OpenAPS and hormones and SMB

One of the most commonly asked questions I see is “How does OpenAPS handle periods?”  Well, lucky me!  I happen to have a teenage girl using OpenAPS…and a blog.  And she is open to bribes to allow me to opine on periods and type 1 diabetes in a public settings.

We used autotune previously on our OpenAPS rigs, but ended up disabling it as a part of our normal loop operations*.  I still run it as a once-in-awhile check, but mostly now depend on autosens for making our basal and ISF adjustments.

A quick note:  Autotune runs once per day (shortly after midnight) to create a new “autotune-profile” that your rig will use for the day with basals and ISFs based on the tune it performs.  The degree to which this autotune-profile can differ from the profile stored in your pump is based on the settings you have in your preferences for OpenAPS.  Once that autotune-profile is generated, changes to your pump settings will not affect the loop until autotune runs again at midnight.  And even then, the new pump settings are only a starting point for autotune to use.

The reason we disabled autotune was two-fold…(1) I don’t like being locked into a profile for the whole day necessarily because (2) hormones (or medicine) can cause us some pretty dramatic changes.  It’s not every month that we get hit super hard.  But, certainly sometimes, the swings needed in our pump settings are really more than you could reasonably ask from an automated program. And they happen in the matter of a couple hours or even less.

We switched to using just autosens for helping us with basal and ISF changes.  It has worked TREMENDOUSLY well.  We have numerous times that it has been able to fairly quickly (within 2 hours or less) detect periods of changing insulin needs and kept us steady, even when I wasn’t paying close attention.

But, every once in awhile, those hormones just come on really strong and fast.  More than autosens can control.  Sunday morning was one of those times.  The morning started off nice and steady.  No signs of problems in her basal rates.


But, when she woke up in the morning around 10am, she informed me her period had started.  Which then led to this by lunch time.  No food involved, and that BG was climbing.


When I saw the SMBs start up shortly after a manual bolus and no food…I knew that it was time to take this basal change more seriously.  Those little SMBs are a good visual clue when it’s time to take more action, I love that.  This was our first time going through a hormonal change with SMBs enabled.

The first thing I did was go to autosens to see what it was autosens doing for me.  And I could see that it was trying to help bring down that high by using temp targets…adjusting target down to 80 from 90 mg/dl to help.  Good.  But, it was also Mother’s Day and I was at the movies on a date with my husband.  Kids were home alone, and I left things alone for the rig to watch and do what it could.  No basal adjustments were made manually at that point.


But, by later that evening, it was clear that the period was not going to simply autosens away, this swing was bigger than some of the others we had.  The SMBs were again a useful visual clue that things weren’t settling down, even with a good front loading of insulin. We were holding steady, not coming back to range.


So, we started to make some manual adjustments to basal, and used autosens to “validate”, in a way, our changes.  If we kept seeing no drop in BGs and autosens adjusting stronger…we knew we needed more.  So, we bumped up from 0.8 to 0.85.  And then from 0.85 to 0.90…


In the end, we have adjusted from a basal of 0.8 u/hour to a basal of 1.3 u/hour to keep her BGs steady.  Which actually corresponded to the amount I would’ve guessed on the correction boluses that it was taking to keep her steady (although above target).  It’s taken us almost 24 hours to make those adjustments, moving about 0.05 or 0.1 u/hour increase at a time. (I did them incrementally and watched how the changes behaved before adjusting again.)  I could’ve just jumped to 1.3 u/hour, as it is a basal rate we are used to with periods, but I didn’t want to overshoot and the loop was doing a good job of keeping her reasonably close to range despite needing over 60% more insulin than usual.

Where do we stand now?  Close to 24 hours since the insulin-resistance started…


Looking at her autosens right now, it’s still seeing that 1.3 u/hour isn’t cutting it and is using a 1.55 u/hour (and a stronger ISF).  Which doesn’t surprise me given the recent SMBs needed to keep her in range.


I will just opt to let the rig take care of things for the rest of Anna’s school day before we make anymore changes to her pump settings.  These insulin-resistant parts of her cycle are powerfully strong, and used to be really hard to know what to do with.  But, between autosens’ numbers and SMBs visuals, this was much easier to navigate without stress or high BGs.  Making changes to her basal wasn’t as mentally burdensome as it used to be.  And hooray for SMBs keeping an insanely good job on controlling hormone-related climbs.

And now I have to bribe Anna for the permission to post.

2 thoughts on “OpenAPS and hormones and SMB”

  1. Could you advise on how you are able to keep your daughter within the range of max 120?

    What is your magic 🙂 perhaps experience?

    Thank you for your awesome blog, I have been keeping up with it frequently especially after the release of SMB. I and I am sure others would love to know how it is working out for you 🙂


    1. I wish I could say she magically stays within 120, but she doesn’t. It’s just an alert level on our Nightscout. In reality, we have alerts set to 130 on our pebble watches. That is the minimum “high BG” we take action on. Anything below that, we let looping take care of. Above 130, we look to see if food has been consumed and usually just let loop handle that too. The exceptions are stress-related high BGs. Those we will correct for, but at half dose since they usually tend to come down fairly quickly too. If she’s eating low-carb (or easy carbs), it is a little easier to stay close to 120. But, we certainly eat higher carb fairly often and then it takes prebolusing and split boluses to really stay under 150.

Leave a Reply

Your email address will not be published.