Fetal ultrasounds aren’t supposed to be done just to satisfy the curiosity of the parents to be, but the truth is that most women do have at least one ultrasound during pregnancy, and some have many. Prenatal ultrasounds are useful for detecting problems with the pregnancy, as well as providing accurate dating of the pregnancy.
Abdominal, Transvaginal, 3D, Doppler, and Echocardiography Ultrasound Pictures
Fetal ultrasound pictures don’t use X-rays that might cause harm to the baby. Ultrasounds are high frequency sound waves that are picked up by a transducer and displayed on the ultrasound screen. Pregnancy scans can be done abdominally or transvaginally; it’s easier to view images transvaginally in early pregnancy, when the embryo is very small, because the transvaginal wand gets closer to the uterus without abdominal fat or organs in the way.
Some special types of obstetric ultrasounds are 3-D ultrasounds, which give higher quality images, Doppler ultrasounds, which can check for circulatory disorders, and fetal echocardiography, which views the baby’s heart chambers, according to the Mayo clinic.
Early Pregnancy Scans for Due Dates, Heartbeats and Bleeding
Ultrasounds done in early pregnancy can visualize the gestational sac around four weeks, right around the time of a missed period. A yoke sac is seen by five weeks, and a beating heart by seven weeks. A pregnancy with a heart rate at seven weeks has a 95 % chance of being viable, according to Joseph Woo, author of "Obstetric Ultrasound: A Comprehensive Guide."
Early ultrasounds are often done to obtain accurate dating for a pregnancy, especially in women with irregular periods. Bleeding in early pregnancy is also a common reason for ultrasound. Multiple pregnancy can also be diagnosed with early ultrasound.
Ultrasound Scans for Fetal Abnormalities in Mid-Pregnancy
Most obstetricians do ultrasounds around 18-20 weeks of pregnancy to scan for common abnormalities, although maternal obesity increases the difficulty of diagnosing fetal abnormalities, according to Catherine Y. Spong, chief of the pregnancy and perinatology branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Md.
Defects such as cleft palate, neural tube defects, limb malformations and cardiac problems can be seen at this time, if a clear view is obtained. Fortuitously, this is also the time where the sex of many babies can also be seen, if they’re cooperative to turn in the right direction during the scan.
The placenta can also be viewed and checked for abnormal placement such as placenta previa, a condition where the placenta covers the cervix , either completely or partially, or is located too close to it.
Ultrasound Scans Late in Pregnancy and 4-D Scans
Ultrasounds are done in late pregnancy to determine the size and position of the baby, the amount of amniotic fluid surrounding the baby, or to follow up on earlier problems seen on ultrasound. The appearance of 4-D ultrasounds done strictly for parental purposes, so that parents can have a very detailed look at their baby’s face, are causing some concern among obstetricians, although no studies have been done to show that fetal ultrasounds are harmful, according to Joseph Woo.
Ultrasound Screening is Beneficial for Parents and Baby
Prenatal ultrasounds allow potentially serious problems to be diagnosed before birth, allowing parents a chance to adjust to difficult diagnoses before delivery and for medical intervention to be planned. Finding out the baby’s sex ahead of time is just icing on the cake.
Sources:
Mayo Clinic, "Fetal Ultrasound" 2009
"Obstetric Ultrasounds: a Comprehensive Guide", Joseph Woo
Sharon Perkins - Sharon is an RN with over 20 years experience in maternal child health, oncology, and ophthalmology. She was the RN coordinator for an ...
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