Foetal development Flashcards
On what day of the menstrual cycle does ovulation occur?
day 14
Where does fertilisation and conception take place?
fallopian tube
What are the stages of cell division?
Zygote
Morula
Blastocyst
After conception, where does the blastocyst travel to?
uterine cavity
On what day does implantation in to uterine cavity take place?
day 23
What happens after implantation of blastocyst into decidua?
hCG released
stimulates ovary to produce progesterone
For how long do HCG levels rise?
rise rapidly up to 10 weeks
What is the basis of a pregnancy test?
HCG levels
How is HCG detected in pregnancy tests?
detected in serum and urine 4 weeks after LMP
What concentration of HCG is detected in a urine +ve PT?
Urine PT +ve when HCG concentration reaches 25 IU/ml
When does early implantation generally take place?
12 days post conception
Which hormone is the main pregnancy hormone?
Progesterone
Which key areas of maternal physiology are effected by progesterone?
cardiovascular
respiratory
uterine quiescence
immune system
How do you diagnose pregnancy?
Clinical: symptoms
signs
Investigations: hCG
USS
What are the two main routes of USS?
transvaginal or transabdominal
What are key dates in foetal development?
4-5 weeks: gestation sac 6mm
5-6 weeks: yolk sac
6 weeks: foetal pole 5mm
6-7 weeks: foetal heart activity
8 weeks: limb buds, foetal movements
How does the size of a foetus change in between weeks 6-12 weeks?
doubles in size every week
What occurs in the uterus/to the foetus in the first 12 weeks of pregnancy?
organs develop
placenta assumes major role (gas exchange, nutrient waste transfer, steroidogenesis)
In which timeframe is their the highest risk of miscarriage during pregnancy?
within the first 12 weeks
What role does the placenta play in the first 12 weeks of pregnancy?
gas exchange
nutrient/waste transfer
steroidogenesis
What are two important complications of early pregnancy?
miscarriage
ectopic (tubal) pregnancy
How many days is the menstrual cycle?
28 days (from first day of LMP to first day of next MP)
Which hormone peaks to trigger ovulation around day 14?
luetnising hormone
What is happening between days 1 - 14?
follicle is growing
What hormone peaks after ovulation?
FSH
What happens after the follicle is released?
follicle becomes corpus luteum (releases progesterone)
Where does ovulation occur?
fallopian tube
What stage of development is the foetus as it travels towards the uterine cavity?
blastocyst
On the diagram fro the lecture, what is site number 2?
cervical ectopic
Where is the most common site of an ectopic pregnancy?
ampulla (of fallopian tube)
How is an ectopic pregnancy in the ampulla usually treated?
laparoscopic surgery to remove fallopian tube
How is a corneal ectopic pregnancy treated?
injection of methotrexate
When does the placenta take over from the corpus luteum in terms of producing progesterone?
after about 14 weeks
What can happen to hCG level in third trimester?
it can drop (therefore won’t detect positive on pregnancy test)
What occurs in maternal blood lakes?
exchange of oxygen and blood waste
What is the main pregnancy hormone?
progesterone
What hormone is the main cause of many health problems in pregnancy?
progesterone
What changes occur to cardiovascular system when you’re pregnant?
HR increases
SV increases
= increase CO
BP decreases (peripheral vascular resistance decreases - allows blood to go to bottom of body more easily)
Nadir in second trimester
(patient might feel dizzy)
What changes occur to respiratory system when you’re pregnant?
SOB - cause can range from physiological (baby growth) to PE
What happens to uterine quiescence in pregnancy?
Uterus becomes quiet - uterine relaxation.
This is caused by progesterone
What do you give to women who are at risk of pre-term labour
progesterone
What happens to immune system in pregnancy?
weakens (less active T cells)
HENCE why baby isn’t rejected
What risk are women with HIV and
severe asthma exposed to when pregnant?
more likely to have exacerbations
What is the most common infection in pregnant women?
UTI
What are symptoms of pregnancy?
ammenhorhoea
morning sickness
breast engorgement and tenderness
mood changes
What investigations should you do to diagnose pregnancy?
hCG
USS
Other than in heightened BMI, when might you use a TV US?
very early on in pregnancy (as uterus is in pelvis)
4-5 weeks US shows:
gestational sac
5-6 weeks US shows:
yolk sac
6 weeks US shows:
foetal pole
6-7 weeks US shows:
Foetal heart
8 weeks US shows:
limb buds
foetal movement
When can you reassure a mother that her baby is healthy?
6.5 weeks
need to be able to hear heart sounds
When can you determine the sex of the baby?
15 weeks
When a baby is born, how many layers does it have?
2: amnion, chorion
When does the dating scan need to be done by?
14 weeks
What else is offered with the dating test?
Down’s screening: transnuchal lucency
What is the risk of miscarriage before 12 weeks?
1 in 4 - 1 in 6
What foetal development occurs after 12 weeks?
Growth and maturation
