Session 10 - Parturition Flashcards Preview

Semester 4 - Reproductive System > Session 10 - Parturition > Flashcards

Flashcards in Session 10 - Parturition Deck (65)
1

What is Labour? (Aside from being the most awesomest political party ever!)

Expulsion of products of conception after 24 weeks.

So yeh. Actually sounds a bit more like UKIP.

2

What is a birth <24 weeks called?

Spontaneous aboriton

3

What is a birth <37 weeks called?

Pre-term

4

What is a birth between 37-42 weeks called?

Term

5

Give three different things you should assess about a babies position before labour

Lie
Presentation
Position

6

What is a babies lie?

• Relationship to long axis of uterus
• Normally longitudinal
• Fetus normally flexed

7

What is a babies presentation?

• Which part is adjacent to pelvic inlet
• Normally head (cephalic)
• Sometimes buttocks (podalic)

8

What is a babies position?

• Orientation of presenting part

9

What occurs in the first stage of labour? (2)

Creation of birth canal
Onset of labour -> Full cervical dilation

10

What are two main phases of the onset of labour?

Latent phase
Active phase

11

What occurs in the latent phase of the onset of labour?

Onset -> 4cm dilation

12

What occurs in the active phase of labour?

Faster rate of cervical change, 1-1.2 cm/hour
Regular uterine contractions

13

What is the main event of the second stage of labour?

Expulsion of foetus

14

What is the normal range of time for the second stage of labour?

Up to 1 hour

15

Outline what happens to the baby in the second stage of labour

- Head flexes as it reaches pelvic floor (reduces presentation diameter)
- Head rotates
- Head sretches vagina and perineum
- Head delivered
- Shoulders rotate and deliver

16

What occurs in the third stage of delivery?`

Expulsion of placenta

17

How does the body facilitate the expulsion of the placenta?

Sheared off by strong contractionas of the uterues
Compresses blod vessels to reduce haemorrhgage
Lasts between five and fifteen minutes

18

What processes are necessary to create a birth canal?

Expansion of soft tissues

19

Give three tissues which are expanded in creation of a birth canal

Cervix
Vagina
Perineum

20

What does expansion of the cervix cause

Foetal membranes to rupture, releasing amniotic fluid

21

How big is the expansion of the cervix, and what facilitates it?

10 cm
Structural changes and a lot of force

22

What is the normal diameter of a baby's head?

9.5cm

23

What is maximum size of birth canal?

Pelvic inlet typically 11cm

24

What is the structure and funciton of cervix during pregnancy?

Tough, thick collagen which is coiled to give it strength in order to retain the foetus

25

What is the process of cervical softening called?

Cervical ripening

26

What three things does cervical ripening involve?

 Reduction in collagen production (Turnover altered)
 Increase in glycosaminoglycans (Disrupts the matrix)
 Reduces aggregation of collagen fibres (Uncoils)

27

What is cervical ripening triggered by?

Prostaglandins
 PG E2 and F2x
 Locally diffused from the uterus
 Once released the cervix is ready to be stretched

28

What happens to myometrium during pregnancy?

Smooth muscles greatly increased in pregnancy

29

How is force generated by myometrium?

By rises in intracellular Ca2+, which increases due to action potentials.
Triggered by spontaneous signals from pacemakers

30

What supresses uterine contractions during pregancy?

Progesterone

31

What maintains corpus luteum in pregancny?

HCG

32

Describe early uterine contractions

Low amplitude every 30 minutes, mother usually not aware

33

Describe late uterine contractions

Higher amplitude, less frequent
Braxton-Hicks contractions

34

What are the contractions of the uteryus made more forceful and frequent by? 2

Prostaglandins (as well as ripening the cervix). Causes increased Ca2+ per action potentional.

Oxytocin
More actionpotentials, threshold lowered

35

What are prostaglandins?

o Biologically active lipids
o Local hormones
o Produced mainly in the endometrium

36

What is production of prostaglandins controlled by?

Oestrogen: Progesterone ratio

37

What happens to prostglandin production when oestrogen > progesterone?

Increased prostaglandins

38

What happens to prostaglandins when oestrogen < progesterone

Low prostaglandins, feature throughout pregnancy

39

Where is oxytocin secreted?

Posterior pituitary

40

Outline the ferguson reflex

 Mechanical stimulation of the cervix due to prostaglandin contractions increases oxytocin secretions, strengthening contractions, stimulating the cervix more, releasing more oxytocin

41

When is oxytocin more effective?

Oestrogen > Progesterone
More smooth muscle receptors

42

What is brachstasis?

Uterine smooth muscle relaxes less than it contracts.
o Unique feature of uterine smooth muscle
o Fibres shorten in the body of the uterus
o Drives the presenting part of the fetus to the cervix

43

Give the normal physiological processes which initiate labour? (8)

o ↑ Fetal Cortisol (?)
o Oestrogen > Progesterone
o ↑↑↑ Prostaglandins from Endometrium of Uterus
o Increased force of uterine contractions
o Cervix Stretched
o Oxytocin released from Posterior Pituitary under the Control of Hypothalamus
 Ferguson Reflex
o Increased frequency of uterine contraction
o Cervix stretched more

44

What causes neonate to take first breath?

Multiple stimuli, such a trauma from the birth and cold cause the neonate to take its first breath

45

What are the two main change causing features of first breath

Reduction in pulmonary vascular resistance
Increased arterial pO2

46

What are the three features of a reduction in pulmonary vascular resistance?

 Blood fills lungs, increased return to LA
 Pressure in LA > RA
 Foramen ovale closes

47

What does increased arterial pO2 cause?

 Ductus Arteriosus contracts

48

How is condition of a neonate scored?

Apgar score

49

What limits maternal blood loss after birth?

Contraction of the unterus, which shears off and expels the placenta (normally after 10 minutes)

50

Why can bleeding after birth be severe?

Blood flow through placenta is normally 500-800ml/minute (10-15% cardiac output).

51

How can post-partum bleeding be treated?

Oxytocic drug

52

What is the most common presenation of a baby?

Most commonly the baby lies longitudinally, in a cephalic presentation, well flexed so that the vertex presents to the pelvic inlet`

53

What are the three P's of labour, problems with which can cause a difficult birth?

Powers
Passage
Passenger

54

What are the powers of labour?

Delivery dependent on myometrium
Contraction and retraction of multidirectional smooth muscle fibres casues progressive shortening

55

In what three ways can uterine contractons be assesed?

Frequency, amplitude and duration

56

What is the passage made up of?

Pelvic inlet
Pelvic cavity
Pelvic outlet

57

What are the measurements of pelvic inlet?

 Shorter in the anterior-posterior plane
 10.5cm diameter

58

What are the measurements of pelvic cavity?

 Circular
 12cm diameter

59

What are the measurements of the plevic outlet?

o Pelvic Outlet
 Shorter in the medio-lateral plane
 11cm diameter

60

What is the passenger?

The size and presentation of the foetus

61

What are the main tree reasons labour is unable to progress?

o Inadequate Power
 Insufficient uterine contraction
o Inadequate Passage
 Abnormal bony pelvis
 Rigid perineum
o Abnormalities of the Passenger
 Fetus too big

62

How can labour be induced?

Labour can be induced by giving the mother Prostaglandins and Oxytocic drugs. These drugs will cause the cervix to begin to ripen and the uterus to begin its contractions.

63

How can the physiological state of the foetus be monitored?

During labour fetal heart rate can be assessed using a Fetal Scalp Electrode.

64

Describe a C-section

Subrapubic Incision
o Linea alba and anterior layers of the rectus sheaths are transected and resected superiorly,
o Rectus muscles are retracted laterall or divided through their tendinous parts allowing reattachment without muscle fibre injury

65

Give two methods of operative delivery?

Forceps
Vacuum extraction