Pregnancy Flashcards
What are the 3 stages of implantation?
- The blastocyst contacts the implantation site of the endometrium (apposition)
- Trophoblasts of the blastocyst attach to the receptive endometrial epithelium (adhesion)
- Invasive trophoblasts cross the endometrial membrane (invasion)
As the trophoblasts migrate across the endometrial tissue, what do they come across?
NK cells (these NK cells only appear in this area around this period of implantation)
What are villous trophoblasts?
Villous trophoblasts cover the chorionic villi and are involved in the exchange of gas and nutriments between the mother and the fetus.
What are extravillous trophoblasts?
Invasive
- Only class I human leucocyte antigens (Cw, G, E; A&B not expressed)
- Less attractive to cytotoxic T-cells
- Enables binding to NK cells
What does the blastocyst then release into the endometrium?
hCG
What is hCG produced by?
Trophoblast cells
What type of molecule is hCG?
Glycoprotein
What effect does hCG have?
Luteotrophic: continues to stimulate the corpus luteum - progesterone (vital for fetal survival)
Production is autonomous - independent of hypothalamus and pituitary
Thought to be the cause of “morning sickness”
What do pregnancy tests detect?
Levels of hCG
How are miscarriages managed medically?
Progesterone receptor antagonist (mifepristone) in combination with a prostaglandin analogue (misoprostol)
How does the blood volume change during pregnancy?
40% increase (Increase in total body water content and plasma volume)
How does red cell mass change during pregnancy?
Red cell mass increases (increased erythropoietin) – but not as much as blood volume –> ‘physiological anaemia’
How does oestrogen affect RAAS?
Oestrogen stimulation of renin-angiotensin-aldosterone leads to water and sodium retention
How does cardiac output change during pregnancy?
Increases 30-50% in pregnancy
rise in stroke volume (30%) and heart rate (10%
What is pre-eclampsia?
Condition that affects some pregnant women, usually during the second half of pregnancy (from around 20 weeks) or soon after their baby is delivered.
One of leading causes of maternal death globally.
What are the indications of pre-eclampsia?
- Persistently high BP
- Proteinuria
- Peripheral oedema
What are other clinical signs of pregnancy due to changes in cardiovascular?
- Fainting
- Haemorrhoids
- Varicose veins