Marian Summers, 22 years old
Every pregnant woman wants to know her due dateand 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 how accurate are dating ultrasounds a tool called a transducer against your belly to examine your fetus using sound waves. An image of your fetus will appear on an accompanying computer screen and while looking at this image, the technician will take some standard measurements from different angles and listen for a heartbeat. Don't worry: This type of exam is painless and risk-free, and seeing your baby for the first time will likely be an enjoyable experience. Naturally, one of the most common questions asked about ultrasound accuracy is: Just how accurate are the due dates that are predicted by an ultrasound?
With transvaginal ultrasound, checking for embryonic development known to occur within a certain time frame more accurately dates a pregnancy. Transvaginal ultrasound how accurate are dating ultrasounds see embryonic development about a week before transabdominal ultrasound, the American Pregnancy Association APA states. A transducer, a wand-shaped probe, is inserted into the vagina and pressed against the vaginal walls directly next to the uterus. It records high-frequency sound waves that create an image see Reference 4. Normally, ultrasounds before until week 4 of pregnancy shows nothing in the uterus and serve no purpose. Pregnancy is dated from the first day of the last menstrual period, so at four weeks, a woman is just due for a menstrual period.
Ultrasounds are a staple of modern obstretrics practice, and if you're pregnant, you're probably going to have a number of them. Personally, I found it super reassuring to check in on my baby at key points along the journey. My first ultrasound simply verified my due date, and that I hadn't miscarried or developed an ectopic pregnancy. A second trimester 3-D ultrasound checked for fetal abnormalities, and towards the end of my pregnancy, the ultrasounds confirmed the baby was still growing.
How accurate are dating ultrasounds
More about how accurate are dating ultrasounds:
Pettker, MD; James D. Goldberg, MD; and Yasser Y. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. 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. Subsequent changes to the EDD should be reserved for rare circumstances, discussed with the patient, and documented clearly in the medical record. When determined from the methods outlined in this document for estimating the due date, gestational age at delivery represents the best obstetric estimate for the purpose of clinical care and should be recorded on the birth certificate. For the purposes of research and surveillance, how accurate are dating ultrasounds best obstetric estimate, rather than estimates based on the last menstrual period alone, should be used as the measure for gestational age. The American College of Obstetricians and Gynecologists, the American Institute of Ultrasound in Medicine, and the Society for Maternal—Fetal Medicine make the following recommendations regarding the method for estimating gestational age and due date:.
A how accurate are dating ultrasounds 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.
For many women, especially after 8 weeks gestation, sufficient information about the baby may be obtained with transabdominal ultrasound only. However, in the early pregnancy, the developing embryo is very small at 6 weeks gestation, the baby is only mm long and a transvaginal ultrasound may be required to get a better image of the baby. Transvaginal ultrasound is safe and commonly performed during all stages of pregnancy, including the first trimester. It will not harm you or your baby. Transabdominal ultrasound involves scanning through your lower abdomen.