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Flashcards in Pregnancy Deck (61)
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1

4 satges to foetal development

embryo
foetus
viability
term

2

Main maternal changes of pregnancy

Increased weight
Increased hormone levels
Increased clotting
Decreased BP
Increase in body temperature
Increased breast size
Increased vaginal mucus production
Increased nausea and vomiting

3

when is start of pregnancy

first day of menstrual cycle that results in fertilisation

4

What happens to levels of hCG during pregnancy

increases during first trimester and peaks here but then declines rapidly at end of first tirmester

5

What happens to levels of placental lactogen during pregnancy

increase steadily whole way through

6

What happens to levels of progesterone during pregnancy

increase steadily whole way through

7

What happens to levels of oestrogens during pregnacny

increase steadily whole way through

8

What are increases in oestrogens, placental lactogens and progesterone paralelled with

Plaental size

9

What produces hCG

Placenta

10

What is the luteo-placental shift

Change from corpus luteum to placenta as main source of progesterone and oestrogens

11

When does placenta become main source of progesterone

10 weeks

12

What facilitates this luteo-placental shift

increase in size of placenta and from 6 weeks the corpus luteum gradually produces less progesterone despite the elevated levels of

13

whats special about fetal adrenal glands

well developed and large even in first trimester

14

What is involvement of fetal adrenals in production of circulating maternal oestrogens

Placenta lacks the enzyme that converts pregnenolone to androgens. The fetal adrenals are able to produce a weak androgen DHEA which is sulphated in the fetal liver to give DHEA-S

15

Significance of androgen produced by fetal

It is inactive so a female fetus isnt exposed to an androgen during development

16

What happens to DHEA-S after its sulphation in fetal liver

circulates to placenta where is converted to 17beat-oestradiol

17

Pathway leading to high levels of circulating maternal oestriol

DHEA-S is induced to be hydroxylated to form 16aOH-DHEA-S which is precursor for estriol. The precursor circulates to placenta where is converted to estriol

18

Reason for increased blood clotting tendency

thought to be protective against losing too much blood during delivery and to do with the interactions between maternal and foetal blood

19

Changes in maternal BP during pregnancy

BP decreases for first two trimesters and is lowest in second then increases during the third one

20

Cause for concern of lowered BP in pregnant women

Susceptible to fainting if stand for too long

21

Reason for increased size of breasts

Increased levels of prolcatin, oestrogens and placental lactogen

22

Reason though to behind altered appetite

Baby puts pressure on GI tract decreasing its distensibility so smaller meals more often are what is suggested

23

Reason for altered emotional state

Hormones

24

Altered joints during pregnancy

Connections between bones in pelvis become more flexible to permit growth of baby

25

2 reasons behind how there is no signs of rejection reaction despite a non self entity surviving in a woman for 9 months

Utero-placental interface produces numerous factors that modify mothers immune response
Placenta expresses bizarre HLA antigens- normaly HLA are very polymorphic with millions of variants however placenta HLA only has 5 variants. The structure of placental HLA is very simplistic giving message to maternal immune system that the tissue is human but not non-self which downregulates action of leukocytes

26

What controls development of the features

Genetic
Environmental factors such as maternal diet

27

Evidence for importance of genetic control

Any chromosome abnormalities show large changes in development

28

Only viable example of too few chromosomes

Turners syndrome- 45-X0

29

When is embryo most vulnerable to abnormalities

Early trimester

30

What is a teratogen

Agent that can hinder embryo development