Induced abortion and risk of small-for-gestational-age birth

Objective: To investigate the possibility of an association between previous induced abortion and subsequent birth of a small-for-gestational-age (SGA) infant. Design: Case-control study. Setting: General and university hospitals. Methods: Cases were 555 women who delivered SGA babies. Controls were 1966 women who gave birth at term (>37 weeks of gestation) to healthy infants of normal weight on randomly selected days at the hospital where cases had been identified. All women in the case and control categories were interviewed on the obstetric wards by one of a team of six interviewers. During the interviews, information was obtained regarding general socio-demographic factors, personal characteristics and habits, gynaecological and obstetric history, general anamnesis, family history of obstetric and gynaecological diseases, and the age of the father of the child. Further information on current pregnancy and delivery was also collected. We used conditional multiple logistic regression (with age as the matching variable), with maximum likelihood fitting, to obtain odds ratios and their corresponding 95% CIs. Included in the regression equations were terms for education, plus terms significantly associated in this data set with the risk of SGA birth (smoking in pregnancy, history of SGA, gestational hypertension and parity). Population: Women admitted to a general and a university hospital. Results: No significant increase in the risk of SGA birth was observed in women with a previous induced abortion [odds ratio (OR) 1.0; 95% CI 0.6-1.7]. The OR for SGA birth was 1.2 (95% CI 0.7-2.1) for preterm and 1.0 (95% CI 0.7-1.4) for term SGA births. Conclusion: This study found no association between risk of SGA birth and induced abortion.