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How To Determine The Fertilization Date Inspite Of Having Positive Pregnancy Test?
Question: If I had my period on March 10th, had unprotected sex every weekend after that. The last encounter being on the 31rst of march. This encounter he didn't orgasm and I took the morning after pill 8 hrs later. On April 5th, 5 days after the lat encounter I took a at home pregnancy test and was positive. On April 18th I had a dating ultrasound and they dated me at 5 weeks 4 days. What is the probability that it was the march 31rst encounter?!
Brief Answer:
It was unlikely due to the March 31 encounter.
Detailed Answer:
Hello and welcome,
If the test was positive 5 days after the sexual episode, then that episode did not cause that pregnancy. It takes about 2-3 weeks after the sexual episode for the urine pregnancy test to come positive [ 2 weeks if the test is ultrasensitive one] . So if it was positive on 5th April, the pregnancy was conceived at least 2 - 3 weeks before 5th or even earlier.
You have used the I pill and also there was no orgasm [ I assume you mean release of sperms] so pregnancy is not possible on 31st March.
If the scan on 18 April said it was 5 weeks 4 days then the date of last menstrual period is around 10th March by the scan which is matching your date. The scan has an error of 3-4 days on either side in early pregnancy but still a urine test does not come positive within 5-6 days as the baby is still not attached to the mother and there are no detectable hormones at that time.
The pregnancy has been conceived at least around 20-23 March most likely and not later according to the scan.
Please also clarify if 10th March was the first or last day of the period for better calculations.
Hope this satisfies your query.
Thanks for using HCM.
Feel free to ask any more questions that you may have.
Dr Madhuri Bagde
Consultant Obstetrician and Gynecologist
It was unlikely due to the March 31 encounter.
Detailed Answer:
Hello and welcome,
If the test was positive 5 days after the sexual episode, then that episode did not cause that pregnancy. It takes about 2-3 weeks after the sexual episode for the urine pregnancy test to come positive [ 2 weeks if the test is ultrasensitive one] . So if it was positive on 5th April, the pregnancy was conceived at least 2 - 3 weeks before 5th or even earlier.
You have used the I pill and also there was no orgasm [ I assume you mean release of sperms] so pregnancy is not possible on 31st March.
If the scan on 18 April said it was 5 weeks 4 days then the date of last menstrual period is around 10th March by the scan which is matching your date. The scan has an error of 3-4 days on either side in early pregnancy but still a urine test does not come positive within 5-6 days as the baby is still not attached to the mother and there are no detectable hormones at that time.
The pregnancy has been conceived at least around 20-23 March most likely and not later according to the scan.
Please also clarify if 10th March was the first or last day of the period for better calculations.
Hope this satisfies your query.
Thanks for using HCM.
Feel free to ask any more questions that you may have.
Dr Madhuri Bagde
Consultant Obstetrician and Gynecologist
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you for answering my question in detail, it gives me less anxiety.
It was the beginning of my last menstrual cycle.
So you believe it was not the 31rst?
And also, I'm very nauseous is there anything that helps ?! I can't eat really, and I feel I'm not getting enough nutrition.
It was the beginning of my last menstrual cycle.
So you believe it was not the 31rst?
And also, I'm very nauseous is there anything that helps ?! I can't eat really, and I feel I'm not getting enough nutrition.
Brief Answer:
Detailed answer below.
Detailed Answer:
Hello and welcome back,
Yes 31st is unlikely as it is too early to give a positive result and also there was no ejaculation, I pill was taken so all factors favor that it was not 31st. If 10th was the first day then on an average the fertile period begins from 20 and ends at 30 with peak fertile days from 22 to 26.
For the nausea, it is very common during the first 3 months. Try to take a dry toast or bread before getting up from the bed in the morning. Get up slowly by turning on one side. Drink less liquids in the morning as that is the time when usually the nausea is the most severe. If these measure do not work use tablet doxinate once or twice daily depending upon the frequency of the nausea.
Also start tablet folic acid once daily 5mg as it helps in preventing brain defects in the baby. Get registered with a good doctor for antenatal care.
With these measures you will be fine.
Take care and feel free for any further queries.
Dr Madhuri
Detailed answer below.
Detailed Answer:
Hello and welcome back,
Yes 31st is unlikely as it is too early to give a positive result and also there was no ejaculation, I pill was taken so all factors favor that it was not 31st. If 10th was the first day then on an average the fertile period begins from 20 and ends at 30 with peak fertile days from 22 to 26.
For the nausea, it is very common during the first 3 months. Try to take a dry toast or bread before getting up from the bed in the morning. Get up slowly by turning on one side. Drink less liquids in the morning as that is the time when usually the nausea is the most severe. If these measure do not work use tablet doxinate once or twice daily depending upon the frequency of the nausea.
Also start tablet folic acid once daily 5mg as it helps in preventing brain defects in the baby. Get registered with a good doctor for antenatal care.
With these measures you will be fine.
Take care and feel free for any further queries.
Dr Madhuri
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Ok thank you so very much.
I appreciate all your answers.
Your the 20th doctor that has said it was not the 31rst, so I guess I should stop worrying.
As long as it wasn't then, I am great.
Thanks again.
Anything else you can tell me?!
I appreciate all your answers.
Your the 20th doctor that has said it was not the 31rst, so I guess I should stop worrying.
As long as it wasn't then, I am great.
Thanks again.
Anything else you can tell me?!
Brief Answer:
Thanks for the appreciation, makes my day.
Detailed Answer:
Hello and welcome back,
Please do not worry so much. There is nothing else that is needed apart from a good doctor for regular follow up and care. Take folic acid and doxinate for nausea, do not over exert yourself [ work as much as you can tolerate without fatigue] avoid prolonged standing, take short frequent meals and take intermittent short breaks during work to rest.
With these you should do well.
I am always here for any further queries.
All my best wishes for a safe pregnancy are with you.
Dr Madhuri
Thanks for the appreciation, makes my day.
Detailed Answer:
Hello and welcome back,
Please do not worry so much. There is nothing else that is needed apart from a good doctor for regular follow up and care. Take folic acid and doxinate for nausea, do not over exert yourself [ work as much as you can tolerate without fatigue] avoid prolonged standing, take short frequent meals and take intermittent short breaks during work to rest.
With these you should do well.
I am always here for any further queries.
All my best wishes for a safe pregnancy are with you.
Dr Madhuri
Note: Revert back with your gynae reports to get a clear medical analysis by our expert Gynecologic Oncologist. Click here.
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
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