Ethnic Differences in Birth Outcomes: Evidence from the MCS

1. Ethnic Differences in Birth Outcomes: Evidence from the MCS Lorraine Dearden, Alice Mesnard and Jonathan Shaw

2. Introduction • This work small part of a wider research agenda on ethnic differences in child outcomes from birth to adulthood • Most previous research on ethnic inequality has focussed on adults • In this presentation just focus on child outcomes at birth • Birth weight (and gestations) important determinants of later cognitive and health outcomes (independent of other factors)

3. Aims of paper • Look at ethnic differences in • Gestation (measured in days) • Birth weight (measured in kilograms) • Do these birth outcomes vary by ethnicity • To what extent can any differences be explained by differences in • Maternal behaviour before birth (e.g. smoking, work ) • Family composition and status • Longer term socio-economic factors • Other parental characteristics (e.g. height, health)

4. MCS data and ethnicity • Focus on children born in 2000/01 in England • Compare outcomes at birth for 4 broad ethnic groups • White • Asian • Black • Other • MCS over-samples ethnic minorities

5. Ethnic Differences in Gestation Figure 3.1 Distribution of length of gestation by ethnicity

6. So how big are these differences? • For white female children average gestation is 277.2 days • For male children the average gestation is lower by • 0.6 of a day when don’t control for other factors (nc) • 0.7 when we control for other factors (c) • All other ethnic groups have lower gestation • 1.4 days Asian child (nc) and 0.8^ (c) • 2.4 days Black child (nc) and 2.5 (c) • 1.7 days Other child (nc) and 1.6 (c) ^ not significant

7. What other factors impact on gestation? Factors that increase gestation: • Mother’s height, mother and father’s education, drinking during pregnancy, stopping work earlier during pregnancy (but not work itself) Factors that reduce gestation • Being underweight for height, diabetic mum, mum with long term illness

8. What does this mean? • Some of these characteristics vary significantly by ethnicity e.g. height, drinking during pregnancy, being underweight for height, diabetes, how early women stop work during pregnancy • Interestingly income has NO effect on length of gestation

9. Ethnicity and Birthweight Figure 3.2 Distribution of birthweight by ethnicity

10. How big are these differences • Average birthweight for white child is 3.37kg • Birthweights of ethnic minority children significantly less that those of white babies • Asian children about 210 to 230 grams less • Black children about 100 to 180 grams less • Other children about 110 grams less • Controlling for other factors does not change this difference

11. What other factors are important Factors that impact positively on birthweight • Mother and father’s height, diabetic mum, parent’s education, INCOME, mother’s weight before pregnancy, having other children, age of mother, stopping work early Factors that impact negatively on birthweight • Smoking during pregnancy (and before), long term illness of mum, being underweight for age

12. Smoking and birthweight – white children

13. Birthweight controlling for gestation • Some factors impact on both gestation and birthweight • Interesting to know whether all their effect is through gestation or whether they impact on both • Stopping work early effect operates purely through gestation • Height, mother’s education and being underweight impacts on both

14. Other issues • Do different factors affect birth outcomes for different ethnic groups in same way? • Our analysis suggests that they do – once you ensure the composition of the two groups are similar • So clear that impact of income is not different across ethnic groups • BUT levels of income across different ethnic groups very different

15. Conclusions • Significant ethnic differences in birth outcomes • These differences are generally reduced but still remain after control for other factors • The way factors influence birth outcomes is not significantly different across ethnic groups • But the distribution of some of these factors across ethnic groups is different