How Many Weeks Pregnant Am I Based on My Last Period?

Q: How Many Weeks Pregnant Am I Based on My Last Period?

Phase One： The calculation of gestational weeks begins from the first day of your last menstrual period, which is considered the first day of the current pregnancy (in reality, conception occurs about two weeks later). <br>Therefore, when referring to gestational weeks, it is typ

Could you please clarify how many weeks pregnant this is?

Based on the information provided, if the first day of your last menstrual period (LMP) was April 15, and you received a positive pregnancy test on June 9, you would be approximately 8 weeks pregnant.
This is calculated by counting from the first day of your last menstrual period.

bb, 30~39 year old female. Ask Date: 2006/06/15

Dr. Zhong Wenzhen reply Obstetrics and Gynecology

Phase One: The calculation of gestational weeks begins from the first day of your last menstrual period, which is considered the first day of the current pregnancy (in reality, conception occurs about two weeks later).
Therefore, when referring to gestational weeks, it is typically two weeks more than the actual conception weeks.
Phase Two: As for determining your gestational age, it is difficult to assess, but fortunately, within the next two weeks, an ultrasound examination measuring the biparietal diameter (the distance from the top of the head to the buttocks) can accurately determine the gestational age.
Based on estimations, your conception date could range between April 30 and May 29, as conception on April 30 may not yield a positive pregnancy test on May 10, while a positive result on June 9 would indicate that conception likely occurred at least 10 to 14 days prior.

Reply Date: 2006/06/15

More Info

To determine how many weeks pregnant you are based on your last menstrual period (LMP), we typically start counting from the first day of your last period. In your case, you mentioned that the first day of your last menstrual period was April 15.
Pregnancy is usually calculated in weeks, and it is important to note that the standard method of calculating pregnancy duration begins from the LMP, not the actual date of conception. This is because most women do not know the exact date of ovulation or conception, but they can reliably identify the first day of their last menstrual period.

Given that your last menstrual period started on April 15, we can break down the timeline as follows:
1. LMP Date: April 15
2. Estimated Ovulation: Typically, ovulation occurs about 14 days after the first day of your last period, which would be around April 29.

3. Conception Window: If you conceived around the time of ovulation, this would likely be between April 29 and May 1.

4. Pregnancy Test Results: You mentioned that you took a pregnancy test on May 10 and received a negative result, which suggests that you were not yet producing enough hCG (the hormone detected by pregnancy tests) to show a positive result. By June 9, you received a positive result, indicating that you were likely pregnant by that time.

To calculate how many weeks pregnant you are as of today, we can look at the timeline:
- From April 15 to June 9 is approximately 8 weeks.

- Since pregnancy is calculated from the LMP, you would be considered about 8 weeks pregnant as of June 9.

However, since you received a positive pregnancy test on June 9, it is likely that you were around 4 to 5 weeks pregnant at that time, depending on the exact timing of ovulation and conception.
In summary, as of June 9, you would be approximately 8 weeks pregnant based on the LMP, but the positive test indicates that you were likely around 4 to 5 weeks pregnant at that time.
It's important to consult with a healthcare provider for an accurate assessment and to confirm the gestational age through an ultrasound, which can provide a more precise estimate of how far along you are in your pregnancy. Ultrasounds are particularly useful in early pregnancy to measure the size of the embryo or fetus and can help clarify any discrepancies in dating based on LMP versus actual conception dates.

In conclusion, based on your last menstrual period starting on April 15, you are approximately 8 weeks pregnant as of June 9, but the positive pregnancy test suggests you were likely around 4 to 5 weeks pregnant at that time. Always consult with a healthcare professional for personalized advice and care during your pregnancy.

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