General/Women's Health, TTC/TTC Technology Posts

Experiment : Identifying ovulation the Clever C(nt)s way

Tracking your ovulation can be a frustrating task. Whether you are doing it for health reasons, contraceptive reasons, medical reasons, investigatory reasons or ‘just’ because you want to target sex to conceive, the good news is nowadays we have a lot of equipment for use in the home that can help at least roughly work out if and when it has occurred.

From the humble Basal Body Thermometer and OPK test to more expensive equipment like an Ava Bracelet or an Ovusense device, you can have a go at working out what on earth is going on with your body and use this to help accelerate things with your medical adviser or target sex to conceive. The more you know, the stronger your position to get and identify the help you need and be a true Clever C(nt).

The die-hard medical method for proving ovulation has occurred is an ultrasound before and after the suspect ovulation date. Which is why this month, when I had an appointment booked for a pelvic ultrasound 5 days after I was due to ovulate, I decided to run this incredibly unscientific experiment to see if I could work out if any of this stuff actually worked in any kind of detail. The answer is it does with a 24 window. If you’re interested, read on.

Using standard cheap ovulation test strips or OPKs (blimey, they have gone up…No longer can you get them for 3 for £1 in Poundland or B&M Bargains, no. Now they are £5 for 5 in bloody Superdrug. Buy on Amazon), a very fancy Clearblue Bluetooth wireless device (Clearblue did send me this for free I should disclose and I will be reviewing it properly soon), my Ava2.0 Bracelet which I already owned and my humble BBT thermometer (lovingly dunked in water by my daughter but still works). I did want to also use the Ovusense but alas, my budget is a bit low still!

So here is my highly unscientific experiment. 


I have a 34 day cycle.

I used: A BBT thermometer– I took my temperature every morning at the same time as soon as I woke up. An Ava Bracelet– a bracelet device which you wear at night. It tracks 9 different parameters to determine your fertile window in advance and then confirms ovulation. A Clearblue Connected ovulation system – ovulation sticks which will let you know when your fertile window is and when your peak fertile window is synching everything into a handy app to your phone via Bluetooth. OPKs – little sticks you dip in urine which will tell you when you have your LH surge (when your peak ovulation will occur).

My method was to track my temperatures using my BBT and Ava after my period ended and then start using OPKs and CB sticks according to the manufacturer’s recommendation (which in my case on a 34 day cycle was to test from day 14) once a day using first morning urine (FMU). I would then confirm ovulation from a sustained rise in BBT temperatures. I was interested to see whether Ava corresponded with all of these devices as well, both in predicting and then confirming ovulation. Having a scan so soon after my ovulation date was useful to confirm that ovulation had occurred for definite, but wasn’t useful enough to confirm these devices were correct with their timings– it has been however, better than nothing. 

I also kept an eye on cervical position and mucus (ew) type as well as I know how much you all love mucus. 

So how did it go

From past experience I actually started with the CB sticks from day 13 (if you’re using them for the first time I would advise this – don’t worry about ‘wasting’ a stick – better to get it right) and when it got closer to when I suspected results might change from the flashing smiley face to the solid one, I did one in the morning with FMU and another in the afternoon using a 3 hour hold to check on things. It’s annoying but as I can attest to from experience, there is a chance if you have a super speedy LH surge you may miss a solid smiley. This goes for if you use the monitor as well.

The average time for a surge to occur before you ovulate is 24-48 hours which is the window these sticks will give you. It’s a rough approximation however and does not guarantee ovulation. If you have PCOS you may find you will have 2-4 surges within your cycle which will make these sticks in co-ordination with a BBT thermometer a bit frustrating. 

My OPKs – first is CD16 and the last is CD19 (a positive)

The first CB stick I did on CD13 was blank – no surprise there. I was interested however when it started showing a flashing smiley face on CD14 which gave me a very wide fertile window as my ovulation was predicted for CD20. An OPK had a faint line but nothing of note.

I then started testing using both with FMU every day and again that afternoon. I finally got a solid smiley on an evening test at 8pm on CD18 (I was worried that I would miss the surge – I suspect that it would have come up on the morning of CD19 however) and had a blazing positive OPK on the morning of CD19. These indicated that I would ovulate around CD20/21.

A note for those who are TTC

Now for all of you who want to try for babies during their fertile window and are reading this for those reasons, I have some information which might interest you. If you want to maximise your chances of TTC and you are a) one of those people blessed with a high sex drive, b) are maybe a bit younger and c) don’t have issues with really going great guns during this time, you won’t have an issue with having a lovely wide fertile window of 7 days in which to have as much sex as possible. Hell, when we were TTC with #1 we looked on it as a challenge.

If you are a) Looking to identify your ovulation date accurately to have an IUI, b) just do not have time for all that rampant nonsense as you have other kids/jobs/a life or c) one or other of you has a low sex drive or erectile/ejaculation/sperm issues, you need that window to work for you. The two days (well, if you can the day) before ovulation are really when you want to be at it so that sperm is waiting for the egg, with maybe a day or so before this to clear out the pipes on both sides, so wasting your precious boffing time too early is frustrating. 

My advice if this is you, is to go every other day or every 2 days until you see the solid smiley or the solid OPK and then try to go every day for the next two days. If you can’t, just go the night that you see the smiley. 

My Ava chart for this month

As I said, Ava had predicted that I would ovulate on CD20 (which as I was on a 34 day cycle sounded about right) so I was again keen to see if the BBT would agree with Ava. Ava predicted my fertile window to start from CD15 but wound up moving my ovulation back a day. As you’ll know from reading my blog post on timing sex within the fertile window and if you’ve read the box above, this would have been intensely irritating for many.

Fertile mucus was noted from CD17.

I had a positive OPK on CD19 which corresponded to ClearBlue. A dip then appeared on my BBT chart on CD19 and I had confirmed ovulation on CD20 a few days later which you can see on the chart below from Fertility Friend. Ava disagreed however and believed I ovulated the day after.


All of the devices did a pretty good job of targeting my ovulation. However, I don’t have PCOS or irregular cycles and I would suspect it would be more frustrating if you did. 

There was a discrepancy of one day for ovulation day between the BBT thermometer and Ava. I would argue that Ava is using more parameters to measure a fertile window, but my trusty BBT thermometer has never been wrong before. Of course, a BBT can only measure ovulation after it has occurred whereas Ava claims it can predict it in advance so it heavily depends on what purpose you are wanting to target things for.

My BBT chart below:

OPKs and Clearblue were actually really easy to use, corresponded to the ovulation dates of both Ava and BBT confirmation, and if you don’t mind being a bit parched at work and nipping in the loo for a second dip around 2/3pm, can be a nice cheap way of tracking things. I had a pelvic scan on DPO4 where the rather snippy sonographer confirmed that I had ovulated from my right ovary.

One day isn’t exactly much is it. However, it could be vital for some of those couples TTC. I’d argue that CB and Ava give you a large fertile window with which to work within, which will give you a good idea when not to have sex if you’re using it as a contraceptive (neither sell themselves as a contraceptive but if you’re not worried about conceiving, it will work for most people fine if you avoid unprotective sex in the fertile window – as lots of new parents sue me….) but if you’re just tracking cycles I would stick to a BBT thermometer.

Baseline is they all basically got there within 24 hours of each other. So it really depends on what you’d prefer to use.

What a helpful article. Any questions fire away!

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