The time when a woman is pregnant
The most likely time for a woman to get pregnant is about14th day after her last menstruation. This time range includes the survival time of sperm and eggs, which is about from the 9th day after the last menstrual period to the 7th day/kloc-0.
Time calculation
According to the time calculation, there are only 8 days from 10 to 18. The period with the highest possibility of pregnancy is from the 9th day after menstruation to the 7th day/kloc-0. Therefore, even if the girlfriend's menstruation is irregular, the time they have sex is far beyond the most likely period of pregnancy.
Physiological knowledge
From the point of view of time and physiology, the possibility of their pregnancy is almost zero. Of course, everyone's physical condition is different, and we can't be 100% sure. However, from the point of view of time and physiology, this possibility is really very small.
Stay calm and rational.
No matter what happens, we should keep calm and rational. Don't blindly guess and draw conclusions, but should analyze according to the actual situation and scientific knowledge. At the same time, we should also respect everyone's privacy and feelings, and don't comment and guess at will.