Antenatal Care Flashcards
When is the 2nd trimester?
From 13-27 weeks
When is the first trimester?
From conception to 12 weeks
When is the 3rd trimester?
From 28-40 weeks
When does the booking visit take place?
Between eight and ten weeks
What investigations and examinations are involved in the booking visit?
Risk assessment - history etc Pulse BP Height, weight, BMI Urinalysis FBC - to detect anaemia Blood group and antibody screen Haemoglobin electrophoresis - sickle cell or thalassaemia Rubella Syphilis Hepatitis B HIV
When is the dating scan?
Between 10 and 14 weeks
What is the purpose of the dating scan?
Confirms viability
Estimates due date based in crown-rump length
Diagnoses multiple pregnancy and chorionicity
Identifies gross structural abnormalities
Can assess for Nuchal translucency - downs
When is triple assessment for downs carried out?
Between weeks 10 and 14
What is involved in triple assessment for downs?
B-HCG
PAPPA - pregnancy associated plasma protein A
Nuchal translucency
What does the screening test result tell you?
Calculates the probability of the foetus having Down syndrome, taking into account maternal factors such as age, weight, family origin, gestation of pregnancy
Cut off level for high risk is 1 in 150
Women are then offered diagnostic testing
Who is offered the quadruple test?
People who did not have the triple test in early pregnancy?
What does the quadruple test measure?
AFP
Beta HCG
Inhibin - A
Oestriol
Again combined with maternal factors such as age, weight and gestational age
When is the quadruple test offered?
15-20 weeks
This is less accurate than the triple (combined) test
Cannot give individual risks for multiple pregnancies, although the triple test can
When are women offered diagnostic tests for Downs syndrome?
If previous screening tests suggest they carry a foetus at higher risk (greater than 1 in 150) of having downs etc
How long does full karyotyping take?
7-10 days
How can commoner aneuploidies (trisomies 13,14 and 21) be tested for?
Fluorescent in situ hybridisation
Can be diagnosed within 48 hours
What is chorionic villus sampling?
Takes sample of cells from placenta
Cells are collected transabdominally under direct ultrasound guidance
When is CVS performed?
10-14 weeks
What is the risk of miscarriages in CVS?
1%
When is involved in amniocentesis?
Takes a sample of amniotic fluid which contains cells shed from the foetal skin and membranes
Amniotic fluid aspirated transabdominally under direct ultrasound guidance
When is amniocentesis performed?
After 15 weeks
What is the risk of miscarriage in amniocentesis?
0.5%
When is the foetal anomaly scan be performed?
Second trimester
Between 18 and 20+6 weeks
What does the foetal scan show?
Structural abnormalities - which may also indicate underlying chromosomal condition
Location of the placenta - eg placenta previa
What are maternal well being checks?
Routine checks carried out through the second and third trimesters
Involves - history, BP measurement, urinalysis
To assess each womans risk of pre-eclampsia or gestational diabetes
How is foetal well being checked in the second and third trimester?
Symphysis fundal height measurement
Asking mother about foetal movements
Option of using CTG and further scans for growth
How is foetal well being checked if growth excessive or restricted?
USS
To assess for growth - abdominal circumference and femur length, head circumference and biparietal diameter
Biophysical profile - foetal tone, movements, amniotic fluid vol
Umbilical dopplers - to check blood flow to foetus
When is foetal presentation checked?
From 36 weeks onwards at maternal/foetal check up
When is the final routine visit carried out, and what is discussed?
40-41 weeks
Discussion about induction of labour
What intrinsic factors govern foetal growth?
Usually genetic factors:
Maternal height and weight
Parity
Ethnic group
Foetal sex
Foetal genes and inherited conditions
What extrinsic factors govern foetal growth?
Maternal: Social class Nutritional status Environment: altitude Pre-existing disease Pregnancy relates disease
Foetal:
Nutrition
Exposure to teratogens- tobacco, narcotics, alcohol, medication
Infective: viral, rubella, cmv, protozoan
What is the definition of small for gestational age?
Foetus that has failed to achieve a specific biometric or estimated weight threshold by a specific gestational age
Either constitutionally small, or intrauterine growth restriction
How is Doppler used to assess growth restriction?
Uterine artery doppler
- assesses resistance within the placenta
- indicates mother is at high risk of pre-eclampsia
Umbilical artery Doppler
- assesses resistance within umbilical artery
- indicates placental failure
What is end diastolic flow on umbilical artery Doppler?
When the placenta is functioning normally, blood flows from mother to baby still in diastolic stage.
End diastolic flow may be absent or reverses in placental insufficiency
How often does diabetes (established or gestational) occur in pregnancy?
2-5 % of cases
65% of these are gestational
35% of these are pre-existing
How is glucose metabolism altered by pregnancy?
Insulin requirements increase throughout pregnancy to term
Normally women are able to increase insulin levels to counter diabetogenic hormones which increase in pregnancy - human placental lactogen, cortisol, glucagon, oestrogen and progesterone
What are the effects of established diabetes on pregnancy?
Maternal hyperglycaemia leads to foetal hyperglycaemia
Foetal pancreatic cells produce insulin - this acts as growth factor
This causes macrosomia, organomegaly and increased erythropoeisis
What are the effects of established diabetes on pregnancy?
Maternal hyperglycaemia leads to foetal hyperglycaemia
Foetal pancreatic cells produce insulin - this acts as growth factor
This causes macrosomia, organomegaly and increased erythropoeisis
Foetal polyuria causes polyhydramnios
Neonatal hypoglycaemia may occur
Surfactant production may be reduced, leading to respiratory distress syndrome at birth
What are the effects of pregnancy on established diabetes?
Ketoacidosis - rare
Retinopathy - increased risk of development - all diabetic women require assessment in pregnancy
Nephropathy - renal function and proteinuria may worsen in pregnancy
Ischaemic heart disease - as pregnancy increases cardiac workload
Increased risk of caesarean or instrumental delivery
What should be advised in pre-pregnancy counselling for diabetic women?
Optimal control of blood glucose - aim for normoglycaemia prior to pregnancy
Assess severity of diabetes - hypertension, retinopathy, nephropathy, neuropathy, cardiac disease
Education - establish need for control
General health - lose weight, stop smoking
Stop ACEis statins and oral hypoglycaemics (apart from metformin)
Folic acid - 5mg
Rubella vaccination
Contraception - until glycemic control achieved
Aspirin 75mg daily from 12 weeks onwards
Induce at 37 weeks
How should women with established diabetes be monitored antenatally?
Glucose control: blood glucose 4x daily Stop ACEis and oral hypoglycaemics, switch to insulin Hba1c every month Educate about hypos
Dietitian review
Dating ultrasound
Down’s syndrome screening
Anomaly screening
Foetal echocardiography at 20-24 weeks
Serial USS every 2-4 weeks
When is labour induced in pre-existing diabetics?
39 weeks
Earlier if glucose control is poor
Vaginally delivery is preferred
In pre-existing diabetes, how is glucose control achieved during labour
Check blood glucose hourly - if glucose >6.0mmol, convert to sliding scale
If insulin dependent, use sliding scale when labour is established
What are risk factors for gestational diabetes?
Previous history of gestational diabetes
Previous large baby >4kg
Previous unexplained still birth
First degree relative with diabetes
Polyhydramnios
Persistent glycosuria
Weight >100kg
Polycystic ovary syndrome
How is an oral glucose tolerance test carried out?
Overnight fasting - eight hours minimum - only water
75g glucose in 250ml water
Plasma glucose measured whilst fasting and at two hours after consumption of the glucose
What result on an OGTT indicates GDM?
Diabetes:
Fasting - > 7.0 mmol
2 hour - > 11.1 mmol
Only one value needs to be abnormal to make the diagnosis
What are risk factors for gestational diabetes?
Previous history of gestational diabetes
Previous large baby >4kg
Previous unexplained still birth
First degree relative with diabetes
Polyhydramnios
Persistent glycosuria
Weight >100kg
Polycystic ovary syndrome
How is an oral glucose tolerance test carried out?
Overnight fasting - eight hours minimum - only water
75g glucose in 250ml water
Plasma glucose measured whilst fasting and at two hours after consumption of the glucose
What result on an OGTT indicates GDM?
Diabetes:
Fasting - > 7.0 mmol
2 hour - > 11.1 mmol
Only one value needs to be abnormal to make the diagnosis
How many times can glycosuria be detected on routine urine dipstick before OGTT should be carried out?
2 occasions of glycosuria
When should women with high risk of GDM undergo timed glucose levels?
At 28 and 34 weeks
Further testing if:
> 6 mmol - Preprandial glucose levels or greater than 2 hours after meal
Or
> 7 mmol - less than 2 hours after meal
If investigations suggest GDM, how can need for insulin be assessed?
Glucose series - measure glucose levels at several points in the day
If consistently > 6 mmol, start insulin therapy
If not, diet may be adequate
How is GDM managed antenatally?
Multidisciplinary team
Measure glucose 4x daily
Diet is first line
Insulin or oral hypoglycaemics if glucose consistently >6.0 mmol or evidence of complications eg macrosomia
Manage as per established diabetes
How is GDM managed antenatally?
Multidisciplinary team
Measure glucose 4x daily
Diet is first line
Insulin if glucose consistently >6.0 mmol
Manage as per established diabetes
What antenatal test screens for spina bifida?
Triple test for downs also screens for spina bifida
Spina bifida is suggested if there is an increase in AFP alone
For which women is foetal echocardiography recommended?
Performed in second trimester
For women with congenital heart
Women with previous children with congenital heart disease
Women who have had a high risk nuchal translucency
Maternal diabetes
Maternal epilepsy
What is the risk of major congenital malformation if the first hba1c is >10%?
25%
When is the OGTT test undertaken?
24-28 weeks
How many women with GDM have recurrence in future pregnancies?
60%
What is the risk of developing type 2 diabetes after having GDM?
50% in the next ten years
What happens to the respiratory rate during pregnancy
It stays the same
What happens to haemoglobin concentration in pregnancy?
It decreases
What happens to renal blood flow in pregnancy?
It increases
What happens to albumin concentration during pregnancy?
It decreases
What happens to maternal heart rate during pregnancy?
It increases
What is the most reliable indicator of gestational age after 13 weeks?
Biparietal diameter
What does the biophysical profile test?
Foetal wellbeing
Assess foetal breathing, foetal movement, amniotic fluid volume, and accelerations
This gives info about the central nervous system and tone
