Background: Vaginal bleeding in early pregnancy is a common presentation in the Emergency Department, often leading to miscarriage in the patient. Uterine bleeding at this stage most often arises from disruption of decidual vessels, with unclear relationship to maternal thrombophilia based on conventional clotting assays. Rotational thromboelastometry (ROTEM), which performs a more comprehensive clotting evaluation, may demonstrate coagulopathic abnormalities contributing to vaginal bleeding in early pregnancy that are not present in normal gestation.
Methods: his was a prospective case control study from a single center. Patients with chief complaint of vaginal bleeding in early pregnancy (less than 20 weeks) were recruited from the ED for ROTEM testing. These results were compared to healthy pregnant women presenting for regular prenatal care at our hospital’s obstetrical clinic. Crude results were analyzed using t-test for ROTEM measures, and differences were then compared using multiple linear regression, controlling for patient age, race, ethnicity, number of prior pregnancies, and estimated gestational age (EGA) in weeks. ROTEM measurements of interest were the clot formation kinetics using EXTEM and INTEM tracings.
Results: Of 67 patients, 28 were from the ED and 39 from the OB clinic. Both groups had similar ages, 30.2 years (+/- 5.1 years) vs. 28.7 years (+/- 5.8 years). ED patients had earlier EGA than OB clinic patients, 7.3 weeks (+/- 6.2) vs. 10.9 weeks (+/- 9.6), p>0.01. Racial and ethnic breakdown was similar between groups. Numbers of prior pregnancies, 3.6 (+/- 2.2) vs. 2.9 (+/- 2.3), was also similar between groups. ROTEM results for INTEM amplitudes between 5 and 25 minutes (A5 through A25) and clot formation time (CFT) were significantly different between groups on crude analysis (p<0.05). After controlling for the patient factors above, no ROTEM result differed between group.
Conclusion: In pregnant patients presenting to the ED with vaginal bleeding before 20 weeks, ROTEM differences were generally not apparent in comparison to non-bleeding patients at the same gestational stage. This suggests that clotting profiles by ROTEM may not be useful in predicting vaginal bleeding within this population. Further analysis, including followup of this cohort to determine pregnancy outcomes based on ROTEM results, is currently planned.