QuestionQUESTION: If the baby is conceived on November 23 or 24 would it be possible to hear the babys heartbeat through ultrasound on December 23.That would barley be four weeks from time of conception. When I went for my first appointment I was not for sure of my LMP, so they did an ultrasound to see how far along I was. I am asking because I thought he was conceived on the November 11 or around there. Really confused.
ANSWER: Dear Stephanie,
Here may be the source of your confusion...
The calculation of gestational age, or pregnancy dating, is not actually based on the conception date. It is based on the LMP date. Always. Even if the LMP date is not known and even if the dating is determined via ultrasound. The ultrasound will automatically calculate the gestational age determined by the measurements of the fetus or gestational sac, etc,..., but that is all based on norms for gestational age calculated from LMP. The actual "full-term" confinement of pregnancy is 40 weeks from LMP to delivery. It is assumed that conception takes place two weeks after the LMP date because most menstrual cycles last 28 days, with ovulation occurring on/about CD 14-15. I know... this is very confusing for women, but that is just how it is.
So... If your baby was conceived on 11/24, then you would have been 6 weeks, 1 day on 12/23 and YES - it would be possible to visualize heart activity at 6 weeks gestation.
I hope that this information has helped you and answered your question. I wish you well!
Brenda
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QUESTION: Thank you for responding to my question and it makes more sense but, I actually heard the heartbeat beating through a vaginal ultra sound. I have been told by several different people that i would only be able to see it beating at 6 weeks not actually hear it. Maybe you could clear this up for me as well.
ANSWER: Dear Stephanie,
Yes, it would typically be a visual via ultrasound. I wonder if they had you on a heart monitor as well and you heard your own heart beat? Also, they have doppler monitors to hear fetal heart tones, but usually you cannot pick that up this early.
Hope that helps a bit. Sorry for the delay in answering. BUSY week!
Brenda
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QUESTION: Brenda ~ Thank you so much for your answers. Basically I am just trying to figure out if he was concieved on November 8-10 or November 24. I feel like that is a big time difference and my doctor should be able to tell me. I do not recall my last LMP date but I am almost positive I did not have one in Novemeber and if I did it was spotty and weird. So at my first appointment they said I was 7 weeks and a couple days my doctor used a LMP date that is not even correct and the vaginal ultra sound to figure my due date of August 8. My doctor says that it would have been possible to hear the fetal heart beat through the vaginal ultra sound at 6weeks, but I have had several people even another doctor tell me it would have been to early if he was concieved on Nov. 24 to hear it even through a vaginal ultrra sound. Secondly when I went to get my ultra sound to find out that i am having a boy he weighed a little over 10oz. and if the November 24 date is correct he would have only been 18 weeks and weighs a lot more than average fetus at that time. But the 10oz. fits with the Nov.9-10 conception date. Also, the November 24 conception date would put my LMP around the time of the November 9 conception date which i know for a fact i did not have one that week, like i said I am almost positive i did not have one at all and they are usually towards the end of the month. I know that is alot of information and you probably cant even tell me one way or the other but if you can at least tell me what date you are leaning more towards that would be very helpful. Thank you for you time.
AnswerDear Stephanie,
OK...again, at 6 weeks, it absolutely is possible for a fetal heartbeat to have been seen via vaginal ultrasound. The gestational sac can typically be visualized as early as 4.5 weeks of gestation and the yolk sac at about 5 weeks. The embryo can usually be observed and measured by about 5.5 weeks. A visible heartbeat can often be seen and detected by ultrasound at about 6 weeks and is usually clearly detectable by 7 weeks. In general, ultrasonography dating of a pregnancy is more accurate than dating using the date of the mother's last menstrual period. The biometric crown-rump measurement (CRL) of the six to 12-week fetus provides the MOST accurate measurement - within three days of true gestational age. From 12 to 18 weeks gestation, other anatomic structures are typically measured and biometric measurements are usually accurate to within a week of gestational age. After 26 weeks gestation, fetal variability has greatly increased and the dating provided by biometric measurement is less accurate, but the method is still used. By late in the third trimester, measurements are accurate only within a two-to three-week window. This is because, after the 1st trimester, babies can begin to grow at different rates due to varying factors - maternal health or lifestyle, uterine conditions, genetics, etc,... So -- your later ultrasound will not be as accurate in dating the pregnancy as the first one was.
Whatever the 12/23 ultrasound determined your gestational week and due date to be would have been most accurate. The ultrasound DOES NOT use your LMP to determine dating. It measures the gestational sac, yolk sac, and/or fetus and determines the gestational age that way - irregardless of the LMP. Your LMP is assumed; it is not programmed in or anything.
If you send me exactly what your gestational age was determined to be OR what the due date was determined to be at the 12/23 ultrasound, I can calculate your estimated conception date for you. I will be off for about a week, but watch for me to come back up and go ahead and submit it and I'll try to help you with the more specific information.
Hope that helps. Be well.
Brenda
