Are you experiencing some spotting and wondering whether it’s implantation bleeding? Or maybe your period is a day or so late, and you think you may be pregnant.
If so, you’re probably wondering how soon you can do a pregnancy test after implantation.
We’ve been there. We know how slowly time passes when you’re waiting to find out if you’re pregnant. Every day feels like a week! But testing too early often leads to false results and disappointment. There are good reasons for holding off on testing for a couple of days.
Let’s look at what a pregnancy test detects and how soon you can test after implantation.
- Implantation is when a fertilized egg attaches to the uterus lining, and can cause light bleeding, known as implantation bleeding.
- Pregnancy tests detect the hormone HCG, which increases after implantation. Urine tests are common, but blood tests can detect HCG earlier.
- It’s generally best to wait about 7 days after a missed period to take a pregnancy test for more accurate results.
- False negatives can occur if testing too early, checking the test too soon, or having diluted urine. If unsure, test again after a few days or consult a doctor.
What Is Implantation?
Following fertilization, the egg travels down the fallopian tube to the uterus. The uterine lining, or endometrium, is ready to accept the fertilized egg. This journey usually takes about six to eight days to happen.
On reaching the waiting uterus, the egg attaches itself and then burrows its way into the lining, preparing to grow. This implantation takes a few days to complete and can sometimes cause some light bleeding (1).
Is It Implantation Bleeding or a Period?
It’s important to note that not all women will experience signs like bleeding or cramps to indicate implantation has happened. Every woman and every pregnancy is different.
- Color and texture: Discharge or spotting from implantation bleeding will generally be dark brown or pinkish. Period blood will often be a vibrant red. There are usually no clots associated with implantation bleeding.
- Length of time you bleed: Implantation bleelasts only from a few hours to a few days while the egg attaches itself. It will usually be light and can stop and start. If your bleeding starts off light but then gets heavier and lasts for four days or more, it’s likely your period.
- The time between ovulation and bleeding: Implantation bleeding will generally happen roughly ten days after ovulation: A period will usually be 14 days after.
- Cramping: Cramps associated with implantation are mild and go away quite quickly. Those associated with a period will be stronger.
What Happens After Implantation?
Let’s explore what happens with hormones after the ovary releases an egg.
During a woman’s monthly cycle, an egg leaves the ovary, but the shell that contained the egg remains, called the corpus luteum. This is responsible for releasing the hormones estrogen and progesterone. It’s the progesterone that we’re interested in here, as it signals the lining of the uterus to prepare itself to receive a fertilized egg.
If the egg does not implant, the progesterone levels drop again, and the uterine lining comes away, resulting in your monthly period. This takes place about two weeks after ovulation.
If implantation happens, the uterus needs to signal the corpus luteum to continue producing progesterone to maintain the uterine lining. This is done by the newly forming placenta releasing a hormone called “human chorionic gonadotropin,” or HCG.
All women have small traces of HCG in their bodies at all times, but after implantation, these levels rise. HCG is the hormone that is tested to indicate a pregnancy.
The amount of HCG typically found in the body won’t be enough to give a positive test. However, during the first eight weeks of pregnancy, HCG levels double every couple of days (3).
So while the waiting game might not be an easy one, just a few days can make a difference between a positive and negative test.
Methods of Pregnancy Testing
There are two ways of testing for HCG levels: urine or blood.
1. Urine Tests for HCG
Home pregnancy tests have improved over the years and are now sensitive enough to detect small amounts of HCG in your urine. The sensitivity of the test is indicated on the packaging as an amount in mlU/ml (milli-international unit per milliliter).
The lower the number of mlU/ml, the more sensitive the testing kit is. The range is usually between 10mIU/ml and 50 mIU/ml.
However, that is unusual, and it generally takes about 10 or more days after ovulation for a test to show a positive result.
Even using the most sensitive of these tests, there might not be enough HCG to be detected yet. This can result in a false negative test, which may be upsetting.
If you do have a negative test, wait a few days and test again. (Or, if you’re like me, test daily until you are sure of your result.) Your urine hormone levels will eventually rise enough for the test to detect a pregnancy if you are, in fact, pregnant.
2. Blood Tests for HCG
HCG can be detected in your blood a lot sooner than in urine. A positive blood test might be detected as soon as six to eight days after conception.
You need to visit your doctor to have a blood test, but they will likely advise you to wait until after your missed period.
Even if you do a home pregnancy test and get a positive result, your doctor may still do a blood test to confirm this.
How Soon After Implantation Should I Take a Pregnancy Test?
There is no definitive time for when you should take a pregnancy test after implantation. While you can take a test as soon as the first day of your missed period, it might be better to wait a week more. Many factors come into play as to how accurate the result might be.
You might have conceived at the beginning of ovulation. In this case, you will likely get a positive test earlier than if you conceived at the end of ovulation.
You might not know that implantation has taken place. Not all women experience implantation bleeding or any other symptoms indicating that it has occurred.
Sometimes, a negative test might happen, even if you are convinced you have had implantation bleeding. These include ectopic pregnancies and tumors.
Many women have irregular cycles due to stress, illness, or normal fluctuations. Timing can be unpredictable, even if your periods are regular. Nearly 70% of women reach their fertile window earlier or later than expected. This will impact when HCG is detectable in your urine. If you ovulate one week later than anticipated, you will need to wait an extra week to get a positive pregnancy test (5).
Editor's Note:Caitlin Goodwin, MSN, RN, CNM
What looks like implantation bleeding is sometimes unrelated luteal phase spotting caused by a second surge of estrogen. Many women experience this completely normal spotting without being pregnant, and many women become pregnant and never experience any implantation bleeding.
False Negative Pregnancy Tests
When you’re trying to get pregnant, the urge to test can be hard to resist. If you take a test and get a negative result, you could still be pregnant. These are some reasons you might get a negative result (6):
- You tested too early: The HCG levels in your urine might not have risen enough to be detected in your urine yet. Ideally, you should wait about seven days after a missed period to do a test. This way, the HCG levels will have increased, and that much-awaited “you’re pregnant!” indicator will be there.
- You checked the test too soon: Follow the instructions carefully on the test, and give it the time needed — usually a minute or more — to do its work.
- Your urine was too diluted: The best time to take a pregnancy test is with your first urine of the day. The HCG levels will likely have built up overnight and can be detected easier.
If your test is negative, wait a few days, then test again, particularly if you tested before or soon after a missed period. If you feel you are pregnant and are still getting negative test results or still don’t get a period after a week, then see your doctor.
Your doctor will probably do a blood test or an ultrasound scan to confirm a pregnancy or help discover the cause of your missed period.
To Test or Not to Test
Many pregnancy tests claim to be accurate from the first day of your missed period, or even earlier. This might not always be the case and you only put yourself through the unnecessary upset that comes with a negative test.
Everyone differs in how quickly or how much HCG they produce after implantation, so now is the time to practice patience. Try to resist peeing on that stick, even though the little devil on your shoulder will be whispering in your ear, “do it.”