I would like to know the accuracy of ultrasounds in the first trimester. Would it be possible for them to be off weeks? I slept with someone on the late night Jan He used a condom, I believe I was on birth control but cant remember for sure , and took Plan B 55 hours later. I had sex with another partner ufatgirlnmotion.comotected for the month of Feb - currently. Given this information, would it be possible that all of my ultrasounds were a month off and I conceived Jan 18?
All you have to do it type the length of the menstrual cycle and the first day of last period. When you will input this information, the calculator will generate the answer. If you want to calculate your gestational age, then add two weeks to the answer.
Special cases of having longer or shower cycles require extra steps. But that is why you calculate the date manually.
A conception calculator considers the fact that a pregnancy lasts for 40 weeks. It does consider the personal cts by incorporating the length of the menstrual cycle in its calculations. However, only about 5 in births are on the due date.
Rest all are either earlier or later. The wheel conception calculator at gynecologist clinic is the non-digital version. When you use the information from ultrasound scans along with conception calculator, the results are accurate.
The date of conception is an assumption but the ultrasound shows the growth of the baby. So, dating scans are more reliable than the conception calculator. But once the baby crosses the 18th week, it is difficult to figure out due date using ultrasound. The crown to rump ratio is only good for the fetus.
You can even use an ovulation calculator to find out the date of conception. Ovulation after the first day of last period before you conceived will be used to calculate.
Ultrasound dating accuracy conception
Most women ovulate between the 11th to 14th day after the first day of the period. Conception can occur practically only within 24 hours after ovulation.
So the date of ovulation will also be conception date. The reason for taking the first day of last period and not the last day is the length of the luteal phase.
Some calculators require you to input information about the luteal phase too.
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When the egg is out of the ovary, the follicle secretes progesterone. This stage is the luteal phase.
When a woman has a longer cycle, her luteal phase remains constant. However, her ovulation date shifts ahead of the 14th day.
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Some babies are naturally larger than average. If your baby is larger, his measurements won't line up with others at the same gestational age. The estimated gestational age is likely to appear incorrect because the measurements would lump your baby in with babies further along in development.
Hormone levels in the blood give the doctor an idea of how far along a woman's pregnancy is.
Is it possible to calculate the day I conceived? Can I increase my chances of having a girl?
The ultrasound combined with the hormone levels and the date of the woman's last period give an accurate estimation, especially if all of the methods give a similar time frame. Later in the pregnancy, the obstetrician or midwife uses measurements of the expectant mother's abdomen.
Called the fundal height, the measurement used goes from the top of the uterus to the pubic bone. This measurement in centimeters usually corresponds to the point in the pregnancy, so a woman at 24 weeks pregnancy should measure around 24 cm. Based in the Midwest, Shelley Frost has been writing parenting and education articles since Her experience comes from teaching, tutoring and managing educational after school programs.
Abdominal ultrasound is not as reliable as vaginal scan, however ALL first trimester ultrasounds are accurate in estimating the gestational age, and have maximum error upto a week.
All of them cannot be way off by a month, so do not worry. Also, you had a condom as protection, took Plan B, and then were on probable birth control too - so chances of conception are nil.
How Ultrasound Can Determine Your Conception Date An ultrasound is yet another way to help establish a conception date. There may be some concern as to how accurate the conception date from an ultrasound would be, and it is actually one of the best and most accurate ways to determine when you are likely to fatgirlnmotion.com: Dr. Vilma Ruddock. The first ultrasound, done between six to ten weeks in your pregnancy, is considered the most accurate method to predict your due date. Ultrasounds that are done later in your pregnancy are not that accurate, and that's why your due date shouldn't be changed if it is already set in the first trimester. Ultrasound examinations from 12 to 22 weeks are regarded as being within 10 days of accuracy (or up to 10 days earlier or 10 days later than the woman's calculated due date). Ultrasounds performed after 22 weeks gestation cannot be used to estimate the due date of the baby because the size no longer reflects the age very well.
If the embryo had lived through the withdrawal bleeding, and then measured small in the first abdominal scan, subsequent scans at 11 weeks, 14 weeks etc would have definitely picked up the discrepancy. You had ultrasound pretty frequently, so that possibility can be ruled out. Hope this helps, please feel free to discuss further.
All the best. Thank you very much for the detailed reply. I have just been concerned because I did not take Plan B until 55 hours after the encounter.
Is it still effective then?
When you use the information from ultrasound scans along with conception calculator, the results are accurate. The date of conception is an assumption but the ultrasound shows the growth of the baby. So, dating scans are more reliable than the conception calculator. At to 5 weeks, a gestational sac may be seen in the uterus using transvaginal ultrasound, Joseph Woo, M.D., explains in "Obstetric Ultrasound: A Comprehensive Guide" 2. Seeing the gestational sac, which looks like a black dot in the uterus, has several benefits: it confirms that a woman is pregnant, confirms that the pregnancy at a very early stage, making dating the pregnancy very accurate, and . The timing of the ultrasound affects the accuracy of determining the gestational age. Early ultrasounds generally are more precise. Later in the pregnancy, babies grow at much different rates, and babies at the same gestational age are more likely to vary in the measurements taken in the ultrasound.
Also is it possible that the withdrawal bleeding was implantation bleeding? Also if for some reason I deliver early would that mean that my conception date was off and that I did possibly conceive in January?
Thanks again. I have just been worried about this all pregnancy and would like to put it behind me.
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I know the stress isn't good for me or the baby. It is very less likely that the bleeding was implantation bleeding, as it does not corelate with your period pattern please mention the date of the period BEFORE 5th February if you recall it.
Also the ultrasounds are supportive of the fact that the bleeding was withdrawal bleed, not implantation bleed. If you deliver early for some reason the disparity is a monththen in that scenario, if you DID conceive from January 18th the baby would be normal, while if you conceived later, the baby would be premature 36 weeks and a paediatrician could tell the difference. All said and done, odds of conception from January 18th encounter are almost zero, only a DNA paternity test would conclusively put this doubt to rest.
Do not stress out, as you can already understand. Take care.
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My previous period was Jan and was on cycle with my birth control. The period I experienced in Feb was early, which I am guessing is because I stopped birth control mid pack. I stopped on the second week on Feb 1st or 2nd. I guess I am having trouble seeing that there is any chance that the Jan 18 encounter would be a possbility since all of these things are against it. Could you explain how it would be a possibility at all?
Earlier ultrasounds are more accurate in terms of predicting the due date, so that's why doctors will usually use the dates and measurements from the first ultrasound of the pregnancy as a reference. As the pregnancy progresses, the accuracy of an ultrasound for predicting due dates decreases. ABSTRACT: Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. As soon as data from the last menstrual period, the first accurate ultrasound examination, or both are obtained, the gestational age and the estimated due date (EDD) should be determined, discussed with the patient, and documented clearly in the medical record. According to this period date, the most likely date of conception would be around 14 days after the period, that is around the 19th of February. Ultrasound has intrinsic error of upto maximum 5 - 7 days, so the probable dates of sex would have been a week before or after the 19th of February, but in NO WAY as early as January 18th.
Would you suggest a DNA test? Hello, All the things are against conception from January 18th. The ONLY possibility and this is like a science fiction movie, as I am just adding together improbable hypothetical situations.
The bleeding experienced on February 5th was implantation bleeding not withdrawal from birth control - Least Likely. ALL the remaining scans continued to be one month off the mark least likely This is the only situationand it is impossible. Yes, I would suggest a DNA paternity test if you cannot forget the thing on your own, and it is continuing to bother you to this great extent.