Fertility Blog by Illume Fertility

When Should I Worry About First Trimester Bleeding in Pregnancy?

Written by Monica Moore, MSN, APRN | July 15, 2024

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In this video:

Early Pregnancy Bleeding, Explained

Monica Moore:

Hi, everyone, Monica Moore here. I'm a nurse practitioner and a health coach at Illume Fertility. On this edition of Ask Monica, we're going to answer a pretty common question that is very stressful for anyone who is going through fertility treatments, and even anyone that isn't and is newly pregnant.

Why do people bleed in the first trimester?

As a nurse practitioner, I think the majority of my emergency calls at night are about this specific concern, and I always want to make patients feel better, because it can feel really scary.

3 Common Reasons for First Trimester Bleeding

There are a few reasons that people can bleed in the first trimester of pregnancy, but I think our mind goes straight to the "bad" ones.

Here are three of the most common causes:

  • One is that we never find a reason. We never see anything by ultrasound.
  • There can be a little bit of what we call implantation bleeding, but we do ultrasounds, and everything still looks good [with the pregnancy].
  • There's sometimes bleeding between where the sac or pregnancy has implanted and where the placental attachment is, which is referred to as subchorionic bleeding. Let's talk more about this. 

What is a subchorionic hematoma (SCH)?

Subchorionic bleeding, or you may even hear a scarier-sounding term, subchorionic hematoma (or hemorrhage), is quite common. Even though the word hemorrhage may sound scary, it just means a bleed.

We're able to detect it via ultrasound because it appears black on the screen. Any kind of fluid in the uterus looks that way.


Often, people still do very well after they have had this happen. We would instruct you to rest for 24 hours, minimize activity, and increase fluids, because being dehydrated can sometimes cause the uterus, which is a smooth muscle, to contract.

What you should know: There is nothing that you did that caused this, and there's nothing that you can do that would prevent this from happening, or fix it, so to speak. The recommendation to rest is based on one or two (kind of small) studies that show that it might be helpful.

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When should I worry about early pregnancy bleeding?

Of course, everyone's mind goes to pregnancy loss when they experience first trimester bleeding. And if you have bleeding that is heavy like a period, particularly accompanied by cramping, call Illume's emergency line. If you're ever feeling scared or unsure, call that emergency line. 

If you're bleeding just a little bit and you're not sure what's going on, we want you to rest and call us in the morning. Depending on when we saw you last, and what your hormone levels were, we may have you come in for blood work or an ultrasound to reassure you at that point.

And should anything concerning be happening, we would go over your next steps with you.

Here's the truth: Many people that go on to deliver full-term, healthy babies had bleeding in the first trimester. It's incredibly common. Subchorionic hematomas (SCH) in early pregnancy actually affect between 18–22% of intrauterine pregnancies.

The Odds Are in Your Favor

As I mentioned before, probably the majority of our phone calls, when we're on emergency calls, have to do with this topic, and the majority of women that have this end up having a healthy pregnancy. So, that is actually the default - as opposed to pregnancy loss.

But certainly, if it looks like you're having a pregnancy loss or pregnancy that's implanted in the wrong place, a place other than the uterus, we would see you, manage this, and give you ideas and support - along with next steps.

So I hope that's helpful, and I hope it reassures you in some way. As always, please feel free to ask us any questions, express any concerns, let us know your thoughts or comments below. Thanks so much.

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