Obs Flashcards
Name 5 teratogenic drugs.
ACEi Sodium Valproate Methotrexate Retinoids Trimethoprim
What does progesterone do during pregnancy? (main pregnancy hormone)
- Secreted by ovary to support thickening of the endometrial lining.
- Modification of maternal physiology: cardiovascular, bronchodilation, uterine quiescene.
- Immunosuppresion (one reason of miscarriage is woman can’t accept the foetus)
Role of HCG in pregnancy?
Responsible for the maintenance of the corpus luteum on the ovary, that continues to secrete oestrogens + progesterone.
Why do levels of HCG fall after 8-10wks of pregnancy (if it is needed to maintain the corpus luteum to secrete oestrogens/progesterone)?
At 8wks gestation, the placenta begins independent production of O&P. So HCG levels fall and corpus luteum recedes.
(Physiological changes in pregnancy)
Cardiovascular?
40%^ in plasma volume, cardiac output + tidal volume.
20%^ RBCs (therefore haemodilution as plasma col increases more than Hb)
Ejection systolic murmur + 3rd heart sound = normal in pregnancy!!!
BP reduces (in 2nd tri, but back to normal by term)
Clotting ^ (^ in factors 7,8,10 and fibrinogen)
(Physiological changes in pregnancy)
Renal?
GFR ^50%
Renal pelvis + ureters dilate (progesterone), ^infection risk.
(Physiological changes in pregnancy)
Endocrine?
T3/4 decrease
Anterior pituitary doubles in size
^cortisol, ^insulin
(Physiological changes in pregnancy)
MSK?
Progesterone softens joints + ligaments.
What are the effects of Progesterone as a SMOOTH MUSCLE RELAXANT during pregnancy?
Relaxes bile ducts = cholestasis
Relaxes bladder/urethra = UTIs
Relaxes blood vessels = Drop BP
Relaxes GOJ + stomach = GORD (use ranitidine + omeprazole).
What does the Dating Scan show? (offered at 10-14wks)
Estimated due date (also can use LMP+7 +9months)
Identifies multiple pregnancies
Nuchal translucency measurement- to screen for chromosomal abnormalities.
What bloods are booked during The Booking Visit (10wks)?
FBC (anaemia in preg usually due to iron def, normal values in early preg= Hb>110. FBC usually repeated at 28wks) Haemoglobinopathies Blood group + antibody screen HIV, Syphilis, Hep B Plus STI screen if <25
What consent is obtained in The Booking Visit
Consent for antenatal screening:
- Combined screening (opt in)
- Quadruple test (if miss combined)
How is the risk of Tri-21 calculated?
Maternal age x risk ratio from combined screening test.
SCREENING POSITIVE = risk of >1/150
What is the significance of nuchal translucency?
The larger it is (>5mm), the higher risk of structural defects.
(blood test from combined screening) What is the significance of PAPP-A (pregnancy-associated plasma protein A)
Protein produced by the placenta during pregnancy.
Low levels = higher risk (of Down’s, Edward’s, Patau’s)
(blood test from combined screening) What is the significance of hCG?
(in 1st + 2nd trimester)
High levels = higher risk of Down’s
Low levels = higher risk of Edward’s/ Patau’s
In the quadruple test (14-20wks), if Down's was detected what would the following results be? (low/high) hCG Inhabin-A AFP Estriol
hCG : up
Inhabin-A : up
AFP : down
Estriol : down
(Prenatal Diagnostic Tests)
NON-INVASIVE:
Explain what US can diagnose?
Neural tube defect
Twin-to-Twin transfusion syndrome
Gastroschisis
(Prenatal Diagnostic Tests)
NON-INVASIVE:
Explain what cffDNA (cell-free foetal DNA) is used for?
For women at higher risk for Down’s, Edward’s or Patau’s
Determines RhD status in RhD negative mothers
Foetal sex determination (for sex-linked disorders)
Single gene disorders (CF)
(Prenatal Diagnostic Tests)
NON-INVASIVE:
Explain what a IONA test can diagnose?
Down’s, Edward’s or Patau’s
Sex determination
(Prenatal Diagnostic Tests)
INVASIVE:
What are CVS / amniocentesis used to diagnose?
And what is the risk?
Down’s
CF
Thalassaemia
1% risk of miscarriage
Process of Chorion Villus Sampling (10-13 wks)?
US guided trans-abdo/trans-cervical
Aspiration of TROPHOBLASTIC CELLS (for karyotyping, PCR, FISH)
Results in 48hrs
Risks: miscarriage (1-2%), vertical transmission of BBV
Process of Amniocentesis? (15+wks)
Aspiration of amniotic fluid which contains foetal cells from skin + gut.
Transabdo, results in 3wks
Risks: miscarriage (0.5%)
What happens if a woman is Rhesus -ve?
Anti-D prophylaxis to prevent rhesus D iso-immunisation + haemolytic disease of the newborn.
Anti-D is offered at28wks, after any sensitising event (trauma), and at delivery.