Antenatal Flashcards
(408 cards)
What effect does progesterone have in pregnancy?
Relaxes smooth muscle:
uterus
gut- constipation + acid reflux
ureters- hydronephrosis
Raises temperature
What effect does oestrogen has in pregnancy?
Breast and nipple growth
Water retention
Protein synthesis
Why does vaginal discharge increase in pregnancy?
Cervical ectopy
Cell desquamation
Vasocongested vagina > increased mucus production
How much does plasma volume increase to in pregnancy?
3.8 Litres
What increases on the FBC are expected in pregnancy?
WCC (10.5)- neutrophilia from invading placenta ESR (x4) Cholesterol b-globulin Fibrinogen
What decreases are expected on the FBC in pregnancy?
Platelets- haemodilution + consumption
Urea
Creatinine
(small degree of hydronephrosis)
What happens to the inferior vena cava when pregnant woman lie supine?
From 20 weeks the gravid uterus compresses the ivc reducing venous return
How can ivc compression in pregnant women be reduced?
Lying in the left lateral position or wedging her tilted 15 degrees onto the left (restores venous return and thus cardiac output).
What effect does progesterone have on the lungs?
Relaxes smooth muscle of the diaphragm causing tidal volume to increase to 700mL
Why do pregnant women get breathless?
Maternal PaCO2 is set lower to allow the placenta to offload CO2 so breath more.
How soon will a pregnancy test give a positive result?
9 days after ovulation (day 23 of cycle)
How long into pregnancy is a pregnancy test positive?
20 weeks
How long does the corpus luteum produce progesterone for?
35 days
What three factors contribute to high risk pregnancies?
- Maternal age above 35
- Previous abnormal baby
- Family history of genetic condition
What does the ultrasound scan at 11-13weeks (+6 days) look for?
Nuchal translucency
Chorionicity- twins
When is the second abnormality scan?
18 weeks
What kinds of things is the ultrasound screen better or worse at identifying?
Good for:
Structural abnormalities that alter external anatomy
- anencephaly, spina bifida
Bad for:
internal structural abnormality- under 50% pick up
- heart disease, diaphragmatic hernia
What is choroid plexus cyst a soft sign for?
Trisomy 21- Down’s
Trisomy 18- Edwards
(choroid plexus is blood supply to brain)
What is echogenic bowel a soft sign for?
Trisomy 21
Cystic fibrosis- associated wit reduced bowel motility
Where is a-fetoprotein synthesised in the fetus?
the GI tract and liver
What pathologies can a high a-fetoprotein indicate?
Increased opening to amniotic sac:
Open neural tube defect
Examphalos
Tube Obstruction:
Kidney (post urethral valves) or gut abnormalities
Turner’s syndrome (XO)
(NB: not Downs which has low AFP)
What is a normal cause of high a-fetoprotein?
Twins
What can cause a low a-fetoprotein?
Chromosomal abnormalities- Down’s syndrome
Diabetic mother
When can amniocentesis be performed?
16 weeks
before then it has a 5% loss rate and may lead to talipes (club foot) or respiratory problems.