), with technical support from four global specialised units, to study growth, health and nutrition from early pregnancy to infancy. It aims to produce prescriptive growth standards, which conceptually extend the World Health Organization (WHO) Multicentre Growth Reference Study (MGRS) to cover fetal and newborn life. The new international standards will describe: (1) fetal growth assessed by clinical and ultrasound measures; (2) postnatal growth of term and preterm infants up to 2 years of age; and (3) the relationship between birthweight, length and head circumference, gestational age and perinatal outcomes. As the project has selected healthy cohorts with no obvious risk factors for intrauterine growth restriction, these standards will describe how all fetuses and newborns should grow, as opposed to traditional charts that describe how some have grown at a given place and time. These growth patterns will be related to morbidity and mortality to identify levels of perinatal risk. Additional aims include phenotypic characterisation of the preterm and impaired fetal growth syndromes and development of a prediction model, based on multiple ultrasound measurements, to estimate gestational age for use in pregnant women without access to early/frequent antenatal care.

Objectives To investigate the demographic and obstetric factors associated with the uptake and success rate of vaginal birth after caesarean section (VBAC).Design Cohort study using data from Hospital Episode Statistics.Setting English National Health Service.Population Women whose first birth resulted in a live singleton delivery by caesarean section between 1 April 2004 and 31 March 2011, and who had a second birth before 31 March 2012. Methods Logistic regression to estimate adjusted odds ratios (OR).Main outcome measures Attempted and successful VBAC.Results Among the 143 970 women in the cohort, 75 086 (52.2%) attempted a VBAC for their second birth.Younger women, those of non-white ethnicity and those living in a more deprived area had higher rates of attempted VBAC. Overall, 47 602 women (63.4%) who attempted a VBAC had a successful vaginal birth. Younger women and women of white ethnicity had higher success rates. Black women had a particularly low success rate (OR, 0.54; 95% confidence interval [CI], 0.50-0.57). Women who had an emergency caesarean section in their first birth also had a lower VBAC success rate, particularly those with a history of failed induction of labour (OR, 0.59; 95% CI, 0.53-0.67). ConclusionIn this national cohort, just over one-half of women with a primary caesarean section who were eligible for a trial of labour attempted a VBAC for their second birth. Of these, almost two-thirds successfully achieved a vaginal delivery.Keywords Administrative data, England, trial of labour, vaginal birth after caesarean.Please cite this paper as: Knight HE, Gurol-Urganci I, van der Meulen JH, Mahmood TA, Richmond DH, Dougall A, Cromwell DA. Vaginal birth after caesarean section: a cohort study investigating factors associated with its uptake and success. BJOG 2014;121:183-193.

The primary aim of the INTERGROWTH-21st Project is to construct new, prescriptive standards describing optimal fetal and preterm postnatal growth. The anthropometric measurements include the head circumference, recumbent length and weight of the infants, and the stature and weight of the parents. In such a large, international, multicentre project, it is critical that all study sites follow standardised protocols to ensure maximal validity of the growth and nutrition indicators used. This paper describes in detail the anthropometric training, standardisation and quality control procedures used to collect data for these new standards. The initial standardisation session was in Nairobi, Kenya, using newborns, which was followed by similar sessions in the eight participating study sites in Brazil, China, India, Italy, Kenya, Oman, UK and USA. The intraobserver and inter-observer technical error of measurement values for head circumference range from 0.3 to 0.4 cm, and for recumbent length from 0.3 to 0.5 cm. These standardisation protocols implemented at each study site worldwide ensure that the anthropometric data collected are of the highest quality to construct international growth standards.

Monitoring and interpreting the growth of preterm infants is a major clinical task for neonatologists. The effectiveness of this process depends upon the robustness of the standard selected. Concerns have been raised regarding the nature of the charts currently being used, as well as their appropriateness for present-day neonatal care. To overcome these problems, there is a need for new prescriptive standards based on a population of preterm infants without evidence of impaired fetal growth and born to low-risk women followed up since early pregnancy for precise gestational age dating. Preterm infants contributing to the new standards should be free of congenital malformations and major clinical conditions associated with impaired postnatal growth. These infants should receive standardised, evidence-based clinical care and should follow current feeding recommendations based on exclusive/predominant breastfeeding. This strategy should provide a population that is conceptually as close as possible to the prescriptive approach used for the construction of the WHO infant and child growth standards. New international standards constructed in this way should contribute to the evidence-based care of these preterm infants.