Flashcards in Pregnancy Deck (25)
At what stage can a fetus survive?
26 weeks without ICU, 22 with ICU.
What risks are associated with the first trimester?
Miscarriage (1/3 of all pregnancies), Vulnerable to teratogens (worst in first but can occur in all trimesters). Physical development abnormalities including spina bifida and cleft pallet.
What difines the three trimesters?
Maternal experience. eg 1st has morning sickness and altered emotions and appetite.
What is the viability limit?
what maternal changes occur in the second trimester?
Increased weight (baby goes from 50g-->1000g)
Increased blood volume
Increased blood clotting
Decreased blood pressure
Altered fluid balance and urinary frequency
Which systems develope in the fetus mainly in the third trimester?
What is the general rule for babies leaving NICU
When the baby has reached the age that would have been full term
37-41 weeks after the first day of the mothers last period.
What does the term conceptus include in its meaning
Everything that came from the zygote, eg embryo and placenta
Which stage of pregnancy poses the greatest risk to the mother?
During what stages of pregnancy are the mothers immune system, hormone levels, emotions, appetite and brain function altered
From the first trimester onwards.
What is the name for severe morning sickness?
What pattern do hCG levels follow during pregnancy?
Rise rapidly and reach a peak at 9 week and the rapidly decline once the placenta takes over hormonal control.
Draw the graph of maternal endocrinology
What is the function of the placenta
Exchange (of nutrients and waste)
Separation (of maternal and fetal systems)
Immunoregulation (whole pregnancy)
Connection (anchors pregnancy in place)
Describe the fetal side of the placenta.
Disk shaped, has the umbilical cord, Maternal blood vessels carrying nutrients to the fetus insert near the centre. Thin fetal membrane surrounds the disk.
During what time period does the cytotrophoblast shell cover the conceptus?
From week 4 (post fertilisation) to 10 weeks gestation
What is the name given to the units of tissue on the maternal side of the placenta?
What is the maternal decidua and how is it related to miscarriage
It is the maternal tissue in between the cotyledons. Failure of the placenta to fully attach the the maternal decidua can result in miscarriage due to the increased pressure caused by cytotrophblast shell break down and spiral arteries taking over causing the placenta to fully detach.
Describe the stages of placental development.
Implantation of conceptus in endometrial epithelium
Trophoblast--> cytotrophoblasts (inner) and synctiotrophoblasts (outer)
Villi develop from ctb and anchoring by stb into endometrium
contact with maternal tissue. Lacunae in stb
hypertrophy of decidual glands
Villi go from primary-> secondary->teriary then invade the spiral arteries and remodel
Spiral arteries have cytotrophoblast plug breakdown.
What is the role of decidula glands in pregnancy
Histotrophic nutrition for the first trimester
Describe the remodelling of spiral arteries
Invasion of cytotrophoblasts
loss of smooth muscle means the arteries can no longer vasoconstrict.
Cytotrophoblastic shell breaks down gradually due to exposure to fetal and maternal blood.
In what was is the placenta like the lungs?
Arterial system carries deoxygenated blood and the venus system carries oxygenated.
What is the difference between a miscarriage and a still birth?
A misscarriage occurs <24 weeks so the baby was not viable
A still birth occurs >24 weeks. A baby born with no signs of life. It is often associated with labour and can happen at any gestational age