MOST LIKELY PERI MENOPAUSE
Thanks for writing to us with your health concern.
At 52, are you having regular clockwork periods ?
If the answer is yes, then the three pregnancy
tests would definitely be reliable.
With 3 tests negative, you would NOT be pregnant for sure.
I think you are easing off into the peri menopause, where cycles would get irregular / delayed and then stop gradually.
Other than peri menopause - stress, tensions on personal or professional front, unaccustomed exercise, rapid changes in your weight, ingestion of hormonal
medications, late nights, erratic eating, changes in climate or altitude, travelling - all these can interfere with your cycles.
It would be good to get your TSH ( thyroid
hormone level ) checked, as thyroid disturbances can delay periods
Also, while the blood work is being done, get your FSH, LH and serum estradiol
levels checked - they would tell you if menopause is near.
At 52, I would say a pregnancy is least likely.
All the best.
Please feel free to ask for further clarifications.