Obstetrics Flashcards
1
Q
What are the main pregnancy hormones?
A
hCG progestins oestrogens human placental lactogen prolactin oxytocin
2
Q
What is the role of hCG and where is it produced?
A
secreted by trophoblastic cells of the blastocyst
role - to signal the presence of the blastocyst to the mother
prevents corpus luteum degenerating so it can persist until the placenta has formed
3
Q
What is the role of progestins and where are they rpoduced?
A
initally come from the corpus lutem and then from the placenta
prepars endometrium and uterus for implantation by causing proliferation, vascularisation and differentiation of the endo metrial stroma
fascilitates myometrial quiescence (stops myometrium contracting too early)
4
Q
What is the role of oestrogens and where are they produced?
A
comes from the ovary initially and then from the foetus too later in pregnancy
role - promotes changes in CVS and alters carbuhydrate metabolism
indicates foetal wellbeing (E3 - declines with foetal distress)
E2 - facilitates progesterone production by increasing endometrial progesterone receptors
5
Q
What is the role of human placental lactogen?
A
mobilises glucose from fat reserves
diabetogenic (raises blood glucose levels) - to help increase nutrient supply to the blastocyst
converts mammary glands into milk secreting tissue
6
Q
What is the role of prolactin and where is it produced?
A
increased levels of prolactin allow milk production
but ONLY when oestrogen and progesterone have declined postpartum
produced in anterior pituitary
7
Q
What is the role of oxytocin and where is it produced?
A
facilitates uterine contraction during labour
milk ejection reflex postpartum
produced in the hypothalamus, secreted by posterior pituitary
8
Q
Between which days of the menstrual cycle is the window of implantation?
A
between day 20-24
will not implant outside this timeframe
9
Q
What are the layers of interface between the placenta and the myometrium?
A
placenta
decidua
myometrium
abdomen
10
Q
What are the varying degrees of morbid adherence of the placenta?
A
normal placenta - invades into decidua
placenta accreta - invades into superficial mometrium
placenta increta - invades into deeper myometrium
placenta percreta - invades through myometrium into nearby organs such as bladder and bowel
11
Q
What risks are associated with morbid placental adherence?
A
poor placental separation - difficult to deliver
retained products –> increased risk of infection
significant post-partum haemorrhage
12
Q
Which type of immunity remains unchanged during pregnancy and which type is dampened?
A
humoral - remains unchanged, Th2 cell based
cell mediated - reduced as progesterone down regulates the production of Th1 cells
this leads to increased Th2 production –> Th2 bias
13
Q
Which conditions in pregnancy do not have a Th2 humoral immunity bias?
A
pre-eclampsia
IUGR
miscarriage
14
Q
Which type of immunoglobulin is screted in breast milk?
A
IgA
15
Q
Which is the only antibody to cross the placenta?
A
IgG
if mum has low levels, baby can get primary immune deficiency hypogammaglobulinaemia
16
Q
Who is at risk of rhesus disease?
A
if the mother is Rh -ve
and the father is Rh +ve
this is because 50-100% of their offspring will also be Rh +ve
not a problem if dad is also Rh -ve
17
Q
Why does Rhesus disease not occur in the first pregnancy?
A
sensitisation in first pregnancy
maternal immune reaction to the Rh +ve antigen of foetal RBC produces IgM which does not cross the placenta to affect this pregnancy
However it does produce memory cells so IgG can be produced ina s subsequen pregnancy and can cross the placenta and affect the baby
18
Q
What does Rhesus disease do to the foetus?
A
causes RBC haemolysis leading to severe foetal anaemia and possible death if not intervention
19
Q
How to prevent Rhesus disease?
A
Anti-D prophylaxis
it destroys the anti-Rh +ve antibodies
given at 28 and 34 weeks after birth
given earlier if any sensitisation events occur
20
Q
How can DM during pregnancy affect the foetus?
A
macrosomic infant (>4kg birthweight)
increased risk of traumatic delivery and shoulder dystocia
still birth
cleft palate
neonatal hypoglycaemia due to hyperinsulinaemia
21
Q
What are the increased risks to the mother of DM durign pregnancy?
A
ketoacidosis
pre-eclmapsia
coronary heart disease
nephropathy etc
22
Q
Which drugs are used to rpomote myometrial quiescence i.e. stop uterine contractions?
A
tocolytic drugs
B2 agonsits - salbutamol and ritodrine
CCB - nifedipine
stop smotth muscle contractions
cause myocytes to become hyperpolarised = cannot depolarise = cannot contract
23
Q
What serum marker can be measured to predict early labour?
A
foetal fibronectin
if raised, give IM steroids and monitor
24
Q
How is labour induced?
A
membrane sweep + Bishop score –> PV prostaglandins like Dinoprostone inserted into posterior vaginal fornix –> mechanical balloon catheter/laminaria tents –> surgical amniotomy +/- oxytocin
25
Which scoring system can be used to assess whether induction of laour may be needed?
Bishop score
<5 = induction will be needed
>9 = labour will likely be spontaneous
26
Which drugs are given to prevent/stop postpartum bleeding?
Oxytocin
Ergometrine (CI in hypertensive women)
combined form - syntometrine
helps deliver placenta
makes uterus contract
27
What are the 3 stages of labour?
1. cervical dilatation (remodelling)
2. myometrial contraction (pushing stage)
3. placental delivery
28
Which drug stops the effect of oxytocin by blocking its receptor?
Atosiban - used in preterm labour
29
What is defined as adequate progress in labour?
2 cm dilation per 4 hours of active labour
30
Give a bried description of the stages of labour.
First stage - preparation
- latent pahse - pianful, irregular contraction, cervical effacement ad dilation up to 4 cm
- active phase - dilated >4cm, regular contractions, majority of dilatation happens in this phase
Second stage - pushing
- passive stage - complete dilatation but no pushing
- active - maternal pushing until delivery
Third stage - delivery of placenta
31
What are the 3 main causes of failure to progress in labour?
1. power
2. passenger
3. passage
32
Name some problems with "power" which affect failure to progress in labour.
poor uterine contractions
most common cause of failure to progress
common in primigravidas
33
Name some problems with the "passenger" which can cause failure to progress in labour.
Malpresentation
malposition of a large baby
34
Name some problems with the "passage" that can cause failure to progress in labour.
inadequate pelvis
cephalopelvic disproportion
35
What are some risk factors for failure to progress in labour?
```
large baby
beach baby
first time mother
previous delayed labour
premature rupture of membranes
```
36
How to assess someone in failure to progress?
palpate abdomen for lie, head and contractions
CTG
colour of amniotic fluid
vaginal examination
37
How to manage delay in the first stage of labour?
```
offer amniotomy
if membranes already ruptured - oxytocin infusion
CTG
FBS if concerns on CTG
cosider LSCS if none of this helps
```
38
How to manage a delay in the 2nd stage of labour?
allow to psuh - 2 hours if primip, 1 hour if multip
if still no imminent delivery - obstetric review for instrumental delivery
39
What are the foetal and maternal parameters recorded on the partogram?
```
FHR - monitors the wellbeing of the foetus
Cervical dilatation
contractions per 10 minutes
drugs and IV fluids given
pulse and BP of the mother
urine
```
40
What are some causes of breech presentation?
- idiopathic
- uterine abnormalities - bicornate uterus, fibroids
- prematurity
- placenta praevia
- oligohydramnios
- foetal abnormalities e.g. hydrocephalus
41
How is breech presentation managed?
External cephalic version at 37 weeks
| LSCS if ECV unsuccessful or contraindicated
42
What are some contraindications for ECV?
```
placenta praevia
multiple pregnancies
APH in last 7 days
ruptured membranes
growth restricted babies
abnormal CTG
mothers wih uterine abnormalities or scars
foetal abnormlity
pre-eclampsia or HTN (increased risk of abruption)
```
43
What is the correct positioning of a baby's head when presenting?
occipito-anterior
44
What causes meconium stained liquor?
foetal distress
foetal maturity
risk of aspiration pneumonia in baby
45
What pain relief medications can be used in labour?
paracetamol and codeine in early stages
entonox - gas and air
opiates - pethidine, morphine, diamorphine
epidural
46
At what spinal level is an epidural administered?
L3-L4
47
What medications can be given epidurally?
local anaesthetics - bupivacaine
opioids - fentanyl, diamorphine
48
What are some complications from an epidural?
```
potential damage to the spinal cord
hypotension and bradycardia
haematoma/abscess at injection site
anaphylaxis
post dural puncture headache
```
49
What are some absolute contraindications for an epidural?
maternal refusal
local infection
allergy to local anaesthetics
50
What conditions are screened for in the foetal anomaly screening programme?
trisomy 21 - down's
trisomy 18 - edward's
trisomy 13 - patau's
51
How are the trisomies screened for?
first trimester - triple test - nuchal translucency + serum beta hCG + Papp-A (combined test)
needs to be done before 13+6
second trimester - quadruple test if late booker or nuchal translucency not obtained
52
Which hormones are tested for in the triple test?
alpha fetoprotein
oestriol
beta-hCG
53
Which hormones are tested for in the quadruple test?
1. AFP
2. oestriol
3. beta-hCG
4. inhibin A
done if after 15 weeks of pregnancy
54
When should the booking visit be?
8-12 weeks
55
When is the nuchal translucency scan?
11-13+6 weeks
56
When is the anomaly scan performed?
18 - 20+6 weeks
57
What risk score is considered a screen positive result?
if the risk is 1 in 150 or worse
58
What further tests can be given in these higher risk pregnancies?
diagnostic testing - same day
amniocentesis or chorionic villus sampling
59
What are the 3 infectious diseases pregnant women are screened for?
HIV
Syphilis
Hep B
60
What disease are newborns screeed for on the blood spot programme?
```
sickle cell disease (and thalassaemia)
congenital hypothyroidism
cystic fibrosis
6 inborn errors of metabolism:
isovolaric acidaemia
maple syrup urine disease
phenyketonuria
Medium chain acyl-CoA dehydrogenase deficiency
homocysteinuria
glutaric aciduria type 1
```
61
What are the 4 baseline parameters on a CTG?
1. baseline foetal heart rate
2. FHR variability
3. number of accelerations - rise in baseline HR
4. number of decelerations - fall in baselines HR
62
What is the difference between early and late deceleration on a CTG?
early - most likely due to uterine contractions
late - whilst the uterus is relaxing, sign of foetal distress
63
What is the most common cause of early deceleration?
head compression due to uterine contraction
64
What is the most common cause of late deceleration?
uterine placental insufficiency/foetal distress
65
What causes variable deceleration?
cord compression
66
What are normal features on a CTG?
baseline HR - 110-160 bpm
variability - >5bpm
accelerations present
no decelerations present
67
For what time frame is a reduced level of variability acceptable and why?
40 mins
baby may be sleeping
68
What is the gold standard investigation for foetal heart rate monitoring during labour?
scalp FHR monitoring
69
Define antepartum haemorrhage.
blood loss of >50mL after 24 weeks of gestation.
70
What are some causes of APH?
```
placenta praevia
vasa praevia
placental abruption
placenta accreta
uterine rupture
```
less dangerous causes:
- cervical polyps
- cervicitis
- carcinoma
- vaginitis
- vulval varicosities
71
Define placental abruption.
When part of the placenta becomes detached from te uterus.
72
What are the risk factors for placental abruption?
```
previous abruption
hypertension
multiple pregnancy
trauma
cocaine and crack
infection
uterine abnomrality
pre-eclampsia
smoking
```
73
How does placental abruption present?
painful + hard, woody uterus + foetal distress
maternal shock inconsistent with small amount of bleeding
could be concealed with no bleeding
posterior abruption could cause back ache
74
What are some complications of placental abruption?
```
foetal death
post partum haemorrhage
uterine yper-contractility
DIC
renal failure
Sheehan's syndrome
```
75
How do you manage placental abruption?
```
admit to hospital - ABC
IV fluids
oxygen
ABO Rh compatible blood or O neg
if safe and term - deliver baby
```
76
Define placenta praevia.
low lying placenta - any part of the placenta has implanted into the lower segment of the uterus
major - fully covering the ceervical os
minor - encroaching the lower segment but not fully covering the os
77
What should be avoided in a lady with a low lying placenta?
Digital PV exams
penetrative intercourse
speculum exam is safe
78
How does a low-lying placenta present?
diagnosed antenatally on 20-week anomaly scan
can be re-checked closer to delivery
79
What kind of bleed will be caused by placenta praevia?
painless
| large amount of blood
80
What are the risk factor for placenta praevia?
```
previous CS
previous TOP - uterine evacuation
multiparity
mother >40
assisstd conception
manual removl of previous placenta
fibroids
endometriosis
```
81
How is placenta praevia managed?
if minor - aim for normal delivery unless placenta is within 2 cm of os
major - elective CS at 38-39 weeks
82
Define vasa praevia.
the major foetal vessels are presenting before the foetus
83
How does vasa praevia present?
painless bleeding
after rupture of membranes
severe foetal distress
84
How to manage vasa praevia?
ABC management of bleeding
| delivery by CS
85
How do you manage a morbidly adherent placenta?
MRI scan if degree of adherence uncertain
elective LSCS at 36-37 weeks
discuss possible interventions - hysterectomy, leaving the placenta in place
86
Define primary PPH.
loss of >500mL in the first 24 hours after delivery
87
What are the causes of primary PPH?
4 Ts:
tone - uterine atony (most common)
trauma - big tear in the genital tract
tisue - retained products i.e. palcenta
thrombin - clotting disorder
88
How do you diagnose uterine atony on abdo exam following delivery?
un-palpable uterus
89
How do you manage PPH caused by uterine atony?
emptying bladder can help
rub the abdomen to help the uterus contract
bimanual compression of the uterus
```
IV syntocinon (combination of ergometrine and oxytocin to help uterus contract)
IM carboprost (or dinoprostone - prostaglandins)
surgical options - B-lynch sutures, internal iliac artery/ uterine artery ligation
```
others - uterine artery embolisation, hysterectomy
90
Define secondary PPH.
excessive blood loss from the genital tract after 24 hours - 12 weeks from delivery
91
What is the most common cause of secondary PPH?
retained placental tissue
92
What are the most common causes for vaginal bleeding in the first trimester?
miscarriage
| ectopic pregnancy
93
What is the commonest cause of direct maternal death?
pulmonary embolism
high risk in post-partum period
thromboprophylaxis - LMWH injection i.e. dalteparin and TED compression stockings
94
What is the gold standard investigation for VTE?
DVT - ultrasound doppler
PE - CTPA
if suspicious - Well's score and D-dimer
95
What is cord prolapse?
When the umbilical cord prolapses though the cervix when the membranes rupture.
96
Why is cord prolapse dangerous?
exposure of the cord leads to vasospasm
| can cause foetal hypoxia
97
What are the risk factors for cord prolapse?
```
PROM
polyhydramnios
long umbilical cord
malpresentation
multiparity
multiple pregnancy
```
98
How to manage cord prolapse?
call 999/pull emergency buzzer
alleviate pressure on cord - put their feet up in the air - Trendelenberg position
transfer to theatre and prep for delivery
99
What's the definition of shoulder dystocia?
failure of the anterior shoulder to pass under the symphysis pubis after delivery of the foetal head
100
What are the risk factors for shoulder dystocia?
```
macrosomia (baby >4 kg)
maternal diabetes
cephalopelvic disproportion
post-maturity that required IoL
prolonged labour
instrumental delivery
```
101
What are the complications of shoulder dystocia to the baby?
```
hypoxia
fits
Cerebral Palsy
brachial plexus injury/Erb's palsy
fractured clavicle or humerus
```
102
What is the only licensed anticoagulant in pregnancy?
Dalteparin (LMW heparin)
103
How does obstetric cholestaiss present and how is it treated?
presents with itchy hands and feet
tx - ursodeoxycholic acid
piriton helps with itching
104
What is a common symptoms of hyperthyroidism during pregnancy?
excessive vomiting
105
What are the side effects of anti-thyroid drugs during pregnancy?
propylthiouracil - maternal liver failure
carbimazole - foetal abnormalities
106
What pre-conceptual advice should you give someone who has diabetes?
```
aim for HbA1c < 48 mmol/L
take 5 mg folical acid
stop ACEi and statins
retinal screening
renal function screening
establish good diabetic control before pregnancy (stay on contraception until then)
```
107
Which diabetic drug is contraindicated in pregnancy?
Gliclazide
108
Which anti-epileptic drugs are contraindicated in pregnancy?
most of them are teratogenic
valproate is the worst - neural tube defects, spina bifida
109
Define gestational hypertension.
new htn after 20 weeks' gestation
systolic >140
diastolic >90
110
Define pre-eclampsia.
gestational HTN + proteinuria
111
Define eclampsia.
gestational HTN + proteinuria + generlaied tonic-clonic seizures
112
What are the risk factors for pre-eclampsia?
```
smoker
young female
first pregnancy
black ethnicity
multiple pregnancy
hypertension
diabetes
FHx
```
113
What is the pathophysiology behind the seizures in eclampsia?
proteinuria --> hypoalbuminaemia --> oedema --> fludi loss into 3rd space = hypovolaemia --> lack of perfusion to vital organs --> cerebral hypo-perfusion --> seizures
114
What is HELLP syndrome?
haemolysis
elevated liver enzymes (AST and ALT)
Low platelets
115
What are the symptoms of pre-eclampsia?
```
oliguria
visual changes, headaches
oedema
RUQ pain (liver capsule stretches)
rapid weight gain
```
116
What are the signs of pre-eclampsia?
```
hypertension
proteinuria
papilloedema
RUQ tenderness
ankle clonus (brisk reflexes are normal in pregnancy but ankle clonus is not)
```
117
What test result is diagnositc for pre-eclampsia?
protein:creatinine ration > 30
118
How do you treat pre-eclampsia?
admit to hospital
only cure is to deliver baby
if not at term, give labetalol to lower BP
give magnesium sulphate to prevent seixures
IoL is safe
119
What prophylactic tx should you give a pregnant woman with a history of pre-eclampsia?
aspirin 75 mg
| from 10-36 weeks' gestation
120
What high risk ladies should be given aspirin during pregnancy?
High BMI
renal disease
known HTN
hx of pre-eclampsia
121
Define premature infant.
infant born before 37 weeks' gestation
122
Define small for dates.
below 10th centile for their gestational age
123
Define large for dates.
above 90th centile for their gestational age
124
Define low birth weight.
baby born with a weight < 2.5 kg
125
Define macrosomia.
baby born weighing > 4 kg
126
Define IUGR.
a baby which has not maintained its growth potential.
127
What are the major complications of premature delivery to the baby?
```
developmental delay
cerebral palsy
chronic lung disease
retinopathy of prematurity
necrotising enterocolitis
```
128
What are the diagnositc crtieria for preerm labour?
persistent uterine activity
+
change in cervical dilatation and/or effacement
129
How can preterm labour be predicted?
measure cervical length with transvaginal USS
| foetal fibronectin levels
130
How to reduce the risk of pre-term birth in those at increased risk?
cervical stitch if length < 3 cm
| IM or pessary progesterone
131
What are the signs of SIRS - systemic inflammatory response syndrome?
3 Ts white with sugar
```
temperature (>38 or <36)
tachycardia (>90)
tachypnoea (>20)
white blood cell count (<4 or >12)
sugar - blood glucose (>7.7 mmol in the absence of DM)
```
132
How should SGA babies be managed during pregnancy?
- growth scans every 2-3 weeks
- umbilical artery doppler to see if baby is getting enough blood
- offer corticosteroids for foetal lung maturity up to 35+6 weeks
133
What are 2 parental risk factors associated with miscarriage?
maternal age > 35
| paternal age > 40
134
What are some causes of miscarriage?
foetal chromosomal abnormalities
maternal illness - infections, pyrexia
trauma
135
What is the definition of recurrent miscarriage?
loss of >= 3 consecutive pregnancies
| before 24 weeks' gestation
136
What are some causes of recurrent miscarriage?
chronic materal disease - DM, SLE
Anti-phospholipid syndrome
uterine abnormality
infection - bacterial vaginosis
parental chromosomal abnormality - balanced Robertsonian translocation
thrombophilia - factor V Leiden deficiency, protein S and C deficiency
137
What serum markers would you look for if you suspected anti-phospholipid syndrome?
lupus anticoagulant antibodies
anti-cardiolipin antibodies
phospholipid antibodies
138
What is a threatened miscarriage?
mild symptoms
| cervical os is closed
139
What is inevitable miscarriage?
severe symptoms
| cervical os is open and you can pass one finger through it
140
What is incomplete miscarriage?
msot of the products have already been passed but there are some retaine dproducts of conception
141
What is a missed miscarriage?
foetus dies in utero without any symptoms
| picked up on USS
142
How does a miscarriage present?
PV bleeding
143
How do you investigate a miscarriage?
speculum exam - allows you to see the cervical os
digital vaginal exam
USS
144
How is a miscarriage managed?
expectant mgmt
ergometrine - to stop profuse bleeding
medical mgmt - mifepristone followed by misoprostol
surgical mgmt - if unacceptable bleeding, pain or significant retained products seen on USS
145
How should recurrent miscarriage be investigated?
refer to specialist recurrent miscarriage clinic
test for anti-phospholipid antibodies
thrombophilia screening
pelvic USS to look at structure of uterus
karyotype foetal products after 3rd foetal loss
146
What is the most common site for an ectopic pregnancy?
ampulla of the fallopian tube
147
What are the risk factors for an ectopic pregnancy?
```
hx of it
PID
damage to the tubes
endometriosis
copper coil
POP
smoking
tubal ligation
```
148
How does ectopic pregnancy present?
always consider ectopic in a sexually active woman with abdo pain, bleeding, fainting, diarrhoea or vomiting
```
uncertain LMP or 6-8 weeks amenorrhoea
unilateral abdo pain
PV bleed
D&V
dizziness and fainting
shoulder pain due to haematoperitoneum - irritates the diaphragm
```
149
How to investigate ectopic pregnancy?
```
pregnancy test - urinary beta hCG
vaginal and speculum exam - cervical motion tenderness/cervical excitation
USS
FBC
group and save
```
150
How to manage ectopic pregnancy?
expectant mgmt if hCG is falling, mild symptoms, no foetal heart activity on USS, woman is haemodynamically stable
medical mgmt - methotrexate - contraception for 3m after as teratogenic
surgical mgmt - laparoscopy - salpingectomy if other tube healthy
other tube unhealthy = salpingectomy
151
What are the SEs of methotrexate?
conjunctivitis
stomatitis
diarrhoea
abdo pain
152
What signs/symptoms do you get with a molar pregnancy?
aka hyatidiform mole
uterus bigger than expected for gestation
hyperthyroidism
painless PV bleed
excessive mornign sickness
high serum hCG --> hyperememsis gravidarum and thyrotoxicosis
