Conception Dates: A Guide for Expecting Mothers

Pregnancy date

Hello, I am worried because there was an error in the middle, and I have reflected on it.
However, I still want to confirm that my menstrual period was from April 5 to April 11, lasting a full week, with a cycle of about 34-36 days.
On the 17th, I accidentally had unprotected intercourse with a friend.
Out of concern, I took pregnancy tests on the 28th and 30th, both of which were negative.
I have been trying to conceive.
My husband and I had normal intercourse on the 25th, 27th, and 30th.
It wasn't until mid-May that I tested positive, with a faint line, and a week later, I got a strong positive result.
At the beginning of June, I had an ultrasound that showed I was over seven weeks pregnant, with the estimated conception date calculated from April 21.
My period tracking app indicated that April 25 was my ovulation day, but I only noticed egg white cervical mucus on the 30th (which I usually observe every month to identify ovulation).
When do you think conception occurred? Thank you.

Niming, 30~39 year old female. Ask Date: 2021/06/14

Dr. Cao Guotao reply Obstetrics and Gynecology

Hello, you should have conceived at the end of April.
Wishing you good health.

Reply Date: 2021/06/14

More Info

Understanding conception dates can be a complex process, especially for expecting mothers who are tracking their menstrual cycles and ovulation. Based on the information you provided, let's break down the timeline and clarify how conception is typically calculated.

1. Menstrual Cycle Overview: You mentioned that your menstrual cycle lasts about 34-36 days, with your last period starting on April 5 and lasting until April 11. This means your next expected period would be around May 9 to May 11, depending on the length of your cycle.

2. Ovulation Timing: Ovulation generally occurs about 14 days before your next expected period. Given your cycle length, ovulation would likely occur around April 25 to April 27. You noted that your ovulation app indicated April 25 as the ovulation day, which aligns with this estimate.

3. Conception Window: Sperm can survive in the female reproductive tract for up to five days, so if you had unprotected intercourse on April 17, the sperm could potentially fertilize an egg released during ovulation. The egg itself is viable for about 12-24 hours after ovulation. Therefore, if you ovulated on April 25, the window for conception would be from April 21 to April 27.

4. Testing for Pregnancy: You mentioned taking pregnancy tests on April 28 and 30, both of which were negative. This is not uncommon, as it can take time for the hormone hCG (human chorionic gonadotropin) to build up in your system after conception. The faint positive result you received in mid-May suggests that implantation likely occurred around that time, which is consistent with conception occurring shortly after ovulation.

5. Ultrasound Confirmation: The ultrasound you had in early June showing that you were about seven weeks pregnant would correlate with a conception date around April 21, which is consistent with your ovulation date and the timeline of your menstrual cycle.

In summary, based on your cycle and the timing of ovulation, it is likely that conception occurred around April 21. The negative pregnancy tests on April 28 and 30 can be attributed to testing too early, as hCG levels may not have been high enough to detect at that time.
If you have further concerns about your pregnancy or conception dates, it is always a good idea to consult with your healthcare provider. They can provide personalized advice and support based on your specific situation. Additionally, tracking your menstrual cycle and ovulation can help you better understand your fertility patterns in the future.
Remember, every woman's body is different, and factors such as stress, health conditions, and hormonal fluctuations can all influence your cycle and ovulation. It's important to be patient and attentive to your body's signals as you navigate this exciting journey into motherhood.

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