The placenta processes your baby’s nutrients, waste and oxygen.
In most pregnancies the placenta attaches to the side of the womb but for some women the placenta attaches lower down and may cover a part or all of the cervix (entrance to the womb). This is called low-lying placenta or placenta praevia.
This often shows up in early ultrasound scans when it is called low-lying placenta. In 90% of cases, the placenta moves upwards as the womb grows. For some women, however, the placenta continues to lie in the lower part of the uterus after 20 weeks. This affects 1 in 200 births.
When this happens it is called placenta praevia. If the placenta covers the cervix, this is known as major placenta praevia.
A note on the difference between placenta praevia and anterior placenta
People sometimes think that low-lying placenta is linked to having an anterior placenta but this is not correct. Anterior placenta simply means the placenta is on the front (belly side) of the womb rather than attached to the back of the womb. Having an anterior placenta is normal and does not cause complications.
How would I know if I had placenta praevia?
Placenta praevia is usually spotted during your normal ultrasound scans but other signs are:
- painless vaginal bleeding in the second or third trimester
- baby in an unusual position in the second or third trimester, breech for example or failure of the head to engage in the pelvis just before labour starts.
If you have any bleeding, contractions or pain in pregnancy you should always contact the hospital.
You may have a transvaginal scan (where the probe is placed inside the vagina) to confirm whether you have placenta praevia.
The risk factors for placenta praevia
In many cases the cause of placenta praevia is unknown but the following risk factors are associated with the condition:
- Maternal age: it is more common in women who are over 40 years
- Previous caesarean section (the risk increases slightly with each one)
- Previous placenta praevia
- Multiple pregnancies
- Previous abortion or surgery in the womb
Treatment for placenta praevia
You will have extra scans if you are found to have a low-lying placenta in a routine scan.
An extra scan is recommended at 32 weeks if:
- you had a caesarean section before
- your placenta covers the cervix (major placenta praevia)
- your placenta is in an anterior position (at the front of the womb) and you have had a previous caesarean section.
If your placenta does not cover the cervix and you have no bleeding during your pregnancy, your extra scan should happen around 36 weeks instead.
There is a risk that you may bleed in the second half of pregnancy (sometimes caused by having sex). Bleeding from placenta praevia can be heavy. If you bleed contact your hospital immediately.
If you have major placenta praevia (the placenta covers the cervix) you may need to stay in hospital after 34 weeks of pregnancy even if you have had no symptoms. There is a small risk that you could bleed suddenly and severely, which may mean that you need an urgent caesarean section. If you are bleeding the baby may need to be delivered.
Placenta praevia is linked to spontaneous preterm delivery and PPROM (waters breaking early), a major cause of premature labour.
Your obstetrician and / or midwife is likely recommend delivery in hospital, rather than a home setting, and caesarean section might be considered the safest option if the placenta is less than 2cm away from the internal os (the part of the cervix that opens into the uterus).
If you have major placenta praevia (where it covers the cervix) or if the placenta is very close to the cervix you will need to have a caesarean section because the placenta lies in the way of your baby being born.
- RCOG (2011) Information for you: A low-lying placenta (placenta praevia) after 20 weeks, Royal College of Obstetricians and Gynaecologists
- RCOG (2011) Placenta praevia, placenta praevia accreta and vasa praevia: diagnosis and management, Green-top Guideline No 27, Royal College of Obstetricians and Gynaecologists
- BMJ Best Practice (accessed Oct 2016) http://bestpractice.bmj.com/best-practice/monograph/667/diagnosis/history-and-examination.html
- BMJ Best Practice (accessed Oct 2016) http://bestpractice.bmj.com/best-practice/monograph/667/basics/aetiology.html
- J David, Steer P et al (2010) High risk pregnancy, management options, Elsevier Saunders
ℹLast reviewed on September 12th, 2016. Next review date September 12th, 2019.
By worried dad (not verified) on 13 Mar 2019 - 00:28
hi my girlfriend went to hospital 2 days ago the doctor tried physically to move placenta as its low she now is bleedin a lot is this a big worry r normal
By Lesley (not verified) on 24 Feb 2019 - 16:55
I'm currently 33 weeks pregnant with my 4th. My placenta isn't blocking the cervix but is too close for a vaginal birth (according to my consultant). It's lying in the posterior position. I'm being told I need a c-section at 37 weeks. Sounds too soon to me. Would it be risky to leave until 38 or 39 weeks? All my other pregnancies were normal vaginal birth at 39+ weeks.
By Midwife @Tommys on 27 Feb 2019 - 11:15
Hi Lesly. You can go back to your consultant and ask for their reasons why they suggest a c/s at 37 weeks as there may be a specific reason this has been suggested for you in this pregnancy. Each case is different. So please do make another appt to see your Consultant and ask if the c/s can be a week or two later. You can also speak to your own midwife about this, it could be a hospital policy, so worth checking with both of them. Take care, Tommy's Midwife
By Khadijah (not verified) on 21 Feb 2019 - 11:41
Good evening. Im still confused about that. It says that completely covering the internal os. But i read some post that grade 1 means minor. Can you explain it to me? Thanks
By Midwife @Tommys on 22 Feb 2019 - 13:25
You are right, grade one placenta praevia is minor so only partially covering or near to the internal os.
By Kavita (not verified) on 16 Feb 2019 - 18:46
I have 31 week ultrasound. The placenta is posterior low lying 1cm away from internal os.
By Nirmal (not verified) on 31 Jan 2019 - 16:30
Diagnosed low anterior placenta 3 cm away from OS at 20week and subsequently now at 40 week another scan reveals same position
doc is saying everything is normal, however, low lying placenta case , says risk of bleeding will be there at labour , better go for c section. Please advise is.it possible for normal delivery than c section
By Midwife @Tommys on 31 Jan 2019 - 16:38
Hi - Thank you for your message.
As your Dr has advised as the placenta is not covering the OS, it is possible for a vaginal delivery, but recommend delivery in hospital, rather than a home setting. You should discuss the risks and benefits of the options for birth with your consultant as it is your decision how your baby is birthed.
By Jisha (not verified) on 17 Jan 2019 - 12:36
33 week pregnent. My placenta is 1 cm away from cervix. Baby is standing position. Hb is 9.8 . First baby 8 year old.it wasormal delivry. Can i give viginal birth?
By Midwife @Tommys on 17 Jan 2019 - 12:54
Hi - Thank you for your message.
If you have been advised that you have a low lying placenta, you should be offered additional scans and monitoring. If at 36 weeks the placenta is still considered low and too close to opening of the cervix you will be advised by consultant/midwife what the options for birth are.
By Anonymous (not verified) on 13 Jan 2019 - 08:02
19 weeks Placenta: Anterior, totally covering os, Grade 1 Baby is breech
That’s written on my latest ultrasound. I’m a little confused that it says Grade 1 but it is totally covering my cervix. Do I have a good chance of my placenta going up? I’m hoping for a normal delivery. Or even if I need cesarian atleast not with previa. Does previa cause baby to breech? oping for your answers.
By Midwife @Tommys on 14 Jan 2019 - 16:32
Hi, You will have to speak to your obstetrician or midwife, this is confusing as grades 3 and 4 totally cover the os, wheras grades 1 and 2 may move out of the way of the cervix as seen above. I expect you will be scanned again at 34 weeks (unless there is any bleeding before) where you will be able to clarify in time to arrange your home-birth.
By Tara Marson (not verified) on 3 Jan 2019 - 21:29
I have just had my 32 week scan and my placenta is still low lying and is currently 1cm away from my womb. This is my 2nd baby, previously I had an emergency c- section with my little girl as I got strep B during labour and both myself and baby had extremely high heart rate. The doctor has said that it's up to me whether I deliver naturally or have a c- section but there is risk of bleeding. I'm finding it really hard to decide what to do for the best. I am booked in for another scan at 38 weeks to see if it's moved but I don't imagine it will much in that time. Any help or advice would be really appreciated. Thank you very much
By Midwife @Tommys on 7 Jan 2019 - 14:55
Hi Tara, I can only assume that your placenta is far enough away from the cervix for your doctor to consider vaginal delivery to be a safe option. I understand your dilemma, and I think it is reasonable to wait until 38 weeks before making that decision.
By Heather (not verified) on 23 Dec 2018 - 09:34
I am 20 weeks pregnant and at my anomaly scan I was told I have an anterior low lying placenta. I've read all this helpful information about what to look out for regarding bleeding etc, many thanks for that. My question is perhaps a silly one but something worrying me...if the placenta is low lying the baby must naturally rest on it a lot of the time. I was told in my first pregnancy to sleep in my left side because it could be harmful to the baby for it to lie on the placenta since it could cut off it's cord supply. Is this a risk with a low lying placenta? Is there a risk of brain damage or developmental impacts to the baby sitting on the placenta? Many thanks
By Midwife @Tommys on 4 Jan 2019 - 16:30
Please try not to worry, there is not evidence whatsoever that there is any risk to your baby's development and having a low lying placenta. With regards to sleeping on your left hand side, we so advise to sleep on your side but this is not due to the cord as the cord can be anywhere in the uterus and your baby moves around, it is to do with your own blood vessels and the supply to the placenta.
I hope this reassures you, you should have a scan later in your pregnancy to check that your placenta has moved away from your cervix.
By Akshaya (not verified) on 22 Dec 2018 - 17:48
After my anomaly at 21 weeks i was told that my placenta was posterior and low lying..3 to 4 cm away from os..im advised bed rest..im concerned about two things..i have a 1.3 yr old kid whom i was adviced not to lift..and i had a csection 1.3 yrs ago...so worried if it is going to be complicated and other risks involved...im a full time working woman and not sure if i should opt not to commute to work..
By Midwife @Tommys on 3 Jan 2019 - 16:53
Please be assured that there is no evidence that bed rest would be beneficial to you or your pregnancy due to the low lying placenta. As long as you feel comfortable, you can do your usual commute, but it would be a good idea to avoid lifting your toddler. As the placenta is 3-4cm away from the os, you will still be able to have a vaginal delivery. If you have any tightenings or bleeding then call your maternity unit straight away.
By Amrutha Narayanan (not verified) on 12 Dec 2018 - 15:38
Now I'm 20 weeks 3 days pregnant. When I had my anomaly scan at 19.5 weeks, it showed that I have anterior low lying placenta, which is 1.6 CM away from the cervix. It's my first pregnancy, and I would like to have a normal delivery. My Gynecologist told me not to worry about it now, it may move upwards further. If my placenta doesn't move upwards, is it possible to have a vaginal delivery??
By Midwife @Tommys on 14 Dec 2018 - 15:23
As your doctor has advised you, it is very likely that your placenta will move up away from the cervix as your uterus stretches to accommodate the growing baby. If the placenta does not move far enough, then you will be advised to have a caesarean section, however this is unlikely as your placenta will usually move. They should re scan you in your third trimester to check where the placenta is, and then speak to you about your options.
By Ayisha (not verified) on 12 Dec 2018 - 07:35
Hi I am 34 weeks now sterday I go for scan they told me my placenta was low lying 1.5cm from internal os but my 20 week and 27 week scan indicates my placenta was anterior upper . I have confused that how can placenta comes to low lying in 34 weeks pls anyone explains me I am in worry bcoz dctr told me it will lead to c section
By Midwife @Tommys on 13 Dec 2018 - 16:24
Hi Ayisha, Thank you for your comment.
It is very difficult to advice you about this, if your placenta was anterior high at 20 and 27 weeks, it is strange that it is now being diagnosed as low. It would be much more beneficial if you speak to your midwife and Dr personally as they can look at your scans and give you a better answer to your question. If the placenta is less the 2cm from the OS then a c section would be recommended as the placenta is too low for the baby to be born vaginally. Please contact your Dr again so that you are fully informed about your plan of care. Take Care, Tommy's Midwives x
By Chirwari (not verified) on 9 Dec 2018 - 11:48
Hi, my wife is 27 weeks pregnancy, today blood was spootted on her underwear , what could be the cause and effects. Previous Fetal growth has slways be reported normal
By Midwife @Tommys on 10 Dec 2018 - 16:40
It is important to be assessed for any vaginal bleeding at 27 weeks. Please go to your nearest maternity unit where your wife will be assessed.
By Love (not verified) on 8 Dec 2018 - 06:47
Hi , i am 32 weeks and 2 days and i have a low lying placenta. And i am flying to spain this friday. Is this very dangerous? I have no bleeding ever since from the stat of my pregnancy and it's my first baby. Any advice?
By Midwife @Tommys on 10 Dec 2018 - 16:44
Hi, Please discuss this with your doctor or midwife. After 28 weeks many airlines require evidence of a healthy and normal pregnancy before you can fly. You can read advice here https://www.nhs.uk/common-health-questions/pregnancy/is-it-safe-to-fly-while-pregnant/
By ABC (not verified) on 5 Dec 2018 - 04:52
My wife is 20 weeks pregnant and she is having Major placenta previa with placenta abutting the os.
Kindly suggest is there any risk with the life and health of mother and baby
By Midwife @Tommys on 5 Dec 2018 - 11:19
If your wife has any abdominal pain, any vaginal bleeding, any episodes of reduced fetal movements, or just "doesn't feel right" than she should go urgently into your nearest hospital maternity unit, to be reviewed by a midwife and obstetric doctor. Every women has her own set of " risk factors" during pregnancy. Your midwife and Dr will be best placed to go through your wife's risk factors as they will know her full medical and obstetric history, so that the care is tailored to her alone. All the best, Tommy's Midwife
By Robin (not verified) on 16 Nov 2018 - 16:42
My wife has sbeen diagnosed with marginal previa . She is currently 22 weeks pregnant . We need to travel via 2 hrs flight at 25 weeks . There has been no bleeding . Cervix lenght is 3.8 cms . Baby growth is normal . Is there a risk in traveling . Please advise
By Midwife @Tommys on 19 Nov 2018 - 09:44
Hi Robin, In 90% of situations where low lying placenta is diagnosed at the anomaly scan, the placenta will move up and out of the way of the cervix as the pregnancy progresses. I can't advise on individual cases as I haven't seen the report, but your midwife or sonographer may be able to tell you if your placenta is covering part of the cervix and what the likely risk is. It goes without saying that if there is any bleeding it is important to be seen immediately.
By Tara (not verified) on 27 Oct 2018 - 03:34
So my placenta is very close to my cervix and no bleeding yet should I worry about it should I stop being Active with my other kids I’m 21weeks
By Michelle Timms (not verified) on 3 Oct 2018 - 13:11
I have not yet had my 20 week scan but at a private scan at 16 weeks I was told I have an anterior placenta.
I am taking my 7 year old daughter to America for 2 weeks 11 days after my 20 weeks scan and I am petrified that they will tell me it is low lying and that I will be unable to fly.
Are you still able to fly with a low lying placenta?
By Midwife @Tommys on 8 Oct 2018 - 15:45
Do you have a history of placenta previa? As you will have read here, the majority of women diagnosed with low-lying placenta at the 20 week scan will find that their placenta rises up as the uterus grows and therefore causes no problems. If you have already been told your placenta is anterior, this is not low lying. Anterior means that it is attached to the front wall.
Until you have information to the contrary, I would not worry about flying.
By Nwokorie chizoba (not verified) on 17 Sep 2018 - 21:19
Am 22 weeks pregnant and has been told that I have a low lying placenta what's my risk of delivery, and is it harmful for my baby
By Midwife @Tommys on 20 Sep 2018 - 12:58
Hi Nwokoriw, Thank you for your comment.
Please feel reassured that it can be common for your placenta to be low lying at this stage of your pregnancy, there is every chance that as your pregnancy grows, the placenta will migrate up the wall of the uterus and out of the way. You should have another scan around 32 weeks to check the location of your placenta, 9 out of 10 women will have a placenta that has moved out of the way so please feel reassured.. If you have any bleeding or abdominal pain then you need to seek medical advice. Hope this helps, take care, Tommy's Midwives x
By salmatanzi (not verified) on 28 Jul 2018 - 15:33
i have placenta previa grade 1.....doctor recommend me to csec...33 weeks scan found the problem..give me some suggestion what should i do now...its 34 weeks 6th day of my pregnancy
By Midwife @Tommys on 30 Jul 2018 - 16:33
Hi Salmatanzi, Without access to your clinical information I can't advise on your delivery but this quote is taken from the RCOG guidance:
'The mode of delivery should be based on clinical judgement supplemented by sonographic information. A woman with a placental edge less than 2 cm from the internal os in the third trimester is likely to need delivery by caesarean section'
The reference for this is https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_27.pdf
I hope this helps and wish you all the best.
By Sian (not verified) on 6 Jul 2018 - 15:24
I went for my anomaly scan at 19 weeks and was told I have a low lying placenta. They have booked another scan in for 34 weeks, what are the chances from now of this moving? If at 34 weeks it hasn't moved, will i have to stay in hospital until i have a c-section? This is my first pregnancy so abit worried.
By Midwife @Tommys on 9 Jul 2018 - 12:09
Hi, At this stage there is no reason to be concerned. In 90% of these situations the placenta moves out of the way before the scan at 34 weeks. If you have any bleeding you should call your maternity unit straight away but in the absence of bleeding please try not to worry and continue with your normal lifestyle. Take care
By Anonymous (not verified) on 6 Jul 2018 - 11:22
I have been told I have a low-lying placenta at my 20 weeks scan, I am now 24 weeks and wondering if I need bed rest
By Midwife @Tommys on 9 Jul 2018 - 12:02
No, in most situations the placenta will move out of the way before the birth is due. If you have not had any bleeding there is no reason to change your lifestyle. You will have another scan at 34 weeks to check the placenta location again and if you do have any bleeding or concerns please contact your maternity department.
By Davinder (not verified) on 18 Jun 2018 - 13:10
Hi I’m 32 week pregnant with low lying placenta last week I have some bleeding & clot I stay in hospital 3 days dr send me home yesterday start again bleeding & clotting not continue now I’m worried because I have 2 c section
By Midwife @Tommys on 21 Jun 2018 - 16:22
I do hope that you have been back to the hospital if you are bleeding again. If your placenta is still low then you would need a c section, this is worrying you then do speak with your midwife about making a birth plan and if there is something in particular that you are worried about.
By Jo (not verified) on 11 Jun 2018 - 19:21
Hi, my placenta was posterior low at my 20 week scan and at 32 weeks is 17mm from the os so it’s moved up a bit. I have another scan booked for 36 weeks - just wondered if it’s likely to move any further or (as it’s been quite a slow process) it will remain below 20mm? Also, I’ve read that with a posterior placenta, C Sections are likely for placentas less than 30mm, so it could have even further to move! I’m frightened about having a C Section and am gutted I may not be having a vaginal birth :( Thank you
By Midwife @Tommys on 13 Jun 2018 - 11:14
It's easiest for you to call us on the pregnancy line (0800 0147800) between 9 am and 5pm, Mon to Fri to talk this through in more detail.
Placenta's can and do move, but there is a limit to how far they will move/grow up and away from the cervix if it's low lying.
Your obstetric consultant is best placed to give you tailor made answers to your questions based on your own personal medical and obstetric history. But we are very happy to talk things through with you too! Speak to you soon
Sophie, Tommy's Midwife
By Shaili (not verified) on 24 May 2018 - 12:57
I found low lying placenta in 18 weeks of pregnancy, my doctor advised me for another scan in 32 weeks. But my placenta is still Low. Is there any chance that it will move upward or it is attached to the uterus. I'm worried about c section delivery.
By Midwife @Tommys on 24 May 2018 - 16:10
Sorry to hear that you are so worried. Yes you would need a c section if your placenta is next to overlapping the cervix. The doctors should speak with you about this. If you do need a c section, we do have lots of information about this if this helps you to prepare: https://www.tommys.org/pregnancy-information/labour-birth/c-sections-everything-you-need-know
Wishing you all the best.
By Sam (not verified) on 9 May 2018 - 14:39
I am 16weeks pregnant I have had spotting throughout this pregnancy that started at about 6 weeks. This is my 7th pregnancy and 4th baby I have had 3 miscarriages one miscarriage I haemorrhaged and nearly died I was in HDU after miscarriage In my second pregnancy I had placenta previa grade 4 was in hospital a lot throughout pregnancy had an emergency c section at 35 weeks and I haemorrhaged. I have been told that my placenta is low lying reaching internal os. How likely is it that my placenta will me and is there a risk of me haemorrhaging? Very anxious and worried.
By Midwife @Tommys on 10 May 2018 - 15:45
Hi Sam, I am sorry to hear that you have had some complicated experiences with your pregnancies!
The person best placed to go through all of your concerns, is an obstetric consultant at your maternity unit. With your pregnancy notes- both for current and historical pregnancies, they can make a predication as to what may be a risk for you in this pregnancy, as well as make a plan of care for what may need to be done for you in this pregnancy. You can get a consultant appointment via your hospital antenatal clinic - you can also ask your midwife to get you an appointment to be seen.
At 16 weeks, it is possible that your placenta will grow away from the cervical os, and therefore no longer cover it. However, this is not the case for every woman, hence why you will need input from an obstetric consultant to keep an eye on placental location, bleeding, birth method etc
Good luck with everything and feel free to get in touch again if we can be of any further assistance to you.
By Sam (not verified) on 12 May 2018 - 08:37
Thank you for your reply I have now been referred to a consultant at the local hospital x