Postpartum Hemorrhage in Patients with Type 1 von Willebrand Disease: A Systematic Review.

Type 1 von Willebrand disease (VWD) is the most common subtype of VWD, comprising 75% of VWD patients. We provide a systematic review of type 1 VWD in pregnancy. Our objective was to evaluate the rate of postpartum hemorrhage (PPH) in patients with known type 1 VWD. The primary outcome was rate of PPH. Primary PPH was defined as a cumulative blood loss ≥1,000 mL, or blood loss accompanied by signs and symptoms of hypovolemia within 24 hours postpartum or requiring blood products. Secondary PPH was defined as significant bleeding 24 hours to 12 weeks postpartum. Relevant articles published in English pertaining to VWD and pregnancy were identified without any time or study limitations. Seven articles ( = 144 pregnancies) met inclusion criteria. The rate of primary PPH was 4/144 (2.8%). The secondary PPH rate was reported in four studies, and occurred in 7/48 pregnancies (14.6%), ranging from 2 to 19 days postpartum. In conclusion, according to this systematic review, the frequency of primary PPH in pregnancies with known type 1 VWD is 2.8%. This is similar to the overall PPH rates of 3% reported in the literature. Although the sample size was small, secondary PPH occurred in almost 15% of pregnancies, while in the overall obstetrical population this occurs in approximately 1% of cases. Patients with known type 1 VWD may not be at increased risk of primary PPH, though they appear to bear increased risk of secondary PPH.