Predelivery maternal fibrinogen as a predictor of blood loss after vaginal delivery.

Purpose: The present study investigated whether fibrinogen level during the first stage of labor is associated with bleeding severity in the third stage of labor.

Methods: We prospectively enrolled 1019 pregnant women with planned vaginal delivery. Upon admission to delivery, maternal fibrinogen levels, hemoglobin content, and coagulation parameters were evaluated. Blood loss in the third stage of labor was systematically measured using a calibrated collecting drape. Univariate and multivariate analyses were performed to identify predictors of PPH (blood loss ≥500 mL) and S-PPH (blood loss ≥1000 mL).

Results: Among 809 vaginal deliveries, mean maternal predelivery fibrinogen was 4.65 ± 0.77 g/L, PPH incidence was 12 %, S-PPH incidence was 3.5 %, and median blood loss was 250 mL. Fibrinogen levels were significantly lower in women with S-PPH (4.22 ± 0.82 g/L) than without S-PPH (4.67 ± 0.75 g/L; p = 0.004), but did not significantly differ between women with PPH (4.67 ± 0.84 g/L) and those without PPH (4.67 ± 0.75 g/L; p = 0.985). Instrumental delivery and predelivery fibrinogen levels were independent predictors of S-PPH. Primiparous status, birth weight >4000 g, genital tract laceration, episiotomy and instrumental delivery were independent predictors of PPH.

Conclusion: For each 1 g/L increase of predelivery fibrinogen level, the risk of S-PPH after vaginal delivery decreases by a factor of 0.405 (95 % CI 0.219-0.750; p = 0.004).