My ovulation day was on Dec. 13. I had a gush of watery cervical mucus on this day and Dec. 14. I also experienced cramping in my lower left abdomen on both days. On Decn 15 I had unprotected sex. What is the probability that I'm pregnant? I am 39!

50 percent, you either are, or you are not. Sorry, there is no percentage, first sex needs to be prior to actual ovulation, to allow time for sperm to reach the egg. Also you did not state what method you were using to track ovulation, are you following body temp, or doing other medical testing. (Charts do not work for many people and are not exact to a day or two anyway)

So, no there is not even a good education guess, If this was actually ovulation and sex was after it, then the odds are very small.

I use an app on my phone to keep up with my cycle. Thanks!

Phone apps are worthless, you would be as good, throwing darts at a board.

they merely assume some standard data. while they work for some women, they will never be exact.

for other women, they can be off a week or even more.

The phone app gives you a starting place, but noticing the change in cervical mucus helps. As was said, many women will follow the norm, but many others will naturally ovulate a bit sooner or later than the average. An egg is viable for about 24 hours, and it's thought that the first half of that time is the best to achieve pregnancy. Keep in mind that timing in only part of it, so odds are not great even if you definitely did ovulate and had sex in time.

All you can do now is wait and see what happens when your next period would be due.