Pregnancy Flashcards
How many weeks are the first, second and third trimesters?
1st trimester: 0-13w
2nd trimester: 13-26w
3rd trimester: 26-39w
What is term?
The time given to the 37th-41st week of pregnancy
What maternal changes happen in the first trimester?
Altered hormones (new baby being made!) Altered brain function (baby brain!) Altered emotional state (aaaah baby!) Altered appetite (quality and quantity) Altered immune function
Note: these changes can also happen during later stages
What maternal changes happen in the second trimester?
Increased blood volume
Increased clotting tendency
Decreased BP
Altered fluid balance (peeing more, drinking more)
Note: these changes can also happen during later stages
What maternal changes happen in the third trimester?
Increased weight Altered joints (pelvic changes)
Which hormone increases rapidly during the first 10 weeks of pregnancy and then falls?
HCG
What is the function of HCG?
Maintains production of oestrogen and progesterone
Morning sickness is thought to be related to rise in which hormone?
HCG (it peaks in the first trimester, and morning sickness is also seen in the first trimester)
Which three other hormones are produced during the second and third trimesters? List these in order of intensity
Progesterone > oestradiol > placental lactogen
What is a conceptus? Give three examples
Everything resulting from a fertilised egg e.g. baby, placenta, fetal membranes
Distinguish between embryo and fetus
EmBryo - Before it’s clearly human
Fetus - baby that’s clearly human
What is a blastocyst?
The initial bilayer of cells
What is a yolk sac?
Preliminary circulatory system attached to the embryo
What classification system is used to classify human development?
Carnegie stages of human development
Discuss the advantage and disadvantage of using other animal foetuses to study human pregnancy
Embryos of various species looks similar
However, size of embryo differs
Length of pregnancy differs
Describe the side of the placenta which faces the fetus
Baby is attached to the umbilical cord, which is attached to a 20cm long disc. This is surrounded by fetal membrane containing amniotic fluid and blood vessels.
What is seen on the maternal side of the placenta?
Cotyledons
Describe the size and distribution of cotyledons on the maternal side of the placenta
BIGGER in the middle, SMALLER around the edges
What is the cotyledon made of?
Branches of blood vessels which come into contact with maternal blood via endometrium
Which vessel carries deoxygenated blood from the fetus?
Umbilical artery
Which vessel carries oxygenated blood from the fetus?
Umbilical vein
Describe the key features of the cotyledons
Anchors the placenta
Provides intimate contact between maternal and paternal tissues
Large SA due to highly branched structure
Effective transport of molecules
List the functions of the placenta
Connects baby to mother Separates maternal and fetal blood Exchanges substances Immunoregulation Biosynthesis of hormones
List two hormones synthesized by the placenta
HcG
Human placental lactogen
Describe placental development
Cytotrophoblast proliferates into the syncytium
A column structure is formed, which branches into villi.
Compare blood flow from mother to baby in the first vs second trimester and explain these changes
1st trimester - cytotrophoblast shell limits blood flow to placenta to reduce generation of oxygen free radicals
2nd/3rd trimester trimester - spiral artery remodelling happens to facilitate increased blood flow when infant growth is greatest
What are the main risks to the mother during pregnancy?
The labour process itself
Left bits of placenta in the uterus (prevents adequate uterine contraction and permits blood flow and loss via spiral arteries)
What are the main risks to the fetus during pregnancy?
Chromosomal abnormalities
Incomplete anchorage of placenta
When are incompletely anchored placentas most common?
First term of pregnancy
When is the limit of viability, before which the likely outcome is stillbirth?
23 weeks
What is the main problem with pregnancy after the 23 weeks have been passed and what causes this?
Early delivery; deteriorating maternal and fetal health, or early onset of labour
If there’s early delivery, which babies are at greatest risk and why? (time period)
Those born before 32 weeks
Due to incomplete development of lungs, brain, digestive system and immune system.
What do you call the babies born between 23 and 32 weeks?
Very preterm babies
What do you call the babies born between 32 and 27 weeks?
Moderately preterm babies
What may indicate stillbirth?
Decreased fetal movement
How can you monitor fetal wellbeing to detect risk of stillbirth?
Ultrasound assessment
Fetal doppler
By which week do the lungs, liver and kidneys grow?
8th week
By which week do the face, ears, fingers and toes grow?
7th week
What is growing at the 6th week?
Face Ears Hands Feet Liver Bladder Gut Pancreas