What may predispose to placenta previa?
uterine scars
fetal complications with previa: preterm, PPROM, IUGR, malpresentation, vasa prevue, congenital abs
What are the types of placenta growing into the uterus?
accrete - attaches
increta - myometrium
percreta - thru myometrium
average blood loss: 3-5000 mL
Risk Factors for placenta previa
other prior uterine surgery such as myomectomy, uterine anomalies, multiple gestations, multiparity, advanced maternal age, erythroblastosis, smoking, and previous placenta previa
When does the first bleed from PP happen?
after 28 weeks - the sentinel bleed - during this time, the lower uterine segment develops and thins, disrupting the placental attachment and resulting in bleeding
What is a circumvallate placenta?
membranes double back over the edge of the placenta, forming a dense ring around the periphery of the placenta.
Often considered a variant of placental abruption, it is a major cause of second-trimester hemorrhage
What is a velamentous placenta? succenturiate?
- blood vessels insert between the amnion and the chorion, away from the margin of the placenta, leaving the vessels largely unprotected and vulnerable to compression or injury
- An extra lobe of the placenta that is implanted at some distance away from the rest of the placenta Fetal vessels may course between the two lobes, possibly over the cervix, leaving these blood vessels unprotected and at risk for rupture
Placenta accrete should be suspected in women with
both a PP and hx of c/s or other uterine surgery
What patients can deliver vaginally with low lying/marginal placentas?
> 2cm from internal os as long as there is no fetal distress or excessive hemorrhage
What is the order of steps for a patient bleeding with suspected PP or PA?
- stabilize - admit, fetal monitoring, IV access, labs
- prepare for hemorrhage - hematocrits, prepare blood; transfuse to maintain Hct 25%
- prep for preterm
if PA,
- plan for abd hysterectomy
- schedule delivery 34-37 weeks
- plan ahead and have back up
Whare are some complications of placental abruption?
preterm
DIC
uterine tetany
hypovolemic shock
“premature separation of the placenta from the uterus”
What are the predisposing factors and precipitating factors of placental abruption?
Hypertension Previous placental abruption Advanced maternal age Multiparity Uterine distension Multiple pregnancy Polyhydramnios Vascular deficiency Diabetes mellitus Collagen vascular disease Cocaine use Methamphetamine use Cigarette smoking Alcohol use (.14 drinks/wk) Circumvallate placenta Short umbilical cord
Precipitating factors: Trauma External/internal version Motor vehicle accident Abdominal trauma Sudden uterine volume loss Delivery of first twin Rupture of membranes with polyhydramnios Preterm premature rupture of membranes
What is the presentation of placental abruption?
Vaginal bleeding
Uterine tenderness/abdominal or back pain
Abnormal contractions/ increased uterine tone
Fetal distress
Fetal demise
what is a couvelaire uterus?
life-threatening condition and occurs when there is enough blood from the abruption that markedly infiltrates the myometrium to reach the serosa, especially at the cornua, that it gives the myometrium a bluish purple tone that can be seen on the surface of the uterus
Consumptive coagulopathy is more likely with
a concealed placental abruption
With placental abruption severe enough to kill the fetus, there are always pathological levels of fibrinogen–fibrin degradation products and/or D-dimers in maternal serum.
What pts must be delivered with placental abruption?
if vital signs are unstable or has a coagulopathy–> regardless of gestational age and steroid administration
Vaginal delivery is preferred as long as bleeding
What are the RFs for uterine rupture?
Prior uterine surgery/uterine scar Injudicious use of oxytocin Grand multiparity Marked uterine distension Abnormal fetal lie Large fetus External version Trauma
What are the RFs for a fetal vessel rupture?
abnormal placentation
multiple gestations
