NCDS Birth Sweep

Sweep details

Dates 1958
Age Birth
Achieved sample 17,415 (cohort members)
Respondents Mothers, midwives
Survey mode Face to face
Data access

Main dataset available via the UK Data Service [SN 5565]. Visit the UK Data Service website to access the data.


The first sweep took place in March 1958, in the week in which the NCDS cohort were born. The survey was known as the ‘Perinatal Mortality Study’ and was focused on investigating the factors associated with good and poor health amongst mothers and newly born babies.

The midwives who delivered all those born in England, Wales and Scotland in that week collected information from mothers about their health and the families into which their children were being born. Information was also recorded about: birth weight, gestational age and progress over the first week, obstetric history, antenatal care, abnormalities during pregnancy, length and abnormalities of labour, analgesia and anaesthesia, mother’s smoking during pregnancy.

Information was also extracted from medical records.

Special features of the birth sweep

Father's social class

Father’s social class was recorded at birth and details about parental occupation were subsequently recorded throughout childhood.

Cohort members have themselves provided detailed information about their own occupations during each adult survey, making the NCDS ideal for studying how people move up and down the social ladder.

The similar information collected in the other cohort studies gives researchers the opportunity to examine how social mobility has changed between generations.

Birth weight and gestational age

Birth weight and gestational age were both recorded during the birth survey. This information has, and continues to be, used extensively by researchers wishing to explore links between perinatal health and later life outcomes.

Parental smoking

Just before the 1958 birth survey went to print, a study in the United States showed that babies whose mothers had smoked during pregnancy tended to weigh less at birth than babies whose mothers had not smoked. A last minute addition to the NCDS birth survey was a question about mothers’ smoking habits, which led to some of the study’s most influential discoveries.

Smoking during pregnancy was associated with significantly lower birth weight and an increased risk of death. Researchers have also been able to use NCDS to examine the longer term impacts on growth throughout childhood and educational achievement.


  • User guides
  • Questionnaires
  • Technical reports
  • Data notes
  • Additional
User guides

Handling missing data in the National Child Development Study – User Guide

This user guide aims to describe and illustrate a straightforward approach to missing data handling, while detailing some more general considerations around missing data along the way.

Date published: 12/07/2021
PDF: 657,33 KB


NCDS Perinatal Mortality Survey User Guide: Additional Variables

Guide to additional variables deposited for NCDS PMS in 2014

Date published: 01/07/2014
PDF: 593,45 KB


NCDS 2006 Re-deposit User Guide

User guide to accompany the redeposit of data up to age 46

Date published: 01/11/2006
PDF: 87,19 KB


NCDS Birth-Age 55 Response and Deaths Dataset User Guide

This document accompanies the deposit of the NCDS Response and Deaths dataset at the UK Data Service in March 2015.

Date published: 01/03/2015
PDF: 647,55 KB


NCDS revised region variables

Date published: 01/03/2012
PDF: 523,56 KB


NCDS Annotated Perinatal Mortality Survey

This is the annotated version of the Perinatal Mortality Survey.

Date published: 01/05/1958
PDF: 5,94 MB

Technical reports

No material of this type is available.

Data notes

No material of this type is available.


Deriving highest qualification in NCDS and BCS70

This Data Note explains the derivation of variables on Highest Educational Qualification obtained by cohort members in the National Child Development Study (NCDS) and the 1970 British Cohort Study (BCS70).

Date published: 01/01/2011
PDF: 514,11 KB


NCDS Birth-Age 50 Target and Achieved Samples

Table of target and actual sweep samples for NCDS up to age 50

Date published: 01/05/2008
PDF: 21,84 KB


NCDS Ethical Review and Consent

Review of the ethical practices throughout NCDS

Date published: 02/06/2014
PDF: 1,76 MB

Contact us

Centre for Longitudinal Studies
UCL Social Research Institute

20 Bedford Way
London WC1H 0AL