Vaginal Ultrasound: Pregnancy Weeks and Due Dates Explained

Vaginal ultrasound gestational age question?

Hello doctor, I would like to inquire about my pregnancy.
An ultrasound shows that I am 6 weeks and 5 days pregnant.
My last menstrual period started on February 26.
I had sexual intercourse on March 11 and March 20.
Can I determine which encounter resulted in the pregnancy? Additionally, when is my estimated due date? Thank you.

Ai Mei, 20~29 year old female. Ask Date: 2023/04/21

Dr. Huang Yuande reply Obstetrics and Gynecology

If the menstrual cycle is regular, the possible time of fertilization can be calculated by taking the date of examination, subtracting 2 weeks, and then counting forward 6 weeks and 5 days.

Reply Date: 2023/04/21

More Info

To determine the likely conception date and due date based on your provided information, we need to analyze the details of your menstrual cycle and the ultrasound findings.

You mentioned that your last menstrual period (LMP) started on February 26. If you are currently 6 weeks and 5 days pregnant, this would place your estimated conception date around 2 weeks after your LMP, which is approximately March 12. This is consistent with the typical ovulation cycle, where ovulation usually occurs about 14 days after the first day of your last period in a regular cycle.

Given that you had sexual intercourse on March 11 and March 20, it is likely that the conception occurred from the encounter on March 11, as it aligns closely with the estimated ovulation date. The sperm can survive in the female reproductive tract for up to five days, which means that intercourse on March 11 could have resulted in conception if ovulation occurred shortly after.

As for your due date, it is calculated based on the first day of your last menstrual period. The standard method for estimating the due date is to add 280 days (or 40 weeks) to the first day of your last menstrual period. In your case, with an LMP of February 26, your estimated due date would be around November 18. However, it's important to note that due dates are estimates and can vary based on individual circumstances and the accuracy of the ultrasound measurements.

Regarding the ultrasound, it is a crucial tool in monitoring the progress of your pregnancy. At 6 weeks and 5 days, the ultrasound should be able to show a gestational sac and possibly a fetal pole, which is the early development of the embryo. If you have any concerns about what was seen during your ultrasound, it is advisable to discuss them with your healthcare provider for clarification.

In summary, based on your last menstrual period and the timing of your sexual encounters, it is most likely that conception occurred around March 11. Your estimated due date would be approximately November 18. Always consult with your healthcare provider for personalized advice and to address any specific concerns you may have regarding your pregnancy.

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