The 5 P's
- Passenger (fetus and placenta)
- Passageway (birth canal)
- Powers (contractions)
- Position of the mother
- Psychologic response
Anterior and Posterior fontanels
- Anterior- larger, diamond shape, approx -2cm, closes by 18months after birth.
- Posterior- is triangular and is approx 1-2cm, closes 6-8 weeks after birth.
- Cephalic (head first) 96%
- Breech (buttocks or feet first) 3%
- Shoulder 1% of the time
Normally the back of the fetus is rounded so that the chin is flexed on the chest, the thighs are flexed on the abdomen, and the legs are flexed at the knees. The arms are crossed over the thorax and the umbilical cord lies between the arms and the legs.
the fetal head may be extended or flexed in a manner that presents a head diameter that exceeds the limits of the maternal pelvis, leading to prolonged labor, forceps or vacuum assisted birth, or CSec.
which is approx 9.25cm at term is the largest transverse diameter and an important indicator of fetal head size.
approx 9.5cm at term, the smallest most critical anteroposterior diameter.
ROA-occiput is the presenting part and is located in the right anterior quadrant of the maternal pelvis.
LSP-sacrum is the presenting part and is located in the left posterior quadrant of the maternal pelvis.
the term used to indicate that the largest transverse diameter of the presenting part, has passed throught the maternal pelvic brim or inlet into the true pelvis and usually corresponds to station 0.
- Primary powers- involuntary uterine contractions
- Secondary powers- voluntary bearing-down efforts by the woman
- Frequency- the time from the beginning of one contraction to the beginning of the next
- Duration- length of contraction from the beginning to the end
- Intensity- strength of contraction
Stretch receptors in the posterior vagina cause release of endogenous oxytocin that triggers the maternal urge to bear down.
the "all four" possition
may be used to relieve backache if the fetus is in an occipitoposterior position and may assist in anterior rotation of the fetus and in cases of shoulder distocia.
1st stage of labor
2nd stage of labor
Fully dilated cervix to the birth of the fetus
3rd stage of labor
from the birth of the fetus until the placenta is delivered.
4th stage of labor
- the average FHR at term is 140 beats/min
- The normal range is 110-160 beats/min
Visceral pain-1st stage of labor (cervical changes)
Somatic pain- 2nd stage of labor (intense, sharp, burning, and well localized)