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How To Determine The Date Of Conception?
Question: Hey Doctor I have a extended question for you regarding a Conception situation. I had sex with a girl on March 18,2016 and April 5 2016 which was the day before the start of her LMP. She actually started bleeding (SPOTTING) on April 6,2016 . She had an ultrasound done on XXXXXXX 2 2016 which stated she was 8 weeks and 1 day pregnant. She also mentioned that she had been having sex with another guy around April 18-27 of 2016,but said she had protected sex with him and they only had sex ONE TIME!! however I don't know If that's true. Can you explain to me what are the chances she was conceived . I am unsure if she got pregnant by me or the other guy. I use the pull out method but I don't know if that was enough . Today I believe she is 16 weeks and 5 days pregnant from her last LMP. Also she is saying her doctor said she got pregnant the week of of her LMP is that true? From my understanding , the fetal age is usually 2 weeks less than her gestational age. If this is true how can this possibly be my child if we only had sex the day before her LMP which was April 5,2016. She also said the doctor gave her the expected due date of January 11,2017(40 weeks) . Overall based on all the information given what could have possibly happen wrong in the ultrasound scan and or the information given for her to believe the child is mines and not someone else. I am basically asking what are the chances this could be my child based on the facts of the information given in the scan and whats is given in the discussion. Can the fetal age and gestational age be the same or that close in the week? Have you heard of any special cases where this could be possible? I need to ensure that I am not the father of the child? Also I was researching about ovulating periods and found out that most ovulation can occur 11-21 after the first day of the menastrual cycle or 12-16 days before the next expected period.With that being stated , Please see the attached ultrasound scan and her external stomach view in the update report section of this discussion. The second picture is dating back to July 20,2016 of her external stomach view, if that helps.
Brief Answer:
DON'T worry, your sex acts are not responsible for conception.
Detailed Answer:
Hi
Dr. Purushottam welcomes you to HCM virtual clinic!
Thanks for consulting at my virtual clinic. I have carefully gone through your query, and I think I have understood your concern. I will try to address your medical concerns and would suggest you the best of the available treatment options.
1)First of all do not panic.
2) USG reports till 8 to 10 weeks are supposed to give accurate gestational age, with hardly 2 to 3 days plus minus average.
- as per USG XXXXXXX 2,2016 pregnancy is 8+2 weeks = LMP as April 6,2016.
- EDD(40 weeks) asper USG, January 11,2017 = LMP as April 4, 2016.
- ovualtion date will be in between 13 to 20 April.
- so chances of conception are with sex act in this duration only.
3)As per your history you had sex activity with this woman on on 18th March and 5th April.
With both calculations as above, she stands no chance of conception out of sexual acts with you. So there is no possibility of getting her pregnant from you.
If she still has such a claim, DNA paternity test can be an option later on.
But as of now, be sure that you are not the father of the baby.
4) It is out context of your question, but the lady always has options and right to terminate unwanted pregnancy if she feels so ; as per the laws of the land where she is staying.
I can understand , how disturbing it must be for you to be hold responsible for fatherhood of the baby. But please be assured that medical or biological facts are supporting that you are not responsible for this pregnancy.
I hope my answer helps you.
Thanks.
Wish you great health.
Dr Purushottam S Neurgaonkar
DON'T worry, your sex acts are not responsible for conception.
Detailed Answer:
Hi
Dr. Purushottam welcomes you to HCM virtual clinic!
Thanks for consulting at my virtual clinic. I have carefully gone through your query, and I think I have understood your concern. I will try to address your medical concerns and would suggest you the best of the available treatment options.
1)First of all do not panic.
2) USG reports till 8 to 10 weeks are supposed to give accurate gestational age, with hardly 2 to 3 days plus minus average.
- as per USG XXXXXXX 2,2016 pregnancy is 8+2 weeks = LMP as April 6,2016.
- EDD(40 weeks) asper USG, January 11,2017 = LMP as April 4, 2016.
- ovualtion date will be in between 13 to 20 April.
- so chances of conception are with sex act in this duration only.
3)As per your history you had sex activity with this woman on on 18th March and 5th April.
With both calculations as above, she stands no chance of conception out of sexual acts with you. So there is no possibility of getting her pregnant from you.
If she still has such a claim, DNA paternity test can be an option later on.
But as of now, be sure that you are not the father of the baby.
4) It is out context of your question, but the lady always has options and right to terminate unwanted pregnancy if she feels so ; as per the laws of the land where she is staying.
I can understand , how disturbing it must be for you to be hold responsible for fatherhood of the baby. But please be assured that medical or biological facts are supporting that you are not responsible for this pregnancy.
I hope my answer helps you.
Thanks.
Wish you great health.
Dr Purushottam S Neurgaonkar
Above answer was peer-reviewed by :
Dr. Prasad
Hey Doctor , I really appreciate your quick response. I have a few more questions in regards to this concern.
1) What does USG Stand for?
2) According to the EDD(40 weeks) asper USG, January 11,2017 = LMP as April 4, 2016., did you mean April 4 or did you mean April 6?
3) as per USG XXXXXXX 2,2016 pregnancy is 8+2 weeks = LMP as April 6,2016. What does the 8+2 weeks mean?
4) She also stated that she been on some meds/antibiotics to help with her intestines issues and said the doctor told her that the meds could have made her more accessible to getting pregnant. Would this contribute to her believing she got pregnant around the times we had sex? Also have you heard of meds contributing to late or early ovulation or periods?
4)
1) What does USG Stand for?
2) According to the EDD(40 weeks) asper USG, January 11,2017 = LMP as April 4, 2016., did you mean April 4 or did you mean April 6?
3) as per USG XXXXXXX 2,2016 pregnancy is 8+2 weeks = LMP as April 6,2016. What does the 8+2 weeks mean?
4) She also stated that she been on some meds/antibiotics to help with her intestines issues and said the doctor told her that the meds could have made her more accessible to getting pregnant. Would this contribute to her believing she got pregnant around the times we had sex? Also have you heard of meds contributing to late or early ovulation or periods?
4)
Brief Answer:
Even with helping medicines pregnancy happens only after ovulation .
Detailed Answer:
Hi there,
Thanks for appreciating the answer and reverting back.
1. USG means Ultra Sono Graphy. Popularly called as ultrasound examination.
2. 8+2 weeks meaning gestation of 8 weeks and 2 days size.
3. Counting LMP from USG guided EDD is for the sake of knowing approximate last Menstrual period, it helps to find out fertile period or likely duration of ovualtion and conception.In your situation it is definitely agter April 15 onwards.
4.The antibiotics can not make her more prone for conception. Even if she has taken medicines to enhance ovulation or easing out fertilization, pregnancy will not be there before ovualtion, means before April 15. And once again your sex act of April 5, has no contribution towards getting pregnancy.
Lastly , if she has got her periods after April5, then you be assured of no role of yours in her becoming pregnant.
I hope this answer helps you.
Thanks.
Dr. Purushottam Neurgaonkar
Even with helping medicines pregnancy happens only after ovulation .
Detailed Answer:
Hi there,
Thanks for appreciating the answer and reverting back.
1. USG means Ultra Sono Graphy. Popularly called as ultrasound examination.
2. 8+2 weeks meaning gestation of 8 weeks and 2 days size.
3. Counting LMP from USG guided EDD is for the sake of knowing approximate last Menstrual period, it helps to find out fertile period or likely duration of ovualtion and conception.In your situation it is definitely agter April 15 onwards.
4.The antibiotics can not make her more prone for conception. Even if she has taken medicines to enhance ovulation or easing out fertilization, pregnancy will not be there before ovualtion, means before April 15. And once again your sex act of April 5, has no contribution towards getting pregnancy.
Lastly , if she has got her periods after April5, then you be assured of no role of yours in her becoming pregnant.
I hope this answer helps you.
Thanks.
Dr. Purushottam Neurgaonkar
Above answer was peer-reviewed by :
Dr. Prasad
Ok great sounds good to me. So even with her telling me she spotted on April 6, does that mean she actually had a period?
Also, How does the Ultrasound scan procedure work when a woman goes in and get her first ultrasound?
1) Does the OB/GYN ask the lady what was her LMP, or is it calculated some other way?
2) Have you ever experienced a pregnancy where a woman said she got pregnant before her period?
3) Can you explain to me in full detail how accuracy of fetal ages and gestational ages are determined from the ultrasound scan and what cases can happen for the information to be inaccurate and another ultrasound scan may have to be done again?
Also, How does the Ultrasound scan procedure work when a woman goes in and get her first ultrasound?
1) Does the OB/GYN ask the lady what was her LMP, or is it calculated some other way?
2) Have you ever experienced a pregnancy where a woman said she got pregnant before her period?
3) Can you explain to me in full detail how accuracy of fetal ages and gestational ages are determined from the ultrasound scan and what cases can happen for the information to be inaccurate and another ultrasound scan may have to be done again?
Brief Answer:
Doctor asks for menstrual history.
Detailed Answer:
Hi there.
1. While doing Ultrasound, either Ob/gyn or sonologist does ask for the last date of menses, and brief history and regularity of the cycle.
2. It is not seen in the clinical practice that a woman gets pregnant and has her regular periods. Only chances are that she is pregnant and gets bleeding with pregnancy incidentally on the same days.
3. Ultrasound scan measures various baby parameters like diameter and circumference of baby's head , baby's length (CRL), abdomen circumference, femur and humerus bone lengths, and as per data in the software it gives estimated age in weeks for the baby.
Ultrasound scans in the 6 to 8 weeks of fetal size have accuracy about dating gestational age. It has only +/- 2 days margin. As the weeks of pregnancy advance then this cannot be so accurate. Later on ultrasounds are usually focussed on finding anomalies in the baby or looking fr normalcy of structures.
I hope this answer helps you.
Thanks ,
Dr Purushottam Neurgaonkar
Doctor asks for menstrual history.
Detailed Answer:
Hi there.
1. While doing Ultrasound, either Ob/gyn or sonologist does ask for the last date of menses, and brief history and regularity of the cycle.
2. It is not seen in the clinical practice that a woman gets pregnant and has her regular periods. Only chances are that she is pregnant and gets bleeding with pregnancy incidentally on the same days.
3. Ultrasound scan measures various baby parameters like diameter and circumference of baby's head , baby's length (CRL), abdomen circumference, femur and humerus bone lengths, and as per data in the software it gives estimated age in weeks for the baby.
Ultrasound scans in the 6 to 8 weeks of fetal size have accuracy about dating gestational age. It has only +/- 2 days margin. As the weeks of pregnancy advance then this cannot be so accurate. Later on ultrasounds are usually focussed on finding anomalies in the baby or looking fr normalcy of structures.
I hope this answer helps you.
Thanks ,
Dr Purushottam Neurgaonkar
Above answer was peer-reviewed by :
Dr. Raju A.T
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