Let’s take a deep dive into implantation bleeding and other early signs of pregnancy. 

By Dr. Mare Mbaye

We all know the basics of how conception works: have vaginal sexual intercourse, wait for the sperm and egg to join and create an embryo, the embryo grows into a fetus, and voila, hello baby! While this may appear to be a simple process, there’s so much more at play here. Let’s fill in the gaps in human reproduction a bit, starting with when the sperm meets the egg.

What is implantation 

Maybe you remember the word “implantation” from your high school sex ed classes years ago but are a little fuzzy on what it means now. Implantation refers to the fertilized egg (or embryo) burrowing into the uterine lining, where it can safely grow, about 7-10 days post-fertilization.

Through a complex system of hormonal signals between the female reproductive system and the brain, the body cyclically grows the uterine lining (endometrium) that would be needed to support a pregnancy. When you’re not pregnant and are on your period, you’re shedding the uterine lining that your body had prepared for the fertilized egg.

Yes, you can be pregnant and have some bleeding 

Many women experience “implantation bleeding” when the fertilized egg implants. It happens because a small portion of that uterine lining might detach and shed during the process of implantation.

It can be confusing because it looks very similar to a light period—it’s spotting right around the time when you usually would get your period. Given this light bleeding, you might understandably think that you’re not pregnant. However, one distinguishing factor that may help is that implantation bleeding should be much lighter in quantity than your normal period.

One distinguishing factor that may help is that implantation bleeding should be much lighter in quantity than your typical period.

When implantation bleeding happens

Implantation bleeding is totally normal and nothing to be concerned about. As we said above, it generally happens 6-12 days post-fertilization, or around the time of your expected period. If you are beyond that timeframe, it is not likely implantation bleeding. There are other types of vaginal bleeding that can happen during pregnancy. In fact, about 20% of women have some bleeding during the first 12 weeks of pregnancy. If you are already pregnant and experiencing vaginal bleeding, talk to your doctor. 

Here’s how to figure out when implantation happens

Other common signs of implantation can include: light cramping (like the bleeding, it’ll feel like what you experience with a regular period, but less intense), mood swings, breast tenderness, nausea and pain in your lower back. Many of these symptoms result from the higher levels of progesterone circulating in your body, which increases to help support the pregnancy (just remember that pro-gesterone is pro-gestation). Keep in mind, these symptoms can be similar to premenstrual syndrome (PMS) or other symptoms that occur between ovulation and a period (known as the luteal phase). 

The bottom line

The bottom line here? If you don’t know about the signs of implantation beforehand, you might just think you’re having an unusually light period. While first trimester miscarriages are common, occurring in 10% of all clinically recognized pregnancies, spotting and light episodes are not associated with a higher risk of miscarriage, especially if they only last one to two days. However, if you have heavy bleeding, particularly if accompanied by pain, that is associated with a higher risk of miscarriage and you should see your provider.

A pregnancy test can often help you in figuring out what’s happening. Implantation cues the production of a pregnancy hormone called human chorionic gonadotropin (hCG), which an at-home pregnancy test detects in urine as soon as three to four days after implantation. By seven days post-implantation (the time of the expected period), 98% of tests should be positive.

However, taking the pregnancy test too soon—either before implantation has happened or when the hCG levels aren’t high enough for a pregnancy test to detect them yet—can result in a false-negative result. If you think you could be pregnant but a pregnancy test is showing a negative result before your expected normal period, it’s worth trying again anywhere from a few days to a week later to see if anything changes.

Taking the pregnancy test too soon—either before implantation has happened, or when the hCG levels aren’t high enough for a pregnancy test to detect them yet—can result in a false-negative result.

Once you get a positive pregnancy test, you’ve passed a major milestone: you were able to get pregnant! This is a big feat in and of itself if you consider that only 15 – 20% of healthy people under the age of 35 get pregnant during a month of trying to conceive with vaginal intercourse

There are a few things you’ll want to think about now: call your OBGYN office to see when they recommend scheduling a prenatal visit. Six to eight weeks into a pregnancy is usually the preferred time frame since that is one of the best times to confirm pregnancy by ultrasound. This ultrasound is used to identify your due date and to confirm that implantation occurred in the uterus and not in one of the fallopian tubes or another site in the abdomen—an emergency situation called an ectopic pregnancy. 

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What else can you do moving forward? Make sure you’re taking your daily prenatal vitamins and have optimized other lifestyle choices like not smoking or drinking and eating healthy, nutritious food. 

Some people advise not to actually start buying anything until later in the pregnancy to make sure it’s proceeding normally, but there is nothing cuter than tiny baby clothes (except maybe baby animals) so we wouldn’t blame you if you embarked on a little daydreaming during the first few weeks of your pregnancy. 

Featured image by Erol Ahmed