2nd trimester ultrasound: Everything you need to know

The second-trimester ultrasound, also known as the morphological ultrasound, is an essential step for future parents. It's an in-depth examination generally performed between the 18th and 22nd week of pregnancy. For around 30 minutes, the radiologist takes a close look at the mother-to-be's uterus using an ultrasound probe. This gives a close-up view of how the baby is developing, focusing on its anatomical structure.

During this session, we examine the internal organs, the spine, the umbilical cord, and may even measure the amount of amniotic fluid around the baby. It's a way of making sure all is well and seeing how the baby is growing inside the uterus.

Objectives of the second trimester ultrasound

Second-trimester ultrasound has several key objectives. Firstly, it aims to detect any fetal malformations and provide a detailed report on the growth of the fetus. It also offers future parents the opportunity to discover their baby's gender, adding an emotional dimension to the experience.

A crucial aspect of this ultrasound is its role in screening for Trisomy 21. By closely examining the fetal neck and measuring the thickness of the translucent zone, medical professionals can assess the potential risk of this genetic condition. The results of this screening, along with other essential information, will be included in the report given to the mother-to-be.

2nd trimester ultrasound: examination procedure

Before the ultrasound, the mother-to-be may be advised to drink water to fill her bladder, thus facilitating visualization of the fetus. Once ready, she will be placed comfortably on the examination table, and a gel will be applied to her belly to facilitate the transmission of sound waves. The ultrasound probe will then be used to methodically explore the uterus, enabling the ultrasound technician to obtain clear, detailed images.

During the examination, the radiologist focuses on specific elements such as the structure of the brain, spine, limbs, umbilical cord, uterine arteries and, of course, the amount of amniotic fluid. Each of these elements is crucial in assessing the health and development of the fetus. 

Prenatal diagnosis and implications 

Second-trimester ultrasound plays a key role in prenatal diagnosis, providing detailed visual information. However, it is important to note that this ultrasound cannot detect all possible abnormalities. Some health problems may not be visible at this stage, and other specific tests, such as blood tests, may be recommended as a complement. 

The report given to the mother-to-be after the ultrasound is an essential document summarizing the results of the examination. It includes details of fetal growth, the presence of any fetal malformations, the umbilical cord, the amount of amniotic fluid, and other important elements. Information on screening for trisomy 21 and other genetic conditions will also be included.