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Date of last update: 10/14/2017.

Forum Name: Obstetrics

Question: Conception date acuracy based on CRL length

 tensedg - Fri Jul 23, 2010 5:33 pm


My First day of last LMP was 28 -march -2010. I have very irregular periods. After than I did not get my cycle.
On april -18-2010, my cousin forced me to have sex . I never had sex with any one other than my husband. Unfortunately I could not tell my husband as he may divorce me even if I am forced.

Me and my husband were trying for a baby and we had regular sex. I took pregnancy test on june -13-2010 and it came positive as my pregnancy symptoms started that day.

I had doctors appointment on june -25-2010 and doctor did vaginal scan and he said I am only 7 week pregnant. and he estimated my due date will be feb- 10- 2011.

On JUly- 12-2010 , again I had vaginal ultrasound(May be I was 9 week 4 days) and due date went to feb-14- 2011.

Doctor said my conception date is around May-20-2010. based on CRL length. How can I know who is the father.
Pls suggest
 Debbie Miller, RN - Sun Jul 25, 2010 6:03 pm

User avatar Hello,
The CRL dating is actually very accurate so I think you are safe to assume your husband is the father since this puts your conception date much later than your encounter with your cousin.

Best wishes.
 lashae - Tue Jul 27, 2010 1:16 pm

I have a similar query, which i would love some assistance.

I had sex the 9,10,17 of july 2010. My boyfriend and i had sex on the 9th without a condom but he came out and masturbated and then he ejaculated. However on the 10th he came in me. I took an emergency pill on the 11 @ 4 and the next one the following day at 4.

On the 17, we had sex and he pulled out, i am not sure if he came out in time but i do know that he came.

My period was due yesterday the 26th but has not come as yet, could i be pregnant?or due to taking the pill my cycle has become a little late? and if there is a possibility which day did i conceive?
 Debbie Miller, RN - Thu Jan 06, 2011 8:34 pm

User avatar Hello,
Pregnancy is always a possibility when you are sexually active and fertile. The emergency contraception is usually quite reliable so chances are not very good you would have become pregnant from the first encounter you mentioned. However, withdrawal is not an effective birth control method and you should use something else preventively. If you were to become pregnant and were unsure of the date, the doctor would order a dating ultrasound - done after a few weeks - to help estimate the due date.

A few days variation in period is considered normal so unless you are late by several days it could just be the normal variation.

Best wishes.

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