conception and prenatal development

what is ovulation?

- release of egg from ovary

- occurs approximately 14 days before first menstrual cycle

what is conception?

union of sperm and egg

what is fertilization?

- sperm enters the ovum

- occurs in the ampulla of the fallopian tube and creates the zygote

what is implantation?

- attachment of ovum to the uterine wall

- ideally occurs 7-9 days after fertilization

- pts may complain of spotting

how many chromosomes does the ovum carry?

- 22 chromosomes

- 1 x sex chromosome

how many chromosomes does sperm carry?

- 22 chromosomes

- 1 x or y sex chromosome

what are the fetal stages of development?

- pre embryonic stage (0-2 weeks)

- embryonic stage (2-8 weeks)

- fetal stage (9 weeks to birth)

what occurs during the pre embryonic fetal development stage?

- 0 to 2 weeks

- conception and zygote formation

- when cell division to morula occurs

what is morula?

- solid ball of cells

- includes trophoblast (outer layer of cells, becomes placenta and fetal membranes)

- includes embryoblast (inner layer of cells, becomes the blastocyst/fetus)

what is the embryonic stage of fetal development?

- 2 to 8 weeks

- critical time for organ structure development

- most vulnerable to teratogens (harmful things)

- development of the germ layers occur

what are the germ layers?

- ectoderm (brain and spinal cord, hair, skin, and nails)

- mesoderm (heart, tissues, blood supply, kidneys, reproductive structures, spleen)

- endoderm (lining of gi and resp tract, bladder and urethra and ear canal, liver and thyroid)

what is the fetal stage of fetal stages of development?

- 9 weeks to birth

- fewer major anamolies caused by teratogens

- organ structures develop functions

- fetus develops in a cephalocaudal formation (head to rump, central-peripheral and simple to complex)

what happens during week 3-4 of fetal development?

- heart beats/pumps blood

- neural tube closes

what happens during week 5-6 of fetal development?

brain growth

what happens during week 8 of fetal development?

- spinal cord development

- ear and kidneys develop

what happens during week 8-12 of fetal development?

heart tones heard on doppler

what happens during week 12 of fetal development?

- kidneys produce urine

- sex may be determined by ultrasound

what happens during week 16-20 of fetal development?

- muscles well developed

- quickening happens (mom feels baby moving)

what happens during week 20 of fetal development?

- vernix (cheesy substance that protects baby in utero) and lanugo (fine hair) develop

- fetus sleeps, sucks, kicks

- eyebrows, eyelashes, and head hair develop

what happens during week 24 of fetal development?

proportional body

- ability to hear

- age of viability (can live outside of mom safely)

- surfactant (protein that helps with lung maturation) forming

what happens during week 28 of fetal development?

- eyelids open

- ability to see

- ability to breath

- can swallow and regulate temp

what happens during week 32 of fetal development?

- brown fat deposits develop

- fetus begins storing iron, calcium, and phosphorus

what happens during week 36-40 of fetal development?

- uterus at full occupancy

- lightening occurs (fetus drops into pelvis)

- maternal antibodies transfer to fetus to provide immunity

what is the placenta?

- has shiny fetal side (shiny shultz) that faces toward fetus

- has maternal meaty side (dirty duncan) that faces toward mom and uterus

what are the functions of the placenta?

- gas exchange

- nutrient transfer

- waste removal

- antibody transfer

- endocrine hormones production

what is amniotic fluid?

- provides cushioning against impact

- stabilize temperature

- barrier against infection

- assist in lung development

- amnion is inner membrane (fluid filled sac)

- chorion is outer membrane (fetal side of placenta)

what is the umbilical cord?

- inserted on fetal side of placenta

- has 2 arteries and one vein (called ava)

- arteries carry deoxygenated blood away from embryo to mom

- veins return oxygenated blood from mom to the embryo

- wharton jelly ( substance inside umbilical cord) is connective tissue that surrounds the vessels for protection

how is gestation expressed?

- weeks and days

ex. 38+4 = 38 weeks and 4 days

how long is the first trimester?

weeks 1-13+6

how long is the second semester?

weeks 14-27+6

how long is the third trimester?

>28 weeks

what is considered a preterm infant?

20+0 to 36+6

what is considered a full term infant?

37+0 to 40+6

what is considered post term?

>42 weeks

what does edd mean?

estimated date of delivery

what is nagle's rule?

first day of last menstrual period +9 months+ 7 days+ correct the year if needed = edd

what is the fundus?

top of uterus

what is a chadwick's sign?

- bluish tint that appears inside vagina due to increased vasculature to the tissue

what is leaukorrhea?

- white grey discharge

- increase and thickening of vaginal secretions

what is goodell's sign?

softening of the cervix

what is striae gravidarum?

stretch marks

what are presumptive signs of pregnancy?

- subjective, what mother feels

- amenorrhea (missed period)

- fatigue

- enlarged breast

- urination increases

- movement/perceived flutters

- emesis/nausea

- skin changes

what are probable signs of pregnancy?

- observed/objective

- positive preg test (uhcg)

- ballottement (return of fetus)

- outline of fetus is palpated

- braxton hicks contractions

- goodall sign

- chadwick sign

- hegar sign (lower uterine segment soft)

- enlarged uterus or abdomen

what are positive signs of pregnancy?

- definite fetus

- fetal heart tones auscultated

- visualization of baby

- fetal movement felt by mom

what does gravida mean?

- number of times woman has been pregnant

- includes miscarriages and current pregnancies

what does para mean?

- number of pregnancies that have reached 20 or more weeks

- regardless of outcome

- includes spontanious abortion or miscarriage (sab)

- is not the number of fetuses

what does nulli mean?

none

what does primi mwan?

first

what does multi mean?

multiple

what are the parts of the gtpal?

- gravidity (# of times a woman has been pregnant)

- term births (# of pregnancies that completed 37+0 weeks gestation or greater)

- preterm births (# of pregnancies that completed 20+0 weeks through 36+6 weeks gestation)

- abortions (# of pregnancies that ended less than 20 weeks either sab or tab)

- living children (# of living children)