Physiological Adaptations to Pregnancy Flashcards
Pregnancy - Key stages
What are the 2 stages of the first trimester (3 months) of pregnancy and at what weeks do they occur?
Weeks 1-12 Preembryonic
At Weeks 3-8 (included in preembryonic): embryonic
think embryo
What are 4 stages of the second trimester and at what weeks do they occur?
think fetus
Weeks 13-26: fetal development
At weeks 9-40 (included in fetal development): fetal period
At week 24 (included in fetal development): viability (fetus can be born at this age and survives)
What are the 2 stages of the third trimester of pregnancy
week 27-40: maturation
week 38-42: delivery
first signs
What are the 5 first signs of pregnancy?
think sickness, missing period, breasts, tired, wanting to eat food
Nausea: caused by endocrine (hormonal) changes
Amenorrhoea: missed period
Breast tenderness: increased production of steriod hormones
Fatigue
Food cravings (PICA): more sensitive sense of smell
first signs
what is hyperemesis gravidarum and what is it treated with?
think sickness and what drug is used to treat it and type of administration
extreme form of nausea: treated with antiemetics via tablets (short term symptoms) or injections (prolonged symptoms)
weight gain during pregnancy
Outline the constituents and their amount of weight gain during pregnancy in: 1. maternal, 2. fetus
think myometrium, fat and blood for maternal
think placenta, amnoitic fluid and fetus for Fetus
Maternal:
- myometrium (0.9kg)
- fat (4kg)
- blood (1.2kg)
Fetal:
- Placenta (0.7kg)
- amniotic fluid (0.8kg)
- fetus (~ 3.3kg)
Weight gain
Outline 4 essential nutrients for pregnancy
- folic acid (pre-pregnancy)
- iron
- vitamin K
- Vitamin B
spiral artery remodlling
Why does the spiral artery get remodelled?
To maximise blood flow to the baby
spiral artery remodelling
outline how spinal artery remodelling occurs, what brings it about and what the results of it are.
for first part, think decidual spiral arteries and vascular cells, size of arteries and result of this
for second part, think what immune cells bring spiral artery remodelling about
for third part, think about what material is in the remodelled vessel and what it replaces and also what happens subsequently
- unremodelled decidual spiral artery changes structure by losing vascular cells
- this increases the size of the arteries, making the arteries high-flow, low resistance vessels.
- these changes are brought by maternal immune cells (dNK cells and macrophages) and completed by invading interstitial and endovascular EVT (extravillous trophoblast).
- the remodelled vessel consists of trophoblasts embedded in a fibrinoid material as a replacement for the layer of VSMCs (vascular smooth muscle cells).
- subsequent re-endothelialisation occurs later in pregnancy
anatomical changes in pregnancy
Outline 6 anatomical/structural changes in pregnancy
think endometrium and uterine arteries, diaphragm, heart and bladder, myometrial cells and what happens to them, what the cervix does, and mucus and what this does. ** mneumonic: IFDMCM**
- **invasion **of endometrium & uterine arteries by trophoblast
- **formation **of placenta
-** displacement **of diaphragm, heart and bladder by growing fetus
- **myometrial **cells undergoing hyperplasia and hypertrophy
- cervix stays firm and non-compliant
- **mucus **plug maintains closed uterine environment
pigmentation and skin changes in pregnancy
What are 2 different pigmentation/skin changes in pregnancy and why do they occur?
think melanin and nigra and think stretch marks and collogen and skin distension
Melasma/chloasma and linea nigra:
- caused by prodution of melanocyte stimulating hormone by oestrogen
striae:
- caused by thinning of collagen fibres and skin distension
maternofetal transfer
True or false? Maternal and fetal blood mix
False, they do NOT mix
maternofetal transfer
how do nutrients get from the maternal blood to the fetal blood
think chorionic villi
via chorionic villi in close contact with maternal blood
maternofetal transfer
what is the placenta permeable to that can cause issues with fetal development
think drinking, injecting drugs, vaping and coffee
permeable to:
alcohol (fetal alcohol syndrome)
heroin
nicotine
caffeine
uteroplacental bloodflow
At 20 and 40 weeks, what is the maternal blood flow through the placenta
@20 wks: 300ml/min
@40 wks: 600ml/min