Obstetric ultrasound is an essential medical tool in the monitoring and care of pregnancy.
Through the use of high-frequency sound waves, obstetric ultrasound creates real-time images of the uterus, placenta, fetus, and other pelvic structures. It is a non-invasive and safe procedure for both the mother and the baby.
Obstetric ultrasound is an integral part of prenatal care and is used at different stages of pregnancy to evaluate specific aspects.
Pregnancy ultrasound
Pregnancy or obstetric ultrasound has multiple uses that benefit both the mother and the baby. Among its main functions are:
- Pregnancy confirmation: helps verify the presence of an intrauterine pregnancy and rule out an ectopic pregnancy.
- Determination of gestational age: helps accurately calculate the weeks of pregnancy, which is essential for estimating the probable due date.
- Evaluation of fetal development: allows measurement of fetal growth and detection of possible congenital anomalies.
- Placental assessment: helps identify problems such as placenta previa or abnormal amniotic fluid levels.
- Detection of multiple pregnancies: confirms whether there is one or more fetuses in the uterus.
- Monitoring of fetal well-being: evaluates fetal heart rate and movements, providing indications of overall condition.
Beyond monitoring in each trimester, obstetric ultrasound also helps guide invasive procedures such as amniocentesis, in which amniotic fluid is collected with a needle, or to plan delivery in cases of complications.
First-trimester obstetric ultrasound (Trim I)
The first-trimester obstetric ultrasound, or Trim I, is performed between the sixth and 14th weeks of gestation. This initial study is crucial for establishing a solid foundation in prenatal care, and among its main objectives are confirming pregnancy, determining gestational age, evaluating fetal viability by detecting the heartbeat, and observing early development.
Additionally, it allows the identification of abnormalities that may be severe congenital defects or the development of an ectopic pregnancy.
Trim I ultrasound also allows nuchal translucency screening, an early indicator of aneuploidies such as Down syndrome.
Second- and third-trimester obstetric ultrasound (Trim II and III)
The second- and third-trimester obstetric ultrasound is essential for evaluating pregnancy progress and ensuring fetal well-being.
Trim II ultrasound is generally performed between the 18th and 22nd weeks of gestation, and this study is known as the structural or morphological ultrasound because it focuses on a detailed analysis of fetal anatomy.
Its objectives include the evaluation of fetal anatomy to detect congenital malformations in vital organs such as the brain, heart, and kidneys.
It also helps determine whether the fetus is growing adequately for gestational age and allows the identification of fetal sex.
Trim III ultrasound is performed from the 28th week until the end of pregnancy. It helps determine fetal position, such as cephalic presentation (head down) or another position.
It evaluates the placenta to identify problems such as placenta previa or placental abruption, and it also checks that amniotic fluid levels are normal.
In addition, it estimates fetal weight, which helps predict possible complications during delivery.
Trim II and III ultrasounds are crucial for making clinical decisions in the final stages of pregnancy and ensuring a safe birth.
4D ultrasound
There is also a 4D ultrasound within obstetrics, which, unlike traditional 2D or 3D ultrasound that produces two-dimensional or static three-dimensional images, adds the ability to observe real-time fetal movements.
This means clearer and more detailed images of the face and fetal movements. It allows observation of fetal behavior such as yawning, smiling, and limb movements.
Although today it is mainly used for recreational purposes and as a tool that helps parents establish an emotional connection by seeing their baby in real time, it has also been shown to help detect certain congenital anomalies such as cleft lip and palate with greater precision than 2D or 3D variants.
It is important to highlight that 4D ultrasound does not replace conventional ultrasounds but rather complements them by providing additional information.
Obstetric ultrasound is an indispensable tool in prenatal care, ranging from supporting pregnancy confirmation to providing data on fetal well-being in its final stages of development, making it a valuable tool in maternal-fetal medicine.
At the ABC Medical Center’s Obstetrics Center, we can provide you with specialized care. Contact us!
Fuentes
MedlinePlus, Scielo, Cigna
