Pregnancy Flashcards
What is a blastocyst?
- a ball of rapidly diving cells
- 200-300 cells
- what implants onto the uterus wall
When does the blastocyst attach to the uterus lining?
- day 5-8
When does the blastocyst implant on the uterus?
- by day 12
The outer cells of the blastocyst form what?
- The placenta
What is the role of the placenta?
- oxygen transport
- nutrient and waste transport
What is the placenta derived from?
- trophoblast and decidual tissue?
Explain how maternal and fetal blood doesn’t mix?
- trophoblast cells -> multinucleate cells -> invade decidua -> breakdown of capillaries
- formation of cavities filled with maternal blood (intervillous space)
- foetal umbilical veins and arteries penetrate into intervillous space
- villus filled with foetal blood
At what stage is the placenta functional?
- by the 5th week
HCG causes what?
- the corpus luteum to secrete progesterone in early pregnancy
- doubles every 48hrs until week 12-14
Maternal oxygen rich blood enters what?
- umbilical veins
What increases the oxygen transport to the foetus?
- fetal Hb = greater affinity for o2
- Increased Hb in foetus
- Bohr effect
Explain the Bohr effect?
- foetal Hb can carry more O2 in lower PCO2 than high
CRH causes??
- acth -> Aldosterone + cortisol
- leading to gestational diabetes and hypertension
Increased HCG may cause?
- hyperthyroidism
What does HCG stand for?
- human chorionic gonadotrophin
Role of HPL
- Human placental lactogen
- growth hormone
- decreases insulin sensitivity in mum
Role of progesterone in pregnancy?
- reduces contraction
- preparation of lactation by development of lobular-alveolar system
Role of oestrogens in pregnancy?
- uterus enlargement
- breast development by growth of ductile system
- relaxation of ligaments
- increase in oxytocin receptors
Explain cardiovascular changes in pregnancy?
- increased cardiac output
- increased heart rate
- decreased BP in 2nd trimester
Explain haematological changes in pregnancy?
- Increase in plasma volume (can cause increased oedema)
- increased RBC
- Decreased Hb
How is anaemia defined in pregnancy?
- 1st trimester Hb< 110
- 2nd or 3rd Hb < 105
Respiratory changes in pregnancy?
- increased respiratory rate
- increased o2 consumption
- decreased pco2
Urinary changes in pregnancy?
- GFR and renal plasma flow increases
- increased urine formation
Why is there an increased risk of VTE in pregnancy?
- hypercoaguable state to reduce risk of haemorrhage
Average weight gain in pregnancy?
11 kg
What causes maternal insulin resistance?
- HPL
- CORTISOL
- GROWTH HORMONES
The 2 metabolic phases of pregnancy?
- 1st trimester = anabolic
- 2nd/3rd = catabolic
Special nutritional needs in pregnancy?
- folic acid
- vitamin D
- high protein
- iron supplementation
- vitamin b
What may be given to induce labour?
- prostaglandins
- oxytocin
Role of prostaglandins in labour?
- ripen cervix
Role of oxytocin in labour?
- increased contraction
- stimulation of prostaglandins (ripen cervix)
Role of oestrogen in labour?
- increases oxytocin receptors?
3 stages of labour?
- cervical dilation
- passage of foetus from birth canal
- passage of placenta
Oxytocin role in lactation?
- milk let down reflex
What hormone stimulates milk?
- prolactin
Define sensitivity?
sensitivity = true positives / (positive + false negatives)
When is the booking scan usually performed?
- 8-12weeks
What does the booking exam incorporate?
- medical hx, surgical hx, social and family hx
- examination
- bloods
- USS
Explain how gestation can be calculated before a scan?
- Naegele’s rule = add 280 days onto LMP
Pseudo sac on USS may indicate?
- ectopic pregnancy else where
Placenta previa?
- condition where the placenta lies over the cervix
- c-section will be required
Trisomy 18?
- Edward’s syndrome
- almost always seen on 20 week scan due to multiple abnormalities
Trisomy 21?
- Down syndrome
- may not always be seen on USS as a spectrum disease
Trisomy 21 is also associated with what conditions?
- duodudenal atreasia
- cardiac defect
Trisomy 13?
- Patau’s syndrome
- multiple physical abnormalities
- generally fatal
When is trisomy screening performed and what does it include?
- first trimester
- trisomy 13, 18, 21
- nuchal translucency test and bloods
Explain nuchal translucency?
- volume of fluid behind the fetal neck
- increased volume associated with increased risk of foetal abnormality
If a pregnancy is deemed high risk of trisomy what test can be done?
- NIPT
- Non-invasive parental testing
- screening only
What diagnostic antenatal tests can be performed?
- amniocentesis
- chorionic villus sampling
Maternal anaemia may be due to what?
- iron, folate, B12 deficiency
When is Anti-D injections given to a mother with rhesus negative status?
- 28 weeks
- any sensitising event
Risk factors for gestational diabetes?
- BMI > 30
- Previous macrosomic baby
- previous gestational diabetes
- 1st degree relative with diabetes
- minority ethnic family origin
How is fetal growth assessed?
- from 24 weeks
- SFH (Symphysis fundal height)
How is pre-eclampsia screened for?
- urinalysis and BP
- High risk advised to take 150mg aspirin
Urinalysis is performed in pregnancy to screen for what>
- UTI
- Asymptomatic bacteria
- pre-eclampsia
- diabetes
Define pharmacokinetics?
- what the body does to the drug
How might absorption of a drug differ in pregnancy?
- morning sickness
- increased plasma volume
- increased fat stores
Folic acid recommendation?
- 400mg daily for 3 months prior and first 3 months
Name some teratogenic drugs?
- ACEi
- ARB
- Lithium
- Antiepileptics
- methotrexate
- androgens
What should be used to treat diabetes in pregnancy
- insulin
- off sulphonyureas
Epilepsy medication has a risk of?
- congenital abnormalitiy
- increase folic acid to 5mg
Drugs used for hypertension in pregnancy?
- labetolol
- methyldopa
Amiodarone in breast feeding?
- neonatal hypothyroidism
Prophylaxis for high risk VTE in pregnancy
- LMWH
Tetracyclines in pregnancy?
- may cause teeth or bone staining
- avoid
Alcohol in pregnancy may cause
- fetal alcohol syndrpme
Phenytoin is what drug, and why should it be avoided in pregnancy?
- antiepileptic
- cleft lip and palate
Valproate may have what affect on feotus
- neural tubal defects
- avoid
What is performed in a 1st trimester trisomy screening test?
- nuchal translucency
- serum markers
What is a normal nuchal translucency?
- less than 3.5mm
If a pregnancy is deemed high risk for trisomy 21 after trisomy screening what is performed?
- NIPT
Explain NIPT
- Screening test
- placental DNA in maternal blood
- predictive value > 90%
Disadvantage of microarray?
- may highlight many polymorphisms
When is a foetal MRI used?
- foetal brain abnormalities
What is a TORCH screen?
- looking for foetal infections
- toxoplasosis
- rubella
- cytomegalovirus
- herpes simplex
HIV
What defines a large for date baby?
- Symphyseal-fundal height > 2cm for gestational age
Causes of large for dates?
- wrong dates
- fetal macrosomia
- polyhdramnios
- diametes
- multiple pregnancy
- obesity
What is foetal macrosomia?
- USS EFW > 90th centile
- > 4.5kg
Risks associated with foetal macrosomia?
- labour dystocia
- shoulder dystocia
- PPH
When would a c-section be recommended in Fetal macrosomia?
- EFW > 5kg
Define polyhydramnios?
- excess amniotic fluid
- amniotic fluid index > 25cm
- deepest pool > 8cm
Causes of polyhydramnios?
- diabetes
- gi atresia
- hydrops fetalis
- viral infection
- idiopathic
Investigations for polyhydroamnios?
- OGTT
- Serology
- antibody screening
- USS
Management of polyamniohydros?
- induced labour by 40weeks
Monozygotic?
- one egg divides
Dizygotic?
- 2 eggs 2 stem
Monochorionic?
- twins share 1 placenta
How often should monochorionic twins be USS?
- 2 times per week after 16 weeks
How often should dichoronic twins be USS?
- Every 2 weeks after 16 weeks
Symptoms of a multiple pregnancy?
- increased symptoms
- increased AFP
- Large for dates
What should be given to multiple pregnancy?
- iron supplements
- folic acid
- low does aspirin
Complications of a multiple pregnancy?
- single fetal death
- twin-to-twin transfusion syndrome
- twin anaemia polycthaemia sequence
Explain twin-to-twin transfusion syndrome? And its treatment
- anastomosis of arterial and venous
- one twin is the donor (olgiohydraminos)
- one twin is the receipt (polyhydraminos)
- treatment < 26weeks = fetoscopic laser ablation
- treatment > 26 weeks = aminoreduction
Complication of fetoscopic laser ablation in twin-to-twin transfusion syndrome?
- twin anemia polycthaemia sequence
Complication of diabetes in pregnancy?
- pre-eclampsia
- polyhyfdramnios
- macrosomia
- neonatal hypoglycaemia
What additional antenatal care should be given to a diabetic mum?
- folic acid 5mg (3 months before to 12weeks)
- low dose aspirin (12weeks to delivery)
Risk factors for gestational diabetes?
- previous gdm
- BMI > 30
- 1st degree relative
- polyhydraminos
- glycosuria
Labour risk in gestational diabetes
- labour dystocia
- shoulder dystocia
- neonatal hypoglycaemia
Hormones that can cause gestational diabetes?
- human placenta lactogen
- cortisol
- growth hormone
How is Gestational diabetes diagnosed
- screening at 24-28 weeks for all
- high risk screening in 1st trimester
- Fasting BG > 5.1
- 2hr BG > 8.5
Folic acid supplementation
- 400mmg 12weeks-12weeks
- 5mg in
obese, diabetics, history of NTD, on anti-epileptics
Typical vitamin D supplementations?
- 10mg supplementation
Pre-pregnancy risks associated with obesity?
- menstrual disorders
- subfertility
Obesity management in pregnancy?
- Gestational diabetes screening
- Hypertension screening
- folic acid 5mg
- Vitamin D 10mg
- aspirin 150mg
- Serial growth scans
- VTE risk assessment
Obesity effect on the foetus?
- congenital anomaly
- macrosomia
- shoulder dystocia
- still birth
- neonatal death
Symptoms of a dural venous sinus thrombosis?
- severe headache
- can cause brain damage
What is Virchow’s triad?
- hypercoaguble state
- venous stasis
- vascular damage
What is used in the prophylaxis and treatment of VTE?
- LMWH
Warfarin in pregnancy?
- should be avoided
- teratogenic
- crosses the placenta
Symptoms of DVT
- Swelling
- oedema
- groin pain
- fever
- increased leg temperature
Symptoms of obstetric cholestasis?
- disease of pregnancy
- diagnosis of exclusion
- severe puritis on palms and soles of feet
Investigations for obstetric cholestasis?
- LFTs deranged
- viral serology
- autoantibodies
1st line investigation for a pregnant woman suspected of having a PE?
- V/Q scan (less radiation)
- CTPA can be done but higher risk
Risks of epilepsy in pregnancy?
- maternal abdo trauma
- PPROM
- Pre-term birth
- hypoxia
- childhood epilepsy
Considerations of anti-epileptic drugs in pregnancy?
- teratogenic
- lowest effective dose should be used
- sodium valproate, teratogenic!
Management of an intra-partum seizure?
- continuous fetal monitoring
- left lateral tilt
- IV lorazepam
- PR diazepam
- may require c-section
Increased MI in pregnancy?
- 3 or 4 times risk of MI
Potential cause of orthopnea in pregnancy?
- peri-partum cardiomyopathy
- presents with orthopnoea (inability to lie flat)
Cardiac changes in pregnancy?
- increased plasma volume
- increased cardiac output
- increased stroke volume
- decreased peripheral resistance
How is hypertension in pregnancy diagnosed?
- 2 readings of > 140/90
- 1 reading of > 160/110
Types of hypertension in pregnancy?
- pre-existing
- pregnancy induced
- pre-eclampsia
Triad in pre-eclampsia
- hypertension >140/90
- proteinuria uPCR > 30
- oedema
Early vs late pre-eclampsia?
- early = diagnosed before 34 weeks, associated with greater placental damage
- late = diagnosed after 34 weeks
Explain the pathogenesis of pre-eclampsia?
- abnormal placental perfusion due to failure of trophoblastic invasion of spiral arteries
- leading to low capacity - high resistance arterial supply
- placental hypoperfusion
Investigations for pre-eclampsia?
- bp
- urinalysis
- colour doppler of uterine artery
- CTG of fetous
Consequences of pre-eclampsia?
- HELLP syndrome
- eclampsia
- pulmonary oedema
- placental abruption
- cerebral haemorrhage
What is hellp syndrome and its symptoms?
- haemolysis, elevated liver enzymes, low platelets
- epigastric/RUQ pain
- abnormal enzyme,es
Symptoms of pre-eclampsia?
- headache
- visual changes
- epigastric pain
- nausea
- oedema
What drug should be given in pre-eclampsia and why?
- low dose aspirin between 16-36weeks
- reduces risk of eclampsia
Cure for pre-eclampsia?
- deliver the baby
When should drug treatment for pre-eclampsia be commenced?
- when blood pressure> 150/100
Drugs used for hypertension in pregnancy>
- labetolol
- nifidipiene
- methylpoda (contraindicated in depression)
What is eclampsia?
- tonic colonic seizures occurring with features of pre-eclampsia
- commoner in teenagers
- 44% occur post-partum
Management of eclampsia?
- control BP (IV labtolol, IV hydralazine)
- prevent seizures (magnesium sulphate)
- delivery of baby
Magnesium sulphate dosage in eclampsia?
- loading dose 4g
- infusion 1g/hrs
Define small for gestational age?
- infant born with birth weight < 10th centile
Causes of small for gestational age?
- placental infarction
- Maternal alcohol, drugs, smoking
- maternal height and weight
- maternal age
- chronic hypertension
What classifies low birth weight?
- infant born < 2500g
What is fetal growth restriction?
- failure to achieve genetic potential for growth
- implies pathological restriction
Below 3rd centile delivery time?
- aim to deliver by 37weeks
Between 3rd and 10th centile delivery time?
- aim to deliver by 39 weeks
Why is magnesium sulfate given in pre-term labour
- reduce seizure risk
What should be seen on umbilical artery doppler?
- forward flow even in maternal diastole
How is SGA identified?
- GROW chart
- USS
- Symphysis fundal height
