Wednesday, 8 September 2010

Home Pregnancy Tests during the Two Week Wait



I know that many people warn against home pregnancy tests (HPTs) during the two week wait, but as my stash above indicates, I am not one of them. The last peer-reviewed head-to-head comparison of HPTs was by Cole and colleagues in 2005, so I picked the top brands from that study and then used the the manufacturers' own data on early sensitivity. I don't know the extent to which these results are directly comparable, as they were tested in different laboratories on different women. From these data, the First Response Early Result test came out looking the best, although all are equal by Day 0.



What about false positives? Cole and colleagues (2005) found no false positives in their lab test tests. Clearblue Digital reports a 0.49% rate of false positives on Day 0. First Response state that women over 41 years old could expect a 4% false positive rate on Day 0 due to high levels of pituitary hCG.

So here is my plan:

Thursday (3dp3dt): Daily tests until I get a negative result to ensure that the trigger is out of my system, then:

Sunday (6dp3dt): Daily tests until Friday 17th (11dp3dt).

Monday 20th (14dp3dt): Blood test.

Sources:
First Response Early Result true positives
First Response Early Result false positives
Clearblue Digital

Clearblue analogue colour change tip

Cole, LA et al., 2005.
Sensitivity of Over-the-Counter Pregnancy Tests: Comparison of Utility and Marketing Messages. Journal of the American Pharmacists Association.
Echner, SF and Timpe, EM. 2003.
Urinary-Based Ovulation and Pregnancy: Point-of-Care Testing. The Annals of Pharmacotherapy.
Cole, LA. 2004.
Accuracy of home pregnancy tests at the time of missed menses. American Journal of Obstetrics and Gynecology.
Butler, SA. 2001.
Detection of Early Pregnancy Forms of Human Chorionic Gonadotropin by Home Pregnancy Test Devices. Clinical Chemistry.

12 comments:

  1. Oh thank you for that!! I may have to go buy myself some First Response! I am so excited for you.

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  2. Wow - that is alot of $$$ sitting there :) Good luck with your "science project" - hoping you get some "positive" news :)

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  3. I'm going to start testing tomorrow: 7dp3dt. I'm not sure what brand I have on hand, but that is a very interesting and informative graph you have there! Good luck to you as you start testing, and I'm very interested to see on what day your trigger tests out and, of course, on what day you get your first positive!!!!!

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  4. Love it! I actually didn't test before, but mainly because I was a chicken. I just wanted to get to believe I was pregnant as long as possible! Turns out I was, so the test would have been nice!

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  5. I think you found something here that even I never researched. Very interesting. Here's hoping you never see a negaive test!

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  6. Good luck!!

    That's exactly what I did both times as well. It made me feel like I was doing something instead of just waiting passively. You know. Like actively waiting. :-)

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  7. Hi! Came across your blog by accident but and found out we live in the same country! Which hospital do you go to? I go to St. Luc and will have my first IVF in October, already taking BCPs.
    Wish you lots and lots of good luck!

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  8. Nice work! I fully endorse the test every day approach. Why not? I also believe the FRER's are the best. Good Luck!

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  9. COngrats on your transfer! I'm only just catching up now. I'm in the anti hpt camp but I came close to testing at home in my last cycle. I'm not sure why hpts scare the crap out of me but they do!
    Sending you LOTS of love and hoping for the best for you .

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  10. I am a scientist too and I love your scientific approach. I will be keen to hear about any other little studies / lit reviews you do. I have thought about trying to calculate my odds of ever having a baby based on age, time that we've been TTC, reproductive history etc, but there are so many unknowns and the stats get a bit complex. Good luck

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