Placenta and umbilical cord Flashcards
Placenta is formed by the
decidua basalis and decidua frondosum
Physiology of placenta
- vital support organ for developing fetus
major functioning unit of placenta
chorionic villus
- contains intervillous space
maternal blood enter the
intervillous space
Placenta Functions
Respiration
- oxygen in maternal blood passes through plac into fetal blood
- co2 returns through the plac to maternal blood
Placental Function
Nutrition
pass from maternal blood through plac to fetal blood
Placenta Function
Excretion
- wast products cross from the fetal blood through the plac to maternal blood
Placenta Function
Protection
provides a barrier between the mother and fetus, protecting the fetus from maternal immune rejection
Placenta Function
Storage
carbs, proteins, calcium, and iron are stored in plac and released into fetal circulation
Placenta Function
Hormone Production
produces hCG, estrogenm and progesterone
Plac Size
- varies with gestational age
- 2-3 mm thickness
- should exceed 4 cm
Normal sono appearence of placenta in 1st trimester
thickened area of hyper gestational age
Normal sono appearence of placenta in 2nd and 3rd trimester
- smooth, homogeneous medium-gray structures
- smooth border and edges
- hyperechoic chorion plate
cystic areas directley behind chorion plate
fetal vessels
plac may be located
ant, post, fundal, rt later, and lt lateral
plac may be implanted over or near
cervical os (previa)
grading is dependent on
echogenicity attributed to calcium and fibrous deposition with advancing age
cause premature maturation of plac
maternal hypertensions, smoking, iugr, multifetal gestation
- no calcification
- smooth basal and chorionic plate
- 1st and early second
Grade 0
- scattered calification throughout the plac
- most common up until 34 w
Grade 1
- calcifications along basal palte
- chorionic plate becomes slightly lobular
Grade 2
- marked calcifications
- distinct hyper loculations extending from chorionic to basal plate
- abnormal before 34 w
Grade 3
- in front of fetus relative to birth canal
- primary cause of painless vag bleeding in 3rd trim
Plac previa
plac previa risk factors
advanced maternal age, multiparity, previous c section, theraputic abortion, or closely spaced pregnancies
plac previa complications
premature delivery, life-theratening maternal hemorrhage, increased risk of plac accretta, stillbirth, and iugr
Plac previa complete
- painless vag bleeding
- placenta cover entire cervical os
plac pervia partial/ incomplete
- painless vag bleeding
- placenta covers one side of cervical os
plac previa marginal
- asymptomatic, painless vag bleeding
- edge of plac covers one side of the cervical os
plac previa low-lying
- asymptomatic
- painless vag bleeding
- edge of plac lies close by doesnt abut cx os, 2 cm
plac vasa previa
- bleeding
- cord compression
- prolapsed cord
- transverse fetal lie
- fetal vessels cross over internal os
Plac abruption
- premature plac detachment
- clinical findings include severe pelvic pain and vag bleeding
plac abruption risk factors
materal hypertension, smoking, diabetes, trauma, plac previa, and short umbilical cord
plac abruption sono findings
- hypoechoic retroplacental mass
- plac thickening
- well defined margins
- sub amniotic or preplacental locations are rare
plac accreta
- chorionic villi of the plac are indirect contact with uterine myo
- attributed to complete or partial absence of the decidua basalis
plac accreta risk factors
multiparity, plac previa, and previous c section
plac accreta sono findings
- obscured or absent retroplacental complex
- numerous plac lakes
plac increta
- plac invades the uterine myo
plac increta sono findings
extension of villi into myo
plac percreta
placental vessels invade uterine serosa and bladder
plac percreta sono findings
extension of villi outisde of ut
amniochorionic seperation
amnion
separated from fetal surface of plac but cant separate from umbilical insert site
amniochorionic seperation
chorion
separated from endo lining but cant separate from plac edge
amnionchorionic separation
- localized fluid between fetal side of plac and amniotic membrane
- membrane can move