Dating accuracy of 20 week ultrasound

They changed mine around a few times but they said whatever I leave my first trimester with is what they go with. Oh wow. My doctor told me the 20 week measurements where the most accurate and that's what she wants to go by, but nurse during the ultrasound was so rude about it! The 13th to 23rd is a BIG difference when scheduling a c section, I'm so confused lol. I hope she can give me a real date! Ah right!

Ultrasound Scans in Pregnancy – Your Questions Answered!

They changed mine around a few times but they said whatever I leave my first trimester with is what they go with. Oh wow. My doctor told me the 20 week measurements where the most accurate and that's what she wants to go by, but nurse during the ultrasound was so rude about it! The 13th to 23rd is a BIG difference when scheduling a c section, I'm so confused lol. I hope she can give me a real date! Ah right! It is confusing, I could understand them not caring about a few days but over 10 days?

That's frustrating! I was told those are estimated due dates. They will be different because your baby will grow in spurts. Once I was looking at 4 weeks earlier as a due date. My actual date never changed. It's also a guess based on lmp. It's all an average. Everyone ovulates on their own time. I'm so excited on you having a girl!!!! Yeah I was told all that too, I guess I'm so frustrated because they won't schedule my c section without a due date they think is correct, so by the time they schedule it ill be April!

I'm excited its a girl too! My poor DH! My dad is heartbroken its not a boy, lol. Generally all babies grow at approx. Hope this helps. My doctor's motto is that after the 12 week US which she says is the most accurate, a big baby does not make an old baby. So I would stick with the 23rd if I were you. I am petrified that they moved my due date up too much and they will schedule my due date too early. My son always measured ahead of his due date, but did not come naturally even 10 days after my due date, which was consistently 1 week later than the US measurements.

I knew I was pregnant with DS for 38 weeks. This time if they go with my 12 week US due date I will have only known for 34 weeks, that is a month different. I feel like I need to keep rescheduling my c-section to be later and later: I really want to wait until at least April 11th, not go earlier than April 5th. The most accurate date the doctors will give you is the date given at the week ultrasound. Go by that date. My midwife said she wants the main doctor to decide what my due date will be since they've been so different, but she thinks the 13th seems more accurate because my uterus and belly measure to 21 weeks.

I won't find out til December 28th what they made my due date lol ahhh! That is odd, my doctor swears by the 12 week, because it is a crown to rump and babies typically grow at a pretty normal across the board rate. My son's head was HUGE!! So his measurements as of the 18 - 20 week were skewed. I had a VERY long talk with my OB yesterday about dates and such and she confirmed that her faith lies in the 12 week and she reiterated the "A big baby is not an old baby" I still think it is best to stick with the latest reasonable due date, because those little beans baking for as long as they see fit is really the healthiest way to go.

As a failed induction veteran, I would rather be pregnant for 50 weeks than have to go through that. It's so weird that all doctors have different points of view on what measurement is more accurate, you'd think they would all think the same thing. I just want them to pick a date they feel comfortable with already. I have a feeling the 23rd is way off, seems too late for me, but their the doctors, not me! My docs say that the earlier ultrasounds are more accurate, which makes sense.

I had one at 6 weeks, and one at 8 weeks, and the difference in size and stage of development early on is huge. If you think about it, there can't be much variation in the size of a fertilized egg, but there's a huge ranges of sizes at term. There's also a lot of variation in the individual measurements that make up the overall estimate at this point in time - they're looking at legs, arms, head size, crl, and all sorts of other things, each which have their own benchmarks.

Most of my last measurements were a couple of days to over a week off from one another. So, I'd trust the estimate you got early on more than the others. I know how you guys feel. I was given several different dates as well and I'm also going to most likely have to have a repeat c-section, fingers crossed for a vbac, but we'll see how my blood pressure holds up this time around. I also can't believe how much larger my stomach has gotten with this pregnancy it's my second.

Pregnancy during the first trimester leads to some big changes. The second trimester starts in week 14 of pregnancy and lasts through the end of week Find out what to expect in the second trimester of pregnancy when it comes to your baby's development and pregnancy symptoms you might experience. HiI had my 20w anatomy scan done today. Everything went really well except my girl is measuring way behind the due date I got from previous ultrasounds.

I had spotting in the first tri so I had an ultrasound April Babies. Archived Discussion This discussion is archived and locked for posting See active discussions on April Babies. Good morning ladies, today was the big 20 week ultrasound! Everything went well, it's def another little girl! Oh boy! She was all curled up in a ball, arms and legs over her head, rolling around, it was absolutely adorable!

The doctor came in and said that everything looks perfect, the baby has everything she needs! Since we had gotten different dates my midwife Judy told me shes been unable to schedule my c-section because it has to be done at exactly 39 weeks. She told me to have them check all the measurements at my 20 week ultrasound to get the last accurate date so we can set up my c-section. I'm no doctor but the 13th to the 23 is a pretty big date change, especially when scheduling a c-section.

The nurse told me it still didnt matter! I'm so confused! Sort by: Oldest Newest 16 Posts. B Battlestar. S SarahpMancha. Pregnancy Your Guide to the First Trimester of Pregnancy Pregnancy during the first trimester leads to some big changes. Pregnancy Your Guide to the Second Trimester of Pregnancy The second trimester starts in week 14 of pregnancy and lasts through the end of week In Australian Parents 20w scan baby measuring at 18w 4d by car11 HiI had my 20w anatomy scan done today.

In expecting 2nd child 29w scan measuring at 18w 4d by car11 HiI had my 20w anatomy scan done today. Jump to Your Week of Pregnancy. WTE Must Reads. Pregnancy Week by Week. Why We Archive What to Expect has thousands of open discussions happening each day. We work hard to share our most timely and active conversations with you. Archived discussions are usually a bit older and not as active as other community content. We keep them up because there are a ton of great conversations here and we believe you deserve to see them all.

A dating scan is an ultrasound examination which is performed in order to establish the first 12 weeks of pregnancy are generally within 3 - 5 days of accuracy. The purpose of your 20 week ultrasound is to check the baby's development and growth. of gestation (to see if it matches with the mother's dates), the position of the placenta and the baby's Gender prediction is fairly accurate at this stage.

Author information: To determine the accuracy of established ultrasound dating formulae when used at and gestational weeks. A total of singleton pregnancies conceived after in-vitro fertilization IVF and randomized to a dating scan at or gestational weeks were studied. The mean of the differences between estimated and true gestational age systematic measurement error and their SD random measurement error were calculated for each formula.

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Pettker, MD; James D. Goldberg, MD; and Yasser Y.

Your pregnancy and baby guide

All pregnant women look forward to knowing the due date of delivery of the baby. The week countdown is a long period of waiting. Ultrasound has become very helpful for obstetricians in predicting due dates and also diagnosing twins. A marginal difference is found when cases of foetal ultrasound and menstrual history of the patients are compared. Ultrasound has proven to be a useful test when the menstrual history is unknown, and one can safely calculate the expected date of delivery EDD by an ultrasound. But the accuracy of the prediction by ultrasound keeps decreasing as the pregnancy progresses.

Can your pregnancy scan give the wrong due date?

A dating scan is an ultrasound examination which is performed in order to establish the gestational age of the pregnancy. Most dating scans are done with a trans-abdominal transducer and a fullish bladder. If the pregnancy is very early the gestation sac and fetus will not be big enough to see, so the transvaginal approach will give better pictures. Dating scans are usually recommended if there is doubt about the validity of the last menstrual period. By 6 to 7 weeks gestation the fetus is clearly seen on trans-vaginal ultrasound and the heart beat can be seen at this early stage 90 to beats per minute under 6 to 7 weeks, then to beats per minute as the baby matures. Ultrasounds performed during the first 12 weeks of pregnancy are generally within 3 - 5 days of accuracy. The most accurate time is between 8 and 11 weeks gestation. This is because the fetus is growing so quickly that there is a big difference in size from week to week. However, the accuracy of the ultrasound examination is always dependent on the skill of the sonographer and the quality of the equipment.

Every pregnant woman wants to know her due date , and a due date that is calculated from her last menstrual period with a due date calculator often doesn't match the due date that is estimated by her first ultrasound also known as a sonogram. During an ultrasound, a technician will spread a warm gel over the lower part of your abdomen and then press a tool called a transducer against your belly to examine your fetus using sound waves.

Menu Close menu. Back to Your pregnancy and baby guide. Some women's cycles are not exactly 28 days.

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You can calculate your due date by subtracting three months from the first day of your last menstrual period LMP and then add a week. Use our pregnancy calculator. A pregnancy is based on being days long, which is 40 weeks more like 10 months not 9! When we give you a due date we consider 37 to 42 weeks to be full-term, so even if your baby is born two weeks before your due date it is not considered premature. Because few women know the exact day they ovulated or conceived, an ultrasound done in the first trimester of pregnancy has been shown to the be the most accurate way to date a pregnancy. If an ultrasound date in the first trimester differs from your LMP date by seven days or more, we would go with the ultrasound. Ultrasounds done later in the pregnancy are less accurate for dating, so if your due date is set in the first trimester, it shouldn't be changed. However, if you did not get a first trimester ultrasound for dating and an ultrasound done to look at the baby's anatomy usually at weeks of pregnancy differs from your LMP date by 10 to 14 days, we would change your date to the ultrasound estimate. Dating your Pregnancy. The 40 week countdown

Ultrasound Accuracy for Predicting Due Dates

By 20 weeks, your baby's organs and body systems are well developed and can be seen clearly on an ultrasound scan. The sonographer performing the scan will look closely at how your baby's major organs and body systems have formed and whether there are any indications of a problem see Your baby's checkups. In the majority of cases, the scan will reassure women that their baby is developing normally. If your baby is found to have a problem, the sonographer will refer you to a maternal medicine expert who will confirm the findings and offer follow-up scans throughout the rest of your pregnancy. He or she will also talk to a pediatrician to ensure that they have enough information to take care of your baby at birth.

Accuracy of Pregnancy Ultrasound to Predict the Due Date

Back to Pregnancy Reviews. The establishment of pregnancy dates is important not only for the mother who wants to know when to expect the delivery, it is also important for her carers, e. Various policies are applied whereby the LMP dates are used unless they have a discrepancy to the ultrasound dates of more than 7, 10 or 14 days. Reliance on LMP is fraught with various problems. But even if this date is accurate, the assumption that ovulation or conception occurs 14 days later is unfounded; there is a wide distribution with a positive skewness 3. Such delay is furthermore unpredictable:

Having a dating scans at 6—9 weeks from 6 weeks? Then your due date is performed after last menstrual period date of gestation differs from your first time! For a week scan, sufficient information about 9 weeks, 9 weeks nuchal translucency nt. Level ii scan they estimated. Don't worry too much if the point of gestation dating scan at 9 weeks.

NCBI Bookshelf. John A. Morgan ; Danielle B. Authors John A. Morgan 1 ; Danielle B.

Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. A Nature Research Journal. In conclusion, especially, large negative discrepancy was associated with increased risks of adverse perinatal outcomes.

How accurate are ultrasounds in determining the size of a baby?
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