Placenta Previa: What Caused This?
A month ago, at 20 weeks, I was put on bedrest (at least until 28 weeks) for marginal placenta previa. I had a miscarriage and a subsequent D&C before I conceived this time. Could that have caused the previa? Could the dilation have caused me to have an incompetent cervix? And finally, what is the likelihood that this or future pregnancies will go to healthy term?Question:
The good news is that most placentas "migrate" upward with the enlarging uterus and at term are no longer low-lying.
"William's Obstetrics" states that if this condition is present at 20 to 25 weeks of gestation, then it will persist as a previa or cause hemorrhage at delivery for just over three percent of women. At 25 to 30 weeks, it persists for about five percent, and if present from 30 to 35 weeks, the risk of it persisting is around 24 percent.
If you are "symptomatic" -- with some bleeding in the second trimester related to the placenta previa -- the chances of it resolving are not as good as if you had no symptoms and your provider found evidence on an incidental ultrasound.
The D&C might have caused some scar tissue high in the uterus, causing the embryo to implant lower down, but so many women have this procedure without this complication that it is probably not the whole reason. Typically, we really don't know why this happens.
Just because you have a placenta previa does not mean that your cervix is incompetent. These two conditions are unrelated. A woman with a previa will not necessarily lose her baby early or have painless dilatation of the cervix as the term incompetent cervix implies. Many cases of previa go to term, if they are not delivered by cesarean before term. If the condition persists into the last month of pregnancy, a cesarean will be planned at about 38 to 39 weeks. This is to prevent hemorrhage at the time of labor, when the cervix can open and expose the placenta.
Once you have this complication, you are at slightly increased risk of this occurring in a subsequent pregnancy, but, by no means is this always true.
I wish you well with this pregnancy.Answer: