Antenatal Care and Screening Flashcards
How many antenatal meetings are normally made prior to 20 weeks gestation?
4
When assessing screening test, what is meant by ‘sensitivity’?
True positive (positive and false negative)
When assessing screening test, what is meant by ‘specifity’?
True negative (negative and false positive)
List points in the history and examination carried out at booking visit
HISTORY: menstrual, medical, obstetric, family, social
EXAM: height, weight, BP, CVS, abdomen
What is Naegele’s rule?
Estimate due date based in onset of women’s LMP (add 9 months and 7 days)
What tests are usually done in an antenatal booking appointment?
Hb Antibodies (Rhesus) Syphilis, HIV, Hep B+C Urinalysis, MSSU C+S Ultrasound
What markers are used to estimate gestational age?
Biparietal diameter
Femur length
What sign suggests a pregnancy is viable on ultrasound?
Fetal heart present
List points in the history and examination carried out at a follow up antenatal visit
HISTORY: physical and mental health, fetal movements
EXAM: BP, urinalysis, symphysis (fundal height), lie and presentation, engagement of presenting part, fetal heart auscultation
What common clinical maternal condition is characterised by high BP and proteinuria on urinalysis?
Preclampsia
What is “foetal lie”?
Relation of foetal spine to maternal spine
Longitudinal lie: parallel to maternal spine
Transverse lie: horizontal to maternal spine
What is “foetal engagement”?
Relation of foetal head to pelvic rim
Which scan is used to screen for foetal anomaly? When is this carried out?
Ultrasound
20 weeks
High AFP and low HCG is associated with increased risk of what particular foetal anomaly?
Spina bifida
List fetal anomalies screened for during pregnancy
Cleft lip Anencephaly Spina bifida Diaphragmatic hernia Cardiac abnormality Renal agenesis Edward's syndrome Patau's syndrome
State the chromosomal mutation found in Edward’s Syndrome
Trisomy 18
State the chromosomal mutation found in Patau’s Syndrome
Trisomy 13
What is ‘placenta praevia’? How is this managed?
A low-lying placenta, overlying the cervical os, after 20 weeks of pregnancy
32 week ultrasound scan followed by a vaginal scan
State the chromosomal mutation found in Down’s Syndrome
Trisomy 21
What tests can be used to detect the risk of Down’s syndrome in 1st trimester?
Skin thickness behind foetal neck (Nuchal translucency)
bHCG and PAPP-A levels
What tests can be used to detect the risk of Down’s syndrome in 2nd trimester?
Blood sample
HCG and AFP levels
Low AFP and high HCG increases/decreases risk of Down’s syndrome
Low AFP and high HCG increases risk of Down’s syndrome
What is a normal ‘Nuchal translucency’ of a fetus?
<3.5mm when CRL is between 45 and 84mm
Low risk on Down’s syndrome screening excludes Down’s syndrome. True/ False?
False
A risk >1:250 of Down’s Syndrome is classed as high risk and requires further investigation. What is recommended as the next best test?
Amniocentesis
List biochemical markers screened for in second trimester
AFP
HCG
Unconjugated oestradiol (UE3)
Inhibin A
What are the 2 main specific diagnostic tests that can be done for foetal karyotyping?
Amniocentesis
Chorionic villus sampling
Which two major haemaglobin disorders are screened for during pregnancy?
Sickle cell anaemia (distorted shape of red blood cells)
Thalassemias (abnormal form or low amount of Hb)
Describe how Rhesus disease can be acquired in the foetus.
Rh+ father and Rh- mother have a Rh+ baby –>
Blood cells enter mother’s bloodstream –>
Invading blood cells produce Rh Igs at delivery –>
In a later pregnancy, Rh Igs attack baby’s blood cells causing Rh disease
List risk factors indicating further testing in women for gestational diabetes
BMI >30 Previous macrosomic baby Previous gestational diabetes FHx of diabetes (1st degress relative) Minority ethnic family origin with high rates of DM
What measurement of symphysis fundal height would require referral for US measurement of fetal sixe?
Below 10th centile
Slow or static growth, e.g. crossing centiles
List factors relating to high risk of maternal preclampsia. How should this be managed?
Previous preclampsia Hypertension during previous pregnancy CKD Autoimmune disease (SLE, APS) Diabetes (type 1 or type 2) Chronic hypertension
75mg aspirin daily from 12 weeks until birth
What clinical conditions can urinalysis pick up during antenatal screening?
UTI
Asymptomatic bacteriuria
PET (Preclampsia)
Diabetes
How is Rhesus disease prevented in the pregnant women?
Anti-D prophylaxis throughout pregnancy
