0300-9041 0300-9041 S0300-90412020000200127 10.24245/gom.v88i2.3716 México 00 00 2020 00 00 2020 88 2 127 129 1 2011 7 419 2 1997 11 223 3 2010 59 1 1 4 2012 283 5 2007 197 390 6 2017 65 S160 7 2011 204 150 8 2015 9 2013 53 236 10 2015 11 American College of Obstetricians and Gynecologists 2002 100:1405