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The Administrative Data Research Network is an ESRC-funded project that ran from October 2013 - July 2018. It is currently at the end of its funding cycle and is no longer taking applications. Administrative data research will be taken forward in a new project, to be launched later in 2018.

SMR02 – Maternity Inpatient and Day Case, 1975-

Title Details

SMR02 – Maternity Inpatient and Day Case, 1975-
Principal investigator(s):
Information Services Division - NHS National Services Scotland
Data collector(s):
Information Services Division - NHS National Services Scotland

Subject Categories

  • Health services and medical care - Health


  • Abstract copyright ADRN.

    The Maternity Inpatient and Day Case dataset (SMR02) collects episode level data every time a mother goes in for an obstetric event and includes information on mother and baby characteristics, birth weight, gestational age, mode of delivery, induction and outcome of pregnancy and where a baby is delivered. The dataset contains patient identifiers (such as name, date of birth, Community Health Index number, NHS number). A wide variety of geographical measures are also included such as Carstairs/SIMD deprivation measures, census output area, NHS Board, Electoral Ward and Parliamentary constituency.

    The Maternity and Day Case data is available from 1975 onwards. An earlier return (known as SMRM) started in 1969 with about 60% national coverage and continued until 1974 with coverage progressively growing. In 1997 revisions were made to the dataset in order to better fit NHS Scotland reporting requirements. Separate data catalogues pre and post 1997 which reflect these changes are available in the Documentation section.

    The Maternity Inpatient and Day Case dataset covers all obstetric events in Scotland. The NHS Information Centre collects similar information for England and Wales. In Northern Ireland, the Hospital Information Branch of the Department of Health, Social Services and Public Safety do likewise.

    The dataset is part of a wide range of health related administrative data collected by the Information Services Division (ISD), on behalf of the NHS National Services Scotland (part of NHS Scotland). ISD has been the authoritative source of Scottish national healthcare statistics for over 50 years. The data is used to enhance decisions about Scottish health care to improve the health of the people of Scotland. ISD is part of the SHIP (ScottisH Informatics Programme), a Scotland wide research platform for the collation, management, dissemination and analysis of Electronic Patient Records. As part of SHIP, ISD delivers Electronic Data Research and Innovation Service (eDRIS), a one stop shop for health research designed to provide a single point of contact and to assist researchers in study design, approvals and data (non-patient or patient identifiable) access in a secure environment (the NSS National Safe Haven).

    The dataset includes the following geographical measures:

    • NHS Board of Residence
    • Council Area
    • Local Government District
    • UK Parliamentary Constituency
    • Scottish Parliamentary Constituency
    • Electoral Ward
    • NUTS
    • Data Zone
    • 2001 Census Output Area
    • 1991 Census Output Area
    • CHP (Community Health Partnerships)
    • Postcode
    • Grid References
    • Urban / Rural Codes
    • Carstairs Deprivation 2001
    • Carstairs Deprivation 1991
    • Scottish Index of Multiple Deprivation measures

    On April 1st 2006, the configuration of NHS Boards was changed with NHS Argyll & Clyde being dissolved. The larger part of its area moved into NHS Greater Glasgow with the remainder moving to NHS Highland.

    Although there is no legal requirement by NHS Boards to submit Maternity and Day case data to ISD, there is national coverage of 98% of all births and pregnancies. As a result, Scotland has some of the best information on pregnancy and births available anywhere in the world. Data is supplied by Hospital Boards to ISD on a continual basis throughout the year with targets to submit their data within six weeks. The dataset is generally fully complete three month preceding the current date. So for example at the end of August, data is available until the end of May.

    Additional information has been added to the dataset over time including smoking during pregnancy (from 1993/94) and drug and alcohol misuse (from 2003/04). In April 1996 diagnostic codes changed from ICD9 to ICD10. Further information on ICD10 is available in the Documentation section.

    The SMR02 can only facilitate the recording of information on three babies (and up to two prior to 1997). A birth is considered premature if the delivery occurs before the 37th week of gestation. Babies with a birth weight of less than 2,500 grams are defined as low birth weight. Babies with a birth weight of less than 1,500 grams are defined as very low birth weight.

    In Scotland the most reliable number of births is based on the civil registration system administered by the National Records of Scotland (NRS). Note that NRS numbers are based on the date of registration of the births rather than the date of birth, so that a child born in late December of one year may not be registered until the following year. There is also around a 2 – 3% shortfall in the number of births when compared to the National Records of Scotland (NRS) birth registrations. Some of this shortfall is due to data on home births not being available from SMR02 data and also some incomplete data submissions supplied from maternity unit.

    The ISD Data Quality Assurance team are responsible for ensuring SMR datasets are accurate, consistent and comparable across time and between sources.

    Data on smoking behaviour is based on self-reported information obtained from mothers at their ante-natal booking visit in the community or at hospital. The ’smoking at booking’ data item was introduced in 1993/94 and it should be noted that, particularly in the earlier years and again more recently, this information is not always recorded and therefore can affect the results. Because of concerns about the quality of ’smoking at booking’ data, care should be taken in interpreting the results. There are also some concerns regarding the completeness of the drug and alcohol misuse fields which were introduced in 2003/04. Finally, an ISD report (2008-2009) provides an assessment of their maternity data (see Documentation section).

    It is always wise for researchers unfamiliar with the data to check with their data suppliers and to raise any questions about data quality. Note that, in general, more recent data from ISD is likely to be of higher quality than that of, say, the 1960s.

    Research Usage and Linkage

    The Maternity and Day Case dataset is used by NHS Scotland and the Scottish Government to analyse performance and improve health care services. The data is also widely used in health research to investigate factors that affect the health of mother and baby, such as smoking, alcohol, drug abuse, age and deprivation.

    The dataset is also included in the ISD Maternity and Neonatal Linked Database which links together a number of birth related datasets. Researchers can apply to access this database, the individual SMR02 dataset or the individual SMR02 dataset linked to a new dataset via the Privacy Advisory Committee. In particular, the ISD Maternity and Neonatal Linked Database also contains the historical SMR11 dataset (1975-2003 – episode level data on discharges from special care baby units), the Scottish Birth Record (SBR - a universal record of all babies born in Scotland from 2002), the Scottish Stillbirth and Infant Death Survey and the birth, stillbirth and infant death records held by the National Records of Scotland. This linked database is the most useful for obstetrics research due to the wealth of information that it holds. The database is manually updated approximately every six months. For research purposes, the linked database is generally available from 1981 onwards and is linked using CHI. Data prior to this point is poorly matched. Further information and summary data on ISD’s Maternity and Births is available from the Documentation section.

    Other acute datasets, such as the General Acute Inpatient and Day Case (SMR01) and Outpatient Attendance dataset (SMR00) are not routinely added to this database but are often linked on an ad hoc basis by ISD Scotland.

    The Scottish Longitudinal Study (SLS) provides a detailed picture of the health and social status of the people of Scotland. The SLS can be linked to the Maternity Inpatient and Day Case dataset and other NHS Scotland health administrative datasets.

Coverage, universe, methodology

Time period:
1975 -
Observation units:
Events and processes
Kind of data:
Individual (micro) level
All obstetric events in Scotland from 1975.

Time dimensions:
Repeated cross-sectional study
Sampling procedures:
No sampling (total universe)
Number of units:
Approximately 120,000 records per year (with 60,000 births).
Method of data collection:

Compilation or synthesis of existing material

Data is supplied by Hospital Boards to ISD on a continual basis throughout the year with targets to submit their data within six weeks. 

Frequency of release:
Data Updated:

Administrative and access information

Crown copyright
Access conditions:
Contact the Network



By principal investigator(s):

  • ISD Scotland (2003) Anonymisation and NHS Scotland National Data Sets, ISD Scotland.
  • Scottish Health Informatics Programme (2012) A Blueprint for Health Records Research in Scotland, Scottish Health Informatics Programme.

Resulting from secondary analysis:

  • Smith, G.C.S., Pell, J.P. (2001) 'Teenage pregnancy and risk of adverse perinatal outcomes associated with first and second births: population based retrospective cohort study', British Medical Journal, 323(476).
  • Hutchinson, S.J., Goldberg, D.J., King, M., Cameron, S.O., Shaw, L.E., Brown, A., Mackenzie, J., Wilson, K., MacDonald, L. (2004) 'Hepatitis C virus among childbearing women in Scotland:', Gut, 53(4), pp. 593-598. 10.1136/gut.2003.027383
  • Smith, G.C.S., Wood, A. M., Pell, J.P., Dobbie, R. (2005) 'Sudden infant death syndrome and complications in other pregnancies', The Lancet, 366(9503), pp. 2107-2111. 10.1016/S0140-6736(05)67888-9
  • Smith, G.C.S., White I.R., Pell, J.P., Dobbie, R. (2005) 'Predicting cesarean section and uterine rupture among women attempting vaginal birth after prior cesarean section', PLoS Medicine, 2(9). 10.1371/journal.pmed.0020252
  • Riordan, D.V., Selvaraj, S., Stark, C., Gilbert, J.S.E. (2006) 'Perinatal circumstances and risk of offspring suicide:', The British Journal of Psychiatry, 189, pp. 502-507. 10.1192/bjp.bp.105.015974
  • Smith, G., Shah, I., White, I., Pell, J., Crossley, J., Dobbie, R. (2007) 'Maternal and biochemical predictors of antepartum stillbirth among nulliparous women in relation to gestational age of foetal death', BJOG: An International Journal of Obstetrics and Gynaecology, 114(6), pp. 705-714. 10.1111/j.1471-0528.2007.01343.x
  • Smith, G.C.S., Shah, I., White, I.R., Pell, J.P., Dobbie, R. (2007) 'Previous Preeclampsia, Preterm Delivery, and Delivery of a Small for Gestational Age Infant and the Risk of Unexplained Stillbirth in the Second Pregnancy:', American Journal of Epidemiology, 165(2), pp. 194-202. 10.1093/aje/kwj354
  • Gray, R., Bonellie, S., Chalmers, J., Greer, I., Jarvis, S., Williams, C. (2008) 'Social inequalities in preterm birth in Scotland 1980-2003:', BJOG: An International Journal of Obstetrics and Gynaecology, 115(1), pp. 82-90. 10.1111/j.1471-0528.2007.01582.x
  • Hockley, C., Quigley, M.A., Hughes, G., Calderwood, L., Joshi, H., Davidson, L.L. (2008) 'Linking Millennium Cohort data to birth registration and hospital episode records', Paediatric and Perinatal Epidemiology, 22(1). 10.1111/j.1365-3016.2007.00902.x
  • Smith, G.C.S., Cordeaux, Y., White, I.R., Pasupathy, D., Missfelder-Lobos, H., Pell, J.P., Charnock-Jones, D.S., Fleming, M. (2008) 'The Effect of Delaying Childbirth on Primary Cesarean Section Rates', PLoS Medicine, 5(7). 10.1371/journal.pmed.0050144
  • Dillon, J.F., McLernon, D. J., Donnan, P.T., Ryder, S., Roderick, P., Sullivan, F. M., Rosenberg, W. (2009) 'Health outcomes following liver function testing in primary care:', Family Practice, 26(4), pp. 251-259. 10.1093/fampra/cmp025
  • Gray, R., Bonellie, S.R., Chalmers, J., Greer, I., Jarvis, S., Kurinczuk, J.J., Williams, C. (2009) 'Contribution of smoking during pregnancy to inequalities in stillbirth and infant death in Scotland 1994-2003:', British Medical Journal, 339.
  • Norman, J.E., Morris, C., Chalmers, J. (2009) 'The Effect of Changing Patterns of Obstetric Care in Scotland (1980-2004) on Rates of Preterm Birth and Its Neonatal Consequences:', PLoS Medicine, 6(9). 10.1371/journal.pmed.1000153
  • Pasupathy, D., Wood, A.M., Pell, J.P., Fleming, M., Smith, G.C.S. (2009) 'Rates of and Factors Associated With Delivery-Related Perinatal Death Among Term Infants in Scotland', Journal of the Americal Medical Association, 302(6). 10.1001/jama.2009.1111
  • MacKay, D.F., Smith, G.C.S., Dobbie, R., Pell, J.P. (2010) 'Gestational Age at Delivery and Special Educational Need:', PLoS Medicine, 7(6). 10.1371/journal.pmed.1000289
  • Love, E.R., Bhattacharya, S., Smith, N.C., Bhattacharya, S. (2010) 'Effect of interpregnancy interval on outcomes of pregnancy after miscarriage:', British Medical Journal, 341.
  • Smith, G.C.S., Wood, A.M., White, I.R., Pell, J.P., Hattie, J. (2010) 'Birth Weight and the Risk of Cardiovascular Disease in the Maternal Grandparents', American Journal of Epidemiology, 171(6), pp. 736-744. 10.1093/aje/kwp448
  • Pasupathy, D., Wood, A.M., Pell, J.P., Fleming, M., Smith, G.C.S. (2011) 'Advanced maternal age and the risk of perinatal death due to intrapartum anoxia at term', Journal of Epidemiology and Community Health, 65(3), pp. 241-245.
  • Smith, G., Wood, A., Pell, J., Hattie, J. (2011) 'Recurrent miscarriage is associated with a family history of ischaemic heart disease:', BJOG: An International Journal of Obstetrics and Gynaecology, 118(5), pp. 557-563. 10.1111/j.1471-0528.2010.02890.x
  • Mackay, D.F., Nelson, S.M., Haw, S.J., Pell, J.P. (2012) 'Impact of Scotland's Smoke-Free Legislation on Pregnancy Complications:', PLoS Medicine, 9(3). 10.1371/journal.pmed.1001175
  • Riordan, D.V., Morris, C., Hattie, J., Stark, C. (2012) 'Interbirth spacing and offspring mental health outcomes', Psychological Medicine, 42(12), pp. 2511-2521.
  • Riordan, D.V., Morris, C., Hattie, J., Stark, C. (2012) 'Family size and perinatal circumstances, as mental health risk factors in a Scottish birth cohort', Social Psychiatry and Psychiatric Epidemiology, 47(6), pp. 975-983. 10.1007/s00127-011-0405-5
  • Wood, M. A., Pasupathy, D., Pell, J.P., Fleming, M., Smith, G.C.S. (2012) 'Trends in socioeconomic inequalities in risk of sudden infant death syndrome, other causes of infant mortality, and stillbirth in Scotland:', British Medical Journal, 344. 10.1136/bmj.e1552

Page last updated: 20/09/2017