Implantation bleeding is rust-colored, light spotting.

By comparison, your period is a steady, light to heavy flow of bright to dark red blood.

Implantation bleeding triggers when youre pregnant, while your period triggers when youre not pregnant.

A woman choosing pads or tampons at a store

ShotShare/ Getty Images

ShotShare/ Getty Images

What Is Implantation Bleeding?

It is a very early sign ofpregnancy.

Each month an egg is released from theovaryand travels through thefallopian tube.

When the egg becomes fertilized bysperm, it starts to divide into multiple cells.

These cells travel to the uterus and implant in the endometrium.

When Does Implantation Bleeding Happen?

The ovaries release an egg (ovulate) 14 days before the start of your menstrual period.

Even if your monthly cycles are irregular, you still ovulate 14 days before your period starts.

This is when fertilization can occur.However, the egg can only be fertilized for 12-14 of those 30 hours.

If a sperm penetrates the egg, the fertilized egg starts cell division and growth.

Within seven days, the single-cell embryo has grown into a cluster of highly organized cells (blastocyst).

When that happens, the blastocyst finishes going through the fallopian tube.

After reaching the uterus, it starts to implant, which can take several days.

If you havent tracked your period before, begin by noting the day each menstrual cycle begins and ends.

Pregnancy tests detect the hormonehuman 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.

Will a Pregnancy Test Be Positive During Implantation Bleeding?

Implantation bleeding happens very early on in pregnancy.

Other Causes of Bleeding

Bleedingmay occur 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.

Your provider will help you determine if your bleeding is concerning and requires medical care.

Generally speaking, it’s best to contact a healthcare provider any time you have unexpected vaginal bleeding.

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.

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