OB ch. 10

conception

fertilization, zygote, morula, traveling to uterus, blastocyst, implantation

fallopian tube

where does fertilization take place

zygote

egg and sperm together makes what

morula

the result of replication (cleavage) and leads to 16 cells

blastocyst

cavity formed in the ball of cells that becomes the amnion

preembyronic

conception to day 14

embryonic

day 15 to eight weeks after conception

fetal

nine weeks until the end of pregnancy

embryonic layers

ectoderm, mesoderm, endoderm

ectoderm

becomes CNS, special senses, skin, and glands

mesoderm

becomes skeletal, urinary, circulatory, and reproductive organs

endoderm

forms respiratory system, liver, pancreas, and digestive system

amniotic fluid

forms in the inner core of blastocyst where fetus develops

umbilical cord

in the middle of the placenta and is the “life line” for the baby

placenta

formed from a trophoblast

amniotic fluid

maintains body temp, source of oral fluid and repository for waste, promotes muscle development, cushions against trauma, weightless state that allows symmetrical development, antibacterial factors in fluid, facilitates normal lung development

polyhydramnios

too much fluid; > 2000mL or 2L

polyhydramnios

leads to GI malformations, cord entanglement, difficulty monitoring FHR, and labor complications

oligohydramnios

too little fluid; < 300mL

oligohydramnios

leads to renal abnormalities, asymmetric growth and development, and cord compression

umbilical cord

has one vein and two arteries, wharton jelly prevents compression, average length is 22 inches and one inch wide, should be central on the placenta

placenta endocrine function

hormones provide direction to mother’s physiology to prioritize supply of nutrients and oxygen needed for fetal growth (respiratory and nutrition)

placenta metabolic function

waste remover (excretory)

placenta circulation function

interface between mom and fetus

red side

maternal side of the placenta

gray side

fetal side of the placenta

placenta endocrine hormones

human chorionic gonadotropin (hCG), human placental lactogen (hPL), progesterone, estrogen

placenta metabolic function

high demand for glucose, fetal metabolic waste products cross placental membrane for excretion by maternal kidneys, one cell layer separates maternal and fetal blood

one cell layer in placenta

separates maternal and fetal blood and breaks occasionally occur in this membrane which can lead to the mixing of maternal and fetal blood which is problematic for Rh- mothers

placental circulation

function is dependent on maternal circulation

teratogens

factors the fetus could be exposed to that can lead to adverse outcomes for the fetus

ductus venosus

liver bypass that connects UV to IVC; liver processes nutrient rich blood

fetal stage circulation

blood travels through three shunts in fetal body; opposite of adult

foramen ovale

RV bypass which is an opening between the right and left atrium to bypass ventricle

ductus anteriosus

lung bypass that connects PA to aorta to bypass pulmonary circulation

fetal respiratory system

surfactant is used to determine fetal lung capacity and the laminar bodies hold the surfactant, L/S ratio is diagnostic marker (2:1)

fetal neurologic system

spinal cord develops from neural tube (ectoderm), chronic poor nutrition, hypoxia, drugs, or environmental toxins can damage CNS, neural tube defects develop from folic acid deficiency

gene

small section of DNA

genetic testing

allows for earlier diagnoses and molecular biology and genomics advancements and allows us to better understand diseases

preimplantation testing

used preconception during IVF to check for genetic or chromosomal abnormalities before implantation

prenatal testing

checks risk or presence of genetic conditions and birth defects in developing fetus

newborn screening

mandatory to detect serious treatable genetic and metabolic disorders before symptoms appear

carrier testing

check to see if disease is carried

diagnostic testing

used to identify, confirm, or rule out medical condition

predictive testing

used to forecast a future outcome, risk, or behavior,

peesymptomatic testing

done on a healthy person to see if they will develop a specific genetic disease later in life

forensic testing

formal scientific testing of physical, biological, or digital evidence to discover facts for legal or criminal cases

nurse role in genetic testing

create pedigree of family hx provided, develop plan of care that incorporates genetic assessment info, assess knowledge, perception, and responses to genetic info, facilitate referrals for specialized genetic services, provide emotional support!!

genetic testing timeline

carrier screening —> transvaginal ultrasound —> NIPT - noninvasive pregnancy testing —> chorionic villus sampling —> amniocentesis —> anatomy scan - transabdominal ultrasound

cfDNA screening

replacing traditional maternal serum screening; simple blood test done during pregnancy to check risk of certain genetic conditions

chromosomal abnormalities

major cause of miscarriage, congenital problems, and gyn disorders

unifactoral inheritance

single-gene disorders have much higher incidence that chromosomal abnormalities

multifactorial inheritance

causes most common congenital malformations

environmental gene mutations

changes genes (ex. UV exposure)

chance gene mutations

normal metabolic processes damage DNA

inherit gene mutations

mutated genes from parents (5-10% of all cancers)

karyotypes

cells from any replicating body tissue can be used except RBCs, nerve cells, and muscle cells; used to provide a pictorial analysis of number, form, and size of chromosomes

monosomies

ex. Turner syndrome

trisomies

most seen; ex. 13, 18, 21

translocations

ex. cri du chat

autosomal dominant

single gene can produce the phenotype

autosomal recessive

two copies of the abnormal gene in a homozygous state are needed to produce the phenotype

x-linked inheritance

associated with altered genes present on the X chromosome and can be either dominant or recessive

multifactorial inheritance

caused by polygenic and environmental factors

autosomal dominant

50% chance there is an affected child with normal mother and affected father

autosomal recessive

25% chance child is affected with two carrier parents

X-linked recessive

typically males are affected and maybe severly

X-linked dominant

50% chance there is an affected child with a normal father and affected mother; males are more likely affected

risk factors

maternal age >35, paternal age >40, >= 2 previous miscarriages, teratogen exposure, consanguinity or incest, family hx genetic conditions, previous child with congenital abnormalities, previous child with developmental or intellectual delays