Flashcards in Chapter 16: Third Trimester Bleeding Deck (29)
How often do we see third trimester bleeding and when do we notice the spotting/bleeding?
- 4 – 5% of pregnancies are complicated by third trimester vaginal bleeding
- Spotting often noted during intercourse, trichomonas cerviticitis workup, and pelvic exams
Discuss blood changes during pregnancy
At term, female’s total blood volume increases by 40% and cardiac output by 30%
o About 20% of this term cardiac output goes to the pregnant uterus, meaning bleeding can get real bad
When do we see placenta previa bleeding and how often?
ii) Usually bleeding is around 29/30 weeks
iii) 1:200 pregnancies
Does placenta previa resolve?
iv) Partial and low lying typically resolve by 32-35 weeks by thinning of the lower uterine segment to get placenta away from the os to prevent issues
How do we diagnose placenta previa?
Dx: Transvaginal US
Risk factors for placenta previa
Placenta previa in prior pregnancies (4-8% recurrence), prior Cesarean delivery or other uterine surgery, multiparity, advanced maternal age, cocaine use, smoking.
How do we manage a bleeding placenta previa patient?
(1) First bleeding episode usually resolves in first 1-2 hours if not severe enough to cause need for delivery
(2) Bed rest, fetal steroids for breathing, close observation
(3) Deliver if bleeding worsens or fetus is at term
(a) Cesarean delivery if 36-37 weeks following amniocentesis to confirm lung maturity If not ready, do 37-38 weeks
Complications of placenta previa
Increased bleeding from lower uterine segment where the placenta was attached at time of C-Section.
(1) Possible placenta accreta (attached to uterine wall through to superficial myometrium), increta (further) percreta (all the way through myometrium to serosa and even possibly into adjacent organs like the bladder)
What is placental abruption
Placental Abruption (Premature separation of the placenta, usually painful)
Complete vs partial placental abruption
Complete = entire placenta separates. Partial = Part of it separates. Marginal = Edge of placenta only
Usual cause of placental abruption
Usually secondary to bleeding in the decidua basalis that separates the placenta off, and usually presents as vaginal bleeding with abdominal pain
Do we always see blood with placental abruption? If no blood, then what?
If blood is trapped behind placenta, = concealed hemorrhage
(a) Dangerous because we don’t suspect bleeding! Can lead to painful uterine contractions, significant fetal heart rate abnormalities, and fetal demise in severe cases
Risk factors for placental abruption
Chronic hypertension, pre-ecclampsia, multiple gestation, advanced maternal age, multiparity, smoking, cocaine use, chrioamnionitis. Trauma also bad.
Previous abruption increases chances in next pregnancy of it by 15-20 fold. Elevated AFP in 2nd trimester increases chance by 10-fold
Management of Placental abruption
(1) Fluids, vitals, delivery if severe hemorrhage. Usuaully just monitor FHR (if stable) for 4 hours
(2) Don’t have to do Cesarean, can do vaginal, but Cesarean is more common
What is a couvelaire uterus and what does it mean?
Couvelaire uterus – Rare event where blood penetrates the uterus to such an extent that the serosa turns blue or purple. Grade with Kleihauer-Betke test to determine amount of fetal/maternal hemorrhage. Possible need for Rh immunoglobulin and/or blood transfusion
Most common cause of coagulopathy in pregnancy:
Labs with placental abruption
May see low fibrinogen, low platelets (DIC is rare but serious), and elevated PT/PTT
What is vasa previa
Passage of fetal blood vessels over the internal os below the presenting part of the fetus
Que es Velamentous insertion
Velamentous insertion – Fetal blood vessels insert into the membranes between the amnion and chorion instead of the placenta and are not protected by Wharton
jelly, or when there is a succenturiate lobe across the os from the main placenta
How often do we see vasa previa and what does it mean when we see it
1:2500 pregnancies. Greatest risk for fetal vessel rupture, which is otherwise rare in pregnancy. Fetal vessel rupture can lead to rapid death, and if not detected before delivery, mortality reaches 60%
How does the APT test work?
Apt test: Distinguish fetal from maternal blood. Blood mixed with water leading to hemolysis, centrifuged supernatant mixed with sodium hydroxide. Fetal blood is pink and maternal is yellow-brown
Vasa previa management in severe cases
Transvaginal US in more emergent settings with color Doppler, leading to delivery via Cesarean or forceps in certain cases
When do we really need to check for vasa previa?
Important during AROM to check for pulsating vessels, which could be a sign of vasa previa
Why does uterine rupture usually occur and how bad is it?
i) Usually at site of previous C-Section. Other causes: Preterm cervical change, Preterm labor
ii) Complete transection from endometrium to serosa. If peritoneum is intact, this is a partial rupture or uterine dehiscence
iii) If Fetal expulsion from rupture into the abdomen occurs, fetal mortality reaches 50-75%, survival being dependent on whether placenta is still attached to uterine wall or not
What is ectropion and when do we see it
f) Ectropion in setting of OCP use
i) Can cause columnar epithelium of endocervix to evert out, causing it to come in
contact with vaginal acidity which can lead to minor bleeding
History and physical for Vasa previa key points
i) History of coagulation issues like vWD? Hemorrhoids? Cervical dysplasia history with no recent pap smear (cervical cancer)?
ii) Don’t begin bimanual until US confirms placental position. Instead do vulva and speculum of vagina and cervix first
Initial therapy for significant bleeding
a) Monitor Vital Signs
b) Large bore IV lines
c) Rapid administration of crystalloid, blood, and blood products
Studies for significant bleeding you should get
d) Studies: CBC, coags, type and cross for four units
e) Rh D negative moms with Rh D + babies may need immunoglobulin