labour and delivery

Question 1

what is labour?

Answer 1

Presence of regular painful uterine contractions becoming progressively stronger and more frequent, accompanied by effacement (cervix undergoes changes – thin, and has contact with the baby) and progressive dilatation of the cervix and descent of the presenting part

Question 2

how does labour start?

Answer 2

starst with bloody mucoid show

Question 3

what is the function of the mucus plug?

Answer 3

seals the uterus to prevent infection getting to the fetus

Question 4

why does the amniotic sac rupture?

Answer 4

bc the head of the fetus is against the cervix –> as uterus contracts, amniotic fluid is expelled

Question 5

how should the amniotic fluid look?

Answer 5

should be clear - may contain bits such as dead cells, fetal urine etc.

Question 6

how does labour end?

Answer 6

Ends with baby coming out along with other products of conception

Question 7

what are Braxton Hicks contractions?

Answer 7

uncoordinated contractions of the uterus around 6-4 weeks before end of gestation

Question 8

what causes Braxton Hicks contractions?

Answer 8

progressive hormonal changes - oxytocin from mum and baby, oestrogen, relaxin and prostaglandin

progressive mechanical changes

Question 9

what does relaxin do?

Answer 9

made by the placenta to relax connective tissue of the cervix and causes softening of the pubic symphysis to allow it to move further apart

Question 10

what do prostaglandins do?

Answer 10

causes contraction of the uterus

Question 11

what does progesterone do?

Answer 11

inhibits uterine contractility during pregnancy –> prevents expulsion of fetus prematurely

Question 12

what does oestrogen do?

Answer 12

increases the degree of uterine contractility –> increases number of gap junctions between adjacent smooth muscle

Question 13

how do levels and ratio of oestrogen and progesterone change over the course of pregnancy?

Answer 13

secreted in progressively greater quantities throughout pregnancy

Increased ratio of oestrogen to progesterone at 7 months - Oestrogen continues to increase while progesterone stays the same or declines

Question 14

what is the Ferguson reflex?

Answer 14

positive feedback mechanism involving oxytocin

Question 15

explain how the ferguson reflex happens

Answer 15

• baby’s head stretches cervix –> feedback on mother’s pituitary
• mother secretes oxytocin
• baby makes own oxytocin
• oxytocin travels to uterine muscle and stimulates contractions –> pushes baby down and stretches cervix
• also stimulates placenta to make prostaglandings
• oestrogen induces more oxytocin receptors
• cycle is repeated until the baby is born

Question 16

how are abdominal muscles involved in labour and how are they activated?

Answer 16

• Abdominal muscles are activated by neurogenic reflexes to contract and their contraction aids the expulsion of the baby

Question 17

what effect does baby’s oxytocin have on the mother?

Answer 17

gets across placenta and directly stimulates smooth muscle in the myometrium to contract. Upregulates the oxytocin receptor

Question 18

how many stages of labour are there?

Answer 18

4

Question 19

how many stages in the first stage of labour and what are they?

Answer 19

latent phase
active phase
transition phase

Question 20

how far is the cervix dilated in the latent phase?

Answer 20

0-4cm

Question 21

what happens during the latent phase of labour?

Answer 21

• Duration not easily determined bc there isn’t much to show for it
• Often long, especially in women having their first baby
• Contractions last 30-60 second and are 5-20 mins apart

Question 22

how far is the cervix dilated in the active phase?

Answer 22

4-10cm

Question 23

what happens in the active phase of labour?

Answer 23

• Cervix dilates at the rate of about 0.5 – 1 cm/hour
• May be faster in multiparous women or slower in first
• Average duration of this phase – 12 hrs
• Contractions last 45-60 seconds and are 2-5 mins apart

Question 24

describe the transition phase contractions?

Answer 24

Transition contractions last 60-90 seconds and are 2-3 mins apart

Question 25

when does the second stage start?

Answer 25

at full dilation of the cervix - 10cm

Question 26

what is the second stage of labour?

Answer 26

pushing

Question 27

describe the contractions in the second phase of labour

Answer 27

o Contractions last 45-90 secs and 3-5 mins apart

Question 28

what happens in the 3rd stage of labour?

Answer 28

* After baby is delivered, placenta and amniotic membrane need to be delivered * Usually within 30 mins

Question 29

what happens in the 4th stage of labour?

Answer 29

• Last from delivery of placenta until postpartum condition of woman stabilises (up to a week afterwards) o 1-2 hours after delivery • Uterus will continue to contract which help the uterus to return back to normal size over the next few days.

Question 30

at what rate does the cervix decrease in size during the 4th stage of labour?

Answer 30

descends 1 cm each day for about 10 days

Question 31

what is the widest and narrowest part of the pelvis?

Answer 31

Pelvic inlet is the widest bit, ischial spines are narrow

Question 32

what does left occiput anterior mean?

Answer 32

Means that baby’s head is slightly off centre in the pelvis with back of the head toward the mother’s thigh. Baby is face down when it comes out

Question 33

what does left occiput transverse mean?

Answer 33

When back of baby’s head points directly at the mother’s thigh

Question 34

why is left occiput transverse more painful?

Answer 34

bc the head doesnt fit into the bony pelvis as well

Question 35

what do fetal stations measure?

Answer 35

Ischial spines can be palpated through the skin. Head can be felt and measured in relation to the ischial spines

Question 36

what is the baseline of the fetal stations?

Answer 36

ischial spines - 0

Question 37

when is the fetal station negative?

Answer 37

• If the presenting part is higher than the ischial spine the station has a negative number

Question 38

when is the fetal station positive?

Answer 38

• Positive means that the presenting part has passed the ischial spine

Question 39

at what fetal station is the outlet?

Answer 39

+4cm

Question 40

what is cervical ripening?

Answer 40

increased softening, distensibility, (effacement and dilatation of the cervix)

Question 41

how does cervical ripening occur and why?

Answer 41

• Due to changes in the biomechanical properties of cervical tissue o Rearrangement and realignment of collagen and an increase in the ground substance when compared early pregnant cervix. o Allows for a thinner cervix which is more able to dilate

Question 42

what is cervical ripening under the control of?

Answer 42

``` o Prostaglandins – produced in uterus o Oestrogens o Progesterone and antiprogesterones o Relaxin – produced by the placenta. Causes softening and thinning of the cervix o Inflammatory mediators o Nitric oxide o Apoptosis ```

Question 43

what is the bishops score?

Answer 43

• A method of measuring whether a pregnancy and labour is progressing at a normal rate or if there’s a need to induce

Question 44

what does the bishops score take into consideration?

Answer 44

Cervix dilation, cervical length, consistency, position and head station

Question 45

what does a bishop score of less than 5 suggest?

Answer 45

score of 5 or less suggests labour is unlikely to start without induction

Question 46

what does a bishop score of 9 or more suggest?

Answer 46

indicates that labour will most likely commence spontaneously

Question 47

what happens during birth?

Answer 47

- engage: baby's head is engaged - flex and descent - positive feedback - full dilation of cervix - internal rotation of head then extension - external rotation so the shoulders can come out - expulsion - cord is tied off - placenta needs to be removed