ULO 7- Physiology and progress of labour & birth

Question 1

Between what weeks is a baby considered full term

Answer 1

38-42

Question 2

What are two physiological changes that must occur for birth to proceed smoothly

Answer 2

Effacement and dilation

Question 3

Identify and explain the stages of labour

Answer 3

First stage- onset of contractions, cervix shortens and dilates, decent of the fetus, ends with full dilation and strong contractions

Second stage- begins with full dilation, expulsive long lasting contractions, pushing and birth of the baby

Third stage- is the birth of the placenta

Fourth stage- first hour or 2 after birth

Question 4

Explain what you might expect of contractions and changes in the cervix in ‘early’ labour

Answer 4

Contractions will be irregular and short lasting, they may also be lesser in strength compared to active labour

The cervix will be softening and preparing to shorten and dilate

Question 5

Explain: Effacement

Answer 5

is the thinning of the cervix and gradual anterior movement of the cervical opening into the vaginal canal

Question 6

Define: Forewaters

Answer 6

is the water between the baby’s head and the cervix. (hindwaters are those behind the baby’s head)

Question 7

Explain reasons for maintaining intact membranes in labour

Answer 7

• Allows for even pressure against the cervix from the baby’s head when surrounded by forewaters
• Reduced risk of ascending infection to the baby

Question 8

List some signs of placental separation

Answer 8

• umbilical cord appears to lengthen,
• there may be some bleeding from the uterine wall as the placenta separates
• urge to push,
• contractions begin again

Question 9

Explain: Active management of third stage

Answer 9

is when women are given an injection of syntocin to activate contractions to expel the placenta and the midwife applies traction to the umbilical cord to separate the placenta from the uterine wall and pulling until placenta is expelled

Question 10

Explain: Physiological management of third stage

Answer 10

is waiting and allowing the woman’s body to detach the placenta from the uterine wall and expel it from the birth canal with contractions and some maternal effort

Question 11

List some of the causes of the onset of labour

Answer 11

• Hormonal trigger from fetus
• Progesterone level drops
• pressure against cervix

Question 12

What are the 3 P’s of influences on labour

Answer 12

Powers- muscular activity
Passages- birth canal
Passengers- uterine contractions, fetus, placenta

Question 13

What are the 7 mechanisms of labour

Answer 13

1. Descent
2. Flexion
3. Internal rotation of the head
4. Extension
5. Restitution
6. Internal rotation of the shoulders
7. Lateral flexion

Question 14

What hormones initiate labour

Answer 14

• Corticotrophin-releasing hormone
• Prostaglandins
• Oxytocin
• Oestrogen
• Progesterone (levels drop)
• Relaxin