How do HPTs work?
Home pregnancy tests look for hcG in your urine. This is one of the first hormones produced when you are pregnant. The amount of hcG in your system in the week before your period is due can vary from pregnancy to pregnancy. It isn’t necessarily a sign of the pregnancy’s viability or a multiple vs. singleton pregnancy. In the week before AF arrives, most pregnant women have 5 – 50 mIU of hcG in their system. That number should double every 2-3 days. The most sensitive HPTs typically test for 25 miU. See HPT Sensitivities.
When will I have hcG in my system?
The pregnancy hormone hcG will start to be produced after implantation, not at the point of conception. So if you ovulate on CD 15, you may have conception occur on CD 16, then implantation occur six days later at CD 21 (or 8 DPO). Most pregnancies implant at approximately 9 DPO (give or take a day). After implantation it can take several days for the hcG to build up in your system enough to trigger a BFP. With an early test, the earliest it is “reasonable” to start testing is at around 10 DPO.
When Can I Test?
The two week wait can seem like an eternity. How early you can test depends upon the sensitivity of the test and the number of tests you are willing to ‘waste’. Generally, the most sensitive tests (such as First Response Early Response or EPT, for example) suggest you can test “Five Days Before your Missed Period”. What this really means is five days before CD28, assuming ovulation on day 14. (This type of cycle is considered the standard even though few women have such a cycle.) This translates to 10 DPO being the first day you could possibly see a BFP if you are pregnant. Many women, though, won’t see a BFP until 12 DPO – or even later. See HPT Sensitivities.
How Early Can I Expect to See a BFP?
Based on Fertility Friend’s extensive database of often obsessive peestick users…
17.2% of positive pregnancy test are reported before 9 DPO
34.4% of positive pregnancy test are reported before 10 DPO
50.4% of positive pregnancy test are reported before 11 DPO
65.7% of positive pregnancy test are reported before 12 DPO
76.9% of positive pregnancy test are reported before 13 DPO
85.4% of positive pregnancy test are reported before 14 DPO
90.6% of positive pregnancy test are reported before 15 DPO
93.6% of positive pregnancy test are reported before 16 DPO
95.3% of positive pregnancy test are reported before 17 DPO
96.8% of positive pregnancy test are reported before 18 DPO
I am not affiliated with Fertility Friend, other than being one of their customers. They offer educational materials, extensive database of charts, peesticks, and symptoms, AND supportive community you can plug into are well worth the nominal fee of joining. It is really an outstanding resource for anyone serious (and obsessive) about TTC. Oh, and they also have a nice app so you can obsess on the down-low 24/7. Check them out:
Do faint lines count?
Yes. Generally speaking, any test line indicates pregnancy assuming you have followed the instructions of the test. A faint line could indicate a low level of hcG, which is to be expected if you are testing early. It could also simply mean that particular test didn’t have much dye. If the line is gray or colorless, you may be looking at an evaporation line. Now, if you see your “faint line” only after breaking the test apart, holding it up to 5 different types of light, scanning it and adjusting the color contrast… that is a different story.
Do I have to use FMU?
Instructions for just about every home pregnancy test make it sound as if first morning urine is the ONLY urine that can be used for testing. This isn’t true. The idea is that FMU is the most concentrated, and therefore would have the most concentrated amount of hcG. But depending on numerous variables, you may find that second morning urine works better… or even late evening urine.
Here is an example from her royal highness’s personal collection. As you can see, second morning urine (SMU) provided a darker line than first morning urine (FMU).
What does 99% accurate mean?
It’s important to understand what this does not mean: 99% accurate does NOT mean that if you are pregnant, the peestick will give you a BFP 99% of the time. Far from it. Accuracy ratings on peesticks refer to how often their peestick compares to clinical peesticks. So if a peestick used in a doctor’s office picks up a pregnancy, a peestick that claims 99% accuracy will pick up that same pregnancy with the same pee 99% of the time.
Do the lines on digital tests mean anything?
Like any sane and rational ttc’er, you may have torn open your digital HPT as if to say “are you SURE you meant to say I am not pregnant?” In doing so, you likely discovered a test strip that looks just like an analog peestick. You may have also discovered that test has two lines and thought “ah-HA! See? I am not crazy, I am pregnant!”
Unfortunately, you may be both insane and not pregnant. Digital tests are different from regular peesticks. The test looks not just for the presence of a second line, but it also reads the intensity and color of that line. It looks for variances that the human eye cannot detect. These tests are not meant to be torn apart. If your digital test says “not pregnant”, do yourself a favor and resist the urge to pop open the casing.
Here is a dissection of a digital test (in this case an FRED). The top test is positive, the bottom test is negative.
How do OPKs work?
Ovulation tests detect lutenizing hormone (LH). This hormone surges 12-48 hours before you ba-GAWK (or release an egg to those of you that don’t speak chicken). On a positive OPK, the test line must be as dark as (or darker than) the reference line. Be sure to read the results within the time limits specified in the instructions. Tests often darken after the time limit
which can results in false positives.
How soon after an positive OPK should we DTD?
Her majesty prefers to not tell her subjects how to conduct their bedroom affairs… but since you asked… It is generally recommended to DTD the same day as the positive OPK and the next two days as well. If your partner has low sperm count, you may want to try DTD every other day instead. Charting can be a useful way to see how soon after a positive OPK you typically ovulate. The best days to DTD is the day before and the day of ovulation.
What if I never get a positive?
Try testing twice a day – perhaps once with SMU and once in the late afternoon. Some women have very short LH surges, and unless they test twice a day they can miss the positive.
Can I use an OPK as an HPT?
Many ttc’ers like to use OPKs as HPTs for fun and sport. How effective is it?
Check out OPK as HPT and decide for yourself.