What You Need to Know about Low Lying Placentas and Placenta Previas

Tuesday, January 24, 2023

A few days ago, a beautiful prenatal yoga teacher in our community reached out and asked if we're seeing an increase in folks with low lying placenta. The short answer, is no. But we wanted to share our longer answer with you because we occasionally get questions from folks wondering if they should still book a childbirth education class or hire a doula if they're diagnosed with Low-Lying Placenta or Placenta Previa. (The short answer is yes!)

Wait, what is the placenta, exactly?

The placenta plays a fascinating and critical role in the the process of growing and birthing a human.

Biologically, the placenta is an organ you grow from scratch to sustain your baby during pregnancy. It’s the connection from parental body to baby body. Interwoven into the uterus via blood vessels, the placenta produces essential hormones responsible for growth, circulates oxygenated blood, and carries waste products away from the the fetus.

Metaphorically, as Angela Garbes’ wrote, in _Like A Mother,_ the placenta is “the site of the first communication and cooperation between [parent] and child, but also their first conflicts and negotiations… this conduit connects the present, past, and future.”

What is low lying placenta?

A typical placenta typically develops in the upper uterine segment. Like this:

This is ideal, because it is out of the way of the lower section of the uterus, or the cervix.

Low lying placenta, or placenta previa, is when the placenta has developed in the lower uterine segment and is very near, partially covering, or fully covering the cervix. Like this:

In the case of partial or full placenta previa at the time of labor, the placenta is covering the cervix and therefore the fetus has no exit.

To be safe, providers are typically looking for the placental edge to be at least 2cm away from the cervical opening in order to decrease the risk of complications during labor.

How do I know I have low lying placenta?

Low-lying placenta or placenta previa is diagnosed through prenatal ultrasounds. Most people will be asymptomatic though some will experience spotting.

Physiologically, we know that, of the 2% of pregnancies diagnosed with previa before or at the 20 week anatomy scan, 90% will resolve before delivery. Only .4% of pregnancies will have previa at term (37 weeks).

Why do such a high percentage resolve on their own? For most people, as the uterus grows, the placenta will naturally pull away from the cervix. And, if you’re wondering, there is nothing you can do on your own to encourage the placenta to move out of the way.

Is low lying placenta or placenta previa more common than it used to be?

Not necessarily! This really comes down to our societal context. There is more imaging being done than ever before, and so it’s not uncommon to be diagnosed with low lying placenta during a 16 or 20 week ultrasound.

More frequent imaging is especially common for pregnant folks who are over 35 or in a high-risk category but is more common than it used to be even for low-risk pregnancies. With more imaging comes more discoveries!

Should I be concerned?

We know that placenta previa is more common in people who have had previous pregnancies, previous Cesarean or other uterine surgery, for people who smoke, and for those carrying multiples. If you fall into one of these categories you can chat with your provider about your choices since, in the very low chance of having previa at term, birth by Cesarean section would be medically indicated.

Since most of the time, placenta previa resolves on it’s own, many birth preferences will remain an option! We often hear that student do not want to register for a childbirth class or hire a doula because of an ultrasound diagnosis at week 20. But, we strongly encourage you to keep an open mind and plan for a vaginal birth in anyway you would otherwise. Scrambling at the last minute can feel very disconcerting.

Want to learn more? Schedule a consultation with someone from the Birthsmarter team, and check out our Childbirth Education Classes, On-Demand, Live-Online, or IRL in NYC, SLC or Phoenix.

Find live, virtual & on-demand classes and support groups near you:

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