What Is an Anterior Placenta?

If you're expecting, you already know that the placenta is a vital part of your pregnancy. This temporary organ has lots of functions, including providing oxygen and nourishment to your growing baby through the umbilical cord, and taking waste away from them.

The placenta can attach to the uterine wall in many different locations. If it's in front of the uterus, close to the abdomen, it's known as an anterior placenta.

Anterior placentas are common, and they don't pose an increased risk to the pregnant person or baby—though the placenta position might make it harder to detect your baby's kicks and heartbeat.

An anterior placenta won't change the shape of your pregnant belly, and it won't make your bump bigger. "An anterior placenta will usually cause no pregnancy or health complications, says Monte Swarup, MD, FACOG, board-certified OB-GYN in Chandler, Arizona, and founder of HPD Rx.

So how do you know if you have an anterior placenta, and what can you expect during pregnancy, labor, and delivery? Keep reading for answers to these questions and more.

What Is the Placenta?

The placenta is an organ that begins developing when the fertilized egg attaches to the uterine wall. Though the placenta is fully formed and functioning by 12 weeks, it continues to grow throughout pregnancy.

The placenta produces hormones to maintain your pregnancy, such as human chorionic gonadotropin (hCG), progesterone, and estrogen. It also connects the parent and baby through the umbilical cord.

Together, the placenta and umbilical cord bring oxygen, nutrients, hormones, and immune protection to your baby. These same structures also take waste away from your baby.

How Common Is an Anterior Placenta?

An anterior placement of the placenta is relatively common. In general, the placenta typically develops wherever the fertilized egg implants on the uterine wall. Up to half of all placentas are in the anterior position, making it one of the most common locations.

Note that the position of your placenta might also change as your uterus expands during pregnancy, which isn't a cause for concern.

Finding Out If You Have an Anterior Placenta

Wondering if you have an anterior placenta? As it turns out, you can't tell your placenta's location just by looking at your belly. The only way to determine placenta positioning is through an ultrasound.

Most pregnant people find out they have an anterior placenta during their anatomy scan around 18 to 21 weeks. In this case, your practitioner will see that the placenta is located in front of your baby.

If you have an ultrasound earlier in your pregnancy, you may find out about an anterior placenta sooner. However, having an anterior placenta on an early ultrasound doesn’t mean that's where the placenta will stay. It's common for the position of the placenta to change as the uterus stretches and grows.

Anterior Placenta vs. Posterior Placenta: What's the Difference?

The placenta can actually take multiple different positions aside from anterior. These include posterior, lateral, fundal, and low-lying.

Note that the placenta can safely attach to the top, sides, front, and back of your uterus. The riskiest position is low-lying, as it can cause placenta previa, which happens when the placenta lies near or over the cervix . This condition can also occur with anterior or posterior placentas, though it's more rare, says Dr. Staci Tanouye, a private practice OB-GYN in Jacksonville, Florida.

Placenta previa makes your pregnancy higher risk, and it often necessitates a C-section because the risk of bleeding excessively is too high.

How an Anterior Placenta May Affect Your Pregnancy

For most of your pregnancy, you're unlikely to notice the placenta, and its location is unlikely to make a difference. However, there are a few factors that might be different if you have an anterior placenta.

Feeling fetal movements

Fetal movements may be harder to feel with an anterior placenta. The first fetal movements are usually detected between weeks 18 to 24, but this may be slightly delayed with an anterior placenta. That's because the placenta forms a cushion between your unborn baby and your belly, which can dampen the force of these kicks.

But you shouldn't think an anterior placenta is causing fewer kicks. It's a good idea to note your unborn baby's typical movements and seek medical attention if they appear reduced.

Hearing your baby's heartbeat

If you have an anterior placenta, fetal heartbeats may be harder to detect with Doppler machines because the placenta blocks the sound waves. But again, this isn't usually a cause for concern, and your technician will have experience navigating the situation.

Getting Diagnostic Tests

Some pregnant people get an amniocentesis; the diagnostic test involves taking a sample of your amniotic fluid with a needle for further testing. Having an anterior placenta can make amniocentesis difficult, though your care team can use ultrasound to make sure your placenta isn't harmed.

Possible increased risk of complications

Having an anterior placenta isn't cause for concern, and most pregnancies progress without any complications. That said, some studies have linked the positioning to an increased risk of certain pregnancy complications, including the following:

• C-section
• Induced labor
• Back labor — Often because the baby is in the occiput posterior position (head down but facing your stomach instead of your back)
• Gestational diabetes
• Placental abruption
• Placenta previa
• Intrauterine growth restriction
• Pregnancy-induced hypertension

Does Anterior Placenta Affect Delivery?

In most cases, an anterior placenta doesn't have a huge impact on your labor or delivery. Your contractions won't feel any different, and your birthing experience isn't likely to be affected.

Both vaginal and C-sections are considered safe. If you have a C-section, your doctor will use ultrasound to find the best incision location. Delivery problems might only arise if your placenta is partly or fully covering the cervix in a low-lying position.

When to Seek Medical Care

An anterior placenta isn't' cause for concern during your pregnancy. If you experience any of these symptoms, it's a good idea to seek immediate medical care.

• Fewer fetal movements or none at all
• Pain in your abdomen
• Vaginal bleeding
• Constant or fast contractions
• Severe back pain
• Firmness or rigidity of your abdomen