Antenatal Care and Screening in Pregnancy Flashcards
what is aneuploidy
an abnormal number of chromosomes
what are the tests for aneuploidy in pregnancy
First trimester screening
- Combined ultrasound and biochemical screening (CUBS)
Second trimester serum screening
Non-invasive pre-natal testing (NIPT)
what is the formula for sensitivity
true positive / (positive + false negative)
what is formula for specificity
true negative / (negative + false positive)
how sensitive is the first trimester screening for downs syndrome and what is the false positive rate
90%
FP 5%
how may women who are high risk in down syndrome first trimester screening will have a baby NOT affected by the conditions
in on 20
what are the green and red pathways
green= low risk pregnancies, midwife led
red= obstetric led care, higher risk pregnancies
what do you start if patient is at higher risk of a VTE
fragmin
is FGM illegal in UK
yes and illegal to facilitate someone leaving country to do it
have to involve social work if think mother will do it to daughter
what tests are done at the booking visit (12 weeks)
BMI BP cardio exam abdo exam Hb ABO, Rhesus syphilis, HIV, Hep B+C urinalysis USS offer down syndrome screening anencephaly, gastroschisis, absent limbs blood group and rhesus status
how do you predict due date from LMP
ass on nine months and 7 days- 280 days
what do you look for the booking USS
viability singleton/ multiple pregnancy gestational age major structural anomalies molar pregnancy estimated date of delivery (CRL)
is there a yolk sac in an ectopic pregnancy
no
what is needed to confirm a pregnancy is viable
heart beat
how do you differentiate a non continuing or ectopic pregnancy if USS is inconclusive
hCG
what is a dichorionic twins
twins that have own placenta and yolk sac
when should screening for sickle cell disease and thalassaemia should be offered
before 10 weeks
what is assessed at the follow up visits (20 weeks)
history - physical and mental health, fetal movements BP urinalysis symphysis- fundus height lie and presentation engagement of presenting part (shouldnt be there <36 weeks) fetal heart auscultation gender cleft lip heart defects placenta praevia talipes spina bifida anecephaly (neural tube defect, skull doesnt form)
when should be be worried about a babies lie
36 weeks onwards
what are the objectives of USS foe feral anomaly
Reduction in perinatal mortality and morbidity
Potential for in utero treatment
Identification of conditions amenable to neonatal surgery
why do you screen for cleft lip
needs surgical correction, sometime SL therapists or NG tubes, generally no long term complications.
- to prevent shock to mother if not expecting it, so she can meet surgeons
- Also can be associated with trisomy 13 and 18 and other genetic syndromes that cause structural abnormalities- do extended scan to look for other abnormalities and if found genetic testing
what anomalies are USS screened for at 20 weeks
cleft lip cardiac anecephaly gross abnormalities- limbs, hands, feet abdominal waal defects- gastoschisis and omphaloceole spina bifida diaphragmatic hernia exomphalos bilateral renal agenesis lethal skeletal dysplasia trisomy 13 and 18
are trisomy 13 and 18 compatible with life
generally no
what is pataus syndrome
trisomy 13
what is edwards syndrome
trisomy 18
what is placenta praevia
when the placenta is low lying in the wombandcovers all or part of the entrance (the cervix). In most women, as the womb grows upwards, the placenta moves with it so that it is in a normal position before birth and does not cause a problem.
what should you be offered If an earlier ultrasound scan (usually between 18weeks0days and 20weeks6days) showed that your placenta extends over the cervix
another abdo scan at 32 weeks
if this unclear vaginal scan
if still low then strongly suggest CS
do all women get offered down syndrome screening
yes
what increases the risk of downs syndrome
maternal age
what is included in the risk assessment for downs syndrome in the first trimester
nuchel thickness HCG (goes up in DS) PAPP-A (goes down in DS) maternal age AFP (alpha feta protein) (goes down)
what is the nuchel thickness
Measure of skin thickness behind fetal neck using ultrasound done at 11+3-13+6 weeks
what is a normal NT value
< 3.5 mm (when the CRL is between 45 and 84mm)
what is a diagnostic test offered for downs syndrome
when 1st trim screening result less than 1 in 250
what is the risk of amniocintesis causing miscarriage
1%
what should be done before downs syndrome screening
counselling
dating US before blood taken to establish gestation
when should you use CRL up until
13 weeks gestation
after this head circumference
who gets 2nd trim screening for aneuploidy (15 to 20+6 weeks)
For those women who miss first trimester screening
For those women in whom CUBS is unsuccessful
what is included in 2nd trim aneuploidy screening
Alpha-fetoprotein (AFP) human Chorionic Gonadotrophin (hCG) unconjugated oestradiol (UE3) inhibin A maternal weight, smoking status, and if applicable, previous affected pregnancy and assisted conception
what does 2nd trim aneuploidy screening
risk of downs syndrome
what is NIPT
non invasive prenatal testing
can identify pregnant women who are at higher risk of having a baby with certain genetic and chromosomal conditions, such as Down’s syndrome (also known as Trisomy 21), Edwards’ syndrome (Trisomy 18) and Patau’s syndrome (Trisomy 13)
detects fetal DNA fragments in a sample of blood taken from the mother
what is FASP
Fetal Anomaly Screening Programme
when is an amniocentesis done
after 15 weeks
maternal choice
if high risk of DS
what are the specific diagnostic tests for DS
amniocentesis
chorionic villus sampling
when is chorionic villus sampling done
after 12 weeks
what is the miscarriage rate of chorionic villus sampling
2%
is LA needed for amniocentesis and CVS
only CVS (bigger needle that samples placenta)
what are haemoglobinopathies screened for
booking appointment
what are haemoglobinopathies
autosomal recessive RBC disorders that result in abnormal haemoglobin
what are the main types of haemoglobinopathies
thalassemias and sickle cell anaemia
how are haemoglobinopathies inherited
AR
50% risk of carrier, 25% not affected, 25% affected
what is thalassemia characterised by
low haemoglobin and RBCs
what can happen in sickle cell anaemia in pregnancy
sickle cell crisis
lot of other complications
what can cause maternal anaemia
Iron deficiency
Folate deficicy
B12 deficiency
when are mothers screened for anaemia
booking and 28 weeks
what is the aim for anaemia treatment
optimise Hb prior to birth
when are rhesus incompatabilities a problem
negative mum
positive baby
worry about mum being previously sensitised and acquiring anti D antibodies
when should all pregnanct women have their blood group and antibody status (e.g. O- is o group and rh -ve) determined
at booking and again at 28 weeks
which type of HDN is more severe
ABO is more common but less severe
Rhesus is more severe but less common
when is jaundice of a newborn pathological
if within 1st day of life
what mental health screening questions should you ask all pregnant women
Do you have new feelings and thoughts which you have never had before, which make you disturbed or anxious?
Are you experiencing thoughts of suicide or harming yourself in violent ways?
Are you feeling incompetent as a mother, as though you can’t cope, or feeling distanced or estranged from your baby? Are these feelings persistent?
Do you feel you are getting worse
what are the risk factors for gestational diabetes
BMI above 30kg/m2
previous macrosomic baby weighing 4.5kg or above
previous gestational diabetes
family history of diabetes (first‑degree relative with diabetes)
minority ethnic family origin with a high prevalence of diabetes
what should you offer women with any one of these risk factors for gestational diabetes
testing for gestational diabetes;
2‑hour 75g oral glucose tolerance test (OGTT) to test for gestational diabetes in women with risk factors
what result = gestational diabete
in a 2‑hour 75g oral glucose tolerance test (OGTT)
a fasting plasma glucose level of 5.6mmol/litre or aboveor
a 2‑hour plasma glucose level of 7.8mmol/litre or above.
what does monitoring symphysis fundal height prevent
undetected intrauterine growth restriction
what are the major risk factors for small for gestational age of babies
maternal age > 40 smoker >11/ per paternal/paternal SGA cocaine daily vigorous exercise previous SGA/ still birth chronic hypertension diabetes with vascular disease renal impairment
when should you measure SFH
each antenatal appointment from 24 weeks
why might FSH be inaccurate
BMI > 35, large fibroids, hydramnios
what should you do if a FSH is below the 10th percentile/ inaccurate
USS to measure fetal size
what should women at risk of pre eclampsia take a prevention
75 mg of aspirin daily from 12 weeks until the birth of the baby
who is at high risk for pre eclampsia
hypertensive disease during a previous pregnancy
chronic kidney disease
autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome
type 1 or type 2 diabetes
chronic hypertension
what are contraindications to aspirin
asthma, previous gastric ulcer
who is at moderate risk for pre eclampsia
first pregnancy age 40years or older pregnancy interval of more than 10years body mass index (BMI) of 35kg/m2or more at first visit family history of pre-eclampsia multiple pregnancy
what is look for in urinalysis
UTI
Asymptomatic bacteriuria- may not have any urinary symptoms, associated with pre term labour
PET- proteinuria
Diabetes
what is screened for at 28 weeks
Glucose tolerance test if they are high risk based on their history
Repeat haemoglobin- haemorrhage is biggest cause of maternal death world wide, want to correct anaemia before surgery/ birth
Repeat antibodies
Intra uterine growth restriction
Macrosomia
Urine: pre eclampsia, UTI (higher risk of preterm labour if untreated)
what can cause increased NT
chromosomal abnormalities (trisomy 13, 18 and 21, turners), cardiac abnormalities
what is MSAFP
maternal serum AFP - produced by liver of developing foetus
what can cause raised MSAFP
twins (more placenta, more AFP)
spina bifida
gastoschisis
(organs in contact with amniotic fluid)
what does hypertension and proteinuria in pregnancy suggest
pre eclampsia
what systems can pre eclampsia affect
any
what is the treatment of pre eclampsia
labetalol orally/ IV (nifedinpine or methyldopa if others not suitable) (to reduce BP) betamethasone IM (to reduce brain inflammation, prevent haemorrhage, help fetal lungs develop, prevent necrotising enterocolitis) hydrasalazine oral (peripheral vasodilators, relaxes vascular smooth muscle) magnesium sulphate IV (peripheral + cerebral vasodilator, membrane stabiliser, anti convulsant to prevent eclamptic seizures, prevent eclampsia)
what is meant by Rhesus -ve
no d antigen on RBCs
what would you expect to find in a Rhesus sensitised mother
she will be rhesus -ve (no anitgen on RBCs) but will have develop anti body
what happens to Hb and bilirubin and coombs test in a Rh +ve affected baby
Hb down
haemolysis up
coombs test +ve (is a measure of haemolysis)
when can anti D be given to prevent immunisation following event of fetal maternal transfusion
ideally within 72 hours, can be within 10 days
how does anti D work
mops up D antigen covered RBCs from fetus, stops them interacting with maternal antibodies
what is the ideal route and dose of anti D
after sensitising event 500 IU IM IV if in large foetal maternal haemorrhage prophylaxis <20 weeks 250 IU >20 weeks 500 IU
what events in pregnancy would you administer anti D after
miscarriage TOP amniocentesis trauma surgical intervention for ectopic pregnancy after delivery
would you give anti D to: Rh -ve mother ABO compatible Rh +ve baby coombs test -ve infant bilirubin level normal
yes- at delivery RBCs will mix and cause sensitisation, problems for later pregnancies
would you give anti D to: Rh -ve mother ABO incompatible Rh -ve baby coombs test -ve infant bilirubin level normal
no
not high risk as baby Rh -ve
would you give anti D to: Rh -ve mother ABO compatible Rh +ve baby coombs test +ve infant bilirubin level increased
yes- probably already sensitised though
would you give anti D to: Rh +ve mother ABO incompatible Rh -ve baby coombs test +ve infant bilirubin level increased
no - haemolysis will be due to ABO incompatability
is anti D given in all pregnancies
yes at 28 weeks
if both parents are Rh -ve what will the baby be
Rh -ve
