Pulmonary embolism associated with transfusion after severe post-partum haemorrhage: is less more?

Transfusion of red blood cells is associated with superficial vein thrombosis (SVT) and venous thromboembolism (deep vein thrombosis and/or pulmonary embolism, VTE). The present study investigated the prevalence of SVT and VTE in women transfused in the peri-partum period.

We carried out an observational study in a tertiary level obstetrics department in the Apulia Region of Southern Italy to investigate VTE in women transfused during or after labour. The study included all women who delivered between January 1^st and November 30^th, 2018. A thrombotic event was defined as an admission with an ICD-9 code of SVT and VTE as a primary or secondary diagnosis. Maternal "near-miss" rate, as defined by the World Health Organization, was calculated and outcome of transfused women was recorded.

From January 1^st to November 30^th, a total of 1,028 women delivered, 39% of them by caesarean section (CS). One-hundred and thirty-two women (12.8%) had been classified with one or more complication codes. Most complications occurred in women who underwent CS with an odds ratio (OR) of 7.0 (95% CI: 4.0-12.5; p=0.000). Twelve women (1.2%) were transfused in the peri-partum period, 7 of them had delivered by CS. The only thrombotic events recorded in the entire cohort of 1,028 patients were isolated pulmonary embolisms observed in 2 out of 12 transfused women. Overall, patients had received a mean of 7.5 units of packed red blood cells (1 patient also received 7 plasma units, while 1 patient also received 1 platelet unit). Consequently, the near-miss rate was 2.0/1,000 deliveries, which is not significantly different from that expected in Italy and in high-income countries.

Pulmonary embolism is a life-threatening complication, which can be associated with transfusion in the peri-partum period.