12%) and 584.8 per 10 000 to women who delivered in hospitals with low severe pre-eclampsia rates (≤0.41; RR 1.75, 95% CI 1.24, 2.45). CONCLUSIONS: While the risks of serious maternal complications in relation to severe pre-eclampsia was similar across hospital delivery volume categories, deaths showed lower rates in large delivery volume hospitals than in smaller volume hospitals. The risk of complications was increased in hospitals with low compared with high severe pre-eclampsia rates. TWEETABLE ABSTRACT: Hospital volume had little impact on the association between severe pre-eclampsia and maternal complications.
Assuntos
Hospitais com Alto Volume de Atendimentos/estatística & dados numéricos , Hospitais com Baixo Volume de Atendimentos/estatística & dados numéricos , Morte Materna/estatística & dados numéricos , Pré-Eclâmpsia/mortalidade , Transtornos Puerperais/epidemiologia , Adulto , Feminino , Humanos , Morte Materna/etiologia , Mortalidade Materna , Distribuição de Poisson , Gravidez , Transtornos Puerperais/etiologia , Análise de Regressão , Estudos Retrospectivos , Estados Unidos/epidemiologiaRESUMO
OBJECTIVE: The objectives of this study were to determine temporal trends in forceps and vacuum delivery and factors associated with operative vaginal delivery. DESIGN: Retrospective cohort. SETTING: Population-based study of US birth records. POPULATION: US births from 2005 to 2013. METHODS: This study evaluated forceps and vacuum extraction during vaginal delivery in live-born, non-anomalous singleton gestations from ≥ 36 to < 42 weeks of gestation. The primary outcomes were vacuum, forceps and overall operative delivery. Obstetric, medical and demographic characteristics associated with operative vaginal delivery were analysed. Multivariable logistic regression models were developed to determine factors associated with forceps/vacuum use. RESULTS: A total of 22 598 971 vaginal deliveries between 2005 and 2013 were included in the analysis. In all, 1 083 318 (4.8%) were vacuum-assisted and 237 792 (1.1%) were by forceps. Both vacuum and forceps deliveries decreased over the study period; vacuum deliveries decreased from 5.8% in 2005 to 4.1% in 2013, and forceps deliveries decreased from 1.4% to 0.9% during the same period. The adjusted odds ratio for forceps delivery was 0.70 (95% CI 0.69-0.72) in 2013 with 2005 as a reference. For vacuum delivery the odds ratio was 0.68 (95% CI 0.67-0.69) comparing the same years. CONCLUSION: Forceps and vacuum deliveries decreased during the study period. Low rates of operative delivery pose a challenge for resident education and may limit the degree to which women have access to alternatives to caesarean delivery. Initiatives that allow future generations of obstetricians to develop expertise in performing operative deliveries in the setting of decreased volume are an urgent resident education priority. TWEETABLE ABSTRACT: Forceps and vacuum delivery decreased significantly in the USA from 2005 to 2013.
Assuntos
Extração Obstétrica/tendências , Padrões de Prática Médica/tendências , Utilização de Procedimentos e Técnicas/tendências , Adulto , Extração Obstétrica/instrumentação , Extração Obstétrica/métodos , Feminino , Humanos , Modelos Logísticos , Forceps Obstétrico , Gravidez , Estudos Retrospectivos , Estados Unidos , Vácuo-Extração/tendênciasRESUMO
OBJECTIVE: To assess hospital variability in and patient and hospital factors associated with caesarean delivery (CD) complications. STUDY DESIGN: Population-based cohort. SETTING: United States delivery admissions. POPULATION: Women who underwent a CD between 2006 and 2012. METHODS: Hospital-specific random-effects log-linear regression models were developed to account for patient, obstetric, and hospital risk factors related to a composite complication outcome including infection, haemorrhage, surgical complications and prolonged hospital stay. Between-hospital variability in rates of CD complications was also estimated. MAIN OUTCOME MEASURE: Composite complication rate. RESULTS: Among 1 339 397 women who underwent CD in 457 hospitals, 6.4% (n = 85 838) experienced a complication. The most frequent complications were haemorrhage, transfusion, length of stay >7 days, and endometritis. Complications were strongly associated with the presence of obstetric factors and pre-existing medical conditions. Complication rates were 54% higher among black (8.8%) than white (5.7%) women (P < 0.001), and were more common in teaching (8.1%) than non-teaching (5.4%) hospitals (P < 0.001). In an adjusted model, the mean complication rate was 6.7%. A small proportion of hospitals (4.8%) had a complication rate greater than twice the mean (≥13.4%). Complications were strongly associated with the presence of obstetrical factors and pre-existing medical conditions. CONCLUSIONS: CD complication rates are strongly associated with patient and obstetric factors. While CD complication rates may be a quality metric of limited utility given the low rate of complications across most hospitals, a small number of hospitals demonstrate particularly high rates of complications. Review of CD complication rates may be an important aspect of quality assurance processes for these centres. TWEETABLE ABSTRACT: A small number of hospitals demonstrate particularly high rates of caesarean complications.
Assuntos
Cesárea/efeitos adversos , Maternidades/estatística & dados numéricos , Adulto , Transfusão de Sangue/estatística & dados numéricos , Cesárea/estatística & dados numéricos , Endometrite/epidemiologia , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Hemorragia Pós-Operatória/epidemiologia , Gravidez , Fatores de Risco , Estados Unidos/epidemiologia , Adulto JovemRESUMO
OBJECTIVE: To determine whether prolonged latency after preterm prelabour rupture of membranes (PPROM) is associated with an increased risk for adverse neurodevelopmental outcomes. DESIGN: This is a secondary analysis of the randomised controlled trial of magnesium sulphate for the prevention of cerebral palsy. SETTING: Multicentre trial. POPULATION: A total of 1305 women with PPROM were analysed, 1056 of whom had an interval of <3 weeks between diagnosis and delivery and 249 of whom had an interval of ≥3 weeks between diagnosis and delivery. METHODS: We evaluated whether the time interval between diagnosis of PPROM and delivery was associated with an increased risk for adverse neurodevelopmental outcomes. Latency was analysed as a continuous variable and categorised by weeks of latency. MAIN OUTCOME MEASURES: The primary outcome was motor and mental Bayley scores of <70 at 2 years of age. Secondary outcomes included motor and mental Bayley scores <85 and mean Bayley scores. Logistic regression was used to control for confounding factors. RESULTS: In the univariate analysis, motor and mental Bayley scores of <70 were similar in the <3 weeks (16.8 and 14.4%) and ≥3 weeks (15.3 and 14.1%) groups. In the regression analysis adjusting for confounding factors, PPROM for ≥3 weeks was an independent risk factor for motor (adjusted odds ratio (aOR) 2.12; 95% confidence interval, 95% CI 1.29-3.49) and mental (aOR 1.83, 95% CI 1.13-3.00) Bayley scores of <70. Neonatal sepsis, gestational age at delivery, maternal education, and race were significantly associated with neurodevelopmental outcomes. CONCLUSIONS: Whereas delivery at later gestational age is associated with improved prognosis for many outcomes, prolonged exposure to an intrauterine environment of PPROM is an independent risk factor for adverse neurodevelopmental outcomes. TWEETABLE ABSTRACT: Prolonged PPROM was associated with motor and mental Bayley scores of <70.
Assuntos
Paralisia Cerebral/prevenção & controle , Ruptura Prematura de Membranas Fetais/prevenção & controle , Sulfato de Magnésio/administração & dosagem , Tocolíticos/administração & dosagem , Adulto , Índice de Massa Corporal , Parto Obstétrico/métodos , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Parto/efeitos dos fármacos , Gravidez , Nascimento Prematuro/prevenção & controle , Fatores de Risco , Estados UnidosRESUMO
OBJECTIVE: Guidelines for pharmacologic obstetric venous thromboembolism (VTE) prophylaxis from the American Congress of Obstetricians (ACOG), the Royal College of Obstetricians and Gynaecologists (RCOG), and the American College of Chest Physicians (Chest) vary significantly. The objective of this study was to determine the practical implications of these recommendations in terms of prophylaxis rates for a tertiary obstetric population. STUDY DESIGN: Cross-sectional. SETTING: Tertiary referral hospital. POPULATION: Patients post-operative day 1 after caesarean delivery. METHODS: This cross-sectional study evaluated rates of pharmacologic prophylaxis for women based on RCOG, ACOG, and Chest recommendations. Medical, obstetric, and demographic risk factors for thromboembolism were reviewed for individual patients. Rates of prophylaxis based on each of the guidelines with 95% confidence intervals were calculated. OUTCOME MEASURE: Recommended pharmacologic prophylaxis. RESULTS: About 293 patients were included in the analysis. Under RCOG guidelines, 85.0% of patients would receive post-caesarean pharmacologic prophylaxis [95% confidence interval (CI) 80.5-88.6%] compared with 1.0% of patients under ACOG guidelines (95% CI 0.3-3.0%) and 34.8% of patients under Chest guidelines (95% CI 29.6-40.4%). Caesarean during labour, obesity, advanced maternal age, pre-eclampsia, and multiple gestation were among the most commonrisk factors. CONCLUSION: Recommended prophylaxis differed significantly. Under ACOG recommendations a small minority of patients would receive prophylaxis, whereas under RCOG recommendations a large majority of patients would receive low-molecular-weight heparin. Given the large differences in prophylaxis rates for post-caesarean thromboprophylaxis based on different guidelines, further research is urgently needed to compare the risks and benefits of recommendations. TWEETABLE ABSTRACT: Recommendations from major society guidelines for post-caesarean thromboprophylaxis differ greatly.
Assuntos
Cesárea/efeitos adversos , Quimioprevenção , Heparina de Baixo Peso Molecular/uso terapêutico , Complicações Pós-Operatórias/prevenção & controle , Guias de Prática Clínica como Assunto/normas , Tromboembolia Venosa , Adulto , Anticoagulantes/uso terapêutico , Cesárea/métodos , Cesárea/estatística & dados numéricos , Quimioprevenção/métodos , Quimioprevenção/normas , Estudos Transversais , Feminino , Humanos , Idade Materna , Avaliação das Necessidades , Obesidade/epidemiologia , Pré-Eclâmpsia/epidemiologia , Gravidez , Gravidez Múltipla/estatística & dados numéricos , Fatores de Risco , Centros de Atenção Terciária/estatística & dados numéricos , Estados Unidos/epidemiologia , Tromboembolia Venosa/epidemiologia , Tromboembolia Venosa/etiologia , Tromboembolia Venosa/prevenção & controleRESUMO
OBJECTIVE: To determine how well antenatal corticosteroids (ACS) were timed, based on the indication for administration for women delivering preterm. DESIGN: Retrospective cohort study. SETTING: Tertiary medical centre. POPULATION: Six hundred and thirty women who had singleton preterm births between 24 and 34 weeks' gestational age. METHODS: Charts from 2006 to 2011 were reviewed for indications for ACS administration, which included premature rupture of membranes, threatened preterm labour, risk factors for spontaneous preterm birth such as short ultrasound cervical length, positive fetal fibronectin, and hypertensive disorders of pregnancy. Charts were reviewed for timing of ACS administration in relation to delivery. MAIN OUTCOME MEASURES: The primary outcome was optimal timing, defined as administration of ACS ≥ 24 hours to ≤ 7 days prior to delivery. RESULTS: Of 630 women who delivered preterm, 589 (93%) received ACS prior to delivery. ACS timing was optimal in 40% (238 of 589) of cases. Women with hypertensive disorders were most likely to have steroids optimally timed (62%). Asymptomatic women at increased risk for preterm delivery were less likely to receive optimally timed ACS (12%). The majority of women who received steroids >2 weeks prior to delivery (57%) received a second course. CONCLUSION: A majority of women who delivered preterm did not receive optimally timed ACS. Diagnostic tools that identified women at risk for preterm birth were not able to identify patients for appropriate steroid timing. Given the range of clinical scenarios in which patients are at increased risk for preterm delivery, further research is needed to assist clinicians in optimising steroid administration. TWEETABLE ABSTRACT: Optimal timing of antenatal steroids prior to delivery does not occur in most cases.
Assuntos
Corticosteroides/uso terapêutico , Doenças do Prematuro/prevenção & controle , Cuidado Pré-Natal , Adulto , Estudos de Coortes , Feminino , Humanos , Gravidez , Estudos Retrospectivos , Fatores de TempoRESUMO
OBJECTIVE: To determine whether maternal haematocrit during pregnancy is associated with offspring IQ. DESIGN/SETTING/POPULATION: A secondary analysis of the Collaborative Perinatal Project, which enrolled women between 1959 and 1966 at 12 university hospitals in the United States. METHODS: We evaluated the relation between maternal haematocrit and IQ at 4 and 7 years of age. Linear and log-linear regression models were used to adjust for possible confounders. Marginal structural models with stabilised weights were used to account for selection bias due to children lost to follow up. MAIN OUTCOME MEASURES: Offspring IQ at 4 and 7 years of age. RESULTS: Of 35 959 patients, 1521 (4.2%) had moderate anaemia, 13 769 (38.3%) had mild anaemia, 18 227 (50.7%) had a normal haematocrit, and 2442 (6.8%) had a high haematocrit. The mean IQ at 4 and 7 years was significantly lower in the moderate and mild anaemia groups than in the normal haematocrit group (92.3 and 94.7 versus 100.6, respectively, P < 0.01, at 4 years; and 90.2 and 93.4 versus 99.1 at 7 years, P < 0.01). The high haematocrit group had a significantly higher mean IQ (104.5 at 4 years; 103.2 at 7 years) when compared with the normal haematocrit group (P < 0.01). Women with moderate anaemia were more likely to have children with IQ of 70-84 at 4 years (RR 1.22, 95% CI 1.08-1.38) and <70 at 7 years (RR 1.59, 95% CI 1.14-2.23). Women with a high haematocrit were more likely to have children with an IQ ≥120 at 7 years (RR 1.22, 95% CI 1.08-1.39). CONCLUSIONS: Maternal haematocrit is associated with offspring IQ at 4 and 7 years of age. TWEETABLE ABSTRACT: There is a nonlinear relation between maternal haematocrit and offspring IQ at 4 and 7 years of age.
Assuntos
Deficiências do Desenvolvimento , Hematócrito , Anemia , HumanosAssuntos
Acetaminofen , Canal Arterial , Estudos de Coortes , Feminino , Humanos , Gravidez , Terceiro Trimestre da Gravidez , Cuidado Pré-NatalAssuntos
Morte Perinatal , Mortalidade Perinatal , Estudos de Coortes , Feminino , Humanos , Gravidez , Pontuação de PropensãoAssuntos
Descolamento Prematuro da Placenta , Sistema de Registros , Estudos de Coortes , Feminino , Humanos , Pais , Parto , GravidezAssuntos
Antiasmáticos , Asma , Estudos de Coortes , Feminino , Humanos , Gravidez , Primeiro Trimestre da GravidezRESUMO
The relative migration ratio of plutonium in various rocks is approximately 100 micrometers per meter of waterflow; the corresponding migration ratio for americium is about 500 micrometers per meter of water flow. Under these conditions radioactive decay will have taken place to such an extent that little plutonium and americium can reach the external environment from a well-designed and isolated geological repository site.
RESUMO
The crystal structure of the tryptic core fragment of the lac repressor of Escherichia coli (LacR) complexed with the inducer isopropyl-beta-D-thiogalactoside was determined at 2.6 A resolution. The quaternary structure consists of two dyad-symmetric dimers that are nearly parallel to each other. This structure places all four DNA binding domains of intact LacR on the same side of the tetramer, and results in a deep, V-shaped cleft between the two dimers. Each monomer contributes a carboxyl-terminal helix to an antiparallel four-helix bundle that functions as a tetramerization domain. Some of the side chains whose mutation reduce DNA binding form clusters on a surface near the amino terminus. Placing the structure of the DNA binding domain complexed with operator previously determined by nuclear magnetic resonance onto this surface results in two operators being adjacent and nearly parallel to each other. Structural considerations suggest that the two dimers of LacR may flexibly alter their relative orientation in order to bind to the known varied spacings between two operators.
Assuntos
DNA Bacteriano/química , Conformação Proteica , Proteínas Repressoras/química , Cristalografia por Raios X , DNA Bacteriano/metabolismo , Isopropiltiogalactosídeo/metabolismo , Modelos Moleculares , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Proteínas Repressoras/metabolismoRESUMO
Six out of eight minor chemical elements, determined by spectroscopic and neutron-activation techniques, were found to be critical in computing a probability that a given copper artifact was derived from one of three types of copper ore: native metal, oxidized ore, reduced ore. Two elements, gold and tin, were apparently alloyed deliberately in many artifacts from both the Old World and the New World.