Does HRV drop during pregnancy?
Yes, steadily. In more than 10,000 pregnancies tracked with an Oura ring, HRV fell by more than 15 ms by week 32 while heart rate rose by about 10 beats a minute. That’s the usual pattern in pregnancies that went to term.
Recovery and readiness scores compare you with your own recent weeks or months. As your heart changes through pregnancy, those scores can run low, because the past they compare you with was a different body.
What we’d do: during pregnancy, stop judging HRV against your old range. Watch it out of interest if you like, but take your questions about how you feel to your midwife or doctor. HRV isn’t a test of how a pregnancy is going.
What the study found
The 2025 study followed Oura ring users through 10,318 pregnancies, from 8 weeks before to after the birth. In pregnancies that went to term:
| Signal | What happened |
|---|---|
| Heart rate | Rose steadily, peaking about 10 beats a minute above the pre-pregnancy level at week 32 |
| HRV | Fell in a mirror pattern, by more than 15 ms at its lowest |
| Temperature | Rose from about week 4, peaking about 0.3 °C higher at week 9, then fell slowly until birth |
| Sleep | More time in bed early on, peaking around week 9. Less sleep and more time awake later |
| Steps | About 2,000 fewer a day around week 8, and over 2,500 fewer near birth |
By week 32 the heart is beating about 10 times a minute faster, and a faster heart leaves less time between beats for the gaps to vary. So a lower HRV is what you’d expect.
A 2026 review of wearable studies in women also found HRV moving with hormone changes across the cycle, on birth control and after menopause.
After the birth
When you start tracking again, build a fresh baseline over two to three weeks before you compare anything.
3 sources
- Adaimi R et al., Temporal trajectories in sleep, temperature trends, cardiorespiratory, and activity metrics measured via Oura Ring during pregnancy, JMIR mHealth and uHealth, 2025pubmed.ncbi.nlm.nih.gov
- Sacha J, Interaction between heart rate and heart rate variability, Annals of Noninvasive Electrocardiology, 2014pubmed.ncbi.nlm.nih.gov
- de Jager E et al., Wearable-derived heart rate variability across the menstrual cycle, hormonal contraceptive use, and reproductive life stages in females: a living systematic review, Sports Medicine, 2026pubmed.ncbi.nlm.nih.gov
