Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

RDA > Lecture 15 + 16 - 2018/2017 > Flashcards

Lecture 15 + 16 - 2018/2017 Flashcards

1
Q

Define labour?

A

Getting the fetus from the uterus to the outside world i.e. uterine activity and cervical change which leads to the expulsion of the fetus and placenta. Labour is also prevention of haemorrhage so that the mother survives and is able to establish lactation to nurture the newborn.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the three P’s of anatomy and physiology of labour?

A
  1. Power - the forces that drive the baby out.
  2. Passage - the birth canal that the baby comes through.
  3. Passenger - the baby.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the challenges in human parturition?

A
  1. Quiescence - of uterus with growth, distension, pressure.
  2. Timing - for safe birth.
  3. Activation - stimulation of uterine musculature changes in genital tract.
  4. Birth - fetal-neonatal adaptations.
  5. Involution - haemostasis, establishing lactation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does a pregnant women maintain quiescence?

A

Typically the uterus is contracting all the time, but during pregnancy the contractions are:

  • weak and poorly coordinated.
  • low amplitude (<10mmHg).
  • low frequency.
  • painless.
  • cervix is firm and closed.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens physiologically in quiescence?

A 
Hormones such as:
-Progesterone. 
-PGI2. 
-Relaxin. 
-PTHrP. 
-Nitric Oxide (NO)
all cause there to be an increase in cyclic nucleotides which causes there to be a decrease in calcium and MLCK, which causes quiescence.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens if there is withdrawal of 1 or more of the substances?

A

It can cause quiescence to stop - baby can be released early.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is labour triggered by?

A

Typically it is triggered by withdrawal of progesterone - it is a functional drop.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is progesterone involved in quiescence?

A

Progesterone reduces prostaglandin F synthesis, it affects calcium transport and it increases beta-adrenergic receptors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What determines gestation length (time that baby is in belly)?

A
  1. Parity.
  2. Age.
  3. Genetics (maternal and paternal).
  4. Race-ethnicity (african/asian = 39 weeks, caucasian = 40 weeks).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Can stress affect gestation length?

A

Stress (steroid hormones or cytokines) can influence the length of gestation - social factors as well as medical. Extreme stress may cause early gestation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When does parturition typically occur?

A

280 days from LMP (37-42 weeks) OR 268 days from conception.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does activation involve?

A
  1. Fetal genome - have to have intact fetus.
  2. Uterine stretch/growth - the uterus cannot stretch forever i.e. twins can cause a shorter pregnancy.
  3. Fetal HPA axis - anencephaly can cause the pregnancy to go on longer.
  4. Up-regulation of myometrium - an increased contraction of myometrium due to increased CAPs.
  5. Melatonin and circadian rhythms - more babies delivered at night than day.
  6. Abnormally - if membranes rupture pre-labour.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe activation - up regulation of myometrium?

A

There is an increase in CAPs (gap junctions - connexin 43). There is an increase in connexin 43 (gap junctions).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are CAPs?

A

Contraction associated proteins that form gap junctions - connexin 43 - which link the muscles of the myometrium together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do CAPs do?

A
  1. Increase myometrial contractility (actin/myosin).
  2. Increase myocyte excitability of ion channels (calcium voltage regulated).
  3. Increase in intercellular connectivity gap junctions multimers of cx43.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do you stop an increase in myometrial activity during activation?

A

Use calcium channel blockers such as nifedipine.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you stop an increase in myocyte excitability ion channels (calcium voltage regulated)?

A

Use beta-2 sympathomimetics e.g. salbutamol.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do you stop an increase in intercellular connectivity gap junctions multimers of cx43?

A

Use prostaglandin synthase inhibitors (COX1 and COX2) e.g. paracetamol.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What role does prostaglandin have in labour?

A
  1. Increases myometrial contractility.
  2. Lead to cervix changes.
  3. Associated with membrane rupture.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do we use prostaglandins to stimulate labour?

A

We use PG analogues such as PG gel (e.g. misoprostol). Or we can put a finger through the cervix to cause tissue trauma to start labour.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is oxytocin?

A

Non-apeptide from the posterior pituitary and genital tract.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Describe how oxytocin is used in labour?

A

Oxytocin is not essential for the initiation of labour, it is used to continue labour (augment). It is also used to prevent post-partum haemorrhage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does oxytocin require?

A

Gap junctions to be effective - it requires the muscle fibres to be connected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the cervix (in labour)?

A

The barrier between the outside world and the baby. During pregnancy the cervix is closed and tight, and during labour the cervix is open.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is cervical ripening?

A 
The cervix remodels itself from a firm hard surface to a soft one.  There is a decrease in progesterone and an increase in estrogen.  This leads to an increase in cytokines, which causes there to be a change in many things:
-infiltration of leukocytes. 
-increase in cytokines. 
-vascular permeability. 
-increase in MMPs. 
-GAG remodelling. 
-Collagen remodeling. 
-Apoptosis.  
Which call cause there to be extra-cellular matrix degradation => cervical remodelling.
26
Q

What are the membranes that surround the baby?

A
  1. Amnion.

2. Chorion.

27
Q

Where does prostaglandin production occur?

A

Between the chorion membrane and the decidua.

28
Q

Where does membrane rupture occur in labour?

A

Zone of altered morphology.

29
Q

What are the stages of birth?

A
  1. Until full dilatation (10cm).
  2. Full dilatation until birth of baby.
  3. From birth of baby until delivery of the placenta.
30
Q

What is a partogram?

A

Graph description of labour - used to look at the progress of labour.

31
Q

What happens in the first stage of labour?

A
  1. Contractions - uterine pressure rises.
  2. Cervical effacement and dilatation.
  3. Descent of the presenting part:
    - SRM = spontaneous rupture of membranes.
    - ROM = rupture of membranes.
    - PROM = premature ROM.

During this stage the head pushes on the cervix and the amniotic fluid comes out. The baby descend into the pelvis (curls into a ball).

32
Q

What adaptations occur for the baby during labour?

A
  1. Continuous breathing.
  2. Cardiovascular adaption.
  3. thermogenesis.
  4. Intermittent nutrition.
33
Q

What is continuous breathing?

A

When the baby is born it has to establish continuous breathing. Oxygen deprivation can

34
Q

What happens if the baby does not establish continuous breathing?

A

It can cause oxygen deprivation which can cause primary apnoea. Baby looks:

  • Purple.
  • Decreased HR and BP.
  • Baby can still respond.
35
Q

What are the cardiovascular adaptations needed?

A

Closure of foramen ovale. 1005 of RV output goes through the lungs, there is a reduction in pulmonary vascular resistance so there is a reduction and eventual closure of the ductus arteriosis.

36
Q

What is thermiogenesis at birth?

A

It is non-shivering brown vascular fat under SNS control - doesn’t have to use energy to make muscles contract.

37
Q

What is intermittent nutrition?

A
  1. The fetus needs a constant supply of nutrients.
  2. In a neonate there is intermittent feeding (risk of hypoglycaemia as baby doesn’t have much fat for gluconeogenesis. 3. There is also the let down reflex - establishment of lactation.
38
Q

What is involution?

A

The placenta separates (cleavage through the decidua basalis) and there are strong contractions to prevent postpartum haemorrhage. There is also increased uterine sensitivity to oxytocin.

39
Q

Define pre-term labour?

A

Labour that occurs at <37 weeks gestation. 9% of births are pre-term.

40
Q

Define very pre-term labour?

A

Labour that occurs at <32 weeks gestation. 2% of births are very pre-term.

41
Q

what is pre-maturity?

A

It is an abnormality - failure of uterine quiescence and a failure of the uterus to keep the baby in the mother until the right time.

42
Q

What is the cost of pre-term birth?

A
  1. Neonatal complications and long term health problems.
  2. Invididual and family costs - personal/emotional toll.
  3. Societal costs - $26 Billion US annually, $1500 in NZ a day in NICU, if born at 26 weeks will spend 12 weeks in NICU - $126,000 by time of discharge.
43
Q

What are the causes of prematurity?

A
  1. Quiescence - endocrine maturation “stress” - severe life event.
  2. Activation - bleeding.
  3. Stimulation - infection.
  4. Involution - XS stretch.
44
Q

What are the main triggering events of pre-term birth?

A
  1. Intrauterine infection.
  2. Uterine over-distension (stretch).
  3. Fetal endocrine activation.
  4. Intrauterine bleeding.
45
Q

What happens in intrauterine infection?

A

Pathogenic microbes ascending through the decidua and fetal membranes from the cervix initiate an inflammatory response. there is a cytokine release, leukocyte infiltration and activation, increase in MMP activity and membrane apoptosis. This can result in premature rupture of the membrane.

46
Q

What happens in uterine over-distension?

A

There are mechanical forces which can cause the uterus to stretch - these forces activate expression of a number of genes involved in parturition - cytokines and chemokines, PGH/COX-2 which result in an increase in prostanoid synthesis and CAPs.

47
Q

What factors can cause uterine over-distension?

A
  1. Multiple gestations.
  2. Polyhydraminos.
  3. Fetal maturation.
48
Q

What happens in fetal endocrine activation?

A

If there is activation of the fetal HPA-axis, this can cause an increase in production of adrenal hormones and an increase in placental estrogen output and a decrease in porgesterone receptor activity which can cause a decrease in quiescence which can cause pre-term labour. Stress in early pregnancy may be associated via this route.

49
Q

What happens in intrauterine bleeding?

A

Ante-partum haemorrhage (bleeding from or into the genital tract), inadequate placentation or 1st trimester bleeding can activate the clotting cascade. This can cause a release of thrombin, plasminogen activators and plasmin. These proteins cause an increase in prostanoid biosyntehsis and protease activation, which can cause cervical ripening and membrane rupture.

50
Q

What are problems of pre-term birth?

A
  1. Immature fetus - often unwell.
  2. Often malpresentation e.g. breech.
  3. Often have maternal comorbidities.
  4. Often have complicated caesarean sections.
  5. Risks of recurrence.
  6. May have poor outcomes.
51
Q

What are pre-term babies often at risk from?

A

Respiratory distress syndrome.

52
Q

What can cause respiratory distress syndrome in neonates?

A

Inadequate lung development - the type 2 alveolar cells which make surfactant (coats the lungs and allows for re-expansion) have not developed. So the baby requires more effort to re-expand the lungs with the next inhalation.

53
Q

What will help for those pre-term babies with respiratory problems?

A

Give the baby steroids.

54
Q

What are the risk factors for pre-term birth?

A
  1. Previous pre-term birth (highest risk).
  2. Smoking.
  3. Multiple pregnancy.
  4. Cervical pregnancy.
  5. Uterine anomaly.
  6. Maternal disease (iatrogenic pre-term delivery may be needed).
  7. Antepartum bleeding.
  8. Polyhydraminos (too much fluid around the baby).
55
Q

What are the non-modifiable risks for pre-term birth?

A
  1. Maternal age.
  2. Obstetric history.
  3. Socioeconomic status.
  4. Race (african american).
56
Q

What are the modifiable risks for pre-term birth?

A
  1. Smoking.
  2. No prenatal care.
  3. Need for cervical surgery - slightly abnormal smear and planning pregnancy, may wait for biopsy?
  4. Reproductive technologies (fertility treatments for multiple pregnancy).
57
Q

Describe the relationship between length of cervix and pre-term risk?

A

Increased cervical length at 18 weeks decreases the risk of spontaneous pre-term delivery at <32 weeks. There is clinical practice to “screen” those at risk - using serum biomarkers, cervico-vaginal fluids, cervical length, uterine activity.

58
Q

What is fetal fibronectin?

A

It is a high MW-glycoprotein (bioglue) that is present in cervico-vaginal fluid in the first trimester. It is seen in cervico-vaginal fluid of 20-30% of women with pre-term labour.

59
Q

What do they use fetal fibronectin for?

A

It is used to see the risk of pre-term labour. If the test is positive (30% will deliver in 7-10 days) if it’s negative (99.5% don’t deliver in 7-10 days).

60
Q

What is tocolysis?

A

Suppression of pre-term labour. The main drugs used are:

  • Calcium channel blockers e.g. Nifedipine.
  • Oxytocin receptor block (atosiban).
61
Q

What are antenatal corticosteroids used for?

A

To help to reduce problems of prematurity. It helps to prevent neonatal respiratory distress syndrome. It can also reduce intra-ventricular haemorrhaging in the brain and necrotising enterocolitis.

62
Q

What is magnesium sulphate used for?

A

Neuroprotection for the mum. Aim to give it 6hrs before birth.

RDA (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions