Antenatal Screening Flashcards
Cardiac physiology of pregnant women?
- Cardiac output increases by 30-50%
- Blood pressure drops in 2nd trimester (expansion of uteroplacental circulation, fall in systemic vascular resistance)
Urinary physiology of pregnant women?
- Increased urine output (increased renal plasma flow)
- UTI (can be associated with preterm labour, must treat)
Blood physiology of pregnant women?
- Anaemia (plasma volume up, RBC up but not as much)
- Iron requirements increase by 1g during pregnancy
- WBC increases slightly
Respiratory physiology of pregnant women?
- Progesterone reduces CO2
- O2 consumption increases
- Plasma PO2 unchanged
GI physiology of pregnant women?
- Oesophageal peristalsis reduced
- Gastric emptying slows, cardiac sphincter relaxes (GORD + heartburn)
- GI motility reduced (constipation)
What are the general aspects of pre-pregnancy counselling?
- 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
How to monitor/manage Pre-eclampsia?
Aspirin 150mg during pregnancy and regular BP check
How to monitor/manage Gestational diabetes?
HbA1c at booking and OGTT at 28 weeks
How to monitor/manage Previous C-section?
Consider elective C-section or vaginal birth after C-section (VBAC)
How to monitor/manage DVT or PE?
Consider antenatal thromboprophylaxis and 6 weeks postnatal treatment
How to monitor/manage Intrauterine growth restriction?
Aspirin 150mg during pregnancy and serial US scan
How to monitor/manage Preterm birth?
Consider transvaginal cervical length scan or cervical suture
What infections are screened for in antenatal care?
Hep B
UTI
Syphilis
HIV
How to monitor/manage these infections?
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
What blood disorders are screened for in antenatal care?
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.
First visit scan purposes?
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
What are the screening tests for chromosomal abnormalities?
- Combined Test
- Triple Test
- Quadruple Test
- Chorionic villus sampling
- Amniocentesis
- Non-Invasive Pre-Natal Testing
- 2nd Trimester USS
What is the first line test for Down’s, Edward’s and Patau’s Syndrome?
Combined Test - Ultrasound and maternal blood tests.
First line and most accurate, carried out at around 11-14 weeks.
What are the abnormal findings on ultrasound?
Measures nuchal translucency: the thickness of the back of the neck.
DS is one cause of a nuchal thickness of >6mm.
What are the abnormal findings on blood test?
Beta-hCG - a higher result indicates a greater risk.
Pregnancy-associated plasma protein-A (PAPPA) – a lower result indicates a greater risk.
What is the triple test?
Performed between 14 and 20 weeks.
It only involves maternal blood tests.
What blood tests does the triple test include?
- Beta-hCG
- Alpha-fetoprotein (AFP) – a lower result indicates a greater risk
- Serum oestriol – a lower result indicates a greater risk
What is the quadruple test?
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.
What is the significance of these tests?
When the risk is greater than 1 in 150, the woman is offered:
Chorionic villus sampling
Amniocentesis
What is Chorionic villus sampling?
Carried out between 10 and 14 weeks
US guided sample of the placental tissue. There is a 1-2% risk of miscarriage.
What is Amniocentesis?
Carried out after 15 weeks, Later in pregnancy, enough amniotic fluid.
US guided aspiration of amniotic fluid.
What is Non-Invasive Pre-Natal Testing (NIPT)?
Fancy way to look at maternal blood for foetal DNA. Check that for abnormalities.
What is the 2nd Trimester USS for?
Structural abnormalities, not so much chromosomal.
