fetal growth & development Flashcards
gestational age is dated from ?
the first day of the LMP
precedes conception, which occurs approx. 2 wks later
gestation takes approximately how many days? months? weeks?
280 days
10 “lunar” months
40 weeks
Nagle’s rule
LMP+ 7 days - 3 months= EDD
what takes place the 1st 2 weeks of pregnancy?
ovulation
fertilization- formation of zygote
formation of blastocyst- hCG production
implantation
what happens during implantation?
embryonic laminar develop
2 flat layers of cells
the first of 3 germ layers
when does the embryonic period begin?
beginning of 3rd week
trilaminar disc in embryonic period 3rd wk) is what?
3 germ layers
ectoderm
skin of genitalia
part of anal canal
nervous system
mesoderm
gonads
ureters
uterus, part of vagina
endoderm
GIT, epithelium
urinary bladder, anorectal canal
male urethra, prostate gland
female urethra, vaginal epithelium, vestibule
disc becomes cylindrical in the 4th week, what does it look like/ form
“salamander look”
buds of arms, ears, legs & facial/neck structures
development during week five?
brain development
head looks big
eyes begin
development during week six?
nose
mouth
palate
development during week seven
neck established
distinctly human form
development during week eight
end of embryonic period
fetus begins
has male/female characteristics
by the end of 1st trimester, fetus can do what?
make respiratory movements urinate swallow move limbs squint frown open mouth
folate acid deficiency can result in what?
neural tube defects- spina bifida, cleft lip
what can fetus do beginning week 14
sucking motion
when do you generally begin to feel the baby move?
18 weeks
quickening
first fetal movements
3rd trimester, weeks 28-40
this is where the baby grows in size & fine tunes the organ systems- nervous system has control over organ function
non-stress test
look at a baby’s heart rate that corresponds to the babies movement…fetal well being in utero
normal growth reflects what?
the interaction of the fetus’ genetically predetermined growth potential & it’s modulation by the health of the fetus, placenta & mother
3 phases of growth & development
cellular hyperplasia (1st 16 weeks) concomitant hyperplasia & hypertrophy (wks 16-32) cellular hypertrophy (32 weeks- term)
evaluating fetal growth
establish GA as early as possible- using hx, LMP, early ULS
monitor wt gain
measure fundal ht at each visit
serial ULS PRN
fundus rises….by_______weeks it is still a pelvic organ
12 weeks
size>date discrepancy
inaccurate dating LGA multiple gestation polyhydramnios molar pregnancy (1st tri) uterine anomaly (fibroid) congenital anomaly
size < dating discrepancy
inaccurate dating intrauterine growth restriction (IUGR) oligohydramnios (having little fluid) congenital anomaly chronic maternal dz viral infxn
large for gestational age (LGA)
birth wt>95th percentile
usually >4000g (8lbs 13 oz)
risk factors for LGA
large mother
GDM
post-date
h/o large babies
complications of LGA
cephalopelvic disproportion
postpartum hemorrhage
stillbirth
neonatal complications
cephalopelvic disproportion (CPA)-
- labor dystocia/prolonged labor
- shoulder dystocia
- maternal soft tissue damage
- increased c/s
shoulder dystocia
head is pushed out of but shoulder is impinged & all the blood rushes to the babies head
have ~ 4min to get baby out before it dies from hemorrhage
neonatal complications d/t LGA
low apgar
hypoglycemia
hematologic abnormalities
hypoglycemia can cause?
seizures
inability to regulate body temp
mngt of LGA
- screen for GDM
- ULS to r/o polyhydramnios, molar -pregnancy, fibroids
- serial ULS to monitor growth
- anticipate cephalopelvic disproportion (CPD) & sequelae, shoulder dystocia, postpartum hemorrhage
- offer delivery @ 39 wks if possible macrosomia
- offer elective c/s
- alert peds at delivery
prognosis of LGA
- risk of subsequent LGA baby
- increased risk of DM eventually in CH
- neonatal complications & sequelae
- increased risk of neoplasia in CH
IUGR
-impaired/restricted intrauterine growth
-significant b/c there is an inverse relationship bet. fetal/neonatal wt % & perinatal mortality
not be confused w/ SGA
SGA
neonatal dx of size below the 10th %
usualy genetic or d/t inadequate nutrition
risk factors of IUGR
poor nutrition/wt gain vascular dz/HTN renal dz infxn genetic abnormality multiple gestation placental problems pregestational diabetic (Type I) drug use/smoking/EtOH hypoxemia/ anemia late onset prenatal care low socioeconomic status prothrombic d/o's ART
symmetrical IUGR
the whole baby is smaller
compromised growth in length, head circumference & wt
asymmetrical IUGR
decreased length & wt, but nml head circumference
aka head sparing
complications of IUGR
increased risk of fetal distress
meconium staining
increased perinatal morbidity & mortality
Dx of IUGR
careful menstrual/medical/OB hx
accurate dating/ early sono
monitor for adequate wt gain
carefully eval fundal ht changes (watch for “progressive” growth, <2cm in 4wks suspicious)
2 sonos 4 wks apart to confirm (esp head & abdominal circumference, AFI check to r/o oligohydramnios)
management of IUGR
limit activity/ bedrest nutrition cessation of smoking fetal surveillance (repeat sonos q 4-6 wks, NST's weekly, BPP's prn, amniocentesis for lung maturity delivery of compromised fetus
birth defects
a major birth defect is one of medical, surgical or cosmetic significance
some causes of birth defects
genetic/ environmental factors maternal age illness drug use physical features of uterine environment
genetic causes of birth defects
single gene d/or (15-20%) chromosomal abnormalities (5%)
environmental exposures & birth defects
maternal illness substance use infxn drugs chemicals radiation hyperthermia mechanical/physical constraints
genetic d/o’s general info
> 90% do not survive to term
multiple organ systems tend to be involved
longevity & fertility of these individuals tend to be reduced
chromosomal abnormalities
single gene d/o’s
non-mendellian patterns of inheritance
chromosomal abnormalities
affect 1:200 newborn infants
nondisjunction, unequal recombination, inversions, deletions/suplications, translocations
single gene d/o’s
autosomal dominant/recessive
x-linked
non-mendellian patterns of inheritance
unstable DNA fragile X syndrome imprinting mitochondrial inheritance etc
maternal illness
pregestational DM
phenylketonuria
androgen producing tumors
autoimmune dz’s
pregestational diabetes
2-3 fold increase in congenital anomalies (esp heart dz, spina bifida)
abnormal fetal growth
newborn hypoglycemia
stillbirth
newborn hypoglycemia
cyanosis
poor eating
seizures
damage to brain cells
phenylketonuria
can be minimized by dietary ctrl
microcephaly
MR
congenital heart dz
androgen producing tumors
virilization of female fetuses
autoimmune dz’s
same or different toxicity to fetus
tx of mother does not always reduce effects on fetus
teratogenic infections
CMV (cytomegalovirus)- can cause seizure, MR, etc
Parvovirus (aka 5th dz)
rubella (eye lesion, heart, CNS, etc)
toxoplasmosis (uncooked meat, cat feces)
varicella (13-20 wks= highest risk; last 10 days)
herpes
syphilis
teratogens
radiation
meds
EtoH, tobacco, recreational drugs
meds that are teratogenic
ACE inhibitors, chloramphenicol warfarin/coumadin/anticoags DES, toluene, iodides, lithium accutane/isoretinoin, tetracycline thalidomide, valproate, lead, rubella vaccine, anticonvulsants, antineoplastics, SSRIs
Avoid what in pregnancy
ibuprofen
ASA
sulfa drugs @ term
trimethoprim
alcohol in pregnancy
no amt considered safe
binge drinking worse than spread out
-no exact dose-response relationship bet amt & damage caused
alcoho + other factors that may effect outcome
maternal age
hih parity
being AA or Native American
genetics
exposure risk factors
low economic status smoking unmarried unemployed illicit drug use h/o sexual/physical abuse h/o incarceration family member who drinks heavily socially transient psychologic stress/mental health d/o
fetal alcohol spectrum d/o (FASD)
describes the broad range of adverse sequelae
- no effect, nml
- fetal alcohol effects (FAE)
- alcohol related birth defects (ARBD)
- fetal alcohol syndrome (FAS)
Fetal alcohol syndrome (FAS)
most severe
affects 1-2 ounces daily
chronic alcohol consumption
what is the most important modifiable risk factor in pregnancy?
tobacco use
pathophys of tobacco use in pregnancy
impaired fetal oxygen delivery
CO exposure
direct damage to fetal genetic material
direct toxicity from >2500 subst. in cigs
directly impair LU develop.
sympathetic activation leading to accelerated HR & reduction in fetal breathing mvnt
genetics
impaired fetal ozygen delivery
placentas of smokers show structural changes that may contribute to abnormal gas exchange
carbon monoxide exposure
carboxyhemoglobin clears slowly from fetal circulation & diminshes tissue oxygenation
adverse effects of tobacco
infertility (maternal) low birth wt miscarriage stillbirth preterm premature rupture of membranes placental abruption/previa preterm delivery congenital malformations postnatal morbidity preeclampsia
opiate exposure risks that are the same for pregnant & nonpregnant women
infxn
psychological stress
violence
S&S of high-risk chemical abuse
late prenatal care multiple missed appts impaired school/work performance past OB h/o SAB, IUGR, premature birth, placental abruption, stillbirth, precipitous delivery CH w/ neuro-developmental problems h/o drug/EtoH problems
OB complications w/ opiate use
preeclampsia 3rd trimester bleeding malpresentation nonreassuring fetal status meconium passage low birth wt perinatal mortality puerperal morbidity
neonatal outcomes in opiate use
premature birth neonatal opiate withdrawal postnatal growth deficiency microcephaly neurobehavioral deficits SIDS
cocaine use in pregnancy
related to dose:stage of pregnancy
dcreased birth wt, length, HC
increased risk prematurity, placental abruption, SAB, fetal death
readily crosses placenta
what is the major mechanism of fetal & placental damage is?
vasoconstriction
possible teratogenic effects of cocain
intestinal atresia
brain anomalies
cognitive development
*possibilities!
how long is cocaine detectable in neonatal urine, meconium, & hair
urine: tests + w/in 2 days of delivery, excreted w/in 12-24 hrs
meconium: + for 3 days
hair: + for months
what is the MC illicit substance taken during pregnancy?
marijuana
impact of marijuana?
unknown
not significantly related to growth measures, prematurity, congenital anomalies
*CH of heavy users had smaller HC at all ages
methamphetamine
neurotoxic agent that damages ending of brain cells containing dopamine
3.5x’s more likely to be SGA
mgnt of pregnant substance users
screen all for EtOH & substance use counsel regarding risks behavioral/pharmacotherapy for addiction multidisciplinary approach test for STIs & tx frequent visits to monitor status of both ULS to get GA, baseline for growth fetal surveillance if complications evident inform peds of possible neonatal w/d
discourage what in women who continue to take illicit drugs?
breastfeeding
