Antenatal Screening

Question 1

Cardiac physiology of pregnant women?

Answer 1

• Cardiac output increases by 30-50%

- Blood pressure drops in 2nd trimester (expansion of uteroplacental circulation, fall in systemic vascular resistance)

Question 2

Urinary physiology of pregnant women?

Answer 2

• Increased urine output (increased renal plasma flow)

- UTI (can be associated with preterm labour, must treat)

Question 3

Blood physiology of pregnant women?

Answer 3

• Anaemia (plasma volume up, RBC up but not as much)
• Iron requirements increase by 1g during pregnancy
• WBC increases slightly

Question 4

Respiratory physiology of pregnant women?

Answer 4

• Progesterone reduces CO2
• O2 consumption increases
• Plasma PO2 unchanged

Question 5

GI physiology of pregnant women?

Answer 5

• Oesophageal peristalsis reduced
• Gastric emptying slows, cardiac sphincter relaxes (GORD + heartburn)
• GI motility reduced (constipation)

Question 6

What are the general aspects of pre-pregnancy counselling?

Answer 6

• General health - Smoking, alcohol, diet, BMI
• Folic acid optimisation
• Up to date cervical smear
• Optimise maternal health - control existing conditions e.g. diabetes
• Stop/change unsuitable (e.g. ACEi, sodium valproate)
• Advise regarding complications
• Advise against pregnancy if significant risk to maternal health

Question 7

How to monitor/manage Pre-eclampsia?

Answer 7

Aspirin 150mg during pregnancy and regular BP check

Question 8

How to monitor/manage Gestational diabetes?

Answer 8

HbA1c at booking and OGTT at 28 weeks

Question 9

How to monitor/manage Previous C-section?

Answer 9

Consider elective C-section or vaginal birth after C-section (VBAC)

Question 10

How to monitor/manage DVT or PE?

Answer 10

Consider antenatal thromboprophylaxis and 6 weeks postnatal treatment

Question 11

How to monitor/manage Intrauterine growth restriction?

Answer 11

Aspirin 150mg during pregnancy and serial US scan

Question 12

How to monitor/manage Preterm birth?

Answer 12

Consider transvaginal cervical length scan or cervical suture

Question 13

What infections are screened for in antenatal care?

Answer 13

Hep B
UTI
Syphilis
HIV

Question 14

How to monitor/manage these infections?

Answer 14

Hep B - passive and active immunisation for the baby
UTI - take MSSU
Syphilis - Penecillin
HIV - Maternal treatment and careful planning reduces risk of vertical transmission

Question 15

What blood disorders are screened for in antenatal care?

Answer 15

Iron deficiency anaemia
Haemolytic disease of newborn

Rhesus -ve women can attack Rhesus +ve baby. They are offered anti-D at 28 weeks and/or following any sensitising event (e.g. vaginal bleeding, amniocentesis) to reduce the risk of passage of antibodies.

Question 16

First visit scan purposes?

Answer 16

Ideally performed between 11 and 14 weeks gestation

Check for:
• Viable pregnancy 
• Multiple pregnancies
• Abnormalities  incompatible with life
• Offer and carry out Down’s syndrome screening

Question 17

What are the screening tests for chromosomal abnormalities?

Answer 17

• Combined Test
• Triple Test
• Quadruple Test
• Chorionic villus sampling
• Amniocentesis
• Non-Invasive Pre-Natal Testing
• 2nd Trimester USS

Question 18

What is the first line test for Down’s, Edward’s and Patau’s Syndrome?

Answer 18

Combined Test - Ultrasound and maternal blood tests.

First line and most accurate, carried out at around 11-14 weeks.

Question 19

What are the abnormal findings on ultrasound?

Answer 19

Measures nuchal translucency: the thickness of the back of the neck.

DS is one cause of a nuchal thickness of >6mm.

Question 20

What are the abnormal findings on blood test?

Answer 20

Beta-hCG - a higher result indicates a greater risk.

Pregnancy-associated plasma protein-A (PAPPA) – a lower result indicates a greater risk.

Question 21

What is the triple test?

Answer 21

Performed between 14 and 20 weeks.

It only involves maternal blood tests.

Question 22

What blood tests does the triple test include?

Answer 22

• Beta-hCG
• Alpha-fetoprotein (AFP) – a lower result indicates a greater risk
• Serum oestriol – a lower result indicates a greater risk

Question 23

What is the quadruple test?

Answer 23

Performed between 14 and 20 weeks.

Identical to the triple test, but also includes blood testing for inhibin-A.

A higher inhibin-A indicates a greater risk.

Question 24

What is the significance of these tests?

Answer 24

When the risk is greater than 1 in 150, the woman is offered:
Chorionic villus sampling
Amniocentesis

Question 25

What is Chorionic villus sampling?

Answer 25

Carried out between 10 and 14 weeks

US guided sample of the placental tissue. There is a 1-2% risk of miscarriage.

Question 26

What is Amniocentesis?

Answer 26

Carried out after 15 weeks, Later in pregnancy, enough amniotic fluid.

US guided aspiration of amniotic fluid.

Question 27

What is Non-Invasive Pre-Natal Testing (NIPT)?

Answer 27

Fancy way to look at maternal blood for foetal DNA. Check that for abnormalities.

Question 28

What is the 2nd Trimester USS for?

Answer 28

Structural abnormalities, not so much chromosomal.