6Ickovics JR, Reed E, Magriples U,et al.Effects of group prenatal care on psychosocial risk in pregnancy: results from a randomised controlled trial[J]. Psychol Health, 2011,26(2 ) : 235-250.
7Gruber KJ, Cupito SH, Dobson CF. Impact of doulas on healthybirth outcomes, J Perinat Educ,2013,22(1):49-58.
8COO Practice,AAO Pediatrics.Immersion in water during labor and delivery.Obstet Gynecol,2014,123(4):912-915.