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Doctor insights on: What Is More Accurate Measuring A Baby Or Lmp

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If LMP and first trim scans all point to same EDD, is the conception date range accurate?

If LMP and first trim scans all point to same EDD, is the conception date range accurate?

Yes: If your dates and ultrasounds are consistent the estimated conception date should be reliable within a few days. Short of tracking ovulation with daily ultrasounds or one of the in vitro methods, that is the best we can do. ...Read more

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Babies can measure too big or too small, does that cause your LMP date to be off? Or make it seem as if you're further along than you thought?

Babies can measure too big or too small, does that cause your LMP date to be off? Or make it seem as if you're further along than you thought?

LMP date could cause: You may have recalled your last period date (lmp)incorrectly and then your due date may not be accurately calculated. You may have gestational diabetes and that can cause a fetus to grow larger more rapidly than it should. You may have decreased blood flow from the placenta to the fetus ( like from smoking) and this can decrease the rate of growth of the fetus. ...Read more

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My LMP was dec 15. I had intercourse dec 20, 21, and 22 then with an ex on january 22. I'm due sept 21. Who its more likely to my babies father ?

My LMP was dec 15. I had intercourse dec 20, 21, and 22 then with an ex on january 22. I'm due sept 21. Who its more likely to my babies father ?

Difficult to say: More likely the dec partner, but timing should have been up to a week before ovulation...Which "might" still result in pregnancy. Jan date should give a october edc. May get better estimation of conception with later pregnancy ultrasound, particularly if due date shifts. Or will need paternity testing. ...Read more

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31 week us baby is measuring 1 week and 4 days ahead. Is this normal? Both earlier us matched LMP to the day. Does this change conception or lmp

31 week us baby is measuring 1 week and 4 days ahead. Is this normal? Both earlier us matched LMP to the day. Does this change conception or lmp

No change: At 31 weeks, your due date is very firmly established and wouldn't change. What can change, of course, is the baby's growth. And it sounds like you're baby is growing well. It's possible if you or your husband (or both) are taller or bigger people, that your baby is just on the larger end of spectrum. Sometimes, if mom has diabetes, there can be macrosomia. Speak with dr. So you know diagnosis. ...Read more

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Do ultrasounds add two preconception weeks when measuring baby? If baby measures 12 w is this supposed to date to LMP or conception?

Yes. LMP.: The gestational age (number of weeks pregnant) stated in the result of the ultrasound already added the 2 preconception weeks. If the ultrasound dating says 12 weeks gestation, that means 12 weeks since the estimated start of the last menstrual period (lmp). ...Read more

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By LMP I am 7w4d today. U/s 2 weeks ago told me turning 5w. Only sac, baby barely visible. Today, fetal pole and hb but baby measuring 5w6d. Problem?

By LMP I am 7w4d today. U/s 2 weeks ago told me turning 5w. Only sac, baby barely visible. Today, fetal pole and hb but baby measuring 5w6d. Problem?

Very early US dating: Not as good as us between 7-13 weeks. Measuring the fetal length (called a crown rump measurement) is the most accurate. The good news is interval growth, including a fetal pole with cardiac activity. Another followup us in 3-5 weeks could confirm additional interval growth and measure the crown-rump distance to re-evaluate dates. ...Read more

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Aug 7th Scan says 12 w 4 d. no lmp to go off. whats accuracy in telling me proper age of baby? and is that from conception?

Aug 7th Scan says 12 w 4 d. no lmp to go off. whats accuracy in telling me proper age of baby? and is that from conception?

Quite accurate: A prenatal dating scan at that part of the pregnancy is quite accurate. All dates are estimates, and in this case, conception would be about 2 weeks after the official start date. That means conception would be 10 weeks and 4 days ago, plus or minus one week. In general, the exact conception date is not important and is never known with certainty, with a "natural"pregnancy. ...Read more

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Does a nhs dating scan measure the baby to your LMP or when you conceived?

Does a nhs dating scan measure the baby to your LMP or when you conceived?

Do not know what: Nhs scan means but any ultrasound during pregnancy will date the gest age , 7-10 weeks is usually the most accurate the farther u get like the 3rd trimester the larger the range is. ...Read more

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Don't need to pinpoint conception day, but two first trim ultrasound give same due date we have no lmp to go off, how accurate is age of our baby?

Don't need to pinpoint conception day, but two first trim ultrasound give same due date we have no lmp to go off, how accurate is age of our baby?

Accurate estimates: Ultrasound dating scans in the first trimester, such as at 8-11 weeks of pregnancy, are very accurate... meaning plus or minus one week. Especially if the doctor feels the fetus is growing appropriately for gestational age through the course of the pregnancy, the original dating estimates were likely very accurate. ...Read more

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Does crl measure the exact age of the baby from LMP or does it measure from growth in uterus once implantation occurred?

Does crl measure the exact age of the baby from LMP or does it measure from growth in uterus once implantation occurred?

CRL: Literally crl measures neither : it relates measured size to an expected age based on normal first trimester growth. It is accurate to +/- 2-3 days (so not exact), if certain lmp or sure ovulation it can reliably estimate ga relative to either conception or lmp. Doctors always date from a known or theoretical lmp, never conception, so there is roughly 14 days difference. ...Read more

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If i conceived on november 25, but don't remember my last menstrual period, what would be my accurate gestational age and what would fetus measure?

If i conceived on november 25, but don't remember my last menstrual period,  what would be my accurate gestational age and what would fetus measure?

2 weeks earlier: If a woman knows she believes she conceived on november 25, then she can use november 11 (2 weeks earlier) as her lmp, for calculating pregnancy-related dates. Today is january 27, so the pregnancy is now 11 weeks. As always, all dates are just estimates. ...Read more

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Hi its been nearly 9 weeks since my LMP started with some pinkish disharge on and off went for scan there was a sac measuring 4-5 weeks but irregular ?

Hi its been nearly 9 weeks since my LMP started with some pinkish disharge on and off went for scan there was a sac measuring 4-5 weeks but irregular ?

Blighted ovum: This sounds like a blighted ovum or missed abortion (miscarriage).This sort of thing doesn't decrease the chance of having a normal baby in the future but it doesn't look good for this time.It is important for you to know that this usually happens because of something wrong with the embryo and not because of something you did or didn't do.Your doctor will probably repeat the ultrasound to confirm. ...Read more

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According to my LMP I should be 8ish wks. But i'm measuring 6 wks. Is this normal?

According to my LMP I should be 8ish wks. But i'm measuring 6 wks. Is this normal?

Could be: You might be mot as far along as you think. You might have ovulated later then you expected. Your doctor will probably repeat you ultrasound to make sure that everything is developing properly. If the pregnancy is progressing normally there is mo reason to worry. Good luck. ...Read more

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My dd is jan 12th but going by my LMP it says dec 19. The jan 12 is from ultrasound and measuring my belly which should I go by?

Usually ultrasound: A due date selected by last menstrual period has two weeks of error built into the result. The most accurate ultrasound due date is dating the pregnancy by vaginal ultrasound between 10-12 weeks. After 16-18 weeks, an ultrasound due date has the same two week error as a pregnancy dated by lmp. It sounds like your doctor believes the ultrasound due date is more accurate for you. ...Read more

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My daughter is 11 years with thickening of endometrial lining measuring 16mm. Is it normal.her lmp was on 28/7/16?

My daughter is 11 years with thickening of endometrial lining measuring 16mm. Is it normal.her lmp was on 28/7/16?

Yes: Early in puberty the cycles are dominated by estrogen which stimulates endometrial buildup. Egg release is not consistent in the first year, but is followed by progesterone formation that triggers the cycle when conception does not occur.If no egg release occurs, a longer interval is expected but a heavier cycle would eventually occur.Up to 90 days is noted between cycles in normal young women. ...Read more

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Due date is july 5th, have regular 30 day cycles. All ultrasounds are measuring perfectly with lmp. When was conception?

Due date is july 5th, have regular 30 day cycles. All ultrasounds are measuring perfectly with lmp. When was conception?

October 12 2013: If your cycles are regular at 28 days you conceived middle of october, probably the 12th. This is just a calculation representing a best guess, it may not be exactly correct. ...Read more