Class 2: Uncomplicated Pregnancy Flashcards
appropriate preconception care leads to…
- improved health outcomes for pregnant persons and fetus/newborns
what are the components of preconception care (2)
- health promotion –> optimize health of person prior to pregnancy
- risk assessment and interventions –> identify individuals at increased risk
reproduction encompassess… (4)
- the reproductive cells from males and females
- the female menstrual cycle
- the process of conception
- the process of pregnancy
define: oogenesis
- the process of egg formation (ovum)
define ovum
- mature female reproductive cell, especially of a human or other animal, which can divide to give rise to an embryo usually only after fertilization by a male cell
define spermatogenesis; when does it begin?
- the formation of a germ cell to a sperm cell
- begins at puberty under the influence of testosterone and continues throughout adult life
define: menstrual cycle, describe the four stages
- physiological preparation for conception
- four stages that occur every 28 days
- involves shedding of the endometrium (stage 1 = menstrual phase), ovary and follicle preparing for release of an ovum (stage 2 = follicular phase), ovulation (stage 3 = ovulation phase), propellation of the ovum towards the uterus (stage 4 = luteal phase)
define: ovulation
- process by which the ovum is expelled from the follicle and is drawn into the fallopian tube
define: conception
same as fertilization?
define: fertilizization
- fertilization of an ovum by sperm when a sperm penetrates the ovum membrane
- results in a zygote, with half the genetic material from the ovum and half from the sperm
define: implantation and when does this occur
- the embedding of a blastocyst in the endometrium of the uterus
- begins about the seventh day after fertilisation of the ovum
define embryonic period; what occurs during this time?
- stage between weeks 3 and 8 after fertilization
- during this time, differentiation of body systems and organs occurs
what is a major concern during the embryonic period
- teratogenicity because all external and internal structures are developing
define: fetal period
- the final stage of development beginnig on the 9th week after fertilization until birth
- period of signif fetal growth
at the time of implantation, two fetal membranes that will surround the developing embryo begins to form. what are they
- chorion
- amnion
the chorion forms from?
- from trophoblast cells
define the chorion membrane, what does it contain, what does it blend with?
- outermost fetal membrane
- blends w placenta, lines fetal side of placenta
- contains the major umbilicial blood vessels
describe the amnion membrane, what does it become and help form
- inner fetal membrane
- becomes the covering of/blends w the umbilical cord and helps form the amniotic cavity filled w amniotic fluid
the amnion forms from?
- inner cells of blastocyst
describe amniotic fluid and what it’s derived from
- fluid inside the amniotic cavity which is derived from maternal blood thru diffusion, fluids secreted by the GI/GU and resp tract of the fetus
what are the function of amniotic fluid (7)
- thermoregulation
- prevent embryo from tangling w membranes, facilitating symmetrical growth
- barrier to infection
- allows freedom of movement for MSK development
- cushion to protect fetus and umbilical cord from trauma
- source of oral fluid and a repository for waste
- enhance fetal lung development
what 2 tests can be done using amniotic fluid
- amniocentesis
- LS ratio
what can an amniocentesis tell you
- identify chromosomal abnormalities
what does LS ratio tell you? when is this test done
- used to measure lung surfactant
- tells us if there is sufficient surfactant to breathe on their own
- done if worried about pregnant person going into pre-term labor
what is a normal amount of amniotic fluid? abnormal?
- normal: 700-1000 mL
- abnormal: <300, >2L
what is a concern w an abnormal amt of amniotic fluid
- can cause abnormalities w fetus
describe the umbilical cord
- cord that provides the embryo w maternal nutrients, oxygen, contains blood vessels,
the umbilical cord is surrounded by? what is the function of this?
- warton’s jelly
- protects umbilical cord from compression
describe the placement of the umbilical cord
- should be in center of placenta
what is the diameter of the umbilical cord at term? average length?
- diameter: 2cm
- length: 30-90cm
at what week does the connecting stalk to the embryo become the umbilical cord
- week 5
how long is pregnancy in calendar months? lunar months? days? weeks?
- spans 9 calendar months
- 10 lunar months of 28 days (280 days total)
- 40 weeks from the 1st day of the last menstrual period
what is the length of each of the 3 trimesters of pregnancy?
- 1st: weeks 1-13
- 2nd: weeks 14-26
- 3rd: weeks 27 through to term
how many stages of fetal development are there? what is each one called?
- pre-embryonic stage
- embryonic stage
- fetal stage
how long is the pre-embryonic stage
- fertilization to end of 2nd week
what occurs in the pre-embryonic stage of fetal development (6)
- fertilization
- cleavage
- morula
- blastocysts
- trophoblast
- implantation
where does fertilization occur?
- in the outer 1/3 of the fallopian tube
after fertilization occurs, what happens?
- cleavage = cells rapidly divide but don’t get bigger
by day 3, the cells become known as?
- morula
by day 4, what occurs?
- cells have organized into an early blastocyst
by day 6-10, what occurs?
- blastocyst implants into endometrium
what are the outer cells of a blastocyst called? what is the function of these cells?
- trophoblast cells
- fnxn: secrete enzymes which allow blastocyst to invade and attach to endometrium
after ovulation, a piece is leftover. what is this called and what kind of structure is it
= corpus luteum
- endocrine structure which is imp if pregnancy occurs
if fertilization occurs, what happens r/t corpus luteum
- fertilized eggs secretes the hormone hCG
- hCG tells corpus luteum it needs to stick around and produce estrogen and progesterone
what role does estrogen and progesterone have when produced by corpus luteum? (4)
- helps prep for pregnancy
- increases blood flow
- increases vascularity
- produce nutrients
how long does the corpus luteum produce estrogen and progesterone
- until ~12 weeks when the placenta takes over
after implantation, the endometrium (lining of uterus) becomes..
- decidua
how long is the embryonic stage of fetal development
- end of 2nd week through 8th week
what occurs in the embryonic stage of fetal development, what is this called
- basic structures of major body organs and main external features are developed = organogenesis
when is organogenesis complete
- by end of the 8th week
what stage of fetal development is the fetus most susceptible to malformations
- embryonic stage
when is the fetal stage of fetal development
- end of 8th week until birth
congenital disorders may be.. (2)
- inherited
- or caused by enviro factors
what are 4 categories of nongenetic factors that influence fetal development
- teratogens
- maternal nutrition (ex. low FA)
- SDoH (ex. income –> poor nutrition)
- advanced maternal age
what are examples of teratogens that influence fetal development (5)
- drugs and chemicals, alcohol
- oral isotretinoin (acne med)
- infections: rubella, varicella
- radiation: xrays, CT scans
- maternal health consitions: ex. diabetes –> hyperglycemia (esp. in embryonic period)
what is the placenta
- the site of “respiration, nutrition, excretion, and storage” for the fetus
what are the 2 sides of the placenta?
- fetal side (chorion frondosum)
- maternal side (decidua basalis) which is dividided into lobules (cotyledons) on the uterine side
how do substances transfer across the placenta? what substances will transfer
- thru diffusion
- not only substances we want (ex. glucose) and ones we dont want (ex. teratogens)
the placenta has an endocrine function. what are the hormones of the placenta? (6)
- progesterone
- placental lactogen
- estrogen
- relaxin
- B-hCG
- infant growth factors (IGFs)
describe the mixing of blood between the pregnant person and fetus
- there is no mixing of blood
by the 5th month of pregnancy, what is between the pregnant person and fetus
- only a single cell layer between them
what are the functions of the placenta (5)
- endocrine function
- site of disposal
- transfer of substances
- store nutrients
- site of excretion
what hormones does the placenta produce? (6)
produces hormones:
- progesterone
- placental lactogen
- estrogen
- relaxin
- B-hCG
- infant growth factors
if the placenta doesn’t implant properly, what can happen?
- spontaneous abortion
describe the role of the placenta and umbilical cord in fetal circulation
- The placenta accepts the blood without oxygen from the fetus through blood vessels that leave the fetus through the umbilical cord (umbilical arteries, there are two of them)
- When blood goes through the placenta it picks up oxygen.
- The oxygen rich blood then returns to the fetus via the third vessel in the umbilical cord (umbilical vein).
what are 3 important structures in fetal circulation
- ductus venosis
- foramen ovale
- ductus arteriosis
what is the role of ductus venosis in fetal circulation
- shunt that allows oxygenated blood from the umbilical vein to partially bypass the liver and connect to inferior vena cava
- closes after birth
where is the foramen ovale located
- openning between the RA and LA of the heart
what is the role of foramen ovale in fetal circulation
- allows the oxygen rich blood to go from the right atrium to left atrium , without going into the lungs first (since fetus isn’t using own lungs to oxygenate blood)
where is the ductus arteriosis located?
- opening from the pulmonary artery to aorta
what is the role of ductus arteriosis in fetal circulation
- sends the oxygen poor blood to the organs in the lower half of the fetal body.
- helps shunt mixed (oxygenate and deoxygenated) blood directly into the aorta where it will eventually travel to the umbilical arteries and back to the placenta.
what occurs during fetal maturation (3)
- viability
- resp system
- fetal circulation
what is fetal viability
- the capability of fetus to survive outside uterus
what is the threshold for fetal viability
- 22-25 weeks
fetal viability has limitations based on…
- CNS function and oxygenation capability of lungs
what occurs during fetal maturation r/t resp system
- pulmonary surfactants in fetal lung
at what point is there a sufficient quntity of pulmonary surfactants? what happens before then?
- at 35 weeks there is sufficient quantity
- before then, will not be able to breathe on its own
what occurs during fetal maturation r/t fetal circulatory system (3)
optimization of transfer of O2 from parent to fetus by:
- fetal HGB carriers more O2 than parental HGB and high HGB concentration
- fetal HR is higher than parental HR
what hormones are present during pregnancy (7)
- human chorionic gonadotropin (hCG or BhCG)
- estrogen
- progestrone
- relaxin
- human placental lactogen
- oxytocin
- prolactin
what is hCG
- biochemical marker of pregnancy (not definitive)
what role does estrogen have in pregnancy (4)
- increases blood flow
- increases uterine mass
- vascularization
- prep breast tissue for lactation
what role does progesterone have in pregnancy (4)
- SM relaxation
- stimulates growth of blood vessels
- helps w implantation process
- stimulates glands to secrete nutrients
what role does relaxin have in pregnancy (3)? When is it highest?
- relax walls of uterus to prevent contractions
- relaxes maternal blood vessels
- relax ligaments in pelvis
- highest in 1st trimester
what role does human placental lactogen have in pregnancy
- insulin antagonist = increases BG for fetus
what role does oxytocin have in pregnancy (2), what is it produced and secreted by?
- produced by hypothalamus
- secreted by posterior pituitary
- acts in contractions
- stimulates milk let down
what role does prolactin play in pregnancy (2)? What is it secreted by
- promote growth of breast tissue & mammary gland development
- milk production
- secreted by anterior pituitary