Antenatal Care Flashcards
what is the purpose of blood and serum screening test for Downs
incorporate results with maternal age and gestation to give a person a risk assessment for Downs, they can then go onto to have diagnostic testing
when can the blood test for Downs be performed
between 11 weeks and 13 weeks 6 days
what do you do if mother wants Downs screening, is 12 weeks, but cannot measure NT
perfrom serum screening
what is measured in blood test for Downs, and what results suggests a high risk result for DOwns
NT - inc
bHCG - inc
PAPP-A - dec
+ maternal age
what is nuchal thickness
measurement of the fluid behind the skin at the back of the foetal neck using US
normal <3.5mm
what conditions is nunchal thickness increased in
chromosomal abnormalities, CVS abnormalities and lots of genetic syndromes
when can serum screening be performed for Downs
between 15-20 weeks
what is measured in serum screening for Downs
bHCG (inc), AFP and UE3 (dec)
what are the diagnostic tests available for Downs
amniocentesis and CVS
what are the risks of CVS and amniocentesis
there is a risk of miscarriage, this would tend to occur within 72 hours of the procedure
1% in amniocentesis and 2% in CVS
what is non invasive prenatal testing
a prenatal test for Downs (and other chromosomal abnormalities) that is not invasive and does not have an accompanying risk of miscarriage
it can currently only be obtained privately
is non invasive prenatal testing diagnostic
no, but it is 99% accurate
when are women screened for anaemia
at booking and at 28 weeks
what is the expected fundal height growth
1cm week
how do you measure fundal height
from the pubic bon to the top of the uterus
what are the expected landmarks for fundal height at 12, 20 and 36 weeks
pubic symphysis
umbilicus
xiphoid process
when should mental heatlh screening occur during pregnancy
at every appointment!
which pregnant women are tested for anti D antibodies and when
all rhesus negative at booking and at 28 weeks
who receives anti D Ig as prophylaxis
all non sensitised Rh neg mothers at 28 and 34 weeks
after sensitising event
what is a Kleihauer test and when would you perform it
calculates how much anti D Ig is needed
done after a sensitising event
what happens if there is a sensitising event and the mother is Rh neg and has received no prophylaxis
can still give anti D Ig as prophylaxis up to 72 hours after event - there is some protection up to 10 days after
route and site of antiD injection
deep IM injection into deltoid muscle
if a Rh positive baby is attacked by Rh Ab from mother, how does it present
RBC haemolysis –> jaundice and haemolutic anaemia
decrease in Hb, increase in bilirubin, positie Coombs tset
what is Naegeles rule
predicts an estimated due date by adding 9 months and 7 days onto womans last menstrual period
what causes hypermesis gravidarum
not entirely sure, thought to be due to raised beta hCG levels (extreme in molar pregnancy)
when does HG commonly occur
between 8 and 12 weeks, can occur up to 20 weeks
does obesity increase riks of HG?
yes
does a personal/family history of HG increase risk?
yes
does smoking increase risk of HG?
no, decreases it
what anti emetics are first line for HG
anti histamines, eg promethazine and cyclizine
which anti emtics are second line for HG
ondansetron and metaclopramide
outline the changes to BP during pregnancy
decrease in DBP during trimester 1 and 2
increase back to pre pregnancy levels by term
drops straight after delivery and then rises an peaks 3-4 days post natally
if a mother is found to have borderline hypertension during pregnancy, what is the likely diagnosis
pre existing hypertension
what is high blood pressure defined as during pregnnacy
- 140/90mmHg on 2 occasions OR >160/100mmHg once
are antihypertensives containdicated in pregnancy
ACEi and ARBs are contraindicated
what are he antihypertensives of choice in pregnancy
1st labetalol
methydopa and nifedipine
define pregnancy induced hypertension
New onset of hypertension without any features of pre-eclampsia after 20 weeks of pregnancy or within the first 25 hours postpartum.
when does PIH usually present and how long does it last
2nd half of pregnancy
around 6 weeks after pregnancy
what does PIH cause a very high risk of
pre eclampsia
after how many weeks can pre eclampsia occur
20
what is HELLp syndrome
a severe manifestation of pre eclapsmia
haemolysis, elevated liver enzymes,low platelets
what is usually the presenting sign of pre eclampsia
rise in blood pressure
outline the aetiology of PE
- failure of normal invasion of trophoblasts cells leads to maladaptation of spinal arterioles - dont dilate and form low resiistance high capacitance vessels. this causes reduced uteroplacenetal blood flow –> oligohydramnios, placental abruption, IUGR, foetal death
- ischaemic placenta inducecs maternal systemic inflammatory hresponse and widespread endothelial damage - vasocoonstriction - kidneys retain more salt –> hypertension
what pharmacological management is given as prophylaxis for PE
75mg aspirin OD from 12 weeks until birth of baby
what is the most significant risk factor for PE
previous PE
is PE more common in primigravidas?
yes
what signs are seen on maternal uterine artery doppler in PE
high resistnace outflow and diastolic notch
what is the main cause of maternal mortlaity in PE
CV accidents and pulmonary oedema
management of PE
deliver if close to or at term
stabilise mother
control BP with drugs
labetalol mechanism of action
a and beta blocker
what is labetalol CI in
asthma - blocks beta receptors too
what can leabetalol cause in the neonate
transienet hypoglycaeia
what is an adverse effect of methyldopa
depression
define eclampsia
Eclampsia is the development of convulsions secondary to pre-eclampsia.
what type of seizures occur in eclampsia
tonic clonic
management of eclampsia
magnesium sulphate IM/IV
how does Mg sulphate treat eclampsia
it decreases the calcium uptake by smooth muscles to prevent fits and lower blood pressure
before which gestation is defined as PTD
37 weeks
is a previous PTL a risk factor for another one?
yes, 20% risk
define SGA
estimated foetal weight/abdominal circumference below 10th centile on population/customised centiles
what are the causes of PTD
- infection - UTI, BV
- over distension, eg polyhydramnios, multiple pregnancy
- vascular
- intercurrent illness, eg pyelonephritis, UTI, pneumonia
what causes babies to be asymmetrically/symmetrically small
symmetrical - usually caused by genetic problems, eg downs
asymmetrical - usually occurs in the 3rd trimester, growth of the body is sacrificed to maintain head growth
what drug is particularly assoicated with a risk of SGA baby
cocaine
define SGA
estimated foetal weight/anbdominal circumference < 10th centile on population/customised centiels
how is SGA diagnosed
- measure foetal abdominal circumference and combined with head circumference and femur length gives estimated foetal weight
- can be combined with liquor volume, amnitoic fluid index and Doppler scan
why are SGA babies particuarlly suceptible to hypothermia
- Increased heat loss due to decrease in subcutaneous fat
- Decreased heat production due to intrauterine stress and depletion of nutrient stores
- Increased surface to volume ratio due to small size
why is betamethasone given to preterm babies
it is a corticosteroid that crosses the placenta - heps foetal lung maturity so helps prevent neonatal complications of premature delivery
what birth weight is considered large for dates regardless of gestational age
>4kg
what symphyseal fundal height is considered large
>2cm more than gestational age
what is a maternal cause of polyhydramnios
diabetes
what are the risks of polyhydramnios
- preterm contractions
- preterm delivery
- premature rupture of membranes
- foetal malposition/death
what is hydrops foetalis
severe odema in baby’s tissues and organs - can be due to rhesus disease or other non immune causes
what happens in acute polyhydramnios
rare, uterus becomes acutely distended and often results in preterm labour
painful for mother, experiences dyspnoea and vomiting
what causes chronic polyhydramnios
conditions where there is a large placenta - multiple pregnancies, chorioangioma of placenta, maternal diabetes
is polyhydramnios assoicated with underlying congenital abnormalities
in a lot of cases yes
how is polyhydramnios diagnosed
by US measurement of amniotic fluid index - add the vertical depth of fluid measured in each quadrant of the uterus together
what is the normal range for AFI
5-24 cm
certain viral infections can cause polyhydramnios - name 3
parvovirus B19, rubella, toxoplasmosis and CMV
is maternal age a risk factor for multiple pregnancy
yes more likely with inc age
what determines the chorionicity of twins
at what stage (how many days in) the egg cleaves
how many placentas do mono and di chorionic twins have
2 placenta in di chorionic and one in monochorionic
how can chorionicity of twins be determines
by US
- membrane shape and thickness
- lamda sign is indicative of dichorionic twins
what is twin-twin transfusion syndrome
when twins are sharing a placenta, one can receive too little blood supply and the other too much
- low urine output, amnitoic fluid and growth in one and oligohydramnios
- high blood pressure and polyhydramnios in the other. this can put strain on foetus and lead to heart failure
what problem with blood can TTTS lead to
one baby gets anaemia and the other polycythaemia
which type of twins are at the greatest risk
monochorionic monozygous twins, there is a risk of cord entanglement and a higher risk of foetal death
management of TTTS
- SFLA to laser shut abnormal blood vessles if before 25 weeks
- if after, amnioreduction or septostomy
where in the world is the prevalence of natural twinning highest
central africa
