When it happens · 4 min read
Placenta previa, abruption, and the scan finding that usually resolves
Someone said the words "low-lying placenta" at your anatomy scan and then moved on, and you've been quietly worrying since. Most of the time this is a finding that resolves itself. Here's what each of the placenta problems actually means.
Last updated August 9, 2026
Low-lying placenta: usually a non-event
A placenta near or over the cervix at the 20-week scan is a common finding, and the great majority migrate clear as the uterus grows upward through the third trimester — the placenta doesn't move so much as the wall it's attached to stretches away. That's why the standard response is a follow-up scan around 32 weeks rather than any change to your life. Only a small minority are still previa at term.
If previa persists
A placenta still covering the cervix near term means a planned cesarean, because the placenta is physically in the way — a vaginal birth would mean delivering through it. Expect a delivery date scheduled before labor is likely to start on its own.
In the meantime, the precautions are specific: nothing in the vagina (no sex, no tampons), avoid heavy lifting and strenuous activity if advised, and report any bleeding immediately. Previa bleeding is classically bright red and painless, and it can be sudden and heavy — which is why the threshold for going in is any bleeding at all.
Abruption is different, and more urgent
Placental abruption is the placenta separating from the uterine wall before delivery. It typically presents with pain — often constant rather than in waves — and a uterus that feels hard, tender, or won't relax, sometimes with bleeding.
The critical detail: in a meaningful share of cases the bleeding is concealed behind the placenta, so there may be little or no blood visible. Severe constant abdominal pain with a rigid abdomen is therefore an emergency even with nothing to see. It affects roughly 1 in 100 pregnancies.
Accreta, briefly
Placenta accreta is where the placenta grows too deeply into the uterine wall and doesn't separate normally after birth. It's much rarer, and the reason it gets named early is that it is managed by planning: delivery at a hospital equipped for it, with a surgical team briefed in advance. Risk is higher after previous cesareans, especially alongside previa — which is why your history gets asked about in that combination.
Common questions
- Is an anterior placenta a problem?
- No — anterior just means it's attached to the front wall of the uterus, which is a normal position. The main practical effect is that you may feel movements slightly later or less sharply early on.
- My 20-week scan said low-lying. What are the odds it resolves?
- Most do. That's exactly why a repeat scan later in pregnancy is standard rather than immediate restrictions — the follow-up is the answer, and it usually brings good news.
- Can I do anything to help it move?
- No, and that's genuinely freeing — position, activity, and rest have no effect on placental migration. Follow any bleeding precautions you've been given and attend the follow-up scan.
If it's this, not that
Still not sure
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Where this comes from
- Placental abruptionMarch of Dimes
- Placenta abruptioMedlinePlus
Every claim on this page traces to one of these. See every source we use →
Written from the sources named above, and it is not a substitute for your own doctor. If something feels wrong to you, that instinct is a good enough reason to call — you know yourself and this family better than any page does.