Antenatal care Flashcards
When does the Booking Appointment take place?
10 weeks
How is the estimated date of delivery calculated before any scans have taken place to determine Crown-Rump Length?
If date of last menstrual period is known:
EDD = LMP + 9 months + 7 days
How many antenatal appointments will a nulliparous woman have?
10
How many antenatal appointments will a multiparous woman have?
8
What should be covered at each antenatal appointment?
General maternal wellbeing, BP, urinalysis, fetal movement and fetal heart rate, measure and plot symphysis-fundal height
What blood tests are offered at the booking appointment?
FBC (check for anaemia and thrombocytopenia)
Haemoglobinopathies
Blood group and rhesus status
Infectious diseases (HIV, hepatitis B, syphilis)
When does the dating scan (a.k.a. early pregancy scan) take place?
12 weeks
Between 11+2 and 14+0 weeks
What forms the combined screening test?
This is an opt-in test that is done at the dating scan (12 weeks) and comprises a measurement of nuchal translucency on USS and a maternal blood test for beta-hCG (Human chorionic gonadotrophin) and PAPPA (pregnancy-associated plasma protein A).
Which conditions are screened for using the combined screening test?
Down’s (T21), Edwards’ (T18) and Patau’s (T13) syndromes
What is the cut off for saying a baby is ‘high risk’ for having one of the syndromes following a combined screening test?
> 1 in 150 = high risk
What percentage of women get a ‘higher probability’ result following the combined screening test?
2%
What is the detection rate of the combined screening test?
~85%
Which diagnostic tests are offered if a women’s combined screening results show a high risk?
Chorionic Villous Sampling from 11 weeks
Amniocentesis from 15 weeks
Both these tests have a 1 in 100 chance of causing miscarriage
What options does a woman have if she misses the chance for combined screening but wishes to know the chance of her baby having Down’s syndrome?
Quadruple screening test - this is a maternal blood test only, available between 15 and 20 weeks, 80% detection rate, 4% false positives
Non Invasive Pre-natal testing (NIPT) - private sector only. 99% detection rate, placental DNA extracted from maternal blood sample.
When should the fetal anomaly scan take place?
Between 18+0 and 20+6 weeks
What is checked at the anomaly scan?
Sonographers have a list of conditions to check for i.e. anencephaly, gastroschisis, heart defects, Trisomies 13 and 18 etc. If an abnormality detected, referral to obstetrician.
Can also determine the sex of the baby at this scan
If a woman is rhesus negative, when will she be offered Anti-D immunoglobulin to prevent rhesus disease of the newborn?
At 28-30 weeks gestation, women will get IV Anti-D Ig
Another IM injection of Anti-D after the delivery if baby is Rhesus positive (cord blood test at birth)
