When to Take a Pregnancy Test for Accurate Results 103


When can you take a pregnancy test? How early will a pregnancy test be accurate? Do you need to wait for a missed period? These are all common questions relating to when to take a pregnancy test and for good reason. It’s not like knowing if you are or aren’t pregnant is some trivial detail—a baby is a big deal, a life-changing, forever deal.

when to take a pregnancy test for accurate results

So, how do you know when to take a pregnancy test?

While many urine pregnancy tests boast they can predict pregnancy 6 days before a missed period, this is arguably inaccurate.

At best, you can get a positive pregnancy test, albeit often faint and with an early result test, 3 days after implantation. A study by the National Institute of Environmental Health Sciences in 2008 found that hCG levels don’t reach the minimum sensitivity of home pregnancy tests until roughly 3 days after implantation with levels as follows:

Day of implantation: 0.65 – 0.78 mIU/mL
Day 2: 1.95 to 2.6
Day 3: 4.55 to 6.13
Day 4: 10.1 to 13.91
Day 5: 21.19 to 30.03
Day 6: 44.2 to 60.97
Day 7: 73.58 to 104.91

The most sensitive over-the-counter test (First Response Early Result) has been shown to pick up levels of 5.5 mIU/mL. Other tests, such as Clearblue, had a much higher treshold of closer to 22 mIU/mL. This would make day 3 to 5 when a positive test would be possible.

Now, implantation can occur 6 to 12 days after ovulation, but in most cases, it’s 8 to 10 days.

So, let’s assume a few scenarios with a 28-day cycle placing ovulation and sex at mid-cycle or cycle day (CD) 14.

Fastest timeline: (DPO 9) (which is quite rare) implantation occurs on CD 20, you might be able to get a faint positive on CD 23 or 5 days before a missed period.

More likely timeline (DPO 12): implantation occurs on CD 23, a test might show faintly positive on CD 26, or 2 days before a missed period.

But at the slow end of the spectrum (DPO 14), implantation occurs on CD 26, a positive is possible the day after a missed period.

Remember, these examples would change with cycle length. For instance, on a 26-day cycle with ovulation at mid-cycle (CD 13) and a slower 12-day implantation lands on CD 25, so a test wouldn’t likely be positive until 2 days after a missed period.

You can use this formula to determine when to take a pregnancy test at the earliest, add about 2 more days for a safer bet:

# Cycle Days/2 + 12
or
Ovulation Date+12

Keep in mind that the sensitivity of the test you use and the time it takes for implantation can vary greatly, and pregnancy tests can be expensive. Early testing can also lead to concerns over false positives (or negatives).

Looking at pregnancy test data:

To support this, over at Fertility Friend, they did a survey of 93,184 charts where women were tracking their periods, ovulation, and/or temperatures and found the following statistics:

pregnancy test statistics when to take a pregnancy test

17 percent of women received a false negative as a result of testing too early, but an impressive 40.7 percent test too early overall with most testing 10 days past ovulation (DPO) or roughly 4 days before a missed period. The average DPO for a positive pregnancy test is 13.6 days, a whooping half a day before a missed period for most ladies. As you can see from the chart above, even a few days make a huge difference.

This data also correlates with a 2014 retroactive look at pregnancy test accuracy studies published in the National Library of Medicine from 1960 to 2013. hCG levels were found not to exceed 10 mIU/ml (the commonly suggested sensitivity of many home tests) until 10 to 12 days after ovulation or 2 to 4 days before a missed period. Further, the study also found that the majority of home tests were not actually able to detect levels this low, and when they were, home-users often misread the tests (squinters). 25 mIU/ml was a more common sensitivity level. A level not reached until 12 to 14 days after ovulation (around the time of a missed period.) The suggestion based on this data was that a test should not be taken earlier than 4 days before a missed period.

This likewise confirms the data shown above for hCG levels by days after implantation that suggested day 3 to 5 would be the earliest time frame for a positive test depending on brand. By ovulation, using the 8 to 10 day average, this would be day 11 to 15, again around the time of a missed period.

Given all of this, the day of your missed period is a fairly safe bet, but about 4 days after is more ideal, as 100 percent of women who were indeed pregnant got a positive test at that point over at Fertility Friend and data on hCG rises in pregnancy against test sensitivity would support a highly accurate result as well.

All that being said, when to take a pregnancy test, what’s the answer?

For the most accurate results, aim for 4 days after a missed period or 16 to 19 days after ovulation. Avoid testing any earlier than 4 days before a missed period or 10 DPO.

If you enjoyed our guide on when to take a pregnancy test you may also find helpful:
Calculating Your Chances of Pregnancy
False Pregnancy Test Results: How Common Are They?
Missed Period, Negative Test: What Gives?
Early Signs of Pregnancy Quiz
Period While Pregnant

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Anonymous

Hello! I’ve a seemingly complicated one ( it’s blowing my mind, anyway) I’m currently on day 41 of my cycle, no period. (last period was June 16-21). I had protected ( with a condominium as my husband recently had a vasectomy and were in “limbo” ) on day 28 (July 13th). I have NO idea what a regular period looks like right now because I am still nursing my 14 month old, but much last period was 33 days. I took three pregnancy tests, the last one was yesterday morning-first thing. All negative. Did I early? Is there any chance… Read more »

How

Hi my husband and I have sex on 1st July and supposed to have my period on 19 July (irregular but ard 28 days cycle) I’m feeling very tired last week and nausea on friday. I did a test on 21st which is last sat but it negative. My period is still not here. When should I do the test again?

AMY

HI I had my period on the 16th of May (31 day cycle) experience some mild cramping and pinkish spotting on the 25th of May which I thought was ovulation spotting that I never had b4 lasted like 4 days and thEn I started experienceing pregnancy symptoms took a test today and it was negative can I still b pregnant from having sex on the 30th

sarah

i had unprotected sex (for a few moments before a condom was put on) on may 27th (the last day of my last period) and two times (no condom, only withdrawal) on june 3rd and took an aftera e.c. pill twelve hours later. i have a 24 day cycle and estimate that i ovulated around the 10th, the 3rd of june being day 15 in my cycle. my breasts have been tender and swollen for the last week and i’ve had slight cramping, but these could be possible side effects of the pill. i’m due for my period on the… Read more »

Juan

Hey so my girlfriend took the first Response pregnancy test. And it was negative but I’m still worried. Her last period was on may 2nd and her ovualion was on the 18th her cycle is 30days. We had unprocected Sex on the 20th and I pulled out. After 7hours she took the plan b pill . Then we were messing around and I sorta penetrated her vagina but no Sex This occurred at may 26. Her period is due tomrrow June 2nd but she feels like she’s having ppregnacy symptoms. She took the test yesterday and it was negative but… Read more »