Care in Pregnancy Flashcards
1
Q
How do we assess the robustness of a screening test?
A
Sensitivity and specificity
Sensitivity= true positive/ all positives Specificity= true negative/ all negatives
2
Q
Describe appointment schedule in low risk and high risk pregnancy and who carries that out?
A
Low risk pregnancy series of routine antenatal with midwife
Booking appointment 8-12 weeks
before 14 weeks is trisomy screening
Review 16 weeks
Anomaly scan at 20 weeks
Seen again 25, 28, 31, 34, 36 weeks
Term is any time 37 – 42 weeks
If haven’t delivered by 38 weeks she is seen again by midwife, then at 40,41 and at 42 weeks if not delivered
High risk pregnancies have care lead by consultant obstetrician. High risk pregnancy has appointment schedule determined by what is going on in the pregnancy (should as minimum get same amount of appointments as normal pregnancy).
3
Q
Describe the 8-12 week booking appointment?
A
this is carried out by the midwife check height, weight, BP Blood tests to look at Hb, ABO, rhesus status and antibodies, syphylis, HIV, Hep B Urinanalysis Secondary appointment for US
4
Q
Describe the 8-12 week US?
A
Confirm viability of pregnancy. This is also the most accurate time to measure gestation using Crown Rump Length and estimate EDD. If miss 8-12 weeks age is estimated using head circumference which is less accurate than CRL. Can also detect any major anomalies.
5
Q
What is used to calculate due date before the dating scan at 8-12 weeks?
A
Naegeles rule predicts EDD based on onset of women’s LMP. Add on 9 months 7 days to get due date > 280 days. Scan is much more accurate so results of that should be used.
6
Q
What do you need to see on scan to tell if a pregnancy is viable?
A
fetal heartbeat (not visible until 6-7 weeks)
7
Q
When are scans offered in pregnancy?
A
8-12 week booking scan
20 week anomaly scan
8
Q
Describe history and exam done at a normal antenatal appointment?
A
HISTORY:
Physical and mental health
Fetal movements
EXAM: BP and urinalysis Symphysis- fundal height Lie and presentation Engagement of presenting part Fetal heart auscultation
9
Q
List the 11 conditions checked for at the 20 week anomaly scan? What other conditions are checked for?
A
anencephaly open spina bifida cleft lip diaphragmatic hernia gastroschisis exomphalos serious cardiac abnormalities bilateral renal agenesis lethal skeletal dysplasia Edwards' syndrome, or T18 Patau's syndrome, or T13
check placenta site
10
Q
Describe placenta praevia and why it is checked for at anomaly scan?
A
Placenta praevia is when the placenta is low lying in the uterus and covers all parts of the cervix. In most women as the uterus enlarges the placenta moves out of the way. If low at the 20 weeks scan then need to check again at 32 weeks. If still low then the woman needs C section for safe delivery around 37-38 weeks.
11
Q
Describe Downs, Edwards and Pataus and what this may mean for the baby?
A
Downs (T21)- difficult to predict how baby affected
Edwards (T18) and Pataus (T13) likely to be lethal if complete
12
Q
Describe trisomy risk assessment in first and second trimester?
A
In first trimester the skin thickness behind the fetal neck (nuchal thickness) is measured. This is measured 11-13+6 weeks and combined with HCG and PAPP A (increased NT = more chance of trisomy)
Second trimester screening can also be done but only for T21
13
Q
How reliable is the trisomy risk assessment in first trimester?
A
detects up to 90% T21 with 5% false positive rate
14
Q
Describe NIPT?
A
non-invasive prenatal testing detects placental DNA fragments in sample of blood taken from mother and is more accurate than combined test so can be offered to women identified as high risk from the combined test (not offered first because it is more accurate in those already identified as high risk). It is still only a screening test (so can’t offer TOP based on result but stops women who don’t need an invasive diagnostic test from having one)
15
Q
Describe diagnostic antenatal tests?
A
these can be done for a range of conditions including T21
Amniocentesis is done after 15 weeks and has a miscarriage rate of < 1%
chorionic villus sampling is done after 12 weeks and has a miscarriage rate of < 2%
16
Q
Describe screening for maternal anaemia and why it is important?
A
Need to optimise Hb during pregnancy to reduce risk of life threatening post partum haemorrhage
Iron (most common), folate, B12 all screened at booking and at 28 weeks
17
Q
Describe rhesus screening and what is given to mothers who are rhesus negative?
A
Blood group and antibody status should be determined at booking and 28 weeks, to prevent fetal anaemia
Anti D injections can be given to prevent D antibodies forming in Rh neg women, given routinely at 28 weeks and after any sensitising event (TOP, antepartum haemorrhage, invasive procedure, external cephalic version, fall or accident)
anti D is given again after birth if baby is rhesus positive (cord blood is tested)
18
Q
Describe screening of fetal growth?
A
Serial measurement of symphysis fundal height (SFH) is recommended at each antenatal appointment from 24 weeks of pregnancy as this improves prediction of SGA neonate
If worried about inaccuracies in measurement (e.g. high BMI, history of fibroids) or worried about low measurements can refer woman for US
19
Q
What cardiac symptoms may women experience during pregnancy and why?
A
Many women experience palpitations and SOB due to awareness of physiological sinus tachycardia, ventricular premature/ ectopic beats and increased minute ventilation
20
Q
What is the most common cause of maternal death in the UK?
A
cardiac disease
21
Q
What are the main heart conditions associated with pregnancy causing severe morbidity and mortality?
A
MI, aortic dissection and peripartum cardiomyopathy
22
Q
Define peripartum cardiomyopathy? What is a common sign?
A
This is defined as the development of heart failure at end of pregnancy or in months following delivery where no other cause is found. Orthopnoea is a common sign.
23
Q
Cardiac conditions should counsel mother against pregnancy?
A
pulmonary arterial hypertension systemic ventricular dysfunction previous peripartum CM with any residual LV impairment severe mitral stenosis severe symptomatic aortic stenosis aortic root > 4.5 cm in Marfans ascending aorta > 5cm with bicuspid A valve severe aortic coarctation
24
Q
Describe normal breathlessness in pregnancy?
A
Very common, up to 75% women and is due to awareness of physiological hyperventilation
more common in the third trimester
worse at rest or when talking, improves with exertion
usually doesn’t limit normal activities
25
What is the most common chronic medical disorder to complicate pregnancy?
asthma
26
How does the treatment of asthma compare in pregnancy vs normally?
treatment does not differ in the treatment of pregnant vs non pregnant
exact same
27
Do asthma drugs cause damage to pregnancy?
no- poorly controlled severe asthma presents a much bigger risk to the fetus than the medication used to treat it
28
Describe labour and asthma?
should be aiming for a vaginal birth, women should continue inhalers during labour (they do not impair uterine activity or delay the onset of labour)
if women are usually on oral steroids during labour they can be given IV hydrocortisone
29
What is the most common cause of direct death in pregnancy and puerperium?
PE
30
The risk of VTE in pregnancy is _______
4-6x higher
31
Where do most DVTs occur in pregnancy?
85-90% of DVTs occur in the left leg, > 70% of DVTs in pregnancy are ileofemoral (the groin)
32
The daily risk of VTE is ______ in puerperium compared to antenatal period
5 x
33
Is measuring d dimers in pregnancy to assess DVT risk useful?
no because they are often naturally raised
34
What can be used to look for DVT?
compression duplex US
35
What investigations may be used to look for PE in pregnancy?
CTPA and V/Q scans are both safe and only associated with negligible radiation to the fetus and are safe
36
Treatment of VTE in pregnancy?
larger doses of LMWH, warfarin should be avoided as it is teratogenic due to its ability to cross the placenta, DOACS are not used in pregnancy
37
Can warfarin be given in pregnancy?
no it crosses the placenta and is teratogenic
38
Describe heparin and warfarin use in the postnatal period?
Neither heparin or warfarin are contraindications to breast feeding
can commence warfarin on 5th post natal day
anticoagulant therapy should be continued until at least 6 weeks post natal and at least 3 months post partum
39
What pregnancy related complications are women with CTD at higher risk of?
```
miscarriage
PET
abruption
FGR
Still birth
Pre term labour
labour/ delivery complications
post natal complications
```
40
What treatment related complications are women with CTD at higher risk of?
```
Teratogenic
fetotoxic
sepsis
diabetes
osteoporosis
```
41
What disease related complications are women with CTD at higher risk of?
Lupus flare- renal or haematological
APS- arterial or venous thrombosis
Rheumatoid and scleroderma- renal deterioration or pulmonary HT
42
Define anti-phospholipid syndrome? How can it be diagnosed?
person has antiphospholipid antibodies (most common are anticardiolipin and lupus anticoagulant) and clinical features of the condition
diagnosis: have clinical features plus positive antibodies x 2 , 6 weeks apart
43
What are some clinical features of antiphospholipid syndrome?
```
arterial/ venous thrombosis
recurrent early pregnancy loss
late pregnancy loss usually preceded by fetal growth restriction
placental abruption
severe early onset pre-eclampsia (PET)
severe early onset FGR
```
44
Describe management of APS in pregnancy?
No thrombosis/ adverse pregnancy outcome - LDA, maternal and fetal surveillance
Previous thrombosis - if on warfarin stop, start LDA + LMWH (treatment dose)
Recurrent early pregnancy loss - LDA + LMWH (prophylactic dose)
Late fetal loss/ severe PET/ FGR - LDA + LMWH (prophylactic dose)
45
Which of these drugs are safe in pregnancy which are not safe?
Steroids, Leflunomide, azathioprine, cyclophosphamide, methotrexate?
safe:
steroids
azathioprine
not safe:
leflunamide
methotrexate
cyclophosphamide
46
Which of these drugs are safe in pregnancy which are not safe?
sulfasalazine, hydroxychloroquine, MMF, penicillamine, gold?
safe:
sulfasalazine
hydroxychlorquine
not safe:
MMF
penicillamine
gold
47
Which of these drugs are safe in pregnancy which are not safe?
chlorambucil, rituximab, adalimumab, infliximab, entanercept?
safe:
rituximab, adalimumab, infliximab, entanercept
not safe:
chlorambucil
48
Is aspirin safe in pregnancy? Are NSAIDs safe in pregnancy?
aspirin is safe
| NSAIDS are not safe if > 32 weeks
49
Describe seizure frequency with epilepsy during pregnancy?
For most women seizure frequency is unchanged or improves
50
Describe the risk to fetus of AEDs vs uncontrolled epilepsy in pregnancy?
the risk to the fetus of uncontrolled seizures is greater than the risks of continuing AED treatment, poorly controlled epilepsy and recurrent seizures are associated with adverse outcomes for the fetus
51
Describe the risks of birth defects in babies of mothers who take AED?
the overall risk of birth defects in babies of mothers who take AED is around 7% as compared with 3% in women without epilepsy, the risk of polytherapy is more at around 16%
52
Describe the use of sodium valproate in pregnancy?
Sodium valproate is associated with a higher rate of serious malformations e.g. neural tube defects and long term neurodevelopmental defects e.g. a reduced IQ, increased risk of ASD, increased ADHD risk and should be stopped or substituted if necessary
53
Describe management of a woman with epilepsy who would like to get pregnant?
counselling before conception is essential, folic acid 5mg/day supplements should be taken before conception and throughout the first trimester, vitamin K should also be taken by women receiving enzyme inducing AEDs in the last 4 weeks before delivery to prevent neonatal haemorrhage, antenatal screening for congenital abnormalities is necessary
54
Describe breastfeeding and AEDs?
mothers on AEDs can breastfeed although manufacturers won't guarantee safety but they are most likely fine
55
Describe labour in women with epilepsy?
most women with epilepsy will have a normal labour and vaginal birth, up to 2.6% will have a seizure, if generalised tonic clonic seizure then maternal hypoxia, fetal hypoxia and acidosis may result
56
What are three categories of hypertension in pregnancy?
pre-existing, gestational/ PIH and pre-eclampsia
57
Define pre-existing hypertension?
this is present at the initial booking visit or before 20 weeks or the patient is already taking medication for hypertension
it is the likely diagnosis if hypertension is present early in the pregnancy because PET or PIH are diseases of the second half of pregnancy
58
Pre-existing hypertension increases the risk of ________________
pre-eclampsia, intra-uterine growth restriction and abruption
59
Management of pre existing hypertension in pregnancy?
ACEi, ARBS and chlorothiazide agents are associated with congenital abnormalities and should be discontinued. Dietary salt intake should be kept low. Aspirin 75 mg should be given from 12 weeks onwards until birth to women at moderate or high risk of pre eclampsia
oral labetolol is 1st line therapy during pregnancy, second line agents are methyldopa and nifedipine. Target BP at <150 / 80-85, if BP < 160/110 birth shouldn't be offered before 37 weeks
60
What are the drugs used for treatment of hypertension in pregnancy?
oral labetolol is 1st line therapy during pregnancy, second line agents are methyldopa and nifedipine.
61
Management of pre existing hypertension in postnatal period and breast feeding?
ACEi, B blockers and nifedipine are all safe in breastfeeding, Methyldopa should be avoided because of the risk of depression.
62
Define gestational hypertension/ PIH?
This is defined as BP > 140/90 after 20 weeks gestation in a previously normotensive woman
there is no proteinuria or other features of pre eclampsia
63
Prognosis of gestational hypertension?
usually resolves within 6 weeks of delivery
64
____ rate of PIH to pre eclampsia
| rate of recurrence is ____
15%
| high
65
Investigations for PIH?
blood tests- FBC, U and E, serum creatinine, calcium, liver biochemistry and LFTs
BP measurements should be done once a week
urine tests for protein to check if pre eclampsia develops
66
Management of PIH?
treat moderate HT 150-9/ 100-9 with oral labetolol
admission to hospital if BP > 160/110 is required
treatment may be required for several weeks post partum
67
Explain what pre-eclampsia is?
condition seen after 20 weeks of pregnancy characterised by pregnancy induced hypertension with proteinuria (>0.3 g/ 24hr) and oedema
it is a common obstetric cause of maternal and perinatal death and morbidity
it is a pregnancy specific multi system disorder with unpredictable, variable and widespread manifestations
there is diffuse vascular endothelial dysfunction and widespread circulatory disturbance
68
Explain the theorised pathophysiology of pre-eclampsia?
* There is thought to be a genetic and/ or environmental predisposition to the development of pre-eclampsia
* Stage 1 involves abnormal placental perfusion due to abnormal trophoblast invasion
* Stage 2 involves the maternal syndrome where the mother responds to the decreased placental perfusion and this is what causes the systemic disease
* There is an imbalance in angiogenic and anti-angiogenic factors which is what causes the widespread endothelial dysfunction and circulatory disturbance
69
List some risk factors for developing pre-eclampsia?
```
Age > 40 yo
FH
Multiple pregnancy
BMI > 30
Primiparity
previous pre-eclampsia
long birth interval
hydrops with large placenta
hydatiform mole
triploidy
pre-existing HT
renal disease
Diabetes of any kind
Antiphospholipid syndrome
RA
Sickle cell
```
70
Describe some potential symptoms of pre-eclampsia?
```
headache
visual disturbance
epigastric/ RUQ pain
nausea and vomiting
rapidly progressive oedema
```
71
Describe some signs of pre-eclampsia?
```
hypertension
proteinuria
oedema
abdominal tenderness
disorientation
SGA
intra-uterine fetal death
hyper reflexia / involuntary movements / clonus
```
72
Investigations for pre-eclampsia?
```
U and Es
Serum urate
LFTs
FBCs
Coagulation screen
urine creatinine ratio
cardiotocography (records fetal heart beat)
ultrasound to assess the fetus
```
73
Management of pre-eclampsia if BP 140/90- 159/109 ?
admit if clinical concerns for wellbeing of woman or baby or high risk of adverse events
offer pharmacological treatment if BP remains above 140/90
BP monitor every 48 hours, more if in hospital
measure FBCs, liver function, renal function twice a week
fetal heart auscultation at every antenatal appointment, US at diagnosis and then every 2 weeks
74
Management of pre-eclampsia if BP > 160/110?
admit to hospital, if BP falls can manage in the community
pharmacological treatment for all women
BP 135/85 or less as target
BP should be monitored every 15-30 minis until falls below 160/110
Measure FBCs, liver function, renal function, 3 times a week
fetal heart auscultation at every antenatal appointment, US at diagnosis and then every 2 weeks
75
The only cure for pre eclampsia is ________
to deliver the baby
76
Indications for birth in pre-eclampsia?
```
term gestation
inability to control BP
rapidly deteriorating biochem/ haematology
eclampsia
other crises
fetal compromise on US or CTG
```
77
If birth in next 7 days due to pre eclampsia is likely what should you do?
offer a course of antenatal steroids
78
List some crises that can develop in pre-eclampsia?
```
eclampsia
HELLP syndrome
pulmonary oedema
placental abruption
cerebral haemorrhage
cortical blindness
DIC
acute renal failure
hepatic rupture
```
79
What is eclampsia?
tonic clonic (grand mal) seizure occurring with features of pre-eclampsia.
80
Management of eclampsia?
control BP with IV labetolol or IV hydralazine
stop/ prevent seizures with IV magnesium sulfate
fluid balance (PO is a big cause of death in mother) safer to run a patient dry at 80ml/ hr
delivery- can aim for vaginal birth if possible
81
What is HELLP syndrome?
haemolysis, elevated liver enzymes, low platelets
| a complication of pre-eclampsia
82
Symptoms of HELLP syndrome?
epigastric/ RUQ pain, nausea, vomiting and jaundice
83
Management of HELLP syndrome?
treatment is similar to eclampsia but may also give blood transfusions to treat anaemia and low platelet levels
if symptoms are severe, prompt delivery is necessary and is advised in all patients who are beyond 34 weeks gestation
84
Secondary prevention of pre-eclampsia?
aspirin after 12 weeks gestation until birth
given to anyone with a high risk factor: previous PIH or hypertension, autoimmune disease, diabetes or CKD) or 2 moderate (> 40 yo, BMI > 35, long birth interval > 10 years, primiparity, FH)
85
Post partum management of pre-eclampsia?
women who wish to breastfeed can have meds adapted appropriately
monitor BP in the post natal period
should consider the woman's long term cardiovascular risk
86
Recurrence of HT disorders in pregnancy?
overall risk of recurrence in future pregnancies is 1/5
| those who developed pre-eclampsia earlier in pregnancy have a higher risk of recurrence
87
Describe calorie requirements in pregnancy?
Eating for 2 is a myth
first 2 trimesters there is no need to increase calories
studies show that the body absorbs extra nutrients from food and becomes more efficient
in last 12 weeks a woman requires 200 extra calories
88
Risks of folic acid deficiency in pregnancy?
can cause spina bifida, heart or limb defects and some childhood brain tumours and anaemia
89
Recommendations for folic acid in pregnancy?
recommend folic acid 400 micrograms supplements 3 months before conception up to end of 12th week if didnt realise pregnant start taking ASAP
90
Who is given high dose folic acid? What dose is this?
```
dose is 5 mg
Previous pregnany affected by spina bifida
Woman/ partner who has spina bifida
Anticonvulsants for epilepsy
Coeliac disease
Diabetes
BMI is 30 or more
Sickle cell anaemia or thalassemia (higher dose of folic acid will also help to prevent and treat anaemia)
Folic acid deficiency
```
91
Vitamin D recommendations in pregnancy?
10 micrograms daily in pregnancy and when breastfeeding
92
Vitamin D deficiency maternal risks?
Osteomalacia, Pre-eclampsia, Gestational diabetes, Caesarean section, Bacteria vaginosis
93
Vitamin D deficiency fetal risk?
SGA, Neonatal Hypocalcaemia ,Asthma/Respiratory Infection, Rickets
94
Ways to reduce risk of listeriosis in pregnancy?
Drink only pasteurised or UHT milk
avoid eating ripened soft cheese such as Camembert, brie or blue veined cheese, hard cheese is okay
avoid pate
avoid undercooked food
make sure ready prepared meals are piping hot
be careful if others/ eating handling these foods
careful of close contact with farm animals
95
Ways to reduce risk of salmonella in pregnancy?
avoid raw or partially cooked eggs or food that may contain them e.g. mayonnaise or mousse
avoid eating raw or partially cooked meat esp poultry and shellfish
96
Ways to reduce risk of toxoplasmosis in pregnancy?
always wash hands before and after handling food
wash all fruit and veg including ready prepared salads
cook raw meats and ready prepared chilled meats thoroughly
wear gloves and wash your hands thoroughly after gardening or handling soil
avoid contact with cat faeces
97
Complications of iron deficiency in pregnancy?
```
tiredness
SOB
preterm labour
still birth
IUGR
low birth weight
placental abruption
post partum haemorrhage
neonatal iron deficiency in 1st 3 months of life
neurodevelopmental delay in the baby
```
98
When is iron deficiency checked for in pregnancy?
looked for at booking appointment and 28 weeks
99
Treatment of iron deficiency in pregnancy?
increase iron intake in diet, iron tablets or liquid, IV iron, can advice women that taking tablets with vitamin c e.g. orange juice can increase absorption, caffeine and tea reduce absorption
100
Are peanuts safe in pregnancy?
yes if no existing allergy
101
Advice for caffeine intake in pregnancy?
limit caffeine to 200 mg a day e.g. 2 cups of coffee or tea
102
Foods to avoid in pregnancy?
```
soft cheese
undercooked meats, cured meats, game
tuna
raw/ partially cooked eggs
pate
liver (too much vit a)
vitamin and fish oil supplements
```
103
Post partum and breastfeeding nutrition?
demands of lactation exceed pre-pregnancy demands by approx 600 k cal a day in exclusive breast feeding
this is very variable
104
Define small for gestational age? (SGA)
infant born with birth weight below the 10th centile
| picked up because abdominal circumference or estimated fetal weight is below the 10th centile on US
105
Define low birth weight? (LBW)
infant with birth weight < 2500g at any gestation
106
Explain the difference between SGA and LBW?
low birth weight is an absolute figure but SGA depends on the baby's gestation so a premature baby will likely have a low birth weight but could be normal weight for gestational age
107
Define fetal growth restriction?
failure to achieve genetic potential for growth, this implies pathological restriction of genetic growth potential
108
Are all SGA babies growth restricted?
no, 70% SGA will be constitutionally small
109
Interventions for SGA should be targeted _________
at SGA below 3rd centile as more likely to have underlying pathology
110
List some causes of SGA?
CONSTITUTIONALLY SMALL: ie the mum and dad are small so it is normal for the baby to be small
PLACENTAL: infarcts, abruption, often secondary to hypertension
FETAL: infection e.g. rubella, CMV, congenital anomalies e.g. absent kidneys, chromosomal abnormalities e.g. Downs
MATERNAL: lifestyle e.g. smoking, alcohol, drugs, age of mum, maternal disease e.g. hypertension
111
List some complications of fetal growth restriction?
higher rates of stillbirth
greater perinatal morbidity and mortality: antenatal and intrapartum hypoxia, hypoglycaemia, hypothermia, polycythaemia, hyperbilirubinaemia, abnormal neurodevelopment in neonate
may need preterm delivery
SGA may be presentation of a maternal comorbidity e.g. 1st sign of pre-eclampsia
112
Describe how SGA is identified and diagnosed?
women are screened for major and minor risk factors and those at risk will get extra scans
abnormal uterine artery doppler at 20 weeks is treated as a major risk factor
if a woman has SFH measurement below the 10th centile or serial measurements which suggest crossing of centiles then they will be referred for serial growth scan
SGA is diagnosed by US measurement of AC and calculation of EFW
113
What may make SFH inaccurate? What may be done?
fibroids or BMI > 35
| women sent for scans to allow fetal growth to be monitored accurately
114
Describe management of SGA through pregnancy?
```
PRINCIPLES:
identify women at high risk of IUGR
early antepartum diagnosis diagnosis
determine aetiology (and treat if can)
regular monitoring
appropriate timing of delivery
```
once SGA is identified, schedule is individualised depending on cause
serial growth scans with umbilical doppler and liquor volume (amniotic fluid) should all be conducted as a minimum
150 mg aspirin at night from 12 weeks should be given in women with risk factors for pre-eclampsia or uterine artery notching at scan
consider offering genetic testing and infection screening
115
Describe management of delivery of SGA?
Time to deliver: find balance between premature delivery and compromise in utero. Below third centile offer delivery from 37 weeks and aim to have delivery by 37 + 6 weeks. between 3rd and 10 th centile offer delivery at 39 weeks.
If no other obstetric indication and doppler is normal then the aim is for vaginal delivery via IOL
abnormal umbilical doppler can mean an increased chance of fetal distress in labour therefore C section may be offered
continuous CTG monitoring in pregnancy is imperitative
antenatal steroids offered for some early deliveries
magnesium sulfate is offered below 32 weeks as thought to offer some protection against cerebral palsy
116
Do most drugs cross the placenta?
yes, most drugs cross except large molecular weight heparin, small lipid soluble drugs cross more quickly.
117
Define pharmacokinetics?
what the body does to the drugs
| e.g. absorption, distribution, metabolism, elimination
118
Describe the different effects pregnancy can have on pharmacokinetics?
- Absorption of drugs can be affected by morning sickness
- Increased plasma volume and fat stores in pregnany means volume of distribution increases
- Decreased protein binding in pregnancy, so there is increased free drug levels
- Increased liver metabolism of some drugs in pregnancy e.g. phenytoin
- Elimination of renally excreted drugs increases so there is an increased GFR
- May need to check concentrations and alter dose during pregnancy and after delivery
119
Define pharmacodynamics?
what the drug does to the body
120
Describe how pharmacodynamics may change in pregnancy?
No significant changes
| Pregnant women may be more sensitive to some drugs e.g. hypotension with antihypertensives in second trimester
121
Describe how drugs can affect the baby in first trimester?
Risk of early miscarriage
Organogenesis
Period of greatest teratogenic risk mainly between 4th and 11th week of pregnancy
Avoid drugs if at all possible unless maternal benefits outweighs risk to fetus
122
What is the period of greatest teratogenic risk?
between 4th and 11th week of pregnancy
123
List some drugs and specific teratogenic effects? (8)
```
ACE/ ARBs- renal hypoplasia
Androgens- virilization of female fetus
Antiepileptics – cardiac, facial, limb and neural tube defects
Cytotoxics- multiple defects, abortion
Lithium- cardiovascular defects
Methotrexate- skeletal defects
Retinoids- ear cardiovascular, skeletal defects
Warfarin- limb and facial defects
```
124
Describe how drugs can affect the baby in the second and third trimester?
Growth of fetus
Functional development: intellectual impairment, behavioural abnormalities
Some agents can have Toxic effects on fetus e.g. chemotherapy
125
Describe how drugs may affect the baby around term?
- adverse effects on labour such as progress of labour and adaptation of fetal circulation e.g. premature closure of ductus arteriosus
- suppression of fetal systems e.g. resp depression
- bleeding with warfarin
- advere effects on baby after delivery such as withdrawal syndrome – opiates or SSRIs
- some drugs can cause sedation and then make it difficult for baby to feed
126
Describe delayed effects a drug might have when taken in pregnancy?
- Diethylstilbestrol
- Thought it might help prevent recurrent miscarriage
- Then years later turned out higher rate of vaginal adenocarcinoma in girls aged 15-20 years whose mothers were exposed to this
- Also higher rate of urological malignancy in boys
- Probably many drugs with these delayed and subtle effects that we are unaware of
127
What can be prescribed acutely in pregnancy for nausea and vomiting?
cyclizine
128
What can be prescribed acutely in pregnancy for UTI?
check local guidelines generally nitrofurantoin, cefalexin (in third trimester trimethoprim)
129
What can be prescribed acutely in pregnancy for pain?
paracetamol
130
What can be prescribed acutely in pregnancy for heartburn?
antacids
131
Most drugs enter breastmilk but ________
few enter in sufficient quantities to cause a problem
132
Some known effects of drugs in breast feeding?
Amiodarone- neonatal hypothyroidism
Cytotoxics – bone marrow suppression
Benzodiazepines- drowsiness
Bromocriptine- suppress lactation
133
Define a large for dates fetus?
one that has an estimated fetal weight greater thanthe 90th centile
clinically the SFh wil be > 2 cm for gestational age
134
Causes/ reasons for large for date fetus?
wrong dates, fetal macrosomnia, polyhydramnios, diabetes, multiple pregnancy
135
Define fetal macrosomina?
"big baby"
| absolute birth weight > 4000g
136
How accurately can you determine fetal macrosomnia?
not very because estimated fetal weight ultrasound has a margin of error up to 10% and is more accurate before 38 weeks
137
Common risk factors for fetal macrosomnia?
maternal diabetes, post term pregnancy, maternal obesity (although note that most women with these risk factors will have a normal weight baby)
138
Complications of fetal macrosomnia?
increases the risk of labour dystocia (baby is physically blocked), or should dystocia (entrapped shoulders) as well as post partum haemorrhage
139
Management of fetal macrosomnia?
exclude diabetes
reassure patient
NICE guideline: in the absence of any other indications, IOL should not be carried out simply because LGA is suspected
140
Define polyhydramnios?
This is defined as excess amniotic fluid. The amniotic fluid index is > 25 cm and deepest pool is > 8cm.
141
Causes of polyhydramnios?
maternal diabetes, fetal anomaly e.g. GI atresia, cardiac deformities, hydrops fetalis due to Rh isoimmunisation, infection (toxo, CMV)
most commonly it is idiopathic
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Symptoms and signs of polyhydramnios?
presentation: abdominal discomfort, prelabour rupture of membranes, preterm labour and cord prolapse
signs: large for dates, malpresentation, shiny tense abdomen and inability to feel fetal parts
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Investigations for polyhydramnios?
OGTT (to check for diabetes), serology to check for toxo, CMV, parvo, Ab screen, USS survey of fetal lips and stomach
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Management of polyhydramnios?
identify underlying cause and treat, mild polyhydramnios can simply be monitored, preterm labour is common due to overdistension of uterus, IOL by 40 weeks
145
Complications of labour with polyhydramnios?
malpresentation, cord prolapse, preterm labour, PPH
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Rate of spontaneous twins and triplets?
twins- 1 in 80
| triplets- 1 in 10 000
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Risk factors for multiple pregnancy?
Assisted conception e.g. clomid, IVF
Ethnicity – higher rates in those of African origin
Geography – Europe 6-9/1000 deliveries, Nigeria 40-50/1000 deliveries, Japan and China 2/1000
Family history on maternal side
Increased maternal age
Increased parity
Tall women > short women
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Define monozygotic vs dizygotic twins?
monozygotic- splitting of a single fertilised egg
| dizygotic- fertilisation of 2 ova by 2 sperm
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Explain chorionicity in multiple pregnancies and all the possibilities?
refers to how many placentas
dizygotic twins will always be dichorionic and diamniotic
with monozygotic twins it depends on the time of the splitting of the fertilised ovum
if splits 1-3 days then DCDA
if splits 4-8 days then MCDA
if splits 8-13 days then MCMA
If splits 13-15 days then will get conjoined twins
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How does a clinician determine chorionicity?
US using the shape and thickness of the membrane, this is most reliably done at the booking scan
151
Why is it important to determine chorionicity of a multiple pregnancy
monochorionic/ monozygotic twins are at higher risk of pregnancy complications and require 2 weekly US to pick up the early signs of twin twin transfusion syndrome
152
Symptoms and signs of multiple pregnancy?
exaggerated pregnancy symptoms e.g. excessive sickness
high AFP
large for dates uterus
multiple fetal poles
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Complications of multiple pregnancy?
Congenital anomalies
Intrauterine deaths (single and both) – higher perinatal mortality (6 times higher than singleton)
Pre-term birth
Growth restrictions – both/discordant
Cerebral palsy – twins 8x higher, triplets 47x higher
Twin to twin transfusion (only in monochorionic pregnancies)– oligohydramnios and polyhydramnios.
Hyperemesis gravidarum
Anaemia
Pre-eclampsia
Gestational diabetes
Antepartum haemorrhage – abruption, placenta praevia
Preterm labour (50%)
Caesarean section
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Antenatal management of multiple pregnancy?
Women with confirmed multiple pregnancy receive consultant led care and attend antenatal clinic every 2 weeks for monochorionic pregnancies and every 4 weeks for dichorionic pregnancies.
Women are given iron and folic acid supplementation, low-dose aspirin to try to prevent hypertensive disorders.
Ultrasound scans are done from 16th week of gestation every 2 weeks where the deep vertical pool, bladder and umbilical artery are assessed
Anomaly scan is done at 18-20 weeks.
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Explain what TTTS is?
A condition where there is disproportionate blood supply to fetuses in monochorionic pregnancies.
Because monochorionic twins share a placenta, anastomoses in the blood supply may not be balanced causing blood from the “donor” twin to flow to the “recipient” twin.
This causes the donor twin to have a decreased blood volume which affects growth and development and leading to decreased urine output, anaemia and oligohydramnios while the blood volume in the recipient twin increases leading to increased urinary output and polyhydramnios, polycythaemia and eventually heart failure.
High morbidity and mortality
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Treatment of TTTS?
if 26/40 fetoscopic laser ablation if > 26/40 then amnioreduction/ septostomy
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What do MCMA twins have high risk of?
cord entanglement and fetal death
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What are higher order births offered and why?
they are offered selective reduction because they are such high risk pregnancies
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Delivery of DCDA, MCDA, MCMA and triplets?
DCDA Twins deliver 37-38 weeks
MCDA Twins deliver after 36+0 weeks with steroids.
Triplets or more – Caesarean section
MCMA- Caesarean section deliver at 32-34+0 weeks
DCDA and MCDA Twins if twin one cephalic can aim for vaginal delivery but may opt for a c-section – maternal choice. Risk of caesarean section after 1st twin delivering vaginally (20%)
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Overall the risk of C section in twins is _____
approx 50%
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Management of labour of multiple pregnancies?
Suggest epidural analgesia because can be used to facilitate operative delivery
fetal monitoring: continuous use of CTGs for both, possibly use a fetal scalp electrode.
Syntocinon after twin 1 to maintain contractions and aid delivery
USS to confirm presentation
Intertwin delivery time aimed for <30min
Risk of PPH- active 3rd stage
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List some causes of pruritis in pregnancy?
No rash
- obstetric cholestasis
Rash
- 3rd trimester - polymorphic eruption of pregnancy
- 1st/2nd trimester - atopic eruption of pregnancy
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List some causes of jaundice in pregnancy?
obstetric cholestasis
AFLP
HELLP syndrome
Causes that are not directly pregnancy related: viral hepatitis, chronic liver disease, autoimmune hepatitis, gallstone disease
164
Explain what obstetric cholestasis (AKA intrahepatitis cholestasis of pregnancy) is and the proposed pathogenesis?
Occurs when there is reduced outflow of bile acids from the liver during pregnancy and then resolves after delivery of the baby. Thought to be related to oestrogen and progesterone levels, maybe a genetic component as more common in those of SA ethnicity.
165
Is Obstetric cholestasis common?
yes - reasonably common - will occur in 1% of pregnancies
more common in those of SA ethnicity
166
What trimester does obstetric cholestasis present in?
3rd trimester
167
There is increased risk of what in obstetric cholestasis?
stillbirth
168
Presentation of obstetric cholestasis?
presents in 3rd trimester with itch without rash, particularly affecting the palms of hands and soles of feet
other symptoms include fatigue, dark urine, pale stools and jaundice
169
Women presenting with pruritis in pregnancy should have what checked?
LFTs and bile acids
170
Management of obstetric cholestasis?
ursodeoxycholic acid, emollients and antihistamines, water soluble vitamin K if clotting deranged
monitor LFTs
consider planned delivery after 37 weeks
171
Is acute fatty liver of pregnancy common? Is it serious?
no this is rare
yes serious with a high risk of liver failure and mortality for both mum and fetus
172
Explain what AFLP is and proposed pathogenesis?
rare condition that occurs in 3rd trimester where there is rapid accumulation of fat in hepatocytes causing acute hepatits
proposed to result from impaired processing of fatty acids in the placenta - result of a genetic condition in the fetus that impairs fatty acid metabolism
the fetus and placenta cannot break down fatty acids so these enter the maternal circulation and accumulate in the liver
173
Presentation of AFLP?
general malaise and fatigue
nausea and vomiting
jaundice
abdo pain
anorexia
ascites
174
What will bloods show for AFLP
LFTs will show a raised ALT and AST
There will also be a raised bilirubin, raised WBC, deranged clotting and low platelets
175
Management of AFLP?
obstetric emergency
admit and deliver baby, most patients recover after delivery but if not may need to consider a liver transplant
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2 common itchy pregnancy rashes?
polymorphic eruption of pregnancy - presents in 3rd trimester
atopic eruption of pregnancy - presents in 1st or second trimester
177
Gravidity vs Parity?
G= no of times a woman has been pregnant regardless of outcomes
P= number of deliveries after 24 weeks
178
Empty sac vs empty sac and yolk sac on US?
empty sac with a yolk sac suggests a viable pregnancy, this should be visible by 6 weeks
179
Pregnancy and cervical smears?
book in for 12 weeks or more post partum
