Having an anterior placenta means that your placenta is positioned in the front of your uterus closest to your abdomen. It is common during pregnancy and usually not a cause for concern. It is diagnosed during an ultrasound at around 18 to 21 weeks of pregnancy.
Your placenta forms where a fertilized egg implants in your uterine wall. It takes nutrients, hormones and oxygen from you to your baby via the umbilical cord. It also removes waste from your baby. The placenta usually grows on the back or top of your uterus, but in the case of an anterior placenta, the placenta grows at the front of your uterus. Think of an anterior placenta like a cushion between your belly and your baby.
The placenta can move as your belly grows, which means your placenta can start in the front, but move towards the top of your uterus as your pregnancy progresses. An anterior placenta does not cause any health problems for you or your baby. In most cases, you will not notice any effects of an anterior placenta.
Why do some people have an anterior placenta?
It is not known why a fertilized egg implants in the front of the uterus as opposed to other locations in the uterus. The front wall of the uterus is still a normal place for an egg to implant and for the placenta to develop. It does not impact the placentas ability to do its job of providing nourishment to your baby.
How common is an anterior placenta?
An anterior placenta is common. The placenta will be in the front of the uterus in up to 50% of all pregnancies. One study showed anterior placentas appear to be more common in people with o-positive blood. Another found that sleeping on your stomach during conception may have something to do with the fertilized egg implanting on the front of your body. There needs to be more scientific evidence to confirm either of these studies.
What is the difference between an anterior and posterior placenta?
The placenta grows in the uterus at the location of implantation (where the fertilized egg attaches to the uterine wall). There are several locations where a placenta can form during pregnancy:
- Posterior: Closest to your spine. In the back of your uterus.
- Anterior: Front of your uterus. Nearest your abdominal area.
- Low-lying: Towards the bottom of your uterus. Covering all or part of your cervix.
- Lateral: On the left or right side of your uterus.
- Fundal: At the top of your uterus.
How will an anterior placenta affect pregnancy?
Having an anterior placenta does not hurt your baby in any way. The biggest impact it can have on your pregnancy is taking longer to feel your baby kick. For that same reason, it might be harder to find your babys heartbeat during a Doppler ultrasound or make certain fetal tests (like amniocentesis) a challenge.
Symptoms and Causes
What are the symptoms of an anterior placenta?
Having an anterior placenta does not cause a lot of symptoms and is not something to worry about most of the time. Some noticeable signs of an anterior placenta are:
- Babys heart rate: It may take longer for your healthcare provider to detect the babys heartbeat with a Doppler ultrasound. The doppler is moved across your belly to detect your babys heart rate. It can take longer because the placenta is between your baby and the Doppler.
- Babys movement: You may feel kicks or punches later than people who have posterior placentas. Most people feel kicks around 18 weeks of pregnancy, but people with anterior placentas may not feel kicks until after 20 weeks. They can also feel weaker or softer because the placenta is acting as a barrier between your baby and your belly.
What causes an anterior placenta?
An anterior placenta is not caused by anything you can control. Once an egg is fertilized, it will implant on the walls of the uterus. This is where your placenta will grow. The placenta growing in the front of the uterus does not affect its function or how your pregnancy is treated.
Are there any risks of having an anterior placenta?
There are risks associated with having an anterior placenta. Most of the risks do not pose a threat to you or your baby:
- Placenta previa: This is when your placenta covers part or all of your cervix. It can cause mild to heavy vaginal bleeding and cause complications.
- C-section: If you have placenta previa, you are more likely to have a cesarean delivery (c-section) because the placenta blocks your baby from exiting your vagina.
- Back labor: Having an anterior placenta increases the chances of having your baby being in the OP position (occiput posterior). This means your babys head is down, but their back is against your back — meaning their face is up. This can cause longer labor and more pain in your back.
What does baby movement feel like with an anterior placenta?
When you have an anterior placenta, it can be harder to feel your baby kick, punch or move around. This is because the placenta acts as a buffer between your belly and your baby. It is common to not feel kicks until after 20 weeks of pregnancy. This is because before 20 weeks your baby may not kick strong enough for you to feel it through the placenta.
Is your belly bigger when you have an anterior placenta?
The shape or size of your belly should not change when you have an anterior placenta. The placenta is a relatively thin organ, so the shape or size of your belly should not be impacted.
Diagnosis and Tests
How is an anterior placenta diagnosed?
Your healthcare provider will determine the location of the placenta during an ultrasound. This ultrasound is done around 18 to 21 weeks of pregnancy and is sometimes referred to as an anatomy scan. This ultrasound measures the size of your baby and all its organs. It is common for the placenta to change positions as the uterus expands, so an anterior placenta is not diagnosed until around 20 weeks.
Management and Treatment
Is there a treatment for an anterior placenta?
There is no treatment for an anterior placenta because it does not usually cause complications. Treatment is only necessary if you have placenta previa or other pregnancy conditions.
Can you still have a vaginal delivery with an anterior placenta?
Yes, you can still have a vaginal delivery with an anterior placenta. Having an anterior placenta does not impact your delivery. The only time your vaginal delivery can be affected is if you have placenta previa.
Does an anterior placenta affect c-section delivery?
No, your c-section is not affected by an anterior placenta. Your healthcare provider will use an ultrasound to locate the position of the placenta and find the best spot to make the incision.
Prevention
How can I reduce my risk of having an anterior placenta?
There is nothing you can do to reduce your risk of having an anterior placenta. Your placenta will grow where your fertilized egg implants in your uterine lining.
Outlook / Prognosis
What can I expect if I have an anterior placenta?
The most challenging part of having an anterior placenta is not feeling your babys movements. If you are a first-time mom, you may wonder why you do not feel kicks as early or as strong as you expected. You might feel anxious waiting to feel your baby move. You may eventually forget you have an anterior placenta because it does not cause any problems.
Can an anterior placenta fix itself?
Yes, an anterior placenta can fix itself by moving locations as your pregnancy progresses. As your uterus expands to accommodate your growing baby, the placenta naturally shifts. Your healthcare provider will not check for an anterior placenta again unless it was covering part of your cervix.
When should I see my healthcare provider?
You should contact your healthcare provider if you notice these symptoms:
- Vaginal bleeding.
- Contractions.
- Severe back or abdominal pain.
- You feel your baby move less.
What questions should I ask my doctor?
When you are told you have an anterior placenta, some questions to ask your healthcare provider are:
- Is my baby OK?
- Does this affect my delivery?
- Do I need to change anything I am doing?
- Will I need treatment for an anterior placenta?
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