持续性枕后位，枕横位的处理原则。臀先露以骶骨为指示点原因1子宫腔过大2胎儿异常。胎儿发育异常病因，遗传 经产妇 糖尿病 巨大儿                    

臀先露的临床表现                                                                                          

臀先露对母儿的影响