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How To Determine The Date Of Conception Using LMP?

Posted on Tue, 12 May 2015

Question: I took a pregnancy test (clear blue advance) on Monday 04/20 and it stated that I pregnant between 2 – 3 weeks.
I need to know when I conceive and unfortunately I am in a situation that is I have intimate with 2 people.
My intimate date is:
04/03
03/27
03/18
03/15
My period as follows:
it seems that my period is not that consistent (most of the time late)
2015-03-07 finish on 03/11
2015-02-06
2015-01-03
2014-11-26
2014-10-28
2014-09-20
2014-08-16
2014-07-10
2014-06-07
2014-05-06
2014-03-30
2014-02-10

Answered by Dr. Dr. Soumen Patra (44 minutes later)

Brief Answer:
03/27 is your conceiving date (mostly). Do TVS scan.

Detailed Answer:
Hello,

Thanks for writing to us. I understand your concern.

According to previous menstrual history, I assume that your period occurs mostly in between 30-35 days (Not consistent).

Your LAST period date was 7th March and next period due date was in between 5th to 10th April.

Ovulation occurs approx 14 days prior to next period due date. In this case, you ovulated in between 22nd to 27th March.

As you intimated on 27/03 (close to your ovulation day or fertile period), I think that it will be your fertilization day or conceiving date.

I suggest you to undergo one Trans vaginal Ultrasound scan to determine the gestational age of the baby and exact conception date (determined by growth and development). Lastly, one DNA test will be worthwhile to confirm paternity with 100% accuracy.

Hope, it helps for your information. If you don't have any other query, you can close the discussion.

Wish your good health and take care yourself.

Regards,
Dr S Patra

For future query, you can directly approach me through

http://doctor.healthcaremagic.com/Funnel?page=askDoctorDirectly&docId=63326

Above answer was peer-reviewed by : Dr. Raju A.T

Follow up: Dr. Dr. Soumen Patra (1 hour later)

Dr. Patra,
Based on your information; if I would ovulate in between 22 to 27 - there is some period before and after that period that I will be still ovulating.
That is my biggest concern.
The one in question is on the 03/04 (april 3) since this is the one that I have intimate with the second person.
What is the possibility of the 03/04 (april 3) intimacy to be the conceiving date in comparison to 03/27; 03/18; 03/15.
Also, will it be depend on the fertility of the sperm from the first and the second person?
How soon can I go with the Trans Vaginal Ultrasound?
How soon can I do the DNA test?

Thanks
XXXXX

Answered by Dr. Dr. Soumen Patra (6 hours later)

Brief Answer:
Details are given below.

Detailed Answer:
Hello,

Thanks for follow up query.

1) Mild spotting or bleeding may occur prior to ovulation due to sudden drop of estrogen level. It is seen among few percentage women.

2) According to your last period date, possibility of conceiving on 3rd April is quite unlike or extremely RARE because you DIDN'T ovulate on that day.

3) After ovulation, ovum can survive 12-24 hrs and after ejaculation, sperm can survive 48-72 hrs inside female genital tract. Therefore, fertilization on 03/04 is quite impossible or unlike.

4) You can undergo Trans vaginal ultrasound scan in this week because you are 3+ weeks pregnant after fertilization.

5) The highly accurate GENETIC DNA Test for paternity may be performed before birth of the child. It can be undergone within 10-15 weeks of gestational age. It is invasive test and you need to take your obstetrician opinion.

Hope, I have answered your query. Kindly, close the discussion if you don't have any other query.

All the best and good luck.

Regards,
Dr S Patra

Note: For further follow up on related General & Family Physician Click here.

Above answer was peer-reviewed by : Dr. Prasad