Revision - Obs 5 Flashcards
(148 cards)
1
Q
Frequency of breech presentation?
A
<5% pregnancies after 37 weeks gestation
2
Q
What are the 4 types of breech?
A
1) Complete
2) Incomplete
3) Extended
4) Footling
3
Q
What is a complete breech?
A
Where the legs are fully flexed at the hips and knees (like a squat)
4
Q
What is an incomplete breech?
A
With one leg flexed at the hip and extended at the knee
5
Q
What is an extended breech?
(AKA frank breech)
A
Both legs flexed at hip and extended at knee (like a pike)
6
Q
What is a footling breech?
A
A foot is presenting through the cervix with the leg extended.
7
Q
Management options of babies that are breech at term (37 weeks)?
A
1) ECV can be offered at 37w
If ECV fails:
2) Choice of vaginal delivery or elective caesarian section.
8
Q
What is the % chance of an emergency c-section if vaginal birth is attempted in breech babies?
A
40%
9
Q
What are women given prior to ECV?
A
Tocolysis –> relaxes the uterus (i.e. suppresses contractions)
10
Q
What medication is used for tocolysis in ECV?
A
Terbutaline
11
Q
What class of medication is terbutaline?
A
Beta agonist
12
Q
Do rhesus D negative women require anti-D prophylaxis prior to tocolysis?
A
Yes
13
Q
What type of breech position is most common?
A
Frank breech (hips and knees fully extended)
14
Q
What complication is more common in breech presentation?
A
Cord prolapse
15
Q
What are some absolute contraindications to ECV?
A
1) C-section is required
2) Antepartum haemorrhage within last 7 days
3) Abnormal CTG
4) Major uterine anomaly
5) Ruptured membranes
6) Multiple pregnancy
16
Q
Management of cord prolapse?
A
Obstetric emergency.
1) the presenting part of the fetus may be pushed back into the uterus to avoid compression
2) if the cord is past the level of the introitus, there should be minimal handling and it should be kept warm and moist to avoid vasospasm
3) the patient is asked to go on ‘all fours’ until preparations for an immediate caesarian section have been carried out
4) tocolytics may be used to reduce uterine contractions
5) retrofilling the bladder with 500-700ml of saline may be helpful as it gently elevates the presenting part
17
Q
Define stillbirth
A
The birth of a dead fetus after 24 weeks gestation.
18
Q
What is used in the induction of labour in stillbirth?
A
Combination of:
1) oral mifepristone (anti-progesterone)
2) vaginal or oral misoprostol (prostaglandin analogue)
19
Q
What can be used to suppress lactation after stillbirth?
A
Dopamine agonists e.g. cabergoline
20
Q
What are the 3 major causes of cardiac arrest in pregnancy?
A
1) Obstetric haemorrhage: major cause of severe hypovolaemia and cardiac arrest.
2) PE
3) Sepsis leading to metabolic acidosis and septic shock
21
Q
What are 5 major causes of massive obstetric haemorrhage?
A
1) Ectopic pregnancy
2) Placenta praevia
3) Placental abruption
4) Uterine rupture
5) Placenta accreta
22
Q
How can a pregnant woman lying on her back lead to hypotension (sometimes enough to lead to the loss of cardiac output and cardiac arrest)?
A
Aortocaval compression:
1) When a pregnant woman lies on her back (supine), the mass of the uterus can compress the inferior vena cava and aorta.
2) The compression on the vena cava is most significant, as it reduces the blood returning to the heart (venous return)
3) This reduces the cardiac output, leading to hypotension.
4) In some instances, this can be enough to lead to the loss of cardiac output and cardiac arrest.
23
Q
Solution to aortocaval compression?
A
The vena cava is slightly to the right side of the body –> place the woman in the left lateral position, lying on her left side, with the pregnant uterus positioned away from the inferior vena cava.
24
Q
In cardiac arrest in pregnancy, how soon after starting CPR should baby and placenta be delivered?
A
Aim is to deliver the baby within 5 minutes of CPR starting.
CPR should be continued for more than 4 minutes.
The operation is performed at the site of the arrest, for example, in A&E resus or on the ward.
25
What are the 3 stages of labour?
1st --> from onset of labour until 10cm dilation
2nd --> from 10cm dilation until delivery of baby
3rd --> from delivery of baby until delivery of placenta
26
How often should foetal heart rate be monitored in labour?
Every 15 mins (or continuously via CTG)
27
How often should contractions be assessed in labour?
Every 30 mins
28
How often should vaginal exam be offered in labour to check progression?
Every 4 hours
29
How often should maternal urine be checked in labour?
4 hours (for ketones & protein)
30
How long does stage 1 of labour typically last in a primigravida?
10-16 hours
31
What is cervical effacement?
Cervix gets thinner
32
What happens in 1st stage of labour?
1) Cervical dilation
2) Cervical effacement
3) Mucus plug in cervix falls out and creates space for baby to pass through
33
Role of mucus plug in cervix during pregnancy?
Prevents bacteria from entering the uterus during pregnancy.
34
What are the 3 phases of stage 1 of labour?
1) Latent
2) Active
3) Transition
35
Describe the latent phase of stage 1 of labour
1) From 0cm to 3cm dilation (progresses at 0.5cm/hour)
2) Irregular contractions
36
Describe rate of progression of dilation of cervix in latent phase of stage 1 of labour
0.5cm/hour
37
Describe the active phase of stage 1 of labour
1) 3cm to 7cm (1cm/hour)
2) Regular contractions
38
Describe rate of progression of dilation of cervix in active phase of stage 1 of labour
1cm/hour
39
Describe rate of progression of dilation of cervix in active phase of stage 1 of labour
1) 7cm - 10cm dilation
2) Strong & regular contractions
40
Describe typical location of baby's head in delivery?
Normally --> OA (i.e. face is facing mother's spine)
Can sometimes be OP
41
What is a vertex presentation in delivery?
Ideal position for delivery
It means the fetus is head down, headfirst and facing your spine with its chin tucked to its chest.
42
What % of babies are vertex at delivery?
90%
43
When do braxton hicks contractions usually occur?
2nd and 3rd trimester
44
What can help reduce braxton-hicks contractions?
Staying hydrated & relaxing
45
Define preterm prelabour rupture of membranes (P‑PROM)
The amniotic sac has ruptured before the onset of labour AND before 37 weeks gestation (preterm).
46
Define prolonged rupture of membranes (also PROM)
Membranes have ruptured more than 18 hours before delivery
47
Survival chance of babies born at 23 weeks?
10%
48
At how many weeks gestation is there an increased chance of survival and full resuscitation is offered in premature babies?
24 weeks onwards
49
Via what 2 mechanisms can be used for prophylaxis of preterm labour?
1) Vaginal progesterone
2) Cervical cerclage
50
Role of progesterone in prophylaxis of preterm labour?
Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery.
51
Who is vaginal progesterone offered to for the prophylaxis of preterm labour?
Women who have a cervical length <25mm on US who are <24 weeks gestation
52
Who is cervical cerclage offered to for the prophylaxis of preterm labour?
Women with cervical length of <25mm on vaginal US between 16 and 24 weeks gestation who have had previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy).
53
Investigation for assessing cervical length in pregnancy?
Vaginal US
54
What length is a 'short' cervix?
<25mm
55
Define prelabour rupture of membranes (PROM)
Rupture of membranes at least 1 hour prior to the onset of labour, at >/=37 weeks gestation.
56
Define pre-term prelabour rupture of membranes (P-PROM)
the rupture of fetal membranes occurring at <37 weeks gestation.
57
What do the fetal membranes consist of?
Chorion & amnion
58
How can a rupture of membranes be diagnosed?
Sterile speculum examination:
1) Look for pooling of amniotic fluid in posterior vaginal fornix (after draining from cervix).
2) Asking the woman to cough during the examination can cause amniotic fluid to be expelled.
3) A lack of normal vaginal discharge (‘washed clean’) can be suggestive of rupture of membranes
59
Why is digital exam contraindication in PROM/PPROM (until the woman is in active labour)?
Risk of infection
60
Position of women for speculum exam in PROM/PPROM?
The woman should be laid on an examination couch for at least 30 minutes –> will allow pooling of any leaking amniotic fluid in the top of the vagina.
61
When is a speculum not required in PROM/PPROM?
if amniotic fluid is seen draining from the vagina.
62
Key differential for PROM/PPROM?
Urinary incontinence
63
Where there is doubt about the diagnosis of rupture of membranes, what 2 tests can be performed?
Test fluid for:
1) Insulin-like growth factor-binding protein-1 (IGFBP-1): Actim-PROM (Medix Biochemica)
2) Placental alpha-microglobin-1 (PAMG-1): Amnisure (QiaGen)
64
What is insulin-like growth factor-binding protein-1 (IGFBP-1)?
A protein present in high concentrations in amniotic fluid (100 – 1000 times the concentration of maternal serum).
65
Describe levels of IGFBP-1 and PAMG-1 in fluid tested in rupture of membranes?
High in fluid tested
66
In all cases of premature membrane rupture, what test should be done?
High vaginal swab:
1) look for GBS - need for abx
2) give information as to a potential cause for PPROM (bacterial vaginosis is commonly implicated).
67
What should always be given in PROM/PPROOM if <36 weeks gestation?
Prophylactic abx to prevent chorioamnionitis
Erhythromycin 250mg 4x daily for 10 days OR until labour is established if within 10 days
68
Abx of choice in PROM/PPROM for preventing the development of chorioamnionitis?
Erythromycin
69
Following PPROM, after how many weeks gestation is induction of labour considered?
>34 weeks
70
In PRROM >36 weeks gestation, if labour does not start, how soon should induction of labour be considered?
24-48 hours: the risk of infection outweighs any benefit of the fetus remaining in utero.
71
Management of PROM/PPROM >36 weeks gestation?
1) Monitor for signs of clinical chorioamnionitis.
2) Clindamycin/penicillin during labour if GBS isolated.
3) Watch and wait for 24 hours (60% of women go into labour naturally), or consider induction of labour.
4) IOL and delivery recommended if greater than 24 hours (but women can wait up to 96 hours – beyond this is their choice after counselling)
72
Management of PROM/PPROM 34-36 weeks gestation?
1) Prophylactic erythromycin 250 mg QDS for 10 days.
2) Monitor for signs of clinical chorioamnionitis, and advise patient to avoid sexual intercourse (can increase risk of ascending infection).
3) Clindamycin/penicillin during labour if GBS isolated.
4) Corticosteroids if between 34 and 34+6 weeks gestation.
5) IOL and delivery recommended.
73
What does oligohydramnios increase the risk of if gestational age is <24 weeks?
Lung hypoplasia
74
How does the cervical length impact management of preterm labour with intact membranes?
If cervical length on US <15mm –> management of preterm labour can be offered.
If cervical length on US >15mm –> indicates preterm labour is unlikely.
75
What cervical length on US indicates preterm labour is unlikely?
>15mm
76
What is an alternative test to US for preterm labour?
Foetal fibronectin
77
What fetal fibronectin indicates that preterm labour is unlikely?
<50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
78
Management options for improving the outcomes in preterm labour?
1) Fetal monitoring (CTG or intermittent auscultation)
2) Tocolysis with nifedipine
3) Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality
4) IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain
5) Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth
79
What is used for tocolysis in preterm labour?
Nifedipine & terbutaline
80
What can be used as an alterantive in tocolysis when nifedipine is contraindicated?
Atosiban (oxytocin receptor antagonist)
81
What monitoring is required following IV magnesium sulphate in preterm labour?
Mothers need close monitoring for magnesium toxicity at least four hourly.
82
How is magnesium toxicity monitored for after giving IV magnesium sulphate?
1) close monitoring of observations
2) tendon reflexes (usually patella reflex)
83
Key signs of magnesium toxicity?
1) reduced RR
2) reduced BP
3) absent reflexes (opposite of tetany in hypomagnesaemia)
84
What % of pregnancies will require IOL?
20%
85
Role of IOL in PROM >37 weeks gestation?
1) Offer IOL
or
2) Wait 24h for spontaneous labour and then offer IOL
86
Give some common examples of maternal health conditions that may require IOL?
HTN
Pre-eclampsia
Diabetes
Obstetric cholestasis
87
Is active genital herpes a contraindication to IoL?
Yes --> c-section instead
88
What Bishop’s score suggests a high chance of a response to interventions made to induce labour (i.e. induction of labour is possible)?
≥8
89
What Bishop’s score suggests that labour is unlikely to progress naturally and prostaglandin tablet/gel/pessary will be required?
<5
90
What will failure of a cervix to ripen despite use of prostaglandins result in?
C-section
91
What 5 things are assessed in the Bishop’s score?
1) Foetal station (0-3)
2) Cervical position (0-2)
3) Cervical effacement/length (0-3)
4) Cervical consistency (0-2)
5) Cervical dilation (0-3)
92
Cervical position scores in the Bishop’s scoring system:
0 - posterior
1 - intermediate
2 - anterior
93
Cervical dilation scores in the Bishop’s scoring system:
0: <1cm
1: 1-2cm
2: 3-4cm
3: >5cm
94
Cervical consistency scores in the Bishop’s scoring system:
0: firm
1: intermediate
2: soft
95
What are the 3 main methods of IOL?
1) vaginal prostaglandin (dinoprostone)
2) amniotomy (artificial rupture of membranes)
3) membrane sweep
4) maternal oxytocin infusion
5) oral prostaglandin E1 (misoprostol)
6) cervical ripening balloon
96
Preferred 1ary method of IOL
Vaginal prostaglandins
97
What prostaglandin is used for the IOL?
E2 (dinoprostone)
98
2 roles of vaginal prostaglandins?
1) cervical ripening
2) uterine contractions
99
How long should a membrane sweep take to produce the onset of labour?
Within 48h
100
When is a membrane sweep offered in:
a) nulliparous women
b) multiparous women
a) 40 and 41 weeks gestation
b) 41 weeks
101
What is often given alongside an amniotomy?
An infusion of artificial oxytocin (Syntocinon) will be given alongside an amniotomy
102
When would the artificial rupture of membranes be used in IOL?
ONLY performed when the cervix has been deemed as ‘ripe’.
1) Only used where there are reasons not to use vaginal prostaglandins
2) Can be used to progress the induction of labour after vaginal prostaglandins have been used.
103
Interpretation of Bishop's score:
<5 indicates that labour is unlikely to start without induction
≥8 indicates that the cervix is ripe, or 'favourable' - there is a high chance of spontaneous labour, or response to interventions made to induce labour
104
Mx if Bishop's score is ≤6?
Vaginal prostaglandins or oral misoprostol
(mechanical methods such as a balloon catheter can be considered if the woman is at higher risk of hyperstimulation or has had a previous caesarean)
If unsuccessful --> c-section (you cannot perform amniotomy if Bishops ≤6 due to unripeness of cervix)
105
Mx if Bishop's score >6?
Amniotomy & IV oxytocin
106
What Bishop's score is required to perform an amniotomy?
>6
107
Aim of rate of contractions in IOL?
4 contractions in 10 minutes
108
Give a contraindication to vaginal prostaglandins in IOL
High risk of uterine hyperstimulation
109
What is often used as an alternative where vaginal prostaglandins are not preferred (e.g. high risk of uterine hyperstimulation)?
Cervical ripening balloon (CRB)
110
What are the 2 means for monitoring during the induction of labour?
1) CTG
2) Bishop's s core
111
When is continuous CTG monitoring required throughout IOL?
If an IV infusion of oxytocin is started
112
What is the main complication of the IOL?
uterine hyperstimulation
113
What is uterine hyperstimulation?
Prolonged and frequent uterine contractions --> foetal distress.
114
What can uterine hyperstimulation be managed with?
1) Consider tocolytics e.g. terbutaline
2) Remove the vaginal prostaglandins if possible and stop the oxytocin infusion if one has been started
115
Give some indications of continuous CTG monitoring in labour?
1) oxytocin infusion
2) maternal tachycardia (>120)
3) significant meconium
4) pre-eclampsia (particularly blood pressure > 160/110)
5) fresh antepartum haemorrhage
6) delay in labour
7) disproportionate maternal pain
116
What is the normal fetal heart rate?
100-160bpm
117
What are the 5 key features to look for on a CTG?
1) Contractions (number per 10 minutes)
2) Baseline foetal HR
3) Variability
4) Accelerations
5) Decelerations
118
Give bpm for following features on a CTG:
a) normal foetal HR
b) baseline bradycardia
c) baseline tachycardia
d) loss of baseline variability
a) 100-160bpm
b) <100
c) >160
d) <5
119
Give some causes of fetal baseline bradycardia on a CTG
1) Increased foetal vagal tone
2) Maternal beta blocker use
120
Give some causes of fetal baseline tachycardia on a CTG
1) maternal tachycardia
2) chorioamnionitis
3) hypoxia
4) prematurity
121
Give some causes of a loss of baseline variability on a CTG
1) prematurity
2) hypoxia
122
What is a normal baseline variability on a CTG?
5-25
123
What are the 4 types of decelerations on a CTG?
1) Early
2) Late
3) Variable
4) Prolonged
124
What are early decelerations?
Deceleration of the heart rate which commences with the onset of a contraction and returns to normal on completion of the contraction.
They correspond with uterine contractions --> lowest peak of deceleration coincides with peak of contraction.
125
Are early decelerations pathological?
Normal, not pathological
126
Cause of early decelerations on a CTG?
They are caused by the uterus compressing the head the fetus, stimulating the vagus nerve of the fetus, slowing the heart rate.
127
What are late decelerations?
Deceleration of the heart rate which lags the onset of a contraction and does not returns to normal until after 30 seconds following the end of the contraction.
I.e. there is a delay between the uterine contraction and the deceleration.
128
What are late decelerations on a CTG caused by?
Late decelerations are caused by hypoxia in the fetus e.g. asphyxia or placental insufficiency
This may be the result of:
1) Excessive uterine contractions
2) Maternal hypotension
3) Maternal hypoxia
129
What are variable decelerations on a CTG?
Variable decelerations are abrupt decelerations that may be UNRELATED to uterine contractions.
There is a fall of more than 15 bpm from the baseline.
130
When does the lowest point of variable decelerations occur?
The lowest point of the declaration occurs within 30 seconds, and the deceleration lasts less than 2 minutes in total.
131
What do variable decelerations often indicate?
Intermittent compression of the umbilical cord, causing fetal hypoxia.
132
What do brief accelerations before and after the variable deceleration indicate?
These are known as ‘shoulders’ - a reassuring sign that the fetus is coping.
133
What is a prolonged deceleration on a CTG?
Lasts between 2 and 10 minutes with a drop of more than 15 bpm from baseline.
134
what do prolonged decelerations often indicate?
Compression of the umbilical cord, causing fetal hypoxia.
These are abnormal and concerning.
135
What are the features of a ‘reassuring’ CTG?
1) no decelerations
OR
2) early decelerations
OR
3) less than 90 minutes of variable decelerations with no concerning features.
136
What are the 4 categories of CTG results?
1) normal
2) suspicious
3) pathological
4) need for urgent intervention
137
Features of a ‘suspicious’ CTG?
a single non-reassuring feature
138
Features of a ‘pathological’ CTG?
two non-reassuring features or a single abnormal feature
139
Features of a CTG that indicates the ‘need for ugent intervention’?
acute bradycardia or prolonged deceleration of more than 3 minutes
140
Potential management options depending on CTG results:
1) Escalating to a senior midwife and obstetrician
2) Further assessment for possible causes, such as uterine hyperstimulation, maternal hypotension and cord prolapse
3) Conservative interventions such as repositioning the mother or giving IV fluids for hypotension
4) Fetal scalp stimulation (an acceleration in response to stimulation is a reassuring sign)
5) Fetal scalp blood sampling to test for fetal acidosis
6) Delivery of the baby (e.g. instrumental delivery or emergency caesarean section)
141
What is a reassuring sign on foetal scalp stimulation?
an acceleration in response to stimulation is a reassuring sign
142
What is the ‘rule of 3s’ for prolonged fetal bradycardia?
3 minutes – call for help
6 minutes – move to theatre
9 minutes – prepare for delivery
12 minutes – deliver the baby (by 15 minutes)
143
What is a sinusoidal CTG?
A rare pattern to be aware of, as it can indicate severe fetal compromise.
It gives a pattern similar to a sine wave, with smooth regular waves up and down that have an amplitude of 5 – 15 bpm.
144
What does a sinusoidal CTG indicate?
It is usually associated with severe fetal anaemia e.g. caused by vasa praevia with fetal haemorrhage.
145
What mneumonic can be used to assess features of a CTG?
DR C BRaVADO
DR - Define Risk (define the risk based on the individual woman and pregnancy before assessing the CTG)
C – Contractions
BRa - Baseline Rate
V - Variability
A - Accelerations
D - Decelerations
O - Overall impression (given an overall impression of the CTG and clinical picture) e.g. normal, suspicious, pathological, need for ugent intervention
146
Describe hormonal changes during labour
Increased concentrations of oestrogen stimulate the production and release of prostaglandins.
Also promotes the formation of oxytocin receptors so that the myometrium is more sensitive to oxytocin.
Prostaglandins and oxytocin are strong myometrial stimulants and play a major role in cervical ripening.
147
What may variable decelerations on a CTG indicate?
Cord compression - can get women to change position
148
