I had my last period on 5th march had sex on 9th march again on 20 to 25 march with other guy who is likely to be father 31 st may ultrasound says im 11 week 1 day pregnant
Hello, Ammy.
Your last period began on 5th March. Typically, ovulation occurs roughly halfway through a menstrual cycle, which for many women can be around day 14 (counting from the first day of the period). However, this can vary widely from woman to woman, and even from cycle to cycle for the same woman.
If you have a regular 28-day cycle:
- Ovulation might have occurred around 18th or 19th March.
- The lifespan of sperm can be up to 5 days inside a woman's body, so if you had sex on 9th March, it's somewhat less likely (though not impossible) for that to result in pregnancy because of the time difference between intercourse and potential ovulation.
- Having intercourse between 20th to 25th March is closer to the potential ovulation time, which might increase the likelihood of pregnancy from this timeframe.
Your ultrasound on 31st May indicates you were 11 weeks and 1 day pregnant. Counting back from 31st May, this places the likely conception date around 16th March. Remember, ultrasounds measure the age of the embryo/fetus from the first day of your last menstrual period (which is known as the "menstrual age"), not from the actual day of conception.
Based on these calculations, it seems more likely that the intercourse you had between 20th to 25th March could have resulted in the pregnancy. However, the earlier date (9th March) cannot be entirely ruled out.
Hope this will ease your mind a bit.