Objective: To define the rate of severe maternal morbidity in different modes of delivery and to find out if the rate of severe morbidity has changed over a 5-year time span.
Design: Retrospective register-based study.
Setting: Finnish Medical Birth Registry and Hospital Discharge Registry.
Population: All singleton deliveries in Finland in 1997 and 2002 (n=110,717).
Methods: Diagnoses and operative interventions recorded in the Hospital Discharge Registry indicating a severe maternal complication were linked with Birth Register data and compared by mode of delivery: spontaneous vaginal delivery (VD), instrumental VD, elective cesarean section and non-elective cesarean section. Main outcome measures were severe maternal morbidity: deep venous thromboembolism and amniotic fluid embolism, major puerperal infection, severe hemorrhage, events requiring operative intervention after delivery, uterine rupture and inversion, and intestinal obstruction.
Results: Severe maternal morbidity was more frequent in cesarean than vaginal deliveries (p<0.001), and more frequent in non-elective than in elective operations (p<0.001). The rate of severe maternal morbidity increased considerably from 1997 to 2002; from 5.9 to 7.6 per 1,000 in all deliveries (p<0.001), from 4.0 per 1,000 to 5.2 per 1,000 in spontaneous vaginal deliveries (p=0.005), from 9.9 per 1,000 to 12.1 per 1,000 in elective cesarean sections (CSs) (p=0.164), and from 19.6 per 1,000 to 27.2 per 1,000 in non-elective CSs (p=0.090), respectively.
Conclusions: Severe maternal morbidity has increased both in cesarean and vaginal deliveries from 1997 to 2002. Cesarean delivery, even an elective one, carries a significantly higher risk of life-threatening maternal complications than VD.