Chapter 16: Third Trimester Bleeding

Question 1

How often do we see third trimester bleeding and when do we notice the spotting/bleeding?

Answer 1

• 4 – 5% of pregnancies are complicated by third trimester vaginal bleeding
• Spotting often noted during intercourse, trichomonas cerviticitis workup, and pelvic exams

Question 2

Discuss blood changes during pregnancy

Answer 2

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

Question 3

When do we see placenta previa bleeding and how often?

Answer 3

ii) Usually bleeding is around 29/30 weeks

iii) 1:200 pregnancies

Question 4

Does placenta previa resolve?

Answer 4

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

Question 5

How do we diagnose placenta previa?

Answer 5

Dx: Transvaginal US

Question 6

Risk factors for placenta previa

Answer 6

Placenta previa in prior pregnancies (4-8% recurrence), prior Cesarean delivery or other uterine surgery, multiparity, advanced maternal age, cocaine use, smoking.

Question 7

How do we manage a bleeding placenta previa patient?

Answer 7

(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

Question 8

Complications of placenta previa

Answer 8

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)

Question 9

What is placental abruption

Answer 9

Placental Abruption (Premature separation of the placenta, usually painful)

Question 10

Complete vs partial placental abruption

Answer 10

Complete = entire placenta separates. Partial = Part of it separates. Marginal = Edge of placenta only

Question 11

Usual cause of placental abruption

Answer 11

Usually secondary to bleeding in the decidua basalis that separates the placenta off, and usually presents as vaginal bleeding with abdominal pain

Question 12

Do we always see blood with placental abruption? If no blood, then what?

Answer 12

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

Question 13

Risk factors for placental abruption

Answer 13

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

Question 14

Management of Placental abruption

Answer 14

(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

Question 15

What is a couvelaire uterus and what does it mean?

Answer 15

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

Question 16

Most common cause of coagulopathy in pregnancy:

Answer 16

Placental abruption

Question 17

Labs with placental abruption

Answer 17

May see low fibrinogen, low platelets (DIC is rare but serious), and elevated PT/PTT

Question 18

What is vasa previa

Answer 18

Passage of fetal blood vessels over the internal os below the presenting part of the fetus

Question 19

Que es Velamentous insertion

Answer 19

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

Question 20

How often do we see vasa previa and what does it mean when we see it

Answer 20

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%

Question 21

How does the APT test work?

Answer 21

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

Question 22

Vasa previa management in severe cases

Answer 22

Transvaginal US in more emergent settings with color Doppler, leading to delivery via Cesarean or forceps in certain cases

Question 23

When do we really need to check for vasa previa?

Answer 23

Important during AROM to check for pulsating vessels, which could be a sign of vasa previa

Question 24

Why does uterine rupture usually occur and how bad is it?

Answer 24

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

Question 25

What is ectropion and when do we see it

Answer 25

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

Question 26

History and physical for Vasa previa key points

Answer 26

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

Question 27

Initial therapy for significant bleeding

Answer 27

a) Monitor Vital Signs
b) Large bore IV lines
c) Rapid administration of crystalloid, blood, and blood products

Question 28

Studies for significant bleeding you should get

Answer 28

d) Studies: CBC, coags, type and cross for four units

e) Rh D negative moms with Rh D + babies may need immunoglobulin

Question 29

End game management for significant bleeding

Answer 29

f) If lots of bleeding and near term, consider emergent delivery, usually with C-S
g) If not a lot of bleeding or fetus is preterm, monitor vitals, coags, and US for fetus and placental condition