Obstetrics Flashcards
1
Q
What is normal labour? Diagnosis made when?
A
Process where foetus and placenta are expelled from the uterus
Painful uterine contractions accompany dilation and effacement of the cervix
2
Q
What mechanical factors affect labour? 3 Ps
A
Powers - degree of force expelling
Passage - dimension of pelvis and resistance of soft tissues
Passenger - diameter of fetal head
3
Q
What are Braxton-hicks contractions?
A
Painless uterine contractions that occur at intervals from 30th week
Can be palpated
4
Q
Who often has poor powers (uterine activity)?
A
Nuliparous
Induced labour
5
Q
What are Montevideo units? How are they calculated? How can you measure them?
A
Measure of uterine activity
Intensity of contraction x frequency of contraction (per 10 mins)
Can be measured using a cardiotocograph (CTG)
6
Q
Where is the pacemaker of the uterus found?
A
Junction of Fallopian tube and uterus on 1 side
7
Q
What physiological change do the coordinated contractions of labour cause? What does this cause?
A
Permanent shortening of the muscle fibres
-> distension tension on less muscular lower part ESP. Cervix
8
Q
What causes the pain in contractions ?
A
Ischemia in myometrial fibres
9
Q
What factors are associated with abnormal lie?
A
Polyhydroaminios, high parity, fetal/uterine abnormalities, conditions that prevent engagement (placenta previa, pelvic tumours, uterine deformities)
Preterm
10
Q
What position in extended breech?
A
Buttocks present and legs are extended so by head
11
Q
What does presentation refer to?
A
The part of the foetus that occupies the lower segment of uterus or pelvis
12
Q
How common is abnormal lie ?
A
1/200
13
Q
Where provides the strongest contractions to push fetes along?
A
Upper uterine segment
14
Q
3 main parts of passage ?
A
Bony pelvis - inlet, mid cavity, outlet
Ischia spine - used to assess decent
Soft tissues - cervical dilation, vagina and perineum need to be overcome in second stage
15
Q
Bony pelvis …
Shape of the mid cavity?
AP diameter of outlet?
What does station 0 mean?
A
Round
12.5cm (transverse is around 11cm at this point)
The head is at the level of the ichial spines, approximately mid cavity (+ve means head below spines -ve means above)
16
Q
Does the coccyx obstruct labour? What can happen after birth?
A
No
Alteration in its position can cause pain
17
Q
Which presentation do you want? Presentation if a 90 degree extension ? 120 degree? What presentation does the head normally deliver in ?
A
Vertex - narrowest diameter (9.5cm)
Brow (13cm)
Face
Occipito-anterior
18
Q
What is ‘attitude’ in relation to foetus?
A
Degree of flex ion of head on neck (you want maximal - vertex presentation)
Think chin to chest
19
Q
3 stages of labour? What happens in each?
A
1- initiation to full cervical dilation
- Latent phase - slow dilation up to 3cm
- Active phase - average 1cm/hr (could be 2cm/hr in multiparous)
2 - full cervical dilation to delivery of foetus
- passive - full dilation till head reaches pelvic floor -> desire to push
- Active - mother pushing (epidural effect)
- delivery of foetus to delivery of placenta
- normally 15 mins
Can have traditional or active management
- delivery of foetus to delivery of placenta
20
Q
How do epidurals affect labour
A
Remove desire to push -> longer labour
21
Q
What happens in traditional (expectant) management for 3rd stage of labour?
Active management ?
A
Light massage of uterus though abdo -> encourages contraction
IM - Syntocinon (syntometrine)
22
Q
What levels of blood loss are normal in delivery?
A
500ml in vaginal
1000ml in C section
23
Q
What aids identification of an abnormal process in labour
A
Partogram - graphic representation of labour with key observations
24
Q
What is the most common cause of slow progress in primiparous labour?
A
Inefficient uterine action
25
In multiparous women with slow labour progress what are you worried about?>
Malposition -> uterine rupture more likely
26
What should you do with hyperactive uterine contractions and vaginal bleeding with fetal heart rate abnormalities?
C section
27
When is tocolysis usually used ?
Iatrogenic Uterine hyperactivity - Eg Prostaglandin administration
28
Why is eating discouraged during labour? What is this called?
Stomach contents can be aspirated
| Under anaesthetic called Mendelson’s syndrome
29
What urinary issue should you consider during labour?
Retention - if neglected -> irreversible damage to detrussor
30
During the general care of labour, some general care things you should think of?
Physical health - obs, mobility, delivery positions
| Mental health - environment, control, partner, birth attendant
31
What to do in persistent inefficient uterine action?
Augmentation (ARM artificial rupture of membranes)
32
What is associated with hyperactive uterine action? What does it ->?
Placental abruption, too much oxytocin, PG side efffect
Fetal distress as blood flow diminished
33
Management of hyperactive uterine action?.
No evidence of abruption -> tocolutic Eg salbutamol (IV/SC)
Usually LSCS due to fetal distress
34
What is augmentation? Egs?
Artificial strengthening of contractions in established labour
ARM, Amniotomy, artificial oxytocin
35
Nuliparous with slow first stage? Poor decent in passive second stage? Longer than 1hr in active second stage?
Augmentation, if no full dilation by 16hr -> c-section
P2nd - oxytocin infusion
A2nd - >1hr spontaneity’s delivery unlikely -> episiotomy, ventouse / forests
36
Rare problems with passage?
Cephalo-pelvic disproportion
| Pelvic variants and deformities
37
How often do you auscultation fetal heart rate?
Every 15mins in first stage
| Every 5 mins in second stage
38
Intrapartum fetal problems
Meconium aspiration
Fetal blood loss
Trauma
Infection (group B strep)
39
What is fetal distress? 3 Egs of signs?
Hypoxia that might result in fetal damage or death if not reversed / foetus delivered urgently
Colour of meconium, fetal heart rate auscultation, CTG, Fetal ECG, Fetal blood (scalp) sampling
40
CTG (cardiotocography) mnemonic
```
DR C BRAVADO
Define Risk
Contractions per 10 mins (<5)
Baseline Rate (110-160)
Variability - variation in fetal heart rate should be >5bpm
Accelerations - with movement / contraction is reassuring
Deceleration
Overall assessment
```
41
What might fetal tachycardia indicate? Bradycardia?
Fever, fetal infection, hypoxia
Sustained deterioration in rate -> acute fetal distress
42
What does a prolonged reduced variability in fetal heart rate suggest?
Hypoxia
43
What do early, variable and late deceleration suggest?
E- synchronous with contraction (normal)
V - vary in timing -> cord compression causing hypoxia
L - persist after contraction -> hypoxia
44
What to do if fetal sustained bradycardia
Deliver urgently
45
Pain relief in labour
Non medical - Eg warm towel / massage
Entonox
Systemic opiates - need antiemetics
Epidural anaesthesia
46
Degrees of perineal trauma ? Management?
1- skin only
2 - perinatal muscles but no sphincter
3 - involving anal sphincter (3a:<50% sphincter, 3b:>50%, 3c:Internal sphincter involved
4- involving anal sphincter and anal epithelium
1/2 - suture with local anaesthetic
3/4 - epidural / spinal and physiotherapy
47
```
Which of the following does NOT increase your risk of multiple pregnancies
FHx of monozygotic twins
Increased maternal age
Induced ovulation
IVF
Japanese Women
```
Family hx of monozygotic twins
| A FHx of dizygotic twins does
48
```
How often do you ultrasound multiple pregnancies?
Monthly from presentation
Monthly from 20 weeks
Biweekly from 20 weeks
Monthly from 28 weeks
Weekly during last trimester
```
Monthly from 20 weeks
49
Gestation for an elective birth?
37 weeks
50
Most common complication of multiple pregnancy ?
Prematurity
51
What is Twin-twin transfusion? When do you get concerned?>
Arterial blood flow from donor goes though placenta to vein of recipient
If >30% discordance in estimated fetal size
52
Complications of twin-twin transfusion
Donor twin?
Recipient?
Donor - IUGR, oligohyroaminos, hypovolaemia, hypotension, anaemia
Recipient - Polyhydraminos, hypertension, polycythaemia, oedema, kernicterus in neonatal period, CHF
53
Management of twin-twin transfusion
Doppler analysis flow for diagnosis
Therapeutic amniocentesis to decrease polyhydoamios for recipient
Intra-uterine blood transfusion (if needed)
Laparoscopic occlusion of placental vessels
54
Risk factors for shoulder dystocia? What is it? What can it lead to?
High birth weight, Maternal diabetes, induced labour, previous shoulder dystocia, too much oxytocin, abnormal lie
Failure of the shoulder to deliver
Mothers pelvis constricts the babies chest -> cord compression -> asphyxiation (acidosis and asphyxiation will set in around 4-5 minutes in shoulder dystocia position)
Erb’s palsy (brachial plexus damage) / clavicular or humerus fracture
55
Management of shoulder dystocia
```
HELPERR
Call for help
Evaluate for Episotomy
Legs - Mc Roberts manoeuvre (pull knees up to chest)
Pressure - suprapubic
Enter - rotational manoeuvres Eg Rubin II
Remover posterior arm
Roll the patient onto hands and knees
```
56
Last resort in shoulder dystocia ?
Deliberate clavicular fracture /
Push head back in and Zavanelli manoeuvre (c-section with cephalic replacement)
Abdo surgery with hysterectomy
57
Risk factors for cord prolapse ? When do over half occur?
Preterm labour, breech presentation, abnormal lie, twin pregnancy
Artificial amniotomy
58
Initial management of cord prolapse
Elevate the presenting part to prevent cord compression ->
Can use tocolytics Eg nifedipine / terbutaline
C-section or expedited delivery Eg with instruments / c section
59
Presentation of amniotic fluid embolus / when during pregnancy does it occur?
Prognosis / natural history?
What else can it cause?
Sudden dyspnoea, hypoxia or hypotension
Any time during the pregnancy
DIC, pulm oedema and adult resp distress syndrome (ARDS) develop rapidly in those who survive the first 30 mins
Post partum haemorrhage
60
What happens in amniotic fluid embolism? RF? When is it most common?
DD?
Liquor enters maternal circulation -> anaphylaxis, sudden dyspnea, hypoxia and hypotension often with seizures and cardiac arrest
RF - strong contraction / polyhydroaminos
When membranes rupture (Labour/CS/TOP)
Eclampsia
61
Management of amniotic fluid embolism ?
O2, fluids,
bloods (clotting, FBC, electrolytes, cross-match)
Blood, fresh frozen plasma
ICU
62
Risk factors for uterine rupture?
Labours with scared uterus, C section / old scar
| Neglected obstructed labour
63
Signs of uterine rupture?
Fetal heart rate abnormalities
Constant abdo pain, vaginal bleeding
Cessation of contractions, maternal collapse
64
Complications of uterine rupture?
Features extruded / acute fetal hypoxia
Massive internal haemorrhage
High recurrence rate
65
Management of uterine rupture
Maternal resuscitation,
| urgent laparotomy for delivery
66
What is uterine inversion ?
| Presentation?
```
Fundus inverts into uterine cavity
Post partum haemorrhage usually (can be massive)
Lower abdo pain
Appearance of vaginal mass
CV collapse
```
67
Management of uterine inversion
General anaesthetic
Fluid replacement, management of hydrostatic pressure
1- Try and manually push uterus back into place with bimanual compression to minimise bleeding
2- O'sullivan technique - fill with warm saline and create a seal to increase pressure
3- Laparotomy
68
Management of epileptiform seizures?
Clear airway, give O2
Diazepam if epilepsy
MgSO4 if eclampsia
69
Difference between induction and augmentation ?
Induction - artificial initiation of labour
| Augmentation - promotes contractions when spontaneous contractions are inadequate
70
What is a ripe cervix ? How can you ripen?
Soft, short, thin, anterior cervix with open os
| Prostaglandin vaginal insert, gel or Foley catheter
71
CIs for induction of labour?
Fetal distress, cord presentation, pelvic tumour, placenta previa, previous repair to cervix, cephalometric disproportion
72
Complications of induced labour
Failed induction, infection, bleeding, cord prolapse, instrumental delivery (15%), Caesarian section (22%)
73
What is the bishops score?
Pre labour scoring system to assist in predicting whether induction of labour will be required
74
Method of inducing labour?
Cervical ripening must be done if bishops score <6
-PG, Foley catheter (manual dilation)
```
Induction
Amniotomy -> rupture of membranes
Monitor fetal heart rate
Oxytocin IV with 5% dextrose
(1-4MU/min -> increase every 30 mins)
```
75
When would you use misoprostol?
After intrauterine death (to deliver)
76
```
You see a pregnant woman at 14 weeks gestation. She has a history of preterm pregnancy at 33 weeks. You perform a vaginal swab and its positive for bacterial vaginosis, but she is asymptomatic. What is the appropriate management?
Oral metronidazole
Vaginal clindamycin
No treatment, she’s asymptomatic
Oral tinidazole
IV ceftriaxone
```
Ans: Oral metronidazole. Significant link between BV and preterm labour. Possible links to miscarriages, low birth weight, and PROM.
Clindamycin cream avoided during 2nd half of pregnancy premature birth. Metronidazole contraindicated in first trimester.
77
Risk factors for preterm labour?
```
Previous preterm labour
BV
Cervical length (short)
Untreated bacteriuria
Prev abdo surgery
Polyhydaminos
Fetal hydrops
Fetal fibronectin
```
78
Maternal causes of preterm labour?
Infection (also genital BV)
HTN, DM, chronic illness
Prev surgery
Smoking, alcohol, drugs, stress, poor nutrition
79
What is fetal fibronectin
Glycoprotein in amniotic fluid
| If present in high amounts and short cervix -> risk of preterm
80
What is fetal hydrops?
Abnormal build of fluid in 2 or more body areas -> sign of underlying disease
81
What are tocolytics used for?
Supress labour
82
Mx of preterm labour? Drugs? What are the requirements for use of pharmaceuticals?
Initial - Hydration, bed rest, avoid repeated pelvic exam (increased risk of infection)
Ultra sound - GA, position, placenta, estimate weight
Supress labour - tocolytics
- prostaglandin synthesis inhibitors - indomethacin
- calcium channel blockers - nifedipine
Requirements - pre term labour
-live immature foetus, intact membranes, cervical dilation <4cm
83
What else does suppressing labour do ?
Give time to administer corticosteroid - betamethasone / dexamethasone
-> help fetal surfactant production but takes 1-2 days to work
84
Absolute CI for tocolytics?
| Relative CI for tocolytics?
Fetal death, chorioamnionitis, maternal condition close to death
Pre-eclampsia, placenta previa, cervix >4cm, pulmonary oedema, fluid overload
85
What do glucocorticoids do at 24-28wks? 28-34wks? What else? What cautions?
24-28 - reduce severity of RDS, overal mortality and rate of IVH (intraventricular haemorrhage)
28-34 - reduce risk of RDS
Help to close PDA and protect periventricular malacia
Systemic infection - TB maternal sepsis, chorioamnionitis
Diabetes
86
What is periventricular malacia ? What can it cause? RF?
White matter surrounding ventricles is deprived of blood
-> cerebral palsy
Premature, LBW, uterine infections, PROM
87
When is a cervical cerclage usually performed? When is it removed? Indications?
Sutures are placed at the internal OS at the end of the 1st trimester and removed in the third trimester
Cervical incompetence
Obstetric hx - silent cervical dilation
-ability of cervix to hold inflated foley during hysterosonogram
88
```
Definition
PROM?
Prolonged ROM?
Preterm ROM?
PPROM?
```
Rupture of membranes prior to labour at any GA
>24hrs betweeen ROM and onset of labour
ROM before 37 weeks
Rupture of membranes before 37wks AND prior onset of labour
89
Most common breech?
Frank - legs extended up to head (60%)
Complete breech (10%)
Footling breech (30%)
90
What is cervical effacement?
Change in shape of cervix from bulb to flat
91
Normal rate of cervical dilation
1-3cm / hr
92
What is antepartum haemorrhage? 3 main causes?
Bleeding after 24 weeks gestation
Placenta previa, placental abruption, vasa previa
93
What is placenta previa? Major? Minor?
Low lying placenta - common at 20 weeks but often moves ‘upwards’ as pregnancy continues
Major - covers internal os
Minor - in lower segment (but does not cover internal OS)
94
Features of placenta previa ? Ix? Mx?
Intermittent PAINLESS bleeding - red/profuse
Often an incidental finding on USS
Breech pregnancy + transverse lie are common
Ix - NEVER do a vaginal exam as can provoke a massive bleed
US - confirms diagnosis
FBC and cross match if bleeding
Mx - Delivery - Major / within 2cm of internal os -> elective c-section at 39 weeks
Over 2cm from internal os -> aim is vaginal
95
What is placental abruption? Main complications? Main causes?
Part/all of the placenta separates from the lining of the uterus before delivery of the foetus (occurs after 24 weeks)
Complications - fetal death (common), DIC, renal failure, maternal death
Causes - IUGR, pre-eclampsia, smoking, cocaine, Hx of abruption, multiple pregnancy
96
Features of placental abruption? O/e? Ix? Mx?
PAINFUL bleeding - blood behind placenta + in myometrium - often DARK compared to previa
May be concealed (pain, no blood) or revealed (with blood)
O/e - Tachycardia, hypotension (MASSIVE blood loss), tender uterus
-> in severe uterus can feel ‘woody’ and the foetus is difficult to feel
- CTG (US not useful unless to exclude placenta previa
MX -
Admit if suspected
IV fluids and serious, blood transfusion considered, opiates analgesia
-If fetal distress -> urgent c section
No distress -> elective c section after 37wks
97
What is vasa previa ?
Fetal blood vessels running in the membranes in front of the presenting part. When membranes rupture vessels may rupture with massive fetal bleeding.
- > leads to vulnerable vessels which are prone to rupture when membranes break during delivery
- > copious bleeding and still birth
98
Diagnostic triad and mx of vasa previa?
Membrane rupture -> painless vaginal bleeding, fetal bradycardia
Immediate emergency c-section (following ROM)
[often too slow to save fetus]
99
What is primary PPH ? Causes? Mx?
>500mls of blood loss in first 24 hrs after delivery
Uterine atony, uterine rupture, clotting disorders
Oxytocin, biannual compression, blood transfusion
100
What is uterine atony? RFs?
Reduced tone -> doesn’t compress vessels
| Previous uterine atony, uterine abnormality, large placenta, placenta previa / abruption
101
What is secondary PPH? Causes? Mx?
Excess blood loss after 24hrs
Retained placental tissue, clot
USS to identify retained products
Give ampicillin and metronidazole as secondary infection common
Carful curette of uterus - histology for choriocarcinoma
102
4 T’s of PPH
Tone - atomy
Trauma - delivery
Tissue - retention of placenta
Thrombin - coagulation disorders
103
Primary, secondary, tertiary prevention of prematurity ?
1 - smoking / STD prevention, cervical assessment at 20wks, reducing multiple pregnancy
2- methods to diagnose and treat existent disease
3 - prompt diagnosis and referral
Drugs - tocolytics (terbutaline, nifedipine, progesterone), corticosteroids
104
Complications of prematurity
Developmental delay
Chronic lung disease -> RDS
Cerebral palsy
Visual / hearing impairment
105
What is pleuperium ? Common issues? Serious problems?
Post natal care - 6 weeks following birth
Common problems = Perineum damage, urinary incontinence (approx. 50%), constipation and haemorroids, mastitis, backache and postnatal depression.
Serious maternal health problems:
Postnatal Psychosis = mania or depression
PPH
Postnatal anaemia (common and overlooked)
Puerperal pyrexia
Thromboembolism (more common following c-section = DVT/PE)
106
Teratogenic drugs - Name 6
Warfarin
ACE inhibitors
Anti-thyroid drugs: Carbimazole (recommended for 2nd and 3rd trimester – block and replace regimen contraindicated), propylthiouracil (recommended for pre-pregnancy and 1st trimester)
Angiotensin II antagonists
Antiepileptics (minus lamotrigine)
Methotrexate
Antibiotics (trimethoprim, tetracycline, doxycycline)
Isotretinoin
Alcohol, cocaine, high dose vitamin
