Objective: To study complications, within six weeks postpartum, after
planned caesarean section (CS) compared with planned vaginal delivery,
among women without formal indication for caesarean section. Design:
Retrospective cohort study. Setting: Swedish national registries.
Population: 714 326 deliveries, 2008-2017. Methods: The risks of
complications were compared between planned caesarean section and
planned vaginal delivery among women without formal medical indication
for planned CS. Adjusted Risk Ratios (ARR) were obtained using modified
Poisson-regression models adjusting for; maternal age, parity, body mass
index, smoking, country of birth, and county. Main outcome measure:
infections, haemorrhage and thromboembolism. Results:. In the planned CS
group (n=22 855), 15% had a postpartum infection compared with 10% in
the planned vaginal group (n=691 471) (ARR=1.6; 95%CI 1.5-1.6), 8.4%
vs 0.6% had haemorrhage >1 litre (ARR=13.4; 95%CI
12.7-14.2), and 0.08% vs 0.05% had a postpartum pulmonary embolism
(ARR=1.7; 95%CI 1.0-2.6). The obtained risk estimates correspond to a
Number-Needed-to-Harm estimate of 17, 14, and 3448, respectively. When
dividing the infections into subgroups, an increased risk of
endometritis (ARR 1.2; 95%CI 1.1-1.3), wound infection (ARR 2.7 95%CI
2.4-3.0), urinary tract infections (ARR 1.5 95%CI 1.3-1.7), and
mastitis (ARR 2.0; 1.9-2.2) was found after planned CS. Conclusion: The
risks of short-term maternal complications were higher in women
delivered by planned CS compared with planned vaginal delivery among
women without formal medical indication for planned CS. Funding: Gorthon
Foundation. Key words: caesarean section, puerperal infection,
haemorrhage, thromboembolism.