Resting heart rate falling in third trimester

[ToastEater]

I'm 31 weeks pregnant, an older mother (43). Currently classified as high risk, largely due to age, although baby has also been measuring a bit small (close to 10th centile).

Throughout this pregnancy my resting heart rate, according to Fitbit, has been rising by a few beats per month, going from 64 prepregnancy to 89 earlier this month. In the last three weeks however it has consistently gone down, falling from 89 to 81, and is now lower than last month's average. My understanding was that heart rate is supposed to rise throughout pregnancy, or at least until the final few weeks, so I don't know what to make of this.

Has anyone else experienced anything like this, and what was the outcome?

Baby is fairly active, moving every day, and I have a growth scan on Monday.

Just looking for experiences, as I'm getting concerned. I've had several losses prior to this, although all in first trimester, and am feeling quite anxious. Hope someone can help.

Bump.
Anyone?

@ToastEater you should chat to a medical professional about this, I'm not sure how many doctors are on MN, but it's best to speak to your GP or Midwife :-)

Honestly, as long as it’s within normal range no one is going to jump up and down about your heart rate. You’re probably a bit more sedentary now you’re heavily pregnant (Fitbits aren’t advanced enough to know exactly what counts as ‘resting’). You may have been slightly anaemic briefly, possibly had a slight infection, were more stressed previously... loads of things can affect HR.

Just looking at my Garmin graph my resting HR has dropped slightly in the last month (I’m 39 weeks pregnant) after having spent the last 6 months slightly increasing.

My theory is that my HR drop is likely due to the change in seasons and thus the cooler temperature and also being less likely to be dehydrated.

Thanks very much for replying

@jazzibelle I hear you but tbh I think it's very unlikely I'll get a useful answer out of either! Both GP and midwife seem crazy busy, I'm struggling to get answers to basic questions and to arrange routine appointments. Plus I had a quick look and I don't think this stuff is well researched yet. Researchers seem to know that HR should go up, on average, each month, but nothing much about individual or monthly variation. Hence why I'm asking for personal experiences :)

@PolarBearStrength
Thanks so much for sharing. I did in fact have a UTI last month so maybe that's it? Also I was tested for anaemia last week after getting breathless and you've reminded me to ask my midwife about the results. So yes that's super helpful. Thanks again and best of luck with the last little bit of your pregnancy!

Surely it's as your probably slowing down now/resting more so your rhr will naturally drop?? Just checked mine on garmin watch and it too seems low snd I'm 37 weeks but have generally been sitting fine most the day xx

Thanks for replying @sarahc336
Hmm, I can imagine that this is the explanation for some people, but not sure if it applies to me. I've checked Fitbit app, and there doesn't seem to be much of a relationship between my steps per month and heart rate. HR has just been going up and up until this month, whilst steps have been going up and down each month.

Ps For anyone reading this thread who's interested, my anaemia screening results came back. Haemoglobin level is 118, down from first trimester at 132 but still within normal range apparently.

I think your body also just becomes used to working harder and more efficient - at first he needs to work really hard to create the additional blood required and pump it but once that's done it will find a way to be more efficient. Plus also you'll be moving around a lot less if you are anything like me! 🤣

@ToastEater try not to worry as my partner is a lecturer in physiology and he said resting heart rate is not a good indicator or anything really especially using a fit bit or watch as they're just not reliable enough. He said resting heart rate can be altered by all sorts, sleep, how much you've eaten or drank, how much your moving, at what speed, also don't forger how much our bodies change in pregnancy. I really don't think you should pay much attention to it to be honest and as long as you can feel your baby moving the same that's the best indicator. I've just checked my rhr for the last week and it's literally all over the place up and down xx

Thanks both for the reassuring words, it really helps to hear of similar experiences, especially in combination with opinion from an expert. It's been so stressful with the pregnancy being high risk as well as a history of loss. Scan on Monday, fingers firmly crossed.