33 day cycle when can i test for pregnancy

If you’re trying to get pregnant, the best time to take a pregnancy test is one week after you’ve missed your period. Why? Because this is really the best way to prevent a false negative result (a negative test in someone who's actually pregnant) result.

Home pregnancy tests can be used as early as the first day after your first missed period in women with regular/predictable monthly menses. If you have irregular periods, you can administer a test 14 days after intercourse, since you likely can’t pinpoint your exact time of ovulation.

Pregnancy tests detect a hormone called human chorionic gonadotropin (HCG), which is produced in early pregnancy. The production of this hormone begins slowly and increases as the pregnancy grows. Standard urine pregnancy tests will detect the HCG level when it reaches 20-50 milliunits/milliliters.

If you take a test too soon (before you've missed your period), the levels of HCG may not be high enough to detect a pregnancy and it could cause a negative result, even though you're actually pregnant.

I advise my patients to wait at least one day after you miss your period. If you wait one week after a missed period, the chance of a false negative is very low if you have a normal monthly menstrual cycle.

Brand name versus generic pregnancy tests

Home pregnancy tests, both brand name and generic, are very accurate at detecting the HCG hormone and any positive result, even a faint line, can be considered positive. HCG is only produced by a pregnancy; any positive result indicates a pregnancy.

You don’t need a serum (blood) pregnancy test to confirm pregnancy. Both urine and blood detect HCG, although the blood test is more sensitive and can detect HCG levels at much lower levels than a urine test. In certain situations, your doctor may want to perform a blood HCG test but it’s not typically needed to confirm a pregnancy.

Although most tests advertise 99% accuracy, the ability of a particular brand to detect HCG at levels less than 50 ml may vary. Some brands may be better able to detect lower levels of HCG than others. If your HCG level is more than 50 ml, which is the detection rate of most tests, even generic tests will detect a pregnancy accurately.

A positive pregnancy test will usually show up around the time of your missed period, on average 14 days after ovulation/fertilization, and rarely earlier than 9-10 days after fertilization/ovulation. Even if the pregnancy test is negative, there is still a chance of getting a positive pregnancy test later on. 

Improve your fertility and get pregnant faster

Obie is your reproductive health coach, helping you reach your goal with expert personalized guidance.

Not an iOS user? Sign up to be the first to know about Obie for Android.

A pregnancy test, no matter if it's blood or urine, only becomes positive after implantation, when the fetus has attached to the uterine wall and connects with the mother's blood system. Implantation, when the fertilized egg implants into the endometrium, happens about 9 days after ovulation and fertilization (range: 6-12 days). The blood pregnancy test will be positive 2-3 days after implantation and the urine test will be positive several days after the blood test has become positive.

When is the early pregnancy test positive?

An early urine pregnancy test will not show up positive until there is enough hCG, the pregnancy hormone, in your body. This hormone isn't even present until several days after the fertilized egg implants into your uterus. Implantation happens 6-12 days after you ovulate. It isn't detectable until around the time of your period (some women don't get a positive result until days after a missed period). While other women are able to take an early pregnancy test (like First Response) a couple of days before their period is due and get a positive test. However, that is not the case for MOST women. Have you ever heard of a "false negative"? It's when you ARE pregnant, but get a negative test and then test a few days later and get a positive. That's what happens most of the time when women test before their periods.

First Response (the test that advertises "99% accurate. Our most accurate results 5 days sooner"), says the following regarding it's accuracy: "4 days before your period, the test is 63% accurate; 3 days before your period 83% accurate; one and two days before 93% accurate." So it's most accurate around the time you miss your period.

When you do a pregnancy test too early, you may get a false negative pregnancy test and be disappointed. Waiting until you miss your menstrual period and until your menstrual period is late, maybe 1-2 days late, will save you money and will give you a better chance to prevent a false negative pregnancy test. A healthy mid-twenties couple without known fertility problems has a 20% chance each month of getting pregnant. 80% will get pregnant within the first year of trying.

What about an at-home urine test?

The best time to take an at-home pregnancy test is first thing in the morning and with your first morning urine. This is when the urine is most concentrated and has the highest level of the pregnancy hormone hCG. Try not to get up and go to the bathroom during the night and then do the test as soon as you get up. 

Despite what many manufacturers of urine pregnancy tests want you to believe, the urine pregnancy test will usually not become positive in most women until about a week after implantation, around the time of a missed period.

Had a negative pregnancy test? Find out what the chances are that you could still be pregnant even though you had a negative pregnancy test. 

When the pregnancy test first becomes positive has a wide variation and depends on several variables. The following variables determine when the home urine pregnancy test becomes positive:

Exact day of ovulation: A urine pregnancy test is usually positive 4-5 days after implantation. However, it's the day of ovulation that's important too, as implantation can only happen if ovulation took place and the egg was fertilized. So if your day of ovulation was later than you thought, then implantation and subsequently the pregnancy test are further delayed, too. That is why it's really important to keep track of your ovulation day so you can start counting the days to implantation, and eventually the positive pregnancy test. 

Timing of implantation: After ovulation, the egg gets fertilized and travels through the fallopian tube toward the uterus. This travel takes on average about a week. Implantation, the attachment of the fertilized egg in the lining of the uterus, occurs on average about a week or later after ovulation/fertilization, but it can happen as early as six days and as late as 12 days after fertilization/ovulation. 

At the time of implantation, the placenta starts making the pregnancy hormone hCG, which then enters the bloodstream. hCG can be detected in the blood about 3 to 4 days after implantation. Urine hCG can be detected about 2 to 3 days after blood hCG can first be seen. Detection of hCG depends on the timing of implantation so hCG can normally be detected in the blood between 9 and 16 days after ovulation (HPT: 12-19 days after ovulation). 

Are there variations in hCG levels?

There is a wide normal variation of hCG levels, both in the blood and the urine. If a woman has low blood hCG levels, for example, then it can take several more days for it to show up on a pregnancy test.

Urine hCG levels change over the course of the day depending on how much you drink and how diluted or concentrated the urine is. Urine pregnancy testing is best done with more concentrated urine. If you drink a lot of fluid, the urine may be too diluted early on in the pregnancy to achieve an hCG concentration adequate for a positive test. 

Are all pregnancy tests the same?

Different pregnancy tests have different sensitivities. The lower the sensitivity, the earlier a pregnancy test becomes positive. Sensitivities are indicated in mIU/mL, the lowest amount of hCG in the urine that tests positive. A sensitivity of 20 mIU/mL requires one-half the hCG level to be positive when compared with a 40 mIU/mL sensitivity level, and it may become positive several days earlier than the pregnancy test with higher sensitivity. Make sure you read the package of the pregnancy test to determine your pregnancy test's sensitivity.

Can you take a pregnancy test on day 33 of your cycle?

How long does it take for hCG to show in 31 day cycle?

How soon will a pregnancy test read positive 30 day cycle?

What day of your cycle will you test positive for pregnancy?