When Did I Really Conceive: October 15 or October 25?

Q: When Did I Really Conceive: October 15 or October 25?

Hello： <br>1. <br>According to the examination results on November 9, the embryo is only 4 weeks and 5 days old. <br>This gestational age is calculated from the first day of the last menstrual period to the date of the examination. <br>Therefore, if we calculate from the date of

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I underwent artificial insemination on October 15th, had intercourse on the evening of October 25th, and tested positive for pregnancy on October 29th.
On November 9th, I visited an obstetrician, and the embryo was measured at 4.5 weeks, with a size of 0.65 cm.
Could you please help clarify whether my actual conception date was October 15th or October 25th? Thank you.

tina, 20~29 year old female. Ask Date: 2005/11/10

Dr. Lü Lizheng reply Obstetrics and Gynecology

Hello:
1.
According to the examination results on November 9, the embryo is only 4 weeks and 5 days old.
This gestational age is calculated from the first day of the last menstrual period to the date of the examination.
Therefore, if we calculate from the date of conception to the examination date, we need to subtract 2 weeks, which means the embryo is approximately 2 weeks and 5 days old, or about 17 days.
Counting back 17 days from November 9 gives us approximately October 23; however, there may be a measurement error of up to one week in the ultrasound.
2.
If conception occurred on October 25, it typically takes at least 10 days or more to detect pregnancy, so the conception date should actually be around October 15.
3.
Therefore, based on the overall analysis, the conception date should be October 15.
4.
According to our hospital's ultrasound, the fetus measures 0.65 cm, which corresponds to 6 weeks of gestation rather than 4 weeks and 5 days, further indicating that October 25 is not the date of conception.
Sincerely,
Dr.
Lu Li-Cheng, Obstetrics and Gynecology

Reply Date: 2005/11/10

More Info

Determining the exact date of conception can be quite complex, especially when considering various factors such as the timing of ovulation, the lifespan of sperm, and the menstrual cycle. Based on the information you provided, let's analyze your situation.

You mentioned that you underwent artificial insemination on October 15 and had sexual intercourse on October 25. You then received a positive pregnancy test on October 29, and a subsequent ultrasound on November 9 indicated that the embryo was approximately 4.5 weeks old, measuring 0.65 cm.

To understand when conception likely occurred, we need to consider the following:
1. Timing of Ovulation: Ovulation typically occurs about 14 days before the start of your next menstrual period. If your menstrual cycle is regular, this can help pinpoint when you are most fertile. If your cycle is irregular, it can be more challenging to determine.

2. Sperm Lifespan: Sperm can live inside a woman's reproductive tract for up to five days. Therefore, if you had sexual intercourse on October 25, and if you ovulated shortly after that, it is possible for sperm from that encounter to fertilize an egg.

3. Artificial Insemination: The procedure on October 15 would have introduced sperm directly into your reproductive tract, which could lead to conception if ovulation occurred shortly after.
Given that you received a positive pregnancy test on October 29, it is likely that conception occurred around this time. The ultrasound on November 9, which indicated that the embryo was about 4.5 weeks old, suggests that conception likely happened shortly after the artificial insemination on October 15.
In summary, while it is possible that sperm from the intercourse on October 25 could have led to conception, the timing of your ultrasound suggests that the artificial insemination on October 15 is the more likely date of conception.

Additional Considerations:
- Menstrual Cycle Variability: If your menstrual cycle is not regular, it can affect the timing of ovulation and, consequently, the timing of conception. If you have a history of irregular cycles, this could complicate the determination of the exact date of conception.

- Pregnancy Testing: Home pregnancy tests detect the hormone hCG, which is produced after a fertilized egg implants in the uterus. This typically occurs about 6-10 days after conception. The fact that you tested positive on October 29 aligns with the timeline of implantation following the artificial insemination.

- Ultrasound Accuracy: Ultrasound measurements can provide an estimate of gestational age, but they are not always precise. The size of the embryo and the gestational age can vary, and the ultrasound is a tool that provides an estimate based on the average growth patterns.

In conclusion, while both dates are close to the time of conception, the evidence suggests that the artificial insemination on October 15 is the more likely date of conception, given the timing of your pregnancy test and the ultrasound findings. If you have further questions or concerns, it would be beneficial to discuss them with your healthcare provider for personalized guidance.

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