Normal labor and delivery

Question 1

Function of uterine contractions

Answer 1

dilate the cervix and to push the fetus through the birth canal

Question 2

Fetus’ ability to successfully negotiate the pelvis is dependent upon the complex interaction of three mechanical variables, known as the “three Ps”

Answer 2

the powers, the passenger, and the passage

Question 3

the force generated by the uterine musculature during contractions

Answer 3

the powers

Question 4

the occurence of how many contractions in 10 minutes defines adequate labor

Answer 4

three to five contractions

Question 5

the long axis of the fetus relative to the longitudinal axis of the uterus. can be longitudinal, transverse, or oblique

Answer 5

fetal lie

Question 6

degree of descent of the leading edge of the presenting part of the fetus, typically measured as distance in centimeters between the leading bony edge of the fetus and the ischial spines

Answer 6

station

Question 7

What has replaced pelvimetry?

Answer 7

clinical trial of the pelvis (trial of labor)

Question 8

refers to the interval between the onset of labor and full cervical dilatation. divided into two phases

Answer 8

first stage of labor

Question 9

period between the onset of labor and the point at which a change in the slope of the rate of cervical dilatation is noted. It is characterized by slow cervical dilatation, and is of variable duration

Answer 9

latent phase (of 1st stage)

Question 10

associated with a faster rate of cervical dilatation and usually begins by 2 to 4 cm of cervical dilatation

Answer 10

active phase (of the 1st phase)

Question 11

minimal rate of cervical dilation for nulliparous and multiparous woman

Answer 11

1. 2 cm per hour for a nulliparous patient
2. 5 cm per hour fo a multiparous patient

*note these values are 2 standard deviations below the mean

Question 12

Average duration of the first stage of labor without anesthesis for nulliparous and multiparous patients

Answer 12

16.5 hr for nulliparous and 12.5 for multiparous

*note anesthesia increases duration of labor ~2hrs

Question 13

refers to the interval between full cervical dilatation (10 cm) and delivery of the infant. It is characterized by descent of the presenting part through the maternal pelvis and culminates with expulsion of the fetus

Answer 13

2nd stage of labor

Question 14

refers to the time from delivery of the baby to separation and expulsion of the placenta

Answer 14

3rd stage

Question 15

The major complication associated with 3rd stage of labor

Answer 15

hemorrhage

Question 16

commonly used endpoint for intervention in the absence of complications (eg, hemorrhage) during the 3rd stage of labor

Answer 16

Retention of the placenta for longer than 30 minutes at term

Question 17

refers to the passage of the widest diameter of the presenting part to a level below the plane of the pelvic inlet. In the cephalic presentation with a well-flexed head, the largest transverse diameter of the fetal head is the biparietal diameter (9.5 cm)

Answer 17

engagement

Question 18

refers to the downward passage of the presenting part through the pelvis.

Answer 18

descent

Question 19

occurs passively as the head descends due to resistance related to the shape of the bony pelvis and by the soft tissues of the pelvic floor

Answer 19

flexion

Question 20

the rotation of the presenting part from its original position (usually transverse with regard to the birth canal) to the anteroposterior position as it passes through the pelvis

Answer 20

internal rotation

Question 21

occurs once the fetus has descended to the level of the introitus. This descent brings the base of the occiput into contact with the inferior margin of the symphysis pubis

Answer 21

extension

Question 22

After the fetal head deflexes (extends), it rotates to the correct anatomic position in relation to the fetal torso; left or right rotation depends on the orientation of the fetus

Answer 22

external rotation

Question 23

refers to delivery of the body of the fetus. After delivery of the head and external rotation, further descent brings the anterior shoulder to the level of the symphysis pubis. The anterior shoulder rotates under the symphysis pubis

Answer 23

expulsion