Pregnancy Flashcards
List some changes that occur to the mother during pregnancy.
Increased weight (3rd)
Increased blood volume (2nd and later)
Increased blood clotting tendency (2nd and later)
Decreased blood pressure (2nd)
Altered brain function (1st and later)
Altered hormones (1st and later)
Altered appetite, quantity and quality (1st and later)- GI imbalance
Altered fluid balance (2nd and later)
Altered emotional state (1st and later)
Altered joints (3rd)
Altered immune system (1st and later)
What is HCG?
Human chorionic gonadotrophin.
Key hormone produced by human pregnancy.
Functional homologue of LH.
Drives production of oestrogen and progesterone from ovaries.
Drives corpus luteum.
Peaks towards the end of the first trimester, then falls dramatically and levels out for the rest of pregnancy.
What are the main maternal hormones that increase in plasma concentration in human pregnancy?
HCG
Placental lactogen
Oestrogen (mainly oestriol)
Progesterone
What is the main risk to maternal health (or life) during pregnancy?
Linked to delivery.
Relatively little risk in the early parts of pregnancy.
What is the size of a fertilised egg?
<1mm
What is the size of an infant?
About 30cm
Define conceptus.
Everything resulting from the fertilised egg: baby, placenta, foetal membranes, umbilical cord.
Define embryo and foetus.
Embryo: the baby before it is clearly human.
Foetus: the baby for the rest of the pregnancy.
Define infant.
Less precise, normally applied after delivery.
What is the placenta?
Connects mother and baby to each other.
What are the functional units of the placenta?
Cotyledons
What is the purpose of the extensive branching of the placenta?
Very large surface area- maternal vascular system set up over it, nutrient rich oxygenated blood flows over it, nutrients and oxygen pass into foetal tissue, and deoxygenated blood flows away. Opposite happens on foetal side.
What are the key features of the placenta?
Very highly branched structure, provides a large surface area (about 11m^2).
Very effective for transport of molecules between maternal and foetal circulations.
Also anchors the placenta (and hence the baby) securely for 9 months.
Intimate contact between maternal and placental tissues- interesting immunology.
What are the placental (or villous) functions?
Separation
Exchange
Biosynthesis
Immunoregulation
Connection
How does the placenta develop?
Starts as a layer of single cells in the blastocyst.
These proliferate and differentiate.
Form simple branched structure, expands iteratively.
