What Are Implantation Cramps?

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Implantation cramps can occur in very early pregnancy when the fertilized egg attaches to the uterine lining. This implantation often occurs around the time when your period would occur (six to 10 days after ovulation). So it is sometimes mistaken for menstrual cramps. In addition, light spotting, known as implantation bleeding, can also occur when this happens.

Not everyone experiences symptoms of implantation, and it’s not clear how often symptoms are noticeable. But according to the American College of Obstetricians and Gynecologists (ACOG), between 15% and 25% of people experience bleeding in the first trimester. Some of those are the result of implantation. 

This article explains the cause, symptoms, and complications of implantation cramps.

stomach cramps

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Cause

After sperm fertilizes an egg, the egg travels down the fallopian tube. The zygote’s journey from the fallopian tube to the uterus is brief, lasting only a few days. During its time in the fallopian tube, a zygote undergoes rapid cell divisions. 

When it arrives at the uterus, it is a blastocyst, ready to implant into the endometrium. Once implanted, this group of cells will eventually become an embryo.

Implantation cramps may occur when the blastocyst burrows into the lining of the uterus. During this process, hormones cause the uterus to contract. Some people experience these contractions as a cramping sensation.

Symptoms

Everyone experiences implantation differently. Many people notice nothing at all, while others experience cramps, light bleeding, or both. If you do experience signs of implantation, you may notice the following: 

  • Cramps that feel like mild menstrual cramps
  • A tingling sensation
  • Spotting

One-sided pain can indicate an ectopic pregnancy. This situation is a medical emergency. So if you notice severe pain or you experience one-sided cramping, seek medical attention right away.

Implantation Cramps vs. Other Cramps


Implantation isn’t the only thing that can cause cramping. Several situations can mimic implantation cramps. So it’s a good idea to be familiar with those circumstances to know how they differ from implantation cramps.

Menstrual Cramps

Since implantation often occurs before or around the time someone learns they are pregnant, it’s possible that what you think are period cramps are implantation cramps (or vice versa). 

Menstrual cramps sometimes occur in the days leading up to your period. These cramps may feel very similar to implantation cramps. 

If cramping is from your menstrual cycle, you would expect the usual amount of menstrual bleeding to accompany or shortly follow your cramps. However, if your bleeding is spotting or lighter than expected, you might consider taking a pregnancy test

Pregnancy tests are most accurate if taken one to two weeks after your missed period.

Miscarriage

A very early miscarriage is pregnancy loss that occurs before the fifth week of pregnancy. At this stage, most people don't yet know they are pregnant, which is why people often do not know when they are having a very early miscarriage. This bleeding is sometimes mistaken for a regular period.

Very early miscarriage is also called a chemical pregnancy. Researchers believe that very early miscarriages occur between 8% and 33% of the time. However, it is difficult to know for sure since many people do not realize they are pregnant when these very early miscarriages happen.

Signs of a very early miscarriage are similar to those of a menstrual period. They include:

  • Abdominal cramps
  • Bleeding
  • Low back pain

Ectopic Pregnancy

An ectopic pregnancy occurs outside of the uterus, usually in the fallopian tube. An ectopic pregnancy is a medical emergency. That’s because as a fertilized egg grows, the fallopian tube can burst and lead to life-threatening blood loss.

The early symptoms of an ectopic pregnancy are similar to those of implantation. They include cramping and bleeding. In addition, though, if your fallopian tube bursts, you may notice further symptoms, including:

  • Sharp pain in the lower abdomen on one side
  • Fainting
  • Low blood pressure
  • Shoulder pain
  • Pressure in the rectum

Ectopic pregnancy is a medical emergency. It is the leading cause of maternal mortality in the first trimester and accounts for 4% of pregnancy-related deaths. For this reason, it is critical to seek immediate medical attention if you experience symptoms of ectopic pregnancy.

Ovulation Pain

Some people experience cramping when they ovulate. This type of cramping is usually discernible from implantation cramping because ovulation typically occurs a couple of weeks before implantation. However, if you have irregular menstrual cycles, telling them apart may be a little more complicated.

Ovulation cramping is similar to implantation cramping in that its main symptoms are mild abdominal pain and spotting. However, the main difference between the two (aside from the timing) is that ovulation cramps may be more one-sided.

Known as "Mittelschmerz," ovulation pain affects more than 40% of menstruating people.

Complications

Implantation and its associated symptoms are not an emergency. However, implantation symptoms can sometimes overlap with those of other conditions that require medical attention. 

If you think you may be pregnant or have been pregnant in the past year and are also experiencing dizziness, fainting, high fever, changes in vision, or swelling of the hands and face, seek medical care immediately.

Summary

Some people experience mild bleeding known as implantation bleeding when they first become pregnant. They may also have mild cramping. However, some people will not notice or experience these symptoms.

It's important to distinguish bleeding caused by implantation from that caused by an ectopic pregnancy or miscarriage. If you have heavy bleeding and other symptoms like severe abdominal pain and nausea or vomiting, call your doctor right away.

A Word From Verywell

If you are hoping to be pregnant but haven't experienced implantation cramps, you may be anxious that you're not pregnant. However, take heart that many people with healthy pregnancies do not experience implantation cramps.

On the other hand, if you are experiencing cramps that do not appear related to your menstrual cycle, you may be wondering if you are pregnant or if something is wrong. Rest assured that often mild cramping is not a sign of something serious. But it is a good idea to be aware of the different things that can cause camping. Some do require medical attention.

Some other things that may cause cramping around the time of your expected period are pre-period cramps, a very early miscarriage, ovulation pain (if your periods are irregular), and ectopic pregnancy. If you notice any warning signs, like a sharp pain, one-sided pain, fainting, or dizziness, seek medical attention right away.

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14 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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