Definition: Childbirth is the period from the onset of regular uterine contractions until expulsion of the placenta..
–at the onset of labor the position of the fetus with respect to the birth canal is critical to the route of the delivery. –It is important to know the fetal position within the uterine cavity at the onset of labor
Fetal lie : is the relation of the long axis of the fetus to that of the mother it is either longitudinal 99% or transverse or oblique (due polyhyd,p.p,ulnine anomali)
Fetal presentation is the portion of the fetal body that is either fore most within the birth canal or closest proximity to it.
1)cephalic presentation. It is classified according to relation ship between the head and the body of the fetus.
2) face presentation Fetal neck sharply extended so that the occiput and back come in contact
3)brown presentation Partially extended head.is the greatest diameter 13.5cm fronto bregmatic
4)Breech. presentation eith.Frank complet footling. Delivery usually by cls
Fetal postion Relation ship of an chosen portion of the fetal presenting pant to the Rt or Lt.side of birth canal
Labor with. Occiput presentation. 1)in the most of the cases the vertex inter the pelvis with the sagittal suture lying in transverse pelvic diameter. (L.O.T).40% (R.O.T).20%
Cardinal movements in the mechanism of labor and Delivery in left.occiput. anterior position Descent Flexion Internal rotation External rotation Expulsion
Descent: This movement is the First requisite for the birth of New born. usually follow the engagement.
Descent occe due to 1)pressure of the A.F 2)Direct pressure to the breech by contraction. 3)bearing down of maternal abd.muscles. 4)extention of fetal body.
Flexion: When descending head meets resistance from cervix –walls of the pelvis or pelvic floor This results in the chin brought into more contact with the fetal thorax. -and the suboccipitobregmatic diameter. will be presentation
Internal Rotation This movement consists of turning of the head in such a manner that the occiput gradually moves toward the symphysis pubis.anteriorly
Extension After internal Rotation the sharply flexed head reaches the vulva and undergoes extension
External Rotation –The delivered head undergoes restitution.to oblique position followed by complition of external rotation to transverse position.
Expulsion Immediately after external Rotation. the anterior shoulder appears under symphysis and the perineum soon becames. Distended by post shoulder
2) onset of labor. The plysiological processes in human pregnancy that result in initiation of labor remain poorly defined. uterotonin production. elevation of the uterotonin receptors in myometriam