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How To Determine The Conception Date?
Question: I am now 26 and a half to 27 weeks when did I conceive if my period was January 10th and was due on February 2nd?
Brief Answer:
around January 20th to 28th. ..
Detailed Answer:
Hi my dear,
First, congratulations for your incoming baby.
Now, coming to your question, If your last period was on January 10th and you are almost 27 weeks pregnant, then :
- most probably, your conception was around January 20 to 28 (most fertile days) while you might have been ovulating around 24th of January.
Hope it answered to your primary question.
Dr.Albana
around January 20th to 28th. ..
Detailed Answer:
Hi my dear,
First, congratulations for your incoming baby.
Now, coming to your question, If your last period was on January 10th and you are almost 27 weeks pregnant, then :
- most probably, your conception was around January 20 to 28 (most fertile days) while you might have been ovulating around 24th of January.
Hope it answered to your primary question.
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you. This confuses me because if I ovulated on the 24th that would give me a lethal phase of 9 days as my period was due February 2nd. I was thinking it would of had to been 18-21st? I could be wrong but that would give me the right luethal phase?
My cycle is 23 days if that helps. When I plug it in online it says i conceived anywhere from 15 the day after my bleeding ended to 21st. Which cycle right since I have 23 day cycle meaning I would ovulate on day 8-10 most likely 9?
My cycle is 23 days if that helps. When I plug it in online it says i conceived anywhere from 15 the day after my bleeding ended to 21st. Which cycle right since I have 23 day cycle meaning I would ovulate on day 8-10 most likely 9?
Brief Answer:
Please provide first date of last 3 monthly periods
Detailed Answer:
Hi back my dear,
Thank you for providing additional data.
Now, you say you have a 23 days monthly cycle. At this point, I need to be sure it is really 23days. Can you provide the first date of your last 3 monthly periods?
My calculations were based on a cycle of 28 days.
If you really have a 23 days cycle, it means that your most fertile days were January 16 to 21.
However, I still need to have the first date of the last 3 monthly periods for a more accurate answer.
Thank you!
Dr.Albana
Please provide first date of last 3 monthly periods
Detailed Answer:
Hi back my dear,
Thank you for providing additional data.
Now, you say you have a 23 days monthly cycle. At this point, I need to be sure it is really 23days. Can you provide the first date of your last 3 monthly periods?
My calculations were based on a cycle of 28 days.
If you really have a 23 days cycle, it means that your most fertile days were January 16 to 21.
However, I still need to have the first date of the last 3 monthly periods for a more accurate answer.
Thank you!
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
I only know the one I had in December I used to be irregular which is why I had trouble conceiving. But the past year or so it has been consistent with 23 or 22 days. The one in December was December 18 or 19th I believe
If this helps in I got 4 positive urine test February 2nd as I didn't get my period. I would think anything after the 23rd would be a stretch since that's only 10 days.
If this helps in I got 4 positive urine test February 2nd as I didn't get my period. I would think anything after the 23rd would be a stretch since that's only 10 days.
Brief Answer:
explained below. .
Detailed Answer:
Hi back my dear,
Indeed, when having irregular periods, it us difficult to calculate the conception date.
Usually, I ask my patients about the first date of 3 last monthly periods, so it would be easier for me to give answers regarding conciving date.
In your case, if positive on 2nd of February, then, taking into account that this starts to happen after 6 days of fertilization. However, here I need to know if the test you did on 2nd February was the first? If not, then when was the first time the test resulted positive?
Still I think your most fertile days were between 16 to 21 January.
Dr.Albana
explained below. .
Detailed Answer:
Hi back my dear,
Indeed, when having irregular periods, it us difficult to calculate the conception date.
Usually, I ask my patients about the first date of 3 last monthly periods, so it would be easier for me to give answers regarding conciving date.
In your case, if positive on 2nd of February, then, taking into account that this starts to happen after 6 days of fertilization. However, here I need to know if the test you did on 2nd February was the first? If not, then when was the first time the test resulted positive?
Still I think your most fertile days were between 16 to 21 January.
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Yes this was my first time as I got 4 positives on the second. The way doctor explained it to me. For 25miu urine test to get positive you need to be 10days pregnant as it starts at five and doubles every 48-72 hours so at 10 days in around 20miu so anything before that I dont think would have gotten it which is why I think I ovulated around the 20th I knew I was pregnant on the 1st as I looked and felt bloated beyond belief
I could be wrong but if I got pregnant on the 24th I dont think I would feel symptoms 8 days later.
But 12-15 days later sounds more realistic to me. Obviously I'm no doctor but it would be hard for me to believe. Knowing my luethal phase has to be at least 12 days. I would think 21st or earlier. Which goes along perfect with 27 weeks? Am I wrong?
I could be wrong but if I got pregnant on the 24th I dont think I would feel symptoms 8 days later.
But 12-15 days later sounds more realistic to me. Obviously I'm no doctor but it would be hard for me to believe. Knowing my luethal phase has to be at least 12 days. I would think 21st or earlier. Which goes along perfect with 27 weeks? Am I wrong?
Brief Answer:
Ovulation occurs 2 weeks before due date;blood b-HCG test most accurate..
Detailed Answer:
Hi back my dear,
Sorry for the late reply.
First, try not to worry.
2-nd you are saying to be 27 weeks pregnant. Have you run the b-HCG blood test? This will give your actual pregnancy age in the most accurate way.
Ovulation occurs 2 weeks before your due date. So, if your due date was February 2nd, then, ovulation might have occurred around January 19th.
All the best!
Dr.Albana
Ovulation occurs 2 weeks before due date;blood b-HCG test most accurate..
Detailed Answer:
Hi back my dear,
Sorry for the late reply.
First, try not to worry.
2-nd you are saying to be 27 weeks pregnant. Have you run the b-HCG blood test? This will give your actual pregnancy age in the most accurate way.
Ovulation occurs 2 weeks before your due date. So, if your due date was February 2nd, then, ovulation might have occurred around January 19th.
All the best!
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
No I did not would you like to see the first ultrasound. Then I will show you the one when they changed it.
When I went on February 3rd to confirm my pregnancy they estimated I was 2-3 weeks. First conception date was 25 January but they changed it when I was at 12 weeks 4 days they said I was closer to 14 weeks and now I'm 27 weeks and 2 days.
When I went on February 3rd to confirm my pregnancy they estimated I was 2-3 weeks. First conception date was 25 January but they changed it when I was at 12 weeks 4 days they said I was closer to 14 weeks and now I'm 27 weeks and 2 days.
Brief Answer:
Yes, can send the reports for further evaluation
Detailed Answer:
Hi back my dear,
Yes, you can send both ultrasound reports and let me have a look at them.
Please bare in mind that the most accurate method to determine the exact age of pregnancy is measuring the b - HCG in the blood.
With regards to ultrasound, having it February 3rd would have confirmed pregnancy but not the exact age. This is because it was too early. This also explains why the date was changed at 12th week.
In fact, the second ultrasound you did on February 12 could have given also a probable age of pregnancy and determined due date. However, still I insist that measuring b - HCG is the most accurate method to determine the final age of pregnancy.
Looking forward to have the reports in.
Dr.Albana
Yes, can send the reports for further evaluation
Detailed Answer:
Hi back my dear,
Yes, you can send both ultrasound reports and let me have a look at them.
Please bare in mind that the most accurate method to determine the exact age of pregnancy is measuring the b - HCG in the blood.
With regards to ultrasound, having it February 3rd would have confirmed pregnancy but not the exact age. This is because it was too early. This also explains why the date was changed at 12th week.
In fact, the second ultrasound you did on February 12 could have given also a probable age of pregnancy and determined due date. However, still I insist that measuring b - HCG is the most accurate method to determine the final age of pregnancy.
Looking forward to have the reports in.
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
The one that said 12 weeks and 4 days was April 9th. But when I got me 3d on later that appointment turns out I was closer to 14 weeks and currently 27 weeks and 4 days
Brief Answer:
There is a tolerance of +/- 2 weeks when analyzing ultrasound report...
Detailed Answer:
Hi back my dear,
Try not to worry, when you analyze an ultrasound report, we consider its accuracy +/- 2 weeks. This is because the age is usually determined by measuring the head circumference and the length of femur (thigh bone) which might differ depending on the development of the baby.
So, if you took the ultrasound on April 9th, it resulted 12 weeks but in fact, we admit it might be 10 weeks or 14 weeks. This explains why the 3rd ultrasound resulted 14 weeks.
Even today, if you say you are 27 weeks, we still think you are 25 or 29 weeks; so nothing worrisome as long as your baby is healthy and pregnancy is going well.
All this confusion has been created because your periods were irregular. However, this should not be a problem.
Forget the age for the moment (although I know it is important for you) and focus on carrying on your pregnancy until you'll have your baby on your arms.
All the best my dear!
Dr.Albana
There is a tolerance of +/- 2 weeks when analyzing ultrasound report...
Detailed Answer:
Hi back my dear,
Try not to worry, when you analyze an ultrasound report, we consider its accuracy +/- 2 weeks. This is because the age is usually determined by measuring the head circumference and the length of femur (thigh bone) which might differ depending on the development of the baby.
So, if you took the ultrasound on April 9th, it resulted 12 weeks but in fact, we admit it might be 10 weeks or 14 weeks. This explains why the 3rd ultrasound resulted 14 weeks.
Even today, if you say you are 27 weeks, we still think you are 25 or 29 weeks; so nothing worrisome as long as your baby is healthy and pregnancy is going well.
All this confusion has been created because your periods were irregular. However, this should not be a problem.
Forget the age for the moment (although I know it is important for you) and focus on carrying on your pregnancy until you'll have your baby on your arms.
All the best my dear!
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Yes all is going well doctor says. But I only had 2 in first trimester. The first one I ever took on February 25th I was 6 weeks and 4 days. But the second one I took I messed a month later at 12 weeks and 4 days but when they measured wrong is what the doctor said and I was really closer to 14 weeks instead of 12. Meaning I was really 7 weeks to 8 at first ultrasound. If the first measurement was right I'd be 26 weeks and 2 days. But I am 27 and 4 days. I guess for me its which one should I trust. Maybe the one at the original conception date was XXXXXXX 25th. But moved it to XXXXXXX 15th which matches perfect since I missed my period on the first of February. So I guess I should trust the second one. The first one was also done at the clinic not with my actual doctor oddly enough she didn't Change the due date
Brief Answer:
ultrasound report on 12th weeks more accurate
Detailed Answer:
Hi back my dear,
As I said earlier, if you tested positive on February 2nd, and with a cycle of 23 days, then your conception would have occurred earlier than 25th January.
You should trust ultrasound report on 12th week that would show a more accurate pregnancy age.
Try not to worry too much and enjoy pregnancy.
All the best!
Dr.Albana
ultrasound report on 12th weeks more accurate
Detailed Answer:
Hi back my dear,
As I said earlier, if you tested positive on February 2nd, and with a cycle of 23 days, then your conception would have occurred earlier than 25th January.
You should trust ultrasound report on 12th week that would show a more accurate pregnancy age.
Try not to worry too much and enjoy pregnancy.
All the best!
Dr.Albana
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
Thank you, I will trust the one where I was supposed to be 12 weeks but instead I was closer to 14. I was just told earlier ones are more accurate but if they messed up then ill have to trust them. It just buggs me they didn't change due date. Still October 18th. But thank you doctor. Have good day.
Brief Answer:
Ok,God bless!
Detailed Answer:
Hi back my dear,
I am happy to hear that you will be at peace now. Forget about conception and focus on your incoming baby. Delivery/due date can't be changed although we (doctors) still give a tolerance of 2 weeks.
So, you can delivery safely 2 weeks (14 days) before 18 October (around 4); or, in case no delivery until 18, then, can wait safely for 2 other weeks (around 2 November- last date).
Actually, the doctors usually give 2 dates for safe delivery:)
All the best and God bless both of you!
Dr.Albana
P.s. if no more query and if your doubts are all cleared, please do not forget to close this discussion! Thank you!
Ok,God bless!
Detailed Answer:
Hi back my dear,
I am happy to hear that you will be at peace now. Forget about conception and focus on your incoming baby. Delivery/due date can't be changed although we (doctors) still give a tolerance of 2 weeks.
So, you can delivery safely 2 weeks (14 days) before 18 October (around 4); or, in case no delivery until 18, then, can wait safely for 2 other weeks (around 2 November- last date).
Actually, the doctors usually give 2 dates for safe delivery:)
All the best and God bless both of you!
Dr.Albana
P.s. if no more query and if your doubts are all cleared, please do not forget to close this discussion! Thank you!
Above answer was peer-reviewed by :
Dr. Chakravarthy Mazumdar
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