Haemostatic changes in the puerperium '6 weeks postpartum' (HIP Study) - implication for maternal thromboembolism

We aim to measure the thrombotic changes during the postnatal period up to 6 weeks after delivery and assess the extent of the risk period.

Prospective observational study.

Queen Elizabeth II, an acute District General Hospital, Hertfordshire.

Women booked at the antenatal clinic and prepared to deliver at the hospital.

We assessed the haemoglobin, platelet count and function, fibrinogen, prothrombin time, activated partial thromboplastin time, protein C, S and antithrombin level and as well as rotational thromboelastometry (ROTEM) from predelivery till 6 weeks postpartum.

A total 50 women were recruited of which four dropped out. Results compared against the finding at 6 weeks after delivery. Platelet was significantly elevated on day 19 compared to day 42 (P < 0.001). Fibrinogen was elevated from predelivery till day 15 after delivery (P < 0.01). Prothrombin time (PT) was low till day 15 (P < 0.05) and activated partial thromboplastin time (APTT) was significantly lower till day 3 after delivery (P < 0.001). ROTEM revealed low clotting time (CT) at predelivery and continued to be low till day 7. Clot formation time (CFT) significantly low till day 25 (P < 0.05). Maximum clot firmness, alpha angle and amplitude at 20 minutes were raised till day 19 (P < 0.001, P < 0.01 and P < 0.001 respectively). While, comparing vaginal delivery against caesarean section there were nonsignificant increase in thrombotic parameters in caesarean section.

Coagulation screens as well as thomboelastometry suggest a persistent hypercoagulation during the first 3 weeks after delivery.