3Rossen J, Okland I, Nilsen OB, et al. Is there an increase of post- partum hemorrhage, and is severe hemorrhage associated with more frequent use of obstetric interventions? [ J ]. Acta Obstet Gynecol Scand ,2010,89 ( 10 ) : 1248 - 1255.
4Wetta LA, Szychowski JM, Seals S. Risk factors for uterine atony/ postpartum hemorrhage requiring treatment after vagina! delivery [ J ]. Am J Obst Gynecol,2013,209(1) :1 -6.
8JanaKiraman V, Ecker J, Kaimal AJ. Comparing the second stage in in- duced and spontaneous labor [ J ]. Obstet Gyneco1,2010,116 ( 3 ) :606 - 611.
9Rossen J, Okland I, Nilsen OB, et al. Is there an increase of postpartum hemorrhage, and is severe hemorrhage associated with more frequent use of obstetric interventions? [J]. Acta Obstet Gynecol Scand,2010, 89(10) :1248-1255.
10Miletig T, Aberle N, Mikulandra F, et al. Perinatal outcome of preg- nancies in w omen aged 40 and over [ J ]. Coil Antropol, 2002,26 ( 1 ) :251-258.
