Antenatal Care and Screening in Pregnancy (incomplete) Flashcards
What gestatational age is the booking scan performed?
11-13 weeks
What is the objective of booking scan?
Assess viability (ex. mole) Number of babies Down's Syndrome Estimate gestational age Detect major structural anomalies Offer DSS
Are the tests and antenatal screening/care regimes compulsory?
No. Choice of mother whether or not to undergo them.
Most accurate way to determine EDD on scan?
Crown - rump length
Why is it important to check for maternal anaemia?
Post partum haemorrhage is the leading cause of maternal death
How to calculate sensitivity and specificity
Sensitivity = True positive /(positive + false negative) Specificity = True negative/(negative + false positive)
What are the two categories of pregancies?
Green pathway - routine antenatal care, normal pregnancy
Red pathway - complicated pregnancy, specific antenatal care
Aspects of history to cover during the booking visit
Menstrual Medical Surgical Obstetric Family Social
Physical examination to perform during booking visit
Height Weight BP BMI CVS Abdomen
Calculating EDD
Naegele’s Rule:
to the LMP simply add on nine months and seven days to arrive at the due date
Investigations to be performed during booking
Hb ABO; Rhesus Syphilis; HIV; Hep B&C; Urinalysis; MSSU C&S Ultrasound:
What history is covered during follow up visits?
Physical and mental health
Fetal movements
What examination is performed during follow up?
BP and urinalysis Symphysis- fundal height Lie and presentation Engagement of presenting part Fetal heart auscultation
What is the normal lie and presentation upto 36 weeks?
longitudinal lie
cephalic presentation
No engagement
Objectives for ultrasound in fetal anomaly screening
Reduction in perinatal mortality and morbidity
Potential for in utero management
Identification of conditions amenable to neonatal surgery
Name an abnormality associated with Down’s syndrome
Cleft palate
What is placenta previa?
when the placenta is low lying in the wombandcovers all or part of the entrance (the cervix
Is a low lying placenta detected in early pregnancy reversible?
Yes
In most women, as the womb grows upwards, the placenta moves with it so that it is in a normal position before birth and does not cause a problem.
If an earlier ultrasound scan (usually between 18weeks0days and 20weeks6days) showed that your placenta extends over the cervix, you should be offered another abdominal scan at 32weeks. If this second abdominal scan is unclear, you should be offered a vaginal scan
What is the impact of increasing maternal age on pregnancy?
increases risk of Down’s Syndrome
Down’s Risk Assessment in 1st Trimester
Measure of skin thickness behind fetal neck using ultrasound (Nuchal thickness; NT)
Measured at 11-13+6 weeks
Combined with HCG and PAPP-A
A value of < 3.5 mm would be considered normal when the CRL is between 45 and 84mm.
Down’s Risk Assessment in 2nd Trimester
Blood sample at 15-20 weeks
Assay of HCG and AFP
Downs risk assessment in both first and second trimester
Incorporation of these measurements / results with maternal age and gestation to give a personal risk
>1:250 high risk and requires further investigation (e.g. amniocentesis)
Specific Diagnostic Tests
Amniocentesis:
- Usually performed after 15 weeks
- Carries a miscarriage rate of 1%
Chorionic villus sampling:
- Usually performed after 12 weeks
- Carries a miscarriage rate of 2%
Second trimester screening for aneuploidy
For those women who miss first trimester screening
For those women in whom CUBS is unsuccessful
Maternal Age + Biochemical Markers: - Alpha-fetoprotein (AFP) human Chorionic Gonadotrophin (hCG) - Unconjugated oestradiol (UE3) - Inhibin A
