Antenatal care and screening

Question 1

• To understand the physiological changes associated with normal pregnancy in the mother
• To understand pre-pregnancy counselling
• To understand the procedure and implications of the antenatal examination
• To understand the basis of screening for fetal abnormality
• To know what screening tests are offered to women and understand their limitations
• To be aware of the ethical dilemmas associated with detection of fetal abnormalities

Answer 1

listen to the PODCAST on Hyperemesis Gravidarum

Question 2

Morning sickness is worse in conditions where what is increased

Answer 2

Human Chorionic gonadotrophin (hCG) - higher in twin pregnancies

Question 3

Physiological changes in normal pregnancy

Answer 3

Cardio

• CO increases
• BP drops in 2nd trimester

Renal

• Increased urine output
• Increase in urinary stasis –> higher UTI risk

Haematology
-Anaemia - plasma volume increases by 50% but RBC mass only by 25%; iron only given if Hb low

Resp
-reduced CO2 output, increased O2 consumption

GI
-reduced GI motility

Question 4

What is physiological in the 3rd trimester, making pyelonephritis more common

Answer 4

Hydronephrosis - build up of urine in kidneys because bladder capacity reduced due to pressure from expanding uterus

Question 5

GI motility is reduced in pregnancy due to a increase and decrease in which hormones

Answer 5

Increased progesterone

Decreased motilin

Question 6

Why is pre-pregnancy counselling important

Answer 6

To consider any existing health or previous pregnancy problems that could factor in to new pregnancy

Question 7

What does pre-pregnancy counselling involve discussion of

Answer 7

General measures

• improve diet
• optimise BMI
• avoid alcohol

Stop smoking

Folic acid supplements

Question 8

What risks should be assessed in pre-pregnancy counselling

Answer 8

Age

Parity - nulliparity (never having completed a pregnancy beyond 20 wks) predisposes to pre-eclampsia, grand multiparty (4+ deliveries predisposes to postpartum haemorrhage)

Occupation - busy jobs not good or those exposed to dangerous substances

Substance misuse - alcohol or drugs

Question 9

Those with known medical problems should discuss what in pre-pregnancy counselling

Answer 9

Optimise maternal health

Psychiatric health is important

Stop/Change any unsuitable drugs

Advise regarding complications associated with maternal medical problems

Occasionally advise against pregnancy

Question 10

Antenatal examination aims to identify what problems in the MOTHER

Answer 10

pre-exisiting or developing illness

‘minor’ problems of pregnancy such as anaemia

Question 11

Antenatal examination aims to identify what problems in the FOETUS

Answer 11

Small for gestational age

Foetal abnormality

Question 12

Antenatal examination aims to identify what SOCIAL problems

Answer 12

Domestic violence

Psychiatric Illness

Question 13

What to do on antenatal examination

Answer 13

Inspection

• size
• scars, stretch marks

Abdo palpation

• assess symphyseal fundal height
• assess lie (longitudinal or transverse)
• estimate liquor volume
• assess engagement/presentation (breech or cephalic)

Auscultate

Question 14

Is antenatal screening compulsory

Answer 14

No, just offered but appropriate counselling should be given prior to screening

Question 15

What screening tests are offered to women (7)

Answer 15

Hep B
Syphilis
Rubella
HIV
MSSU
Anaemia - iron deficiency anaemia
Isoimmunisation (antibodies against blood groups) - commonest is rhesus disease

Question 16

What are you looking for on the first visit scan

Answer 16

Ensuring pregnancy is viable
Identify number of pregnancies
Identify any abnormalities
Offer Down’s syndrome screening

Question 17

Down syndrome is a chromosomal abnormality characterised by

Answer 17

3 copies of chromosome 21

Question 18

Down’s syndrome increases with

Answer 18

maternal age

Question 19

Multiple screening tests are available for down’s syndrome but what should parents be aware of in regards to these tests

Answer 19

They only provide a risk of their baby being affected

Further testing will be offered to definitively tell if a baby is affected

Question 20

Ethical dilemmas associated with detection of fetal abnormalities

Answer 20

Terminating

Question 21

First trimester USS occurs at how many weeks

Answer 21

10-14

Question 22

What test is done for Down’s syndrome screening

If there’s a high risk result, what further testing options can be overfed

Answer 22

Nuchal translucency - very difficult

CVS (chorionic villous sampling) – sample from placenta
Amniocentesis – sample from amniotic fluid
Non-invasive Prenatal testing (bloods taken and checked specially)

Question 23

Screening for neural tube defect isn’t routine since introduction of 1st trimester screening

What neural abnormalities can the 1st trimester US detect

Answer 23

anencephaly and sometimes spina bifida

Question 24

2nd trimester biochemical screening is carried out for neural tube defects if…

Answer 24

not able to get nuchal translucency measurement in 1st trimester US

Question 25

What marker is raised in neural tube defects

Answer 25

AFP

Question 26

2nd trimester US is performed for what purpose

Answer 26

Detecting foetal abnormality

2nd trimester is good time to screen fro major structural abnormalities BUT is poor for chromosomal abnormalities (50% with down’s have normal USS)

Question 27

What major structural abnormalities can be detected on 2nd trimester USS

Answer 27

Hypoplastic left heart

Exomphalos (weak abdominal wall –> abdominal contents protrude out but still covered in sac)

Cleft lip

Question 28

Screening for foetal abnormalities generally comprises of (3)

Answer 28

Features in history
Ultrasound
Maternal serum biochemistry