Phisiology Of Labour

Question 1

Describe the three stages of normal labour.

Answer 1

1st stage- from onset of labour pains until the cervix is fully dilated
2nd stage- from full cervical dilation to delivery
3rd stage- placental separation and expulsion

Question 2

Which hormones contribute to the onset of labour?

Answer 2

There is a rise in the amount of oestrogen realised at the onset of labour. Oestrogen opposes progesterone and progesterone inhibits contractions and prevents realise of oxytocin.
As oestrogen levels rise, this stimulates the realise of prostaglandins which causes contractions. The fergussons reflex assists in labour.

Question 3

What initially keeps the cervix closed? What causes the cervix to open?

Answer 3

The cervix is made of elastic and collagen tissue which keeps it closed. Prostaglandins realise breaks down the elastic tissue causing the cervix to become dilated.

Question 4

Name the 7 cardinal movements involved in the mechanism of labour.

Answer 4

1. Decent
2. Flexion
3. Internal rotation
4. Extension
5. Restitution
6. External rotation
7. Lateral flexion

Question 5

What is the period of time following delivery of the placenta called? How long does this period last for?

Answer 5

Puerperium lasts for six weeks

Question 6

What is the name given to the shrinking of the uterus following childbirth?

Answer 6

Uterine involution