4.2b Process of Labor Flashcards
1
Q
Process of Labor
A
- Process of moving fetus, placenta, and membranes out of the uterus and through the birth canal
2
Q
Signs of Labor
A
- Lightening
- Return of urinary frequency
- Backache
- Stronger Braxton-Hicks contractions
- Weight loss 0.5-1.5 lbs
- Surge of energy
- Increased vaginal discharge (bloody show)
- Cervical ripening
- Possible rupture of membranes
3
Q
Onset of Labor (Factors)
A
- Changes in maternal uterus, cervix, pituitary gland
- Hormones produced by normal fetal hypothalamus, pituitary gland, adrenal cortex
- Progressive uterine distension and increased intrauterine pressure
- Increased concentration of estrogen, oxytocin, and prostaglandins
- Decreasing progesterone levels
4
Q
What Gets Labor Going?
A
- Interaction of maternal and fetal hormones
- Uterine distension
- Placental aging
- Increase in prostaglandins
- Increased estrogen
- Decreased progesterone
5
Q
1st Stage of Labor
A
- Onset of contractions until full dilation of cervix
Latent (Early) Phase - More effacement progress and less descent
Active Phase - Rapid dilation of cervix and increased rate of descent
6
Q
2nd Stage of Labor
A
- Cervix Fully Dilated until Birth of Infant Latent Phase (Passive Fetal Descent) - Fetus descends passively through birth canal and rotates to anterior position due to contractions. No urge to bear down yet Active Phase (Pushing) - Strong urge to bear down (fetus presses on stretch receptors)
7
Q
3rd Stage of Labor
A
- From birth until placenta is delivered
- Next uterine contraction causes placenta to separate from uterine wall and get expelled
8
Q
4th Stage of Labor
A
- Delivery of placenta and first 2 hours of birth
9
Q
MECHANISMS OF LABOR
A
10
Q
Engagement
A
- Biparietal diameter of head passes through pelvic inlet
Nulliparous - Occurs before onset of active labor
Multiparous - Head is freely moveable above pelvic brim until labor
11
Q
Asynclitism
A
- Fetal head deflected anterior or posterior in pelvis
- Can cause cephalopelvic disproportion
12
Q
Descent
A
- Progress of presenting part through pelvis
FORCES INVOLVED - Pressure from amniotic fluid
- Pressure from fundus contractions
- Pressure from diaphragmatic and abdominal contractions
- Extension and straightening of fetal body
Measured by Station
- Descent accelerates at 5-6cm dilation
- Most apparent when membranes have ruptured
13
Q
Flexion
A
- Occurs when descending head meets resistance of cervix, pelvic wall, pelvic floor
- Chin brought in close contact with fetal chest
14
Q
Internal Rotation
A
- Occiput rotates anterior and face rotates posterior
- Head almost always rotates when it hits pelvic floor
15
Q
Extension
A
- Fetus passes through lower border of symphysis pubis first
- Head emerges by extension
