Baseline parameters for rotational thromboelastometry in healthy labouring women: a prospective observational study

The aim of this study was to establish rotational thromboelastometry (ROTEM^® ) baseline parameters in labouring women at term gestation. The secondary aim was to compare these reference ranges with those from previous studies on labouring women and from the manufacturer.

A prospective, observational study.

Tertiary referral hospital.

Healthy women in labour.

Ethics approval was granted for an opt-out recruitment approach. ROTEM^® testing was performed in labouring women at term gestation. Women with any condition affecting coagulation were excluded. ROTEM^® Delta reference ranges were derived by calculating the 2.5% and 97.5% centiles for INTEM/EXTEM/FIBTEM parameters including amplitude at 5 minutes (A5), coagulation time (CT) and maximum clot firmness (MCF).

ROTEM^® parameters were measured in labouring women before delivery. The following tests were performed: FIBTEM, EXTEM and INTEM.

One hundred and twenty-one women met the inclusion criteria, with a mean (± SD) age of 29.6 ± 5.4 years and median (interquartile range) gestation of 39.4 weeks (37.4-40.4 weeks). Seventy-five (62.0%) women were nulliparous and 71 (58.7%) delivered vaginally. The median and interquartile ranges for selected ROTEM^® parameters were: FIBTEM A5, 21 mm (IQR 18-23 mm); EXTEM A5, 55 mm (52-58 mm); and EXTEM CT, 52 seconds (48-56 seconds).

The FIBTEM/EXTEM/INTEM amplitudes were higher than the manufacturer's reference ranges for non-obstetric patients. The FIBTEM MCF upper and lower limits were higher and the EXTEM/INTEM CT was shorter and narrower in range. This study provides reference ranges for ROTEM^® values in healthy labouring women at term gestation with uncomplicated pregnancies.

This is the first study to report on ROTEM^® reference ranges with over 120 healthy labouring women of normal weight at term gestation.