Antenatal Care and Screening Flashcards
How many scans in pregnancy?
- 2 scans (booking and 28 weeks)
What do you screen for antenatally on booking?
- STI (HIV and Syphilis)
- Molar pregnancy
- Ectopic preg.
- how many babies
- conditional testing for Down $
- ESTIMATED DD
- anemia
- rhesus status
Most accurate way to estimate DD on usg?
-crown-rump length
What to look for in USG?
- abdominal wall and heart defects
- anencephaly
- spina bifida
- placenta privia
What is the importance of consistent screening
-post partum hemorrhage leading cause of DEATH worldwide
What is the risk of UTI?
- pre-term labour
How accurate is Down syndrome ?
- -false positive rate of 5%
What does the midwife label the pregnancy as?
- red pathway : obstetric input (miscarriage hx)
- green pathway : low risk pregnancy
What suggests an ectopic preg?
- no yolk sac
When is the pregnancy considered to be viable?
- when a heart beat is detected
What is examined during the antenatal follow up visits?
BP and urinalysis Symphysis- fundal height Lie and presentation Engagement of presenting part Fetal heart auscultation
When should the baby be lying longitudinally ?
—-by 36 weeks
What are the objectives of USG for fetal anomaly?
- Reduction in perinatal mortality and morbidity
- Potential for in utero treatment (to treat spina bifida laproscopically)
- Identification of conditions amenable to neonatal surgery
Significance for screening for cleft-lip?
- a.w Trisomy 13 and 18
- so the mom is expecting this from her baby
Poor survival rate of baby?
- trisomy 18 and 15
- cardiac abnormalities
What is placenta praevia?
- low-lying placenta in womb (covers the cervix)
Can you tell the morbidity of a Down $ baby?
- range
- –some need lifelong support
Risk of down $ baby in 40 y.o and older deliveries?
1 in 100
How to Dx Down $?
- Nuchal thickness
- measured at 11-13weeks+6days
- combined with HCG and PAPP-A
When is nuchal thickness considered to be normal?
—-if CRL is 45-84mm (value of <3.5mm is normal)
Alternative for amniocentesis for those at a high risk of having a baby with certain genetic and chromosomal conditions?
cffDNA testing, non-invasive prenatal testing (NIPT) - cell free fetal DNA in maternal blood; detected at 7 wks of pregnancy
When is amniocentesis performed? Its miscarriage risk?
- after 15 weeks
- 1%
When is chorionic villi sampling performed?
- after 12 weeks
- 2% miscarriage risk
Signs of rhesus status?
- middle cerebral artery lucency on USG of the fetus suggests anemia??
- red cell rise in maternal blood
Pts with inaccurate SFH?
- those with BMI>35
- large fibroids
- hydramnios
What is advised for women with HIGH- risk of pre-eclmapsia?
- take 75mg of aspirin daily from 12 weeks gest. until BIRTH —–those at hig risk: CKD pt/hypertensive disease
What is advised for women with HIGH- risk of pre-eclmapsia?
- take 75mg of aspirin daily from 12 weeks gest. until BIRTH —–
What is meant by sensitivity?
- how often a test generates a POSITIVE result for the condition being tested on
- a test with 90% sensitivity will correctly return a POSITIVE result for 90% of people who have the disease —but 10% will return a false negative (people who should have returned as a positive)
What is meant by specificity?
- a test’s ability to correctly generate a negative result for people who don’t have the condition
–a high-specificity test will correctly rule out almost everyone who doesn’t have the condition
What is Naegele’s Rule?
- predicts the estimated DUE date based on the onset of the woman’s LMP (first day)
- –add on 9mo & 7days
How accurate are the 1st trimester screening of Down Syndrome?
- a sensitivity of 90%
- false positive rate of 5%
- —but ONE in 20 women who have a HIGH risk result will have a baby NOT affected by DOWN’s
What invx are done during the booking visit?
- Hb
- ABO; Rhesus
- Syphilis; HIV; Hep B & C
- Urinanalysis; MSSU C&S
- USG
What should be looked for on USG?
- confirm Viability (HR)
- single/multiple pregn
- estimated gestational age
- structural abnormalities
What fetal abnormalities can be seen on USG?
- anencephaly
- open spina bifida
- cleft lip
- diaphragmatic hernia
- gastroschisis
- exomphalos
- b/l renal agenesis
- Patau’s $ (trisomy 13)
- Edwards’ $ (Trisomy 13)
- lethal skeletal dysplasia
What is decided if an earlier USG scan (18wks and 20 wks6days) showed the placenta extends over the cervix ?
- another abdominal scan should be scheduled at 32 weeks
- if unclear : VAGINAL scan
How many scans are done during a normal pregnancy?
- To check DD, # of pregnancies, Down $ (IF you want): 10 weeks -13 weeks6days
- Another anomaly scan at 18 wks- 20wks + 6 days
Other causes of increased nuchal translucency ?
- Turner’s $
- Downs $
- Cardiac anomalies
- —-chromosome abnormalities
How to find the risk a woman holds to get a Down Syndrome bbY?
- in 1st and 2nd trimester: use USG in conjuncture with AFP and hCG results and incorporate with maternal AGE and gestation to find a PERSONAL risk
–>1:250= means HIGH risk (do amniocentesis)
What should be offered to the mother after she is told of her risk (LOW or HIGH)?
- accurate pregnancy dating
- detailed COUNSELLING
When is a 2nd trimester screening done?
at 15-20+6wks
- when women MISS their first trimester screening
- to those in whom CUBS is UNSUCCESSFUL
- —Maternal age+Biochem. Markers (AFP/hCG/ UE3/Inhibin A)
What is CUBS?
Combined Ultrasound and Biochemical Screening Test at 11-14 weeks
When is the mother tested for maternal anemia?
- screened at Booking and at 28 wks
(Iron def., Folate def., B12 def.)
—–blood group and antibody status also determined now.
How does Rh Hemolytic disease develop?
- RH(-) mom and a Rh (+) bby
- at delivery: Rh (+) bby blood cells enter the MOTHER’S bloodstream> prodn of Rh Abs
- Rh antibodies remain
- —NEXT pregnancy: Rh Abs ATTACK the baby’s blood cells
At the booking appointment, how do you evaluate the risk of the mom having GDM?
- BMI >30kg/m2
- previous MACROSOMIC baby (4.5kg or above)
- previous gestational diabetes
- family hx of diabetes
- minority ethnic origin with HIGH diabetes prevalence
How to dx GDM?
- use 2hr 75g ORAL glucose tolerance test (for those with GDM risk)
- diagnose it if:
FASTING plasma glucose is 5.6mmol/L or ABOVE
OR
2HR plasma glucose of 7.8mmol/L or above
When is serial measurement of the SFH recommended at?
- EACH antenatal appointment (from 24 wks) ——improves prediction of SGA neonate
When may the SFH measurement be inaccurate?
- BMI>35
- Large fibroids
- hydramnios
What medical conditions indicate a HIGH risk of developing PRE-ECLAMPSIA?
- CKD
- hypertensive in LAST pregnancy
- Type 1 or 2 Diabetes
- chronic H/T
- autoimmune disease: SLE or Anti-phospholipid syndrome
Factors indicative of LOW risk of pre-eclampsia?
- 1st pregnancy
- > 40y.o
- pregnancy interval of MORE than 10 years
- BMI of 35kg/m2
- family hx of Pre-eclampsia
- Multiple pregnancy
Purpose of Urinanalysis?
- UTI
- PET (proteinuria)
- Diabetes
- Asymptomatic bacteriuria
What are co-variables to consider for the development of down syndrome?
- Smoking status
- previously affected pregn.
- assisted conception
What additional risk may thalassemia hold for the mother and baby?
- issue of CARDIOMYOPATHY for the mother d/t iron overload
-increased risk of fetal growth restriction - with 9m.o of little to no chelation= ENDOCRINOPATHIES may develop in the mom
(DM, hypothyroidism, hypoparathyroidism)
