tailieunhanh - NONVERTEX PRESENTATIONS, SHOULDER DYSTOCIA, AND CORD ACCIDENTS

Breech is a longitudinal presentation in which the cephalic pole occupies the fundus and the caudal (podalic) pole lies in the lower segment of the uterine cavity or within the birth canal. Overall breech presentation occurs in 3%–4% of singleton pregnancies commencing labor, but has a much higher incidence in multiple gestations (., 25% of first twins and 50% of second twins are breech). The incidence rises further in higher order multiple pregnancies. Other associations with breech presentation include: earlier gestations (35% at 28 weeks, 25% at 28–32 weeks, 20% at 32–34 weeks, 8% at 34–35 weeks, 2%–3% at. | L NONVERTEX PRESENTATIONS SHOULDER DYSTOCIA AND CORD ACCIDENTS BREECH PRESENTATION DEFINITIONS ASSOCIATIONS INCIDENCES And importance Breech is a longitudinal presentation in which the cephalic pole occupies the fundus and the caudal podalic pole lies in the lower segment of the uterine cavity or within the birth canal. Overall breech presentation occurs in 3 4 of singleton pregnancies commencing labor but has a much higher incidence in multiple gestations . 25 of first twins and 50 of second twins are breech . The incidence rises further in higher order multiple pregnancies. Other associations with breech presentation include earlier gestations 35 at 28 weeks 25 at 28-32 weeks 20 at 32-34 weeks 8 at 34-35 weeks 2 -3 at 36 weeks a prior breech over 4-fold increase after one and up to 30-fold after three placental placement . placenta previa oligohydramnios fetal congenital anomalies . hydrocephalus pelvic tumors impinging on the uterus or birth canal . leiomyomata and uterine anomalies . bicornuate septate uterus . As presentations are thought to be a matter of fetal-uterine accommodation breech presentation may be caused by any aberration of this adaptive process or of the fetal attitude. Thus breech presentation is not a disease or an abnormality. However breech presentation may be an important sign of congenitalfetal compromise. For example breech presentation is increased with chromosomal anomalies . trisomies 18 and 21 neuromuscular abnormalities . familial dysautonomia and skeletal malformations . spina bifida meningomyelocele . The incidence of major congenital anomalies 403 Copyright 2001 The McGraw-Hill Companies. Click Here for Terms ofUse. 404 BENSON PERNOLL S HANDBOOK OF OBSTETRICS AND GYNECOLOGY . anaencephaly hydrocephaly in breech presentations is more than double 6 that found in vertex. Additionally delivery of the breech fetus imposes perinatal risks of birth anoxia and birth trauma as well as maternal risks of traumatic