Normal Labour And Intrapartum Monitoring Flashcards
(31 cards)
Define labor.
series of continuous, progressive, regular painful uterine contractions of sufficient frequency, strength and duration to cause cervical effacement and dilatation leading to expulsion of fetus
Which 5 conditions are needed for labor to be normal?
- Spontaneously without interventions
- In vertex cephalic presentation
- Through birth canal
- Without assistance
- Without maternal and fetal complications
What are Braxton Hicks?
Mild contractions, often irregular non-progressive that may occur from 30wks gestation (more common after
36wks) and may often be confused with labor.
Define the following terms:
-Presentation
-Lie
-Position
-Attitude
Presentation: determined by the part of the body of fetus that is foremost within or close to the birth canal. Can be Cephalic(head first),breech(bottom first), cord or shoulder.
*Lie: the relation of fetal axis to that of the mother. *Position: relation of an arbitrarily chosen potion of
presenting part to the maternal pelvis.
*Attitude: the posture assumed by the fetus. It can be flexion or extension(associated with larger presenting diameter and malposition).
Define the following terms:
-Caput
-Moulding
-Station
Caput: swelling of the most dependent portion of fetal head. Normally few millimetres thick but can be extensive in prolonged or obstructed labour.
•Moulding: overlapping of the bones of the fetal head in cephalic presentation due to external compression. Severe moulding may indicate Cephalopelvic Disproportion(CPD).
•Station: relation in centimetres of bones of presenting part to the level of ischial spines. Designated in centimetres depending how far the presenting part is above or below. Station 0 is at ischial spines.
Stage 1 of labor is divided into which 2 phases.
Latent phase and Active phase
What is the average duration of labor in a primigravida and a multigravida?
12 to 18 hours in primigravida
6 to 10hrs in multigravida
State the 4 stages of labor.
Stage 1: Cervical dilatation
Stage 2: Stage of expulsion
Stage 3: Placental stage
Stage 4: Maternal homeostatic stabilization
What is stage 2 (lasts 1-2 hrs) divided into?
Passive descent and Active push
What happens in the active phase of labor?
- Cervix dilates from 4cm to 10cm
- This lasts 2 to 6 hrs
What happens in latent phase?
- Begins at onset of regular contractions
- Cervix dilates to 3cm to 4cm
- Takes 3 to 8 hrs
What happens during passive descent?
Involves no maternal urge to push. Fetal head is relatively high in pelvis.
What happens during active push?
Involves maternal urge to push due to reflex mechanism stimulated by fetal head that lies low in pelvis. Valsalva maneuver occurs.
What happens during stage 3?
- Begins after delivery of fetus
- Placenta, cord and membranes are delivered
- Lasts 30 minutes
What happens in stage 4 of labor?
- Involves postnatal assessment of the maternal vital signs to rule out danger signs for complications e.g. post partum haemorrhage.
- Continues for about 1-4hrs after delivery.
Lists the changes in position included in the mechanism of labor.
- Engagement
- Descent
- Flexion
- Internal rotation
- Extension
- Restitution
- External rotation
- Expulsion
Define descent.
Continuous movement of the fetus through the birth canal.
What is engagement?
Passage of widest transverse diameter of presenting part through plane of pelvic inlet
What happens during flexion?
Refer to the handout slide 17
How does the fetus internal rotate?
Fetal head rotates in mid pelvis from transverse to antero-posterior by 1/8th of the circle.
What happens during extension?
Fetus has descended to the level of maternal vulva with sub-occipital region hinging under the pubic symphysis where birth canal curves upward.
Two forces act on the head of the fetus:
Downward and upward force of uterine contractions.
Upward and forward force of pelvic floor
The result is the delivery of the fetal head.
What happens during restitution?
Fetal head rotates 1/8th of circle in a direction opposite to internal rotation.
Describe the hormonal factors that lead to initiation of labor.
Progesterone: Keeps uterus relaxed; inhibits prostaglandins and oxytocin.
Estrogen: Rises before labor; boosts prostaglandins, oxytocin receptors, and contractions.
Prostaglandins: Trigger contractions by increasing calcium in muscle cells.
Oxytocin: Strengthens contractions; works with prostaglandins.
CRH (from placenta): Increases near term; raises fetal cortisol.
Fetal cortisol: Boosts estrogen production; promotes prostaglandins.
What happens during expulsion?
- Anterior shoulder hinges underneath pubic symphysis.
- Anterior shoulder is delivered first
- Posterior shoulder then body follows.
