Implantation Bleeding vs. Periods

Implantation bleeding, which happens before a person knows they are pregnant, may be confused with menstrual bleeding. Implantation bleeding usually occurs about six to 12 days after fertilization and does not mean anything is wrong. 

While implantation bleeding does not require medical care, it is important to alert your healthcare provider whenever you experience bleeding while pregnant.

This article discusses implantation bleeding and how it compares to menstrual bleeding.

A woman choosing pads or tampons at a store

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What Is Implantation Bleeding?

Implantation bleeding is light vaginal bleeding or spotting when a fertilized egg implants into the lining of the uterus (endometrium). It is a very early sign of pregnancy.

Each month an egg is released from the ovary and travels through the fallopian tube. When the egg becomes fertilized by sperm, it starts to divide into multiple cells. These cells travel to the uterus and implant in the endometrium. The endometrium has many blood vessels, so it is possible for bleeding to occur as the egg attaches to the lining.

It’s estimated that about 15% to 25% of pregnant people experience first-trimester bleeding.

Implantation Bleeding Signs and Appearance

Implantation bleeding appears as light vaginal bleeding or spotting. You may notice a blood-tinged discharge or a pink color when you wipe after using the bathroom. Implantation bleeding is much lighter than menstrual bleeding.

Other signs of early pregnancy that may occur with implantation bleeding include:

  • Cramping
  • Headache
  • Fatigue
  • Nausea
  • Breast tenderness
  • Mood changes

Timing and Length

Implantation bleeding may last for a few hours or a couple of days. It often comes and goes, and the bleeding is very light.

It happens at a certain point during the menstrual cycle. This bleeding usually occurs between days 20 and 24 if you have a 28-day cycle. It is also possible to become pregnant and not experience any bleeding.

Period bleeding starts on the first day of your cycle. If you notice that you are having light bleeding or spotting earlier than your period usually occurs, it could be implantation bleeding.

How to Tell the Difference Between Implantation and Period Bleeding

Implantation and period bleeding may appear similar, but some key differences exist. First, implantation bleeding is light. It is often only noticeable when you wipe after using the bathroom. The color of implantation bleeding is usually light pink or rust.

Menstrual bleeding is heavier than implantation bleeding. The bleeding is usually bright or dark red and can be thick in consistency.

Both early pregnancy and premenstrual syndrome (PMS) can cause symptoms such as bloating, headaches, and mood changes. 

The only way to know if you are pregnant is to take a pregnancy test. Pregnancy tests detect the hormone chorionic gonadotropin (hCG). This hormone is made when the fertilized egg implants in the uterus. The production of hCG rapidly builds up each day in early pregnancy. Taking a pregnancy test one week after your missed period is best for the earliest detection.

How Much Blood Is Normal for Implantation Bleeding?

Implantation bleeding is very light. It may appear as spotting or rust-colored discharge, which you may notice after using the bathroom. It is likely your period if you experience heavier bleeding. If you are unsure of the cause of your bleeding, see your healthcare provider.

Other Causes of Bleeding During Pregnancy

Bleeding may occur in early or late in pregnancy. It may be harmless, or it could signal a serious problem. Bleeding in the first trimester happens in about 15 to 25 out of every 100 pregnancies. 

In early pregnancy, an increase in blood vessels occurs in the cervix. This can raise the likelihood of light bleeding or spotting after sex or a pelvic exam. Possible causes of vaginal bleeding during early pregnancy may include:

Possible causes of vaginal bleeding in later pregnancy may include:

  • Inflammation of the cervix
  • Problem with the placenta
  • Preterm labor

When to Seek Medical Care

Implantation bleeding is not serious and does not require medical care. However, it is important to alert your healthcare provider any time you experience bleeding when you are pregnant. Your provider will help you determine if your bleeding is concerning and requires medical care.

Summary

Implantation bleeding is light vaginal bleeding or spotting when a fertilized egg implants into the uterine lining. It often appears as a pink or rust-colored discharge. Implantation bleeding occurs around days 20 to 24 in a 28-day cycle.

Menstrual bleeding during your period is usually heavier and happens on the first day of your cycle. Period bleeding usually appears bright or dark red. To know if you are pregnant, take a pregnancy test about one week after your missed period. 

Frequently Asked Questions

  • Will a pregnancy test be positive during implantation bleeding?

    Implantation bleeding occurs very early in pregnancy. Because this type of bleeding happens before a missed period, a pregnancy test will likely not be able to detect the pregnancy yet. This is because the uterus does not start producing increased levels of hCG until the fertilized egg is attached to the endometrium, and the hCG level increases daily. 

  • Can implantation bleeding feel like a period?

    Implantation bleeding and other early pregnancy symptoms may feel like a period. In addition to bleeding, you may notice fatigue, headaches, and mood changes. However, implantation bleeding is much lighter than menstrual bleeding. 

  • How close to your period can implantation occur?

    Implantation usually occurs during days 20 to 24 of the menstrual cycle if your cycle is 28 days long. The menstrual period begins on the first day of the cycle.

6 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.
  1. Hendriks E, MacNaughton H, MacKenzie MC. First trimester bleeding: evaluation and management. Am Fam Physician. 2019;99(3):166-174.

  2. American College of Obstetricians and Gynecologists. Bleeding during pregnancy.

  3. Office on Women’s Health. Knowing if you are pregnant.

  4. Committee opinion no 700: methods for estimating the due date. Obstetrics & Gynecology. 2017;129(5):e150-e154. doi:10.1097/aog.0000000000002046

  5. Office on Women’s Health. Your menstrual cycle.

  6. Office on Women’s Health. Premenstrual syndrome (PMS).

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.