What maternal factor is associated with increased risk of postpartum hemorrhage?

Multiple pregnancies, such as twins or higher-order multiples, are associated with an increased risk of postpartum hemorrhage due to several physiological factors. When a woman is carrying more than one fetus, her body experiences greater uterine distension. This can lead to a more significant loss of tone in the uterine muscles after delivery. A well-toned uterus contracts effectively to expel the placenta and limit bleeding; however, in cases of multiple pregnancies, the uterus may be overstretched, making it less capable of contracting properly. Consequently, this can result in increased risk of uterine atony, which is one of the leading causes of postpartum hemorrhage.

The other listed factors do not correlate significantly with the same level of risk. Short labor duration may actually be associated with a different set of risks but isn’t a direct factor for postpartum hemorrhage. A pleasant delivery experience is more subjective and not a contributing factor to hemorrhage risks, while low maternal weight does not directly cause postpartum hemorrhage but may be associated with other complications. Hence, the connection between multiple pregnancies and increased risk of postpartum hemorrhage is well-established in maternal health literature.