Third Trimester Bleeding Flashcards
If a patient presents with spotting or bleeding accompanied with contractions or cramping this could indicate
cervical dilation and labor
two concerning reasons for bleeding in the 2nd and 3rd trimester
placenta previa
placental abruption
complication of pregnancy which placenta lies over the cervix instead of along one of the uterine walls → diagnosed during routine ultrasound but can present with vaginal bleeding
placenta previa
this occurs when placenta begins to separate from the wall of the uterus prematurely (prior to delivery) → may cause painful contractions
placental abruption
the 3 main vessels of the placenta and what cushions them?
2 arteries and 1 vein
Wharton’s Jelly
what does the placenta provide the fetus?
nutrients, water, oxygen
way to excrete waste
How does placental weight compare to fetal weight?
approximately one seventh the fetal weight
what is the mean amniotic fluid at term?
500 ml
The placenta has immunological properties and produces what?
steroid hormones, estrogen, progesterone, growth factors, pituitary like hormones and proteins
mechanisms that substances transverse the placental membrane
passive diffusion
facilitated diffusion
active transport
endocytosis and exocytosis
what kind of substances readily diffuse through the trophoblastic membrane?
highly lipid soluble
How are respiratory gases (oxygen and carbon dioxide) transported between maternal and fetal circulation?
partial pressure gradient between the 2
glucose transfer from mother to fetus rates will ___ as maternal glucose concentration increases
decreases
painful bleeding + rigid abdomen
abruptio placenta
plainless bleeding
placenta previa
Ddx for painless bleeding in 3rd trimester
placenta previa
vasa previa
Ddx for painful bleeding in the 3rd trimester
placenta abruption
uterine rupture
labor
causes of abruptio placenta
hypertension
cocaine use
trauma
multiparity
Method used to diagnose abruptio placenta
pelvic ultrasound
treatment for abruptio placenta
hospitalize for hemodynamic management → C-section
complications of abruptio placenta
dessimated intravascular coagulation
infarcts in the maternal surface of the placenta that occur when there is separation of the placenta from the uterus
placental infarcts
premature aging of the placenta due to maternal complications, poor nutrition, smoking may cause what on the placenta?
calcifications
implantation on or close to the cervical os either total or partial or marginal
placenta previa
How do you differentiate partial or marginal placenta previa?
dilation of cervix and method of diagnosis
leading cause of 3rd trimester bleeding
placenta previa
encroachment of placenta on margins of the cervical os
marginal placenta previa
risk factors for placenta previa
advanced maternal age, multiparity, smoker and cocaine use in pregnancy, male sex, hx of C-section, prior abortions and uterine surgery, hx of placenta previa
90% of placenta previa found in 2nd trimster resolve by the 3rd → changes in architecture secondary to differential growth of lower uterine segment during 2nd and 3rd trimester may account for
placental migration
this occurs when chorionic villi attach to the myometrium rather than limited to the decidua basalis
acreta
this occurs when the chorionic villi invade the myometrium
increta
this occurs when chorionic villi invade through the myometrium to the level of the serosa or beyond it
precreta
rupture of fetal vessel that transverse the membranes in the lower uterine segment/cervical os → painless vaginal bleeding
vasa previa
treatment for vasa previa
immediate C section
umbilical cord inserts into the fetal memrabens (choriamniotic membranes) then travels within the membrane to the placenta (between the amnion and chorion) → exposed vessels lack Wharton’s jelly and are vulnurable to rupture
velementous insertion
not every pregnancy with velamentous cord insertion results in vasa previa, only those where …
blood vessels are near the cervix
