MECHANISM OF LABOUR

FETAL LIE The relation of the long axis of the fetus to that of the mother Longitudinal lie is found in 99% of labours at term Predisposing factors for transverse lie/oblique lie multiparity placenta previa, hydramnious uterine anomalies

FETAL PRESENTATION The presenting part is the portion of the body of the fetus that is foremost in the birth canal The presenting part can be felt through the Cx on vaginal examination Longitudinal lie  cephalic presentation breech presentation Transvrse lie  shoulder presentation

CEPHALIC PRESENTATION Head is flexed sharply  vertex / occiput presentation Head is extended sharply  face presentation Partially flexed  bregma presenting (sinciput presentation) Partially extended  brow presentation BREECH PRESENTATION Frank breech Complete breech Footling breech

ATTITUDE Posture of the fetus folded on itself to accommodate the shape of the uterus Flexed head, thighs, knees &feet The arms crossed over the chest Face presentation extended concave contour of the vertebral column

c (A) vertex (B) sinciput (C) brow (D) face I D .'" ' A B ! 1\ 11 A B ii F c (A) vertex (B) sinciput (C) brow D (D) face Longitudinal lie. Ce­phalic presentation. Differences in attitude of fetal body,

Longitudinal lie. Frank breech presentation. I I Longitudinal lie. Frank breech presentation. Longitudinal lie. Complete breech presentation.

Longitudinal lie. Incomplete, or footling, breech presentation.

POSITION The relation of an arbitrary chosen point of the fetal presenting part to the Rt or Lt side of the maternal birth canal The chosen point Vertex presentation  occiput Face presentation  mentum Breech presentation Sacrum Each presentation has two positions Rt or Lt Each position has 3 varieties : Ant, transverse, post OA ROA LOA ROT LOT ROP LOP OP

LONGITUDINAL LIE VERTEX PRESENTATION LOP LOA ~ 'tJ

Longtitudinal Lie.Vertex Presentation A. Right occiput posterior (ROP) Right occiput transverse (ROT) s A Longtitudinal Lie.Vertex Presentation

(1 bJ 3~ al ta tb oj a ill Sf a! w Cc ht p( fit tb fe c Right occiput anterior (ROA). w Cc ht p( fit tb fe w c al ta tb oj

Lt mento-ant Rt mento-ant Rt mento-post Longitudinal lie. Face presentation. Left and right anterior and right posterior positions.

~ Longitudinal lie Breech presentation LSP

Transverse lie. Right acromiodorsoposterior position (RADP) Transverse lie. Right acromiodorsoposterior position (RADP). The shoulder of the fetus is to the mother's right, and the back is posterior.

Lever action producing FLEXION of the head; conversion from occipitofrontal to suboccipitobregmatic diameter typically reduces the anteroposterior diameter from nearly 12- to 9.5 cm.

Left lateral Knee chest

Squatting Standing

Types of episiotomy Medio-lateral Median Lateral J shaped 20

2.Engagement;descent, flexion 6. Restitution (external rotation) Cardinal movements in the mechanism of labor and delivery, left occiput anterior position. 302 2.Engagement;descent, flexion 6. Restitution (external rotation) 3. Further descent, internal rotation 4. Complete rotation, beginning extension

,. ,0 Mechanism of labor for right occiput posterior position, anterior rotation.