2. An Exploratory Analysis of the Socio-demographic Characteristics of Married versus Unmarried Mothers Evie Gardner, Karen Casson, Helen Dolk, School of Nursing; Ann Marie Gray School of Criminology, Politics and Social Policy, University of Ulster

3. Literature  Lone mothers in England and Wales are at particularly high risk of having a low birthweight baby, even after controlling for deprivation (Pattenden et al., 1999; Collingwood et al., 2006)  Much of the literature looks at lone or sole mothers with a dearth of information being available on those births which are jointly registered with the father living at either the same or at a different address  Relationship with the father at the time of birth is a major factor as to whether the mother chooses to register the birth solely or jointly (Graham et al., 2007)  Lone motherhood is associated with poverty, poor mental health and low rates of breastfeeding (Borooah, 2007; Bradshaw & Mayhew, 2005; Gray & Carragher, 2007)  Partner and family support has been shown to be protective of adverse pregnancy outcomes (Hoffman & Hatch, 2008)

4. Background – TSN project  Unmarried registrants live in the most deprived areas, are younger and have high prevalence of maternal smoking  Unmarried registration status is a risk factor for adverse pregnancy outcomes  It is important to look at the four separate registration groups as opposed to married and unmarried because joint unmarried registrants are at higher risk as well as sole registrants  The effect of registration status on adverse pregnancy outcomes is only partially explained by maternal age, multiple birth, smoking and deprivation  Further individual and household characteristics are available in the NILS dataset

5. Aim  The overall aim of the NILS study is to investigate why unmarried mothers are at higher risk of adverse pregnancy outcomes (as shown by TSN study), by investigating their socio- demographic and household characteristics  To describe the socio-demographic and household characteristics of mothers of different registration status i.e. where the birth is registered to the mother alone, to the mother and father at different addresses, to the mother and father at the same address (married and unmarried)  To investigate whether ‘clusters’ of unmarried registrants can be defined, based on socio-demographic and household characteristics, including the level of social support in the form of the household members

6. Method  An approximate 28% sample of the Northern Ireland population are NILS members  Our NILS dataset is based on babies born between May 1999 and April 2002 who are NILS members and/or whose mum and/or dad are NILS members. (Census information may be 1 year before or 2 years after the birth)  Linked to these data: 2001 census person data (including relationships to baby) 2001 census household data NI Multiple Deprivation Measure 2005 indices at SOA level Land and Properties Service data Child health system data (including birthweight and gestational age) This will involve one-way encryption

7. Registration Status

8. Age less than 20 years Almost one- third of sole registrants are less than 20 years old %

9. Household Member Employed One-third of sole registrants are living in a household where someone is in employment %

10. Highest Social Class Only 4% of sole registrants are in the highest social class %

11. Owner Occupied Tenure Fewer than 1 in 3 sole registrants live in an owner- occupied household %

12. No Educational Qualification (Household Reference Person) For sole registrants, almost half of the household reference persons have no educational qualification %

13. ‘Father’ figure in Household Father, mum’s husband, mum’s partner are not mutually exclusive, Only babies born before the census %

14. Grandparents in Household % Only babies born before the census

15. No other Adult in Household %

16. Conclusions  Gradient of registrant groups – sole, different address, same address, married – for socio-demographic variables  Not only sole registrants who are deprived in terms of socio- demographic factors but also two other unmarried groups  Sole registrants would appear to have high levels of family support i.e. 60% are living with at least one other adult and just over one-quarter were living with at least one grandparent of child  NILS data useful to understand the distribution of socio- demographic factors among registrant groups  Limitation - some analysis is limited to births before the census which results in household composition being after the birth of the baby and a smaller number of cases

17. Future Analysis  Further analysis will investigate whether household composition is important in distinguishing risk of adverse pregnancy among unmarried registrants  Cluster analysis of socio-demographic and household characteristics in order to investigate which subgroups of sole registrants are at higher risk of adverse pregnancy outcomes (similarly other unmarried registrants)  Analysis of Multiple Deprivation Measures  Analysis of Land and Properties Service data  Linkage with Child Health data (including birthweight, gestational age and maternal smoking)  Ongoing analysis will investigate whether household composition is an explanatory variable in the risk of low birthweight and preterm birth

18. Acknowledgements TSN was funded by the HSC R&D function of the Public Health Agency. The help provided by the staff of the Northern Ireland Longitudinal Study (NILS) and NILS Research Support Unit is acknowledged. NILS is funded by the HSC R&D function of the Public Health Agency. The NILS-RSU is funded by the ESRC and the Northern Ireland Government. The authors alone are responsible for the interpretation of the data.