What is the chance of pregnancy 5 days before menstruation (infertile days)?

To @Natii 🦩 :

The human body is not programmed, the differences in the duration of the cycle of 2-3 days are normal and should not be alarming. This is influenced by various factors.

The chances of conception on the first day of menstruation are low, it is up to an infertile day. If the condom was put on correctly, did not slip off during intercourse or broke, there is no risk of pregnancy.

Fertile days begin a few days before ovulation and last up to 3-4 days after ovulation, and the best chances of getting pregnant are on the day before ovulation and on the day of ovulation. Ovulation usually occurs about 14 days before the next menstrual period. At the same time, it should be borne in mind that - depending on the source - the life expectancy of sperm in the female genital tract is estimated at 2-3 days, up to a maximum of 5 days.

It is possible to calculate what day ovulation falls on if your menstrual cycles are regular. Nevertheless, if you are not planning pregnancy, it is worth taking care of securing each intercourse. If you do not want to use barrier methods of contraception (such as a condom), I recommend consulting a gynaecologist who will present other options for protection against pregnancy (e.g. hormonal). I encourage you to read: https://www.gdziepolek.pl/kategorie/antykoncepcja

What chance of conception i on the first day of the period. If I had unprotected intercourse?
This Czykl lasts 7 days, it is regular 27-31, I use the flo application. And he shows me that this Czykl lasted 27 days, 3 days less. So I got my period 3 days earlier. And two days earlier I ran out. Why is it so? Now we have used - contraception, condom. During the first day of the period. Condom well used. Was it because of intercourse that my period could have been shortened? Is this normal.