Shortening follicular phase

[Wednesdayonline]

What can cause the follicular phase to shorten all of a sudden? Ovulation is usually cd19/20, last 2 months it has been around CD15/16. I have a shorter luteal phase so this is making my cycle length around 27 days long. Not upset about it and obviously still within normal range, but I'm wondering why the sudden change?

I came off the pill in May 2024, so could it just be my body settling? Me getting older (I'm only 30 though)? Only other thing I can think of is I've started doing more cardio recently, but that's only a few hours on the weekend of hiking/dance/ab class, before I did more strength training and swimming so I wasn't inactive.

Potentially it could be better rather than worse? Considering a “standard” cycle is 14 days luteal and 14 days follicular. Maybe your hormones have regulated? I think you don’t want too short a follicular phase but equally not too long - 15/16 days sounds good!

Vitamins can shorten it

This has happened to me this month too. All I've done is clean eaten for 6 weeks and started acupuncture and Chinese herbs. My has gone from ovulating on day 16 to day 12! My cycle is usually 30 days long too. Strange! I wouldn't be too disappointed with yours as it's in good range!

15-16 days suggests a healthier cycle than 19-20 days, so I would be happy about this.
Lots of things could cause a change, from changing your diet, or weight loss/gain, to fluctuations due to undiagnosed conditions (eg mild PCOS).
I wouldn't worry unless your follicular phase becomes too short. I assume you are tracking with BBT so you will know if this happens.