OBJECTIVES To determine whether twins in recent cohorts show similar academic performance in adolescence to singletons and to test the effect of birth weight on academic performance in twins and singletons. DESIGN Follow-up study. SETTING Denmark. PARTICIPANTS All twins (n=3411) and a 5% random sample of singletons (n=7796) born in Denmark during 1986-8. MAIN OUTCOME MEASURES Test score...

BACKGROUND Hypospadias is associated with twinning. The incidence of hypospadias in monochorionic and dichorionic male twins is, however, yet to be determined. METHODS All medical records of monochorionic and dichorionic twins admitted to our neonatal nursery between January 2004 and August 2013 were reviewed for the presence of hypospadias. RESULTS A total of 350 monochorionic and 303 dich...

OBJECTIVES The causes of the large and persistent Black-White disparity in preterm birth (PTB) are unknown. It is biologically plausible that chronic stress across a woman's life course could be a contributor. Prior research suggests that chronic worry about experiencing racial discrimination could affect PTB through neuroendocrine, vascular, or immune mechanisms involved in both responses to s...

OBJECTIVES To determine whether twins have lower IQ scores in childhood than singletons in the same family and, if so, whether differences in fetal growth explain this deficit. DESIGN Cohort study. SETTING Scotland. PARTICIPANTS 9832 singletons and 236 twins born in Aberdeen between 1950 and 1956. RESULTS At age 7, the mean IQ score of twins was 5.3 points lower (95% confidence interval...

BACKGROUND The association between area characteristics and birth outcomes is modified by race. Whether such associations vary according to social class indicators beyond race has not been assessed. METHODS This study evaluated effect modification by maternal birthplace and education of the relationship between neighbourhood characteristics and birth outcomes of newborns from 1999-2003 in the...

BACKGROUND The HIV epidemic in Russia has increasingly involved reproductive-aged women, which may increase perinatal HIV transmission. METHODS Standard HIV case-reporting and enhanced perinatal HIV surveillance systems were used for prospective assessment of HIV-infected women giving birth in St. Petersburg, Russia, during 2004-2008. Trends in social, perinatal, and clinical factors influenc...

OBJECTIVE To identify the factors associated with childhood undernutrition. DESIGN Cross-sectional survey. SETTING Hlabisa health district in KwaZulu/Natal, South Africa. SUBJECTS Eight hundred and sixty-eight children aged 3-59 months. METHODS Questionnaire survey and anthropometric survey of 516 random households with children in the health district. Multivariate analysis took into ac...

OBJECTIVE To evaluate the relationship between breastfeeding and hospitalization for pneumonia among children under 1 year old. METHODS Ecological study using secondary data of hospitalizations for pneumonia (outcome) and breastfeeding prevalence data (exposure) among children under 1 year old living in the Brazilian state capital cities and the Federal District in 2008. A negative binomial m...

BACKGROUND Climate change is expected to have adverse health effects, but the association between extreme ambient temperatures and stillbirth is unclear. OBJECTIVES We investigated acute and chronic associations between extreme ambient temperatures and stillbirth risk, and estimated the attributable risk associated with local temperature extremes in the United States. METHODS We linked 223,...