If a woman is told at an ultrasound that she has a low lying placenta this can often cause her to feel confused and worried. The sonographer may mention that the woman might need to have a caesarean and if she is planning a vaginal birth this can throw her plans into chaos.
Often it is a week or two before her next prenatal appointment with her care provider so she is left to stress (and Google) for information.
When she finally sees her midwife or doctor they almost always reassure her that the placenta will move and its not a big deal. Meanwhile she has spent the last weeks freaking out and trying to figure out if her baby will be ok and if she needs a caesarean.
This article is to give information and reassurance if you are that woman who has been told you have a low lying placenta and are waiting to see your care provider.
So what exactly is a low lying placenta and why is it a problem?
Ideally the location of the placenta will be at least 2cm from the cervix, if it is less than or very close to 2cm away from the cervix it is considered a low lying placenta. If it is covering or partially covering the cervix it is a placenta previa. Partial or complete placenta previa at the time of birth means that the baby cannot move through the cervix and caesarean is the only safest option. Placenta previa can also cause bleeding during pregnancy.
Does the placenta move?
Technically no, however its location relative to the cervix opening does change. The best way to describe it to you is an analogy.
Picture a half inflated balloon with a black dot drawn low down near the opening, now blow up the balloon completely.
The dot didn't move location, however because the balloon became larger the distance between the dot and the opening increased.
That's similar to whats happening with a women's uterus as it grows during pregnancy. Where the placenta implanted isn't actually going to change but as the uterus grows up and larger the distance between the placenta and the cervix increases.
What happens once you've been told you have a low lying placenta?
If the placenta is low then you will likely have a scan at 30-34 weeks to confirm that the placenta is well away from the cervix. If your placenta is covering the cervix then you may have a scan every few weeks to monitor your pregnancy. In the unlikely event that your later scans show that the placenta is in a location that is unsafe for a vaginal birth then you will have plenty of time to plan a positive caesarean birth.
How close can the placenta be to the cervix for a vaginal birth?
Every care provider will have a slightly different minimum distance between the placenta and the cervix for them to feel comfortable with a vaginal birth. It often ranges from 2-4cm but check with your midwife or doctor for their specific figures.
Is there anything I can do to help the placenta move?
Where the placenta has attached to the uterus wall cannot be changed. However you can help yourself by remaining positive about your baby's birth. Keep communicating with your care provider if you are concerned and remember that over 95% of placentas are well clear of the cervix by the time of birth.