Initial blood tests fertility investigations

[Magix86]

Hi. My GP has referred me for initial investigations including bloods and an ultrasound. I'm just a bit confused about timing of the blood tests and hoping someone can help! GP says I need to have one 7 days before my period is due, but my cycles are between 25 and 28 days and I believe I ovulate early, around cd10. The second test she said needs to be "within 7 days" of my period but I'm not sure exactly what this means...is this any time in the 7 days after I start bleeding? My periods usually last about 4 days.Thanks in advance!

As far as I'm aware these will be the day 3 and day 21 tests. Day 3 is obvious, you do it on CD3 of your cycle.

The day 21 test can be trickier if you don't have a standard 28 day cycle. It assumes you ovulate on CD14 and have a 14 day luteal phase, therefore testing you 7 days post ovulation. Which is not true for some!

You should research a little about when to do the day21 test since if you do it at the wrong time in your cycle, you may get readings which don't really reflect the true levels of your hormones. The day21 test is checking progesterone levels.

@Flederjo thank you 🙂 I'm confused if it is the day 3 test why the GP didn't just tell me day 3 and instead said "within 7 days of your period"....but I'm on day 1 now so will go on day 3 on Tuesday!
I can't seem to find much info on the day 21 test if your cycles vary and also probable early ovulation so hoping others on here may also share their experiences and advice on which day to go. My cycle that ended today has been 25 days but last month was 28 days so is quite tricky to predict unfortunately 😒

Hey! I found this page which explains it pretty well, with graphs to help! I think the main point is to do it 7 days after ovulation, so you'll need to track that relatively accurately. OPKs and temping, plugging the info into the Fertility Friend app or similar would be the best bet!

www.myfertilityfocus.com/day-21-progesterone-test-beware/

Thank you so much! That explains it really well 😊 I'll go for day 3 bloods tomorrow morning and will try my best to track ovulation to go 7 days after for the day 21 bloods. I don't temp but do use opks which have been pretty consistent around showing a peak on cd10. Imagine that will end up with bloods around day 17 or 18 instead of 21. Really appreciate the help here! 🙏🏻