Placenta Previa Flashcards
What are the causes of antepartum hemorrhage?
- placenta: placenta previa, placenta abruption
- vagina: trauma, vaginal infection
- cervix: cervicitis, cervical ectropion
- fetal: vasa previa
What are the risk factors for placenta previa?
- maternal age > 35 years
- multiparity
- cigarette smoking (2 fold increase)
- previous C section
- multifetal gestation
- ARTs
What is the clinical presentation of placenta previa?
- painless vaginal bleeding
- at end of second trimester & after
- first bleed is not fatal but second could be
- bleeding + <25mm cervical length -> chance of delivery within 7 days
How is placenta previa diagnosed?
- transabdominal ultrasound (can be identified at 18-22 week anomaly scan)
- transvaginal ultrasound (more accurate & safe)
- digital examination -> in theatre with double set up technique
- MRI -> for placenta accrete spectrum
How is placenta previa diagnosed?
- transabdominal ultrasound (can be identified at 18-22 week anomaly scan)
- transvaginal ultrasound (more accurate & safe)
- digital examination -> in theatre with double set up technique
- MRI -> for placenta accrete spectrum
When should patients with placenta previa follow up?
- if patient had previous C section -> at 28 weeks & 32 weeks -> if still present at 36 weeks
- if no previous C section -> evaluate at 32 weeks -> if still low lying at 36 weeks
How should a low lying placenta or placenta previa be managed?
1- hospitalization after first bleed
2- steroids given for preterm gestations
3- elective CS at 36 weeks to 37 weeks if mother has no bleeding
- vertical laparotomy incision for ease of access & hysterectomy if needed
When should an emergency C section be preformed?
patient with massive bleeding that didn’t stop
1- resuscitate & transfuse blood
2- C section
How is bleeding controlled?
1- uterotonic medication (oxytocin & misoprostol)
2- hemostatic sutures at lower uterine segment
3- compression sutures
4- foley balloon tamponade
5- uterine artery ligation (unilateral then bilateral)
6- internal iliac artery ligation
7- hysterectomy if all other methods fail
What are the outcomes of placenta previa bleeding?
- maternal mortality increased 3 times
- preterm birth
- neonatal death
- low birth weight babies
What is the classification for placenta accreta spectrum?
- Accreta -> villi anchor in myometrium
- Increta -> Villi invade myometrium
- Percreta -> Villi invade till serosa
What are the risks & complications of placenta accreta spectrum?
- hemorrhage & peripartum hysterectomy
- occurs more with prior C section
- ICU admission risk
- red cell transfusion
- URINARY TRACT INJURIES
- prolonged hospital stay
What are the characteristics of PAS seen on ultrasound?
1- placenta lacunae
2- thinning of retroplacental myometrium
3- disruption of bladder-uterine serosal interface
4- bridging vessels from the placenta to the bladder-serosal interface
5- placental bulge that pushes outwards & distorts the contour of the uterus
How is PAS managed?
1- elective C section (if diagnosed preoperatively)
- delivery between 34-36 weeks
- patient & husband counseled on hysterectomy
2- Conservative
- cutting the cord & leaving the placenta inside & suturing the uterus
- if left for spontaneous resorption -> serial monitoring with US or MRI
- risk of coagulopathy, sepsis, PE, & AV malformation
What is vasa previa & how is it diagnosed?
- blood vessels travel in the membranes & come across cervical os -> gets torn with rupture of membrane or cervical dilatation
diagnosed by -> intrapartum or antepartum vaginal bleeding immediately followed by fetal compromise
