The incidence and pattern of thromboembolic complications in obstetric and gynaecological patients in Scotland between 1981 and 1992 was investigated by analysing ICD coded data retrieved from the SMR1 and SMR2 database. The effect of mode of delivery and maternal age over 35 on risk of thromboembolism in pregnancy was also assessed. 0.076% of gynaecological episodes were subsequently complicated by thromboembolic events. Nineteen percent of those suffering thromboembolic complications within two weeks of discharge were referred back to gynaecology. The incidence of deep venous thrombosis (DVT) in those under 35 years and over 35 years was 0.615/1000 maternities and 1.216/1000 maternities respectively. Respective figures for postnatal DVT were 0.304/1000 and 0.720/1000 and for pulmonary thromboembolism (PTE), 0.108/ 1000 and 0.405/1000. In both age groups, emergency caesarean section was associated with a higher incidence of DVT than elective caesarean section and vaginal delivery.