Placenta previa — also spelt praevia — means ‘placenta first.’
It's an uncommon condition which occurs in around 0.5% of pregnancies.
Instead of implanting on the uterine wall, the placenta implants partly or wholly over the cervix – which can block your baby’s descent into the vagina for birth.
However, it's not all doom and gloom if you're diagnosed with placenta previa or low-lying placenta.
If you have a low lying placenta at 18-20 weeks, it is still very early to tell what could happen in most cases.
In your third trimester (until around 36 weeks) the bottom part of your uterus does most of it's growing and stretching, taking the placenta with it. It doesn't ‘migrate' upwards, but being attached to the uterine wall, it's carried upwards. In only 0.5% of cases, the placenta doesn't move up with the uterus. An ultrasound late in your third trimester will give you and your carer a better picture on what is really going on and if it's of real concern.
Who Is Most At Risk For Placenta Previa?
While the cause of placenta previa is often unknown, it's less common in first pregnancies. Placenta previa may be found in multiple pregnancies as a result of a larger surface area of the placenta. It may also be from scarring on the lining of your uterus, which may be from a prior caesarean section or curette.
Some studies have recently shown that those using assisted reproductive technologies could be at increased risk for placenta previa. The delayed implantation of the fertilised egg can result in the egg settling lower down the uterine, rather than conception taking place at ovulation. In which case, the ovum usually settles high up in the uterine cavity. It has also been suggested that fertility specialists may be inserting embryos lower in the uterus, to aim for higher success rates.
Given that the number of caesarean sections and ART procedures are on the increase, this may result in a growing incidence of placenta previa. The following other issues have been found to increase your risk of placenta previa:
- If you have a large or abnormal placenta (e.g. twins)
- If you have had a previous caesarean section or uterine surgery
- If you are a smoker or use illegal drugs
- If you are over 35 years of age
- If you’ve had many previous pregnancies
Symptoms of Placenta Previa
Symptoms include sudden, painless, bright red bleeding, usually towards the end of the second trimester to the third trimester. You may experience some cramping. The bleeding may stop by itself, but you can experience further bleeding before you reach your estimated due date. The blood loss can be quite heavy so it is important to seek medical attention immediately. On the other hand, some women will have no bleeding at all until they go into labour.
It is important to be reminded that it's the mothers blood which is lost, not the babies. The more centrally the placenta is situated over the cervix, the earlier the haemorrhage and the greater the amount of blood lost. The main reason for infant deaths with placenta previa is where the baby has been born prematurely, before 36 weeks of pregnancy.
Given that there are several causes of bleeding during pregnancy, this one symptom alone is not an accurate diagnosis of placenta praevia – other diagnostic tests will be needed to confirm if you’ve not been previously diagnosed. For example, a placental abruption also results in sudden, bright red, heavy blood loss.
What Is The Treatment for Placenta Previa?
If you have placenta previa, you will likely need to birth your baby by caesarean section depending on the grade or degree of placenta previa. You may be able to birth vaginally if you have a grade 1 or 2 placenta previa (minor placenta previa), however if you have grades 3 or 4 (major placenta previa), a caesarean section will be necessary. This wont be booked in immediately, if you don't go into labour before hand, you will likely be booked in at around 38 weeks when your baby is more mature. If you go into labour prior to this you will need an emergency caesarean. A grade 4 placenta previa will often mean being admitted to hospital at the first bleed and remaining as an inpatient until birth.
Some women may find the thought of a c-section upsetting. Not being able to birth their baby vaginally may leave some women feeling like their birth will be a failure on their part. However birthing your baby by c-section is not a failure — it's the safest way (and sometimes the only way) to bring your baby into the world.
If you have trouble dealing with your emotions, it's important to seek the help of an experienced perinatal psychologist, who specialises in pre and postnatal issues. It can also be helpful to join some support groups for c-section healing. See the Birthrites and Birthtalk websites for more info.
What Can I Do If I Am Diagnosed With Placenta Previa?
Unfortunately, there is nothing you can do to change the position of the placenta. Therefore, there is little you can do to help the situation.
Ensure your iron levels are adequate, in order to prevent anaemia. An effective, quality iron supplement is essential for keeping your iron stores topped up. Speak to your naturopath for an effective, but gentle brand. During pregnancy, you are more prone to constipation, and some iron supplements may increase your chances of getting constipated.
If you have experienced bleeding, you may be required to take bed rest, at home or in hospital, depending on your situation.