mechanism of labour

MECHANISM OF LABOUR
Mechanisms of labor, or the cardinal movements of labor, refer to the changes in position of the fetal head during passage through the birth canal in the vertex presentation
1- Engagement is descent of the biparietal diameter of the fetal head below the plane of the pelvic inlet.
2- descent
3- Flexion
4- Internal rotation
5- Extension
6- Restitution and external rotation
7- Delivery of the body

Some terms in labour you should know
Tachysystole??
The presence of more than five contractions in 10 minutes for a period of 20 minutes is abnormal and is defined as tachysystole.

Contractions are painful???
Why?
1- Hypoxia because of the duration of the contraction.
2- Compression of the nerve endings in the myometrium.
3- Cervical stretch and dilatation
During each uterine contraction, the maternal blood supply to the intervillous space is severely reduced and may be cut off. This reduces the fetal O2 supply and allows less time for exchange of waste products from the fetus to the mother. Most normal fetuses can stand intermittent hypoxic ischaemia, the fetus often needs to be carefully monitored during labour.