Pregnancy outcome and family size in systemic lupus erythematosus: a case-control study

To establish pregnancy outcomes and family size in a geographically defined population of systemic lupus erythematosus (SLE) patients.

One hundred and thirty-eight SLE patients (all women satisfying at least four American Rheumatism Association criteria) and 276 age-matched female controls, from the Nottingham area, were interviewed by a single investigator. Demographic details and maternity histories were obtained, and the data collected were analysed statistically to calculate odds ratios (ORs) for risk of fetal loss (through miscarriage, stillbirth and abortion). Family size was also determined in White and non-White cases and controls.

Women with SLE are at greater risk of spontaneous fetal loss than their healthy counterparts (OR = 2.21, 95% CI 1.46-3.35, P < 0.01) and they are more likely than controls to have a surgical abortion (OR 2.44, 95%, CI 1.22-4.87, P = 0.01). The excess risk of both of these outcomes exists both before and after diagnosis of SLE. The median number of children in White and non-White families of cases and controls is the same, i.e. two. White women with SLE, however, appear less likely than controls to have more than two children, whereas non-White lupus women tend to retain their propensity to have larger families, i.e. more than two children.

We confirm that lupus women who have, or later develop, SLE are at greater risk of pregnancy loss by spontaneous or surgical means. We have also shown that race, and the inherent differences in social and cultural influences, appears to be an important determinant of ultimate family size; White women with SLE have fewer children than controls, whilst non-White lupus women tend to have larger families.