Exam 3: Unit 5: Placenta Previa
What is the incidence of placenta previa in term pregnancies?
1 in 200 pregnancies at term
How does smoking increase the risk for placenta previa?
2.6-4.4% increased risk because decreased uteroplacental oxygenation --> increased need for placental surface area
____% of women will have uterine contractions with bleeding
20
To be on expectant bed rest, what must the status of bleeding be?
< 250 ml or no bleeding without contractions
How many weeks do you have to be to be at home/expectant management?
< 36 weeks
What maternal age is at an increased risk for placenta previa?
> 35
When would the mom in active management?
Any fetal maternal deterioration or progression, if >36 weeks
What is placental migration?
As the cervix starts effacing and moving up into the lining of the endometrium, and as the cervix starts dilating, the placenta migrates upward which may help with marginal placental previas
A previous history of what three things increases the risk for placenta previa?
C-section, previa or D&C
Why is placenta previa a problem?
Can completely or partially occlude cervical os or be close enough to cervical os that causes bleeding as the cervix dilates and effaces
What is complete placenta previa?
Covers cervical os completely
What is a low lying placenta?
Exact location of placenta in relation to the cervical os is not able to be determined
What is done if s/s of shock occur?
Immediate C-section
What does a serial ultrasound tell us?
Location of the placenta
Which type of placenta previa is the best?
Low lying because there's a chance of the placenta migrating up when the uterus grows
What is expectant management?
Maternal surveillance while mom is at home
Is placenta previa painful?
No
When is expectant management done?
No complications, waiting for fetal maturation, continuous maternal surveillance
Will FHR be changed from placenta previa?
Normal FHR unless major detachment occurs
What is done for the first visit with a mom with placenta previa?
Obtain U/S and Monitor for contractions and FHR
What causes placenta previa?
Placenta implanted in the lower uterine segment
What are the two reasons for bleeding late in pregnancy?
Placenta previa and placental abruption
What is placental abruption?
Premature separation of the placenta from the uterine lining
Why is living at high altitudes a risk for placenta previa?
Same as smoking
What type of onset might placenta previa have? Why?
Small amount of bleeding at first, may clot/stop then begin again s/t to stretching and thinning of the lower uterine segment that occurs during the 3rd trimester As the uterus grows, the placenta is gradually disrupted and bleeding occurs
What must the fetus' condition be for the mom to stay at home?
Stable
What is a marginal placenta?
The edge of the placenta is seen on a transvaginal ultrasound to be 2.5 cm or closer to cervical os
Even though the VS are normal, what is decreasing?
Urinary output
What is done for a complete placenta previa?
Usually c-section
What is done for a marginal placenta?
Usually c-section
What clinical manifestations are present with placenta previa?
Usually painless, bright red vaginal bleeding after 20 weeks gestation
Will contractions or cramping be present with placenta previa?
Usually without contractions or cramping (80%)
What do the VS look like in placenta previa?
VS normal
If a patient is bleeding from the vagina, what should you avoid doing?
Vaginal exam because we don't want to cause more bleeding or contractions
What is done for a low lying placenta?
Will allow to go into labor with vaginal delivery, but emergency c-section may occur
Will a mom with placenta previa at home be on bed rest?
don't order complete bed rest because of increased risk of DVTs (bed rest with bathroom privileges, range-of-motion in bed, walking around the house as long as she's not bleeding)
Why does amount of bleeding matter?
hemorrhage - early or late signs of shock
What three things determined how to manage placenta previa?
o Gestational age o Amount of Bleeding o Fetal condition
What are the four effects placenta previa can have on the fetus?
o Malpresentation - breech or transverse o Anemia o Preterm birth (can cause death) o Stillbirth
What are the types of placenta previa?
o Marginal o Complete o Low-lying
What are the risk factors for placenta previa?
o Previous C-section, previa or D&C o Maternal age > 35 o Multiple gestation o Multipara o African American/Asian Decent o Smoking o Living in high altitudes o Male fetus
What can be used to diagnose placenta previa?
o Serial Ultrasound o Labs: H&H, Platelet count, coagulation studies, Type & Screen in case she needs blood
Home on ________ bedrest (< 36 weeks) and mild bleeding <____ ml or has stopped with no __________________
partial 250 contractions
Why are multiparas at risk for placenta previa?
scar tissue formation
How will the uterus feel if placenta previa is present?
soft, non-tender uterus with normal tone yet fundal height > than GA
Why will they be in the hospital if > 36 weeks?
will have C-section or if higher midline can have delivery, but need to weigh risk vs. benefits
