Antenatal care Flashcards
What is gestational age?
duration of the pregnancy starting from the date of the last menstrual period
What is gravida?
total number of pregnancies a woman has had
What is primigravida?
patient that is pregnant for the first time
What is multigravida?
patient that is pregnancy for at least the second time
What is para?
number of times the woman has given birth after 24 weeks gestation, regardless of whether the foetus was alive or stillborn
What does nuliparous mean?
patient that has never given birth after 24 weeks gestation
What does primiparous mean?
patient that has given birth after 24 weeks gestation once before
What does multiparous mean?
patient that has given birth after 24 weeks gestation two or more times
When is the first trimester?
start of pregnancy until 12 weeks gestation
When is the second trimester?
13-26 weeks gestation
When is the third trimester?
27 weeks gestation to birth
When do foetal movements start?
20 weeks
When is the booking clinic?
before 10 weeks
What happens at the booking clinic?
baseline assessment
plan the pregnancy
When is the dating scan?
10 - 13+6
What happens at the dating scan?
accurate gestational age is calculated from the crown rump length
multiple pregnancies are identified
When is the anomaly scan?
18 - 20+6
When are antenatal appointments?
weeks:
16
25
28
31
34
36
38
40
41
42
When is the oral glucose tolerance test carried out in people at risk of gestational diabetes?
24-28 weeks
and at booking if previous gestational diabetes
When are anti-D injections administered to rhesus negative pregnant people?
28-34 weeks
What vaccines are offered to all pregnant people?
whooping cough (pertussis) from 16 weeks gestation
influenza (Flu) in autumn or winter
What supplements should pregnant people take?
folic acid 400mcg from before pregnancy to 12 weeks (reduces neural tube defects)
vitamin D
What vitamin supplement should pregnant people avoid?
vitamin A (teratogenic at high doses)
What foods should pregnant people avoid?
liver or pate (high in vitamin A)
unpasteurised diary or blue cheese (risk of listeriosis)
undercooked or raw poultry (risk of salmonella)
What are the effects of alcohol in pregnancy?
miscarriage
small for dates
preterm delivery
foetal alcohol syndrome
What are the features of foetal alcohol syndrome?
microcephaly (small head)
thin upper lip
smooth flat philtrum (groove between the nose and upper lip)
short palpebral fissure (short horizontal distance from one side of the eye to the other)
learning disability
behavioural difficulties
hearing and vision problems
cerebral palsy
What does smoking during pregnancy increase the risk of?
foetal growth restriction
miscarriage
stillbirth
preterm labour and delivery
placental abruption
pre-eclampsia
cleft lip or palate
sudden infant death syndrome (SIDS)
What are the recommendations around flying in pregnancy?
safe in uncomplicated healthy pregnancies up to:
37 weeks in a single pregnancy
32 weeks in a twin pregnancy
What forms the antenatal screening programme for Down’s syndrome?
11-14 weeks = combined test
14-20 weeks = triple test
14-20 weeks = quadruple test
What is involved in the combined screening test for Down’s syndrome?
US to measure nuchal translucency (thickness of the back of the neck)
maternal blood tests:
beta-HCG
pregnancy-associated plasma protein-A (PAPA)
What is involved in the triple screening test for Down’s syndrome?
maternal blood tests:
beta-HCG
alpha-fetoprotein (AFP)
serum oestriol
What is involved in the quadruple screening test for Down’s syndrome?
triple test plus maternal blood testing for inhibin-A
When is antenatal testing for Down’s syndrome offered?
risk of Down’s greater than 1 in 150 (occurs in around 5% of tested pregnant people)
What are the antenatal tests for Down’s syndrome?
before 15 weeks = chorionic villus sampling (US-guided biopsy of the placental tissue)
after 15 weeks = amniocentesis (US guided aspiration of amniotic fluid using a needle and syringe)
non-invasive prenatal testing (not definitive but less invasive)
How is hypothyroidism managed during pregnancy?
increased levothyroxine dose
aim for a low-normal TSH level
What hypertension medications should be stopped during pregnancy as they cause congenital abnormalities?
ACE inhibitors (e.g. ramipril)
ARBs (e.g. losartan)
thiazide and thiazide-like diuretics (e.g. indapamide)
What medications can be used to manage hypertension during pregnancy?
labetalol (other beta-blockers may have adverse effects)
CCBs (e.g. nifedipine)
alpha-blockers (e.g. doxazosin)
What anti-epileptic drugs are safe in pregnancy?
levetiracetam
lamotrigine
carbamazepine
What anti-epileptic drugs should be avoided in pregnancy and why?
sodium valproate - causes neural tube defects and developmental delay
phenytoin - causes cleft lip and palate
What DMARDs are safe during pregnancy?
hydroxychloroquine (first-line)
sulfasalazine
What DMARD should be avoided during pregnancy?
methotrexate
Why should NSAIDs be avoided during pregnancy unless absolutely necessary?
premature closure of the ductus arteriosus in the fetus
delay labour
(block prostaglandins - maintain the ductus arteriosus, soften the cervix, stimulate uterine contractions)
What can use of beta blockers during pregnancy cause?
foetal growth restriction
hypoglycaemia in the neonate
bradycardia in the neonate
What can the use of ACE inhibitors and ARBs in pregnancy cause?
oligohydraminos (reduced amniotic fluid)
miscarriage or foetal death
hypocalvaria (incomplete formation of the skull bones)
renal failure in the neonate
hypotension in the neonate
What can the use of opiates during pregnancy cause?
neonatal abstinence syndrome
What is the presentation of neonatal abstinence syndrome?
3-72 hours after birth with:
irritability
tachypnoea
high temperatures
poor feeding
What can the use of warfarin during pregnancy cause?
foetal loss
congenital malformations - particularly craniofacial problems
bleeding during pregnancy, postpartum haemorrhage, foetal haemorrhage, intracranial bleeding
Why should lithium be avoided during pregnancy unless other options have failed?
congenital cardiac abnormalities - particularly Ebstein’s (tricuspid valve is set lower on the right side of the heart, causing a bigger right atrium and a smaller right ventricle)
What are the potential risk of SSRIs during pregnancy?
first-trimester = congenital heart defects, paroxetine has a stronger link with congenital malformations
third-trimester = persistent pulmonary hypertension in the neonate
neonates can experience withdrawal (usually mild)
What causes congenital rubella syndrome?
maternal infection with the rubella virus during the first 20 weeks of pregnancy
What are the features of congenital rubella syndrome?
congenital deafness
congenital cataracts
congenital heart disease
learning disability
Why is chickenpox dangerous in pregnancy?
more severe in the mother (e.g. varicella pneumonitis, hepatitis, encephalitis)
foetal varicella syndrome
severe neonatal varicella infection (if infected around delivery)
What is done when a pregnant person is exposed to chickenpox?
check blood for antibodies
if non-immune = IV varicella immunoglobulins within 10 days of exposure
What is the treatment of chickenpox during pregnancy?
oral aciclovir within 24 hours of onset of rash in a patient that is more than 20 weeks gestation
What are the features of congenital varicella syndrome?
foetal growth restriction
microcephaly, hydrocephalus and learning disabilities
scars and significant skin changes located in specific dermatomes
limb hypoplasia (underdeveloped limbs)
cataracts and inflammation in the eye (chorioretinitis)
What can listeriosis in a pregnant person cause?
miscarriage
foetal death
severe neonatal infection
What are the features of congenital CMV?
foetal growth restriction
microcephaly
hearing loss
vision loss
learning disability
seizures
How is toxoplasmosis spread?
faeces from a cat that is a host of the parasite Toxoplasma gondii
What are the features of congenital toxoplasmosis?
classic triad of:
intracranial calcification
hydrocephalus
chorioretinitis (inflammation of the choroid and retina in the eye)
What are the complications of parvovirus B19 infection during pregnancy?
miscarriage or foetal death
severe foetal anaemia
hydrops fetalis (foetal heart failure)
maternal pre-eclampsia-like syndrome
How is the Zika virus spread?
Aedes mosquitos
sex with someone infected with the virus
What are the features of congenital Zika syndrome?
microcephaly
foetal growth restriction
other intracranial abnormalities such as ventriculomegaly and cerebellar atrophy
What can happen if a rhesus-D negative person becomes pregnant with a rhesus positive child?
likely at some point, that the blood from the baby will cross into the mother’s bloodstream
mother’s immune system will recognise the rhesus-D antigen as foreign and produce antibodies to it - mother has become sensitised to rhesus-D antigens
during subsequent pregnancies, the mother’s anti-rhesus-D antibodies can cross the placenta
if the foetus is rhesus-D positive, this can result in haemolytic disease of the newborn
When are anti-D injections given to rhesus-D negative pregnant patients?
routinely at:
28 weeks gestation
birth - if the baby’s blood group is found to be rhesus-positive
within 72 hours of a sensitisation event - e.g. antepartum haemorrhage, amniocentesis procedures, abdominal trauma
What is the Kleihauer test used for?
assess how much foetal blood has passed into the mother’s blood during a sensitisation event after 20 weeks
used to assess whether further doses of anti-D is required
How is the Kleihauer test performed?
adding acid to a sample of the mother’s blood
foetal haemoglobin is naturally more resistant to acid
foetal haemoglobin persists in response to the added acid, whilst the mother’s haemoglobin is destroyed
number of cells still containing haemoglobin (remaining foetal cells) can then be calculated
What is the definition of small for gestational age?
foetus measures below the 10th centile for their gestational age
What are the two US measurements used to assess foetal size?
estimated foetal weight (EFW)
foetal abdominal circumference (AC)
What is the defined as severe small for gestational age?
below the 3rd centile for their gestational age
What is low birth weight defined as?
birth weight of less than 2500g
What are the two categories of causes of small for gestational age?
constitutionally small (matching the mother and others in the family and growing appropriately on the growth chart)
foetal growth restriction/intrauterine growth restriction
What are the two categories of causes of foetal growth restriction?
placenta mediated growth restriction
non-placenta mediated growth restriction
What are the causes of placenta mediated growth restriction?
idiopathic
pre-eclampsia
maternal smoking
maternal alcohol
anaemia
malnutrition
infection
maternal health conditions
What are the causes of non-placenta medicated growth restriction?
genetic abnormalities
structural abnormalities
foetal infection
errors of metabolism
What signs may indicate foetal growth restriction other than the foetus being SGA?
reduced amniotic fluid volume
abnormal doppler studies
reduced foetal movements
abnormal CTGs
What are the short term complications of foetal growth restriction?
foetal death or stillbirth
birth asphyxia
neonatal hypothermia
neonatal hypoglycaemia
What are the long term complications of foetal growth restriction?
increased risk of:
cardiovascular disease, particularly hypertension
T2DM
obesity
mood and behavioural problems
What are the risk factors for small for gestational age?
previous SGA baby
obesity
smoking
diabetes
existing hypertension
pre-eclampsia
older mother (>35 years)
multiple pregnancy
low pregnancy-associated plasma protein-A (PAPPA)
antepartum haemorrhage
antiphospholipid syndrome
What is the management of pregnant people at low risk of SGA?
monitoring of symphysis fundal height at every antenatal appointment from 24 weeks onwards
What is the criteria for a pregnant person to have serial growth scans with umbilical artery doppler?
three or more minor risk factors
one or more major risk factors
issues with measuring the symphysis fundal height (e.g. large fibroids, BMI>35)
symphysis fundal height <10th centile
What is the management of pregnant people with SGA?
monitored closely with serial US measuring:
estimated foetal weight and abdominal circumference to determine growth velocity
umbilical arterial pulsatility index
amniotic fluid volume
treat modifiable risk factors (E.g. smoking)
early delivery where growth is static or there are other concerns
identify underlying cause:
blood pressure and urine dipstick for pre-eclampsia
uterine artery doppler scanning
detailed foetal anatomy scan by foetal medicine
karyotyping for chromosomal abnormalities
testing for infections
What is defined as being large for gestational age/macrosomia?
estimated foetal weight >90th centile
What is a high birthweight?
> 4500g
What are the causes of macrosomia?
constitutional
maternal diabetes
previous macrosomia
maternal obesity or rapid weight gain
overdue
male baby
What are the risks to the mother of macrosomia?
shoulder dystocia
failure to progress
perineal tears
instrumental delivery or caesarean
postpartum haemorrhage
uterine rupture (rare)
What are the risks to the foetus of macrosomia?
birth injury
neonatal hypoglycaemia
obesity in childhood and later life
T2DM in adulthood
What investigations are done in macrosomia?
US to exclude polyhydramnios and estimate the foetal weight
oral glucose tolerance test for gestational diabetes
How can the risks surrounding delivery in macrosomia be reduced?
delivery on a consultant lead unit
delivery by an experienced midwife or obstetrician
access to an obstetrician and theatre if required
active management of the third stage
early decision for caesarean section if required
paediatrician attending the birth
What is monozygotic?
identical twins from a single zygote
What is dizygotic?
non-identical twins from two different zygotes