Pregnancy Flashcards

1
Q

What are the features of the 1st trimester?

A
  • Most risky part
  • Miscarriage risk highest
  • N+V “morning sickness”
  • Hard to tell someone is pregnant
  • Increased urinary frequency - hormones alter kidney function
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2
Q

What are the risks of the 1st trimester?

A
  • High miscarriage risk (esp weeks 10-12 when placenta becomes less anchored as cytotrophoblast plug breaks down)
  • Incomplete anchorage of placenta
  • Defects in gamete production - too many/few chromosomes: Turner’s (XO), YO inviable, Kelinfelter’s XYY, Down’s trisomy 23, loss of autosome = fatal)
  • Major congenital abnormalities
  • Functional defects + minor congenital abnormalities
  • Spina bifida
  • Cleft palate
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3
Q

What is the 1st trimester?

A

Weeks 0-13

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4
Q

What are the features of the 2nd trimester?

A
  • Urinary frequency normalises

- Mother starts to feel baby moving

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5
Q

What are the risks of the 2nd trimester?

A
  • Stillbirth
  • Increase in maternal blood clotting tendency
  • Drop in BP –> maternal fainting
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6
Q

What is the 2nd trimester?

A

Weeks 14-26

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7
Q

What are the features of the 3rd trimester?

A
  • Increased urinary frequency as uterus pushes on bladder
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8
Q

What are the risks of the 3rd trimester?

A
  • Increase in maternal blood clotting tendency
  • Gestational diabetes
  • Preeclampsia
  • Preterm labour
  • Preterm premature rupture of membranes
  • Placental previa + placental abruption
  • Intrauterine growth restriction
  • Malpresentation (breech, etc.)
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9
Q

What is the 3rd trimester?

A

Weeks 27-39

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10
Q

What is the main purpose of the 2nd trimester?

A

?

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11
Q

What are the maternal changes associated with pregnancy?

A

Increased:

  • Weight
  • Hormone levels/ altered endocrine system
  • Blood clotting tendency
  • Basal body temp
  • Breast size
  • Vaginal mucus production
  • N and V

Decreased:
- Blood pressure

Altered:

  • Brain function
  • Appetite
  • Fluid balance + urination frequency
  • Emotional state
  • Joints
  • Immune system
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12
Q

What are the main purposes of the 3rd trimester?

A

?

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13
Q

How does the placenta develop?

A
  • From single layer of cells in blastocyst
  • Cells proliferate + differentiate
  • Expands iteratively
  • Cytotrophoblast shell limits blood (oxygen) supply to embryo during early developing to reduce no. of oxygen free radicals

Day 9 PF:

  • Blastocyst implants into decidualising endometrium
  • Surrounded by inner cytotrophoblast and outer synctiotrophoblast which has fluid filled spaces called lacunae

Day 13-20 PF:

  • STB bumps into maternal blood supply
  • Slow flow of blood into lacunae
  • CTB begins to invade into the STB to form a primary villus and trophoblastic shell

Day 21- 28 PF:

  • CTB eventually reaches outside to cut off maternal blood supply
  • Creating a low oxygen tension environment (~3%)

End of 1st TM:

  • Fewer CTB so that syncitium and placental capillaries can be close together
  • During first trimester, endometrial glandular hypertrophy
  • Histotrophic nutrition
  • 8 weeks PF CTB plugs as maternal spiral arteries start to break down
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14
Q

How is steroidogenesis an example of the three-way interaction in pregnancy?

A
  • Maternal adrenals, placenta, foetal adrenals and foetal liver all involved
  • Maternal adrenals make DHEA-S and cortisol from maternal LDL-cholesterol
  • Maternal LDL-cholesterol –> prenenolone –> progresterone in placenta
  • Placental pregnenolone –> foetal adrenals –> DHEA-S –> foetal liver –> 16aOH DHEA-S
  • Foetal liver DHEA-S + 16aOH-DHEA-S –> placenta
  • Maternal cortisol –> placenta –> cortisone
  • Maternal DHEA-S + foetal liver DHEA-S –> placenta –> oestrone 17B oestradiol
  • Foetal 16aOH-DHEA-S –> oestriol in placenta
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15
Q

Define conceptus

A

Everything resulting from fertilised egg - baby, placenta, foetal membranes, umbilical cord

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16
Q

What are the main placental structures?

A
  • Chorion (foetus)
  • Umbilical arteries (deoxygenated)
  • Umbilical vein (oxygenated
  • Placental villus
  • Basal plate (mother)
  • Uterine arteries and veins
  • Subdivided into 30-60 cotyledones - contain 1+ villi
17
Q

Define foetus

A

Baby after clearly human

18
Q

Define infant

A

Less precise, normally applied after delivery

19
Q

How are ultrasound imaging and foetal dopplers used in foetal assessment?

A
  • Confirming pregnancy
  • Dating pregnancy
  • Assessment of suspected early pregnancy failure or ectopic pregnancy
  • Estimating date of delivery
  • Checking placenta
20
Q

Why do the maternal spiral arteries need to be remodelled?

A
  • arteries as they are in uterus can’t carry enough blood for rapidly growing uterus
  • lose endothelium + smooth muscle cells –> v distended vessel - can take large volumes of blood @ low pressure in 2nd + 3rd trimesters
21
Q

When does spiral artery remodelling start?

A

Week 6 PF

22
Q

How do hormone levels change during pregnancy?

A
  • HCG peaks at 8-11 weeks

- Progesterone, oestrone + placental lactogen all gradually increase to VERY HIGH levels