Signs and symptoms
How many weeks are classes as the first trimester and name 3 signs and symptoms at this stage
1-12= preembryonic
3-8= embryonic
Nausea
amenorrhoea
breast tenderness
fatigue
food cravings/ pica
Do the maternal and foetal blood ever mix
NO
Why is immune regulation important in a pregnant mother
It prevents the rejection of the embryo
Name some structural and anatomical changes during pregnancy
Invasion of endometrium and uterine arteries by trophoblast
formation of placenta
growing foetus displaces diaphragm, heart, bladder
myometrial cells undergo hyperplasia and hypertrophy
cervix becomes firm and non-compliant
mucus plug forms creating closed uterine environment
How many stages of labour are there and which is typically the longest stage
3
1 The time between onset of labour and full cervical dilation can be many many hours long
2 from dilation to delivery <1hr
3 delivery to expulsion of the placenta
What substance causes 'morning sickness' and where is it released from
Growth differentiation factor 15
released by the placenta
How does the immune system of the mother protect the growing embryo
Pregnancy hormones have anti-inflammatory functions
mucus plug in cervix which is rich in antimicrobial proteins
amniotic fluid also rich in antimicrobial proteins
Name some respiratory system changes that occur due to pregnancy
15-20% increase in O2 consumption
flaring of ribs due to relaxin
40% increase in minute ventilation due to increased tidal volume
respiratory alkalosis occurs as pCO2 is lowered but increased renal compensation occurs through HCO3 maintaining mild alkalotic blood pH
What hormone is available in high quantities during labour due to a positive feedback loop
oxytocin
Roughly how much weight is gained during pregnancy
roughly an extra 10kg
Name some functions of the placenta
Nutrient and gas transfer- passive diffusion
Transfer of waste products
Immune protection- IgG crosses the placenta
Steroid and peptide hormone production e.g. hPL, hCG, relaxin, leptin
Support for the foetus
What does the term semi-allogenic mean regarding an embryo
The semi-allogeneic fetus derives half of its genetic maternal from the mother. The other half, inherited from the father, leads to the expression of proteins that are foreign to the mother
Name 2 hormones that lead to physiological changes during pregnancy
Oestrogen- stimulate uterine growth, initiates CV changes, promotes ductal development in breast
progesterone- decidualisation of endometrium, uterine quiescence, relaxant effect on MSK, respiratory changes
Relaxin- uterine relaxation, softening of pubic symphysis
hCG- mantains corpeus luteum, immune tolerance
human placental lactogen- breast development, inhibits maternal glucose uptake
oxytocin- uterotonic
prolactin- amniotic fluid genesis, osmolarity and volume, immunity
Name some differences between Braxton Hicks contractions and labour pains
Braxton Hicks does not result in cervical dilation/effacment
they are often irregular, of less force and can change depending on levels of activity from the mother
often felt in the abdomen and not the pelvis like labour pain
Name 1 skin change that can occur during pregnancy and why this happens
Melasma/cholasma, linea nigra- caused by production of melanocyte stimulating hormone by oestrogen
Striae- caused by thinning of collagen fibres and skin distension
How does the rate of maternal blood flow through the placenta change as pregnancy progresses
It increases from 300ml/min at 20 weeks, to 600ml/min at 40 weeks
What is the most abundant leukocyte in the uterus and what does it express
Uterine natural killer cells
Express killer-cell immunoglobulin like receptor. This binds to HLA-G during pregnancy to reduce the cytotoxic function of uNK cells and therefore promoting invasion and placentation of the embryo
Name 3 haematological changes that occur during pregnancy
40-50% increase in plasma volume
erythrocyte number increases but less than plasma volume
become hypercoagulable to prevent blood loss during labour but increases risk of embolism during pregnancy
What are the 4Ps of birth
Power- strength of uterine contractions
Passage- maternal tissues and bony pelvis
Passenger- size and position of foetus and placenta
Psyche- patients psychological state during labour e.g. anxiety
Why does fundal height reduce around 40 weeks
As the foetal head engages with the birth canal ready for labour, fundal height reduces
What are the 3 shunts that allow the flow of oxygenated blood from the placenta to reach the foetus
Ductus arteriosus- bypasses the lungs
Ductus venosus- bypasses the liver
Foramen ovale- allows flow of blood between right and left atria
What molecules do the villous and extra-villous trophoblast express and what are the role of these molecules
HLA-E
HLA-F
HLA-G
HLA-C
they remodel spiral arteries
Name some renal system and GI changes that occur during pregnancy
enlargement of kidneys
dilation of ureters and of renal pelvix
GFR increases by 40%
renal blood flow increases by 30-50%
increased tubular reabsorption of NA+ leading to oedema
reduced motility of GI tract- leading to constipation
relaxed lower oesophageal sphincter- heartburn
Name some triggers for labour (parturition)
Contraction associated proteins (CAPS)
oestrogen
Corticotrophin releasing hormone (CRH)
oxytocin
PGE2, PGF2a
IL-1b