- Labor is coordinated sequence of involuntary uterine contractions resulting in effacement and dilatation of cervix, followed by expulsion of products of conception
The five P's include :
A. Passenger: the fetus
- Attitude - relationship of fetal body parts to each other; normal intrauterine posture is completely flexed.
- Lie - relationship of fetal spine to maternal spine. Longitudinal or vertical is when fetus is parallel to mother's spine; transverse or horizontal if fetus is at right angle to mother's spine.
- Presentation - portion of fetus that enters pelvis first; presenting part could be cephalic or breech (frank or footling).
- Position - relationship of fetal reference point to one or four quadrants or sides of mother's pelvis. Maternal pelvis side: L-left, R-right; Fetal reference points: O-occiput, M-mentum, B-brow, S-sacrum; Maternal Pelvis quadrant: A-anterior, T-transverse, P-posterior.
- Station- degree of engagement from presenting part to ischial spine; Station O means at ischial spine.; minus station means above spine, and plus station ios below the spine.
B. Passageways
- Pelvis - (please see section for pelvis)
- Soft tissues - lower uterine segment, cervix, vagina and introitus.
C. Powers
- Forces acting to expel fetus; primarily by involuntary uterine contractions, secondarily by voluntary bearing down.
- Functions of uterine contraction are effacement and dilation.
D. and E. Person/psychological response
- Response to contraction, perceptions and beliefs, prenatal care and education, suppor systems and communication skills.
