Why is a Level 3 ultrasound performed at 22–24 weeks of pregnancy?

Generally, the main reasons for undergoing a Level III ultrasound between 22 and 24 weeks of pregnancy include the fetus's organs being largely developed, adequate amniotic fluid facilitating observation, screening for congenital heart defects, detecting limb developmental abnormalities, and identifying gastrointestinal tract malformations. If abnormalities are detected during the examination, it is recommended to promptly follow the guidance of professional doctors for further management. Detailed explanations are as follows:

1. Fetal Organs Are Largely Developed

At this stage, the major organs of the fetus have largely developed. A Level III ultrasound can clearly visualize the structure and morphology of these organs to assess whether development is normal. Pregnant women should maintain a balanced diet, consuming foods rich in proteins and vitamins, to provide sufficient nutrition for fetal development.

2. Adequate Amniotic Fluid Facilitates Observation

During this period, the volume of amniotic fluid is relatively optimal, providing a good acoustic window for ultrasound imaging, resulting in clearer images and enabling more accurate assessment of fetal condition. Pregnant women should drink adequate amounts of water to maintain normal amniotic fluid levels and avoid dehydration or excessive amniotic fluid accumulation.

3. Screening for Congenital Heart Defects

A Level III ultrasound allows detailed examination of the fetal heart structure and timely detection of congenital heart defects, such as atrial septal defect and ventricular septal defect. If mild abnormalities are identified, regular follow-up examinations under a physician's guidance are recommended, as some conditions may improve as the fetus develops. Severe cases may require surgical treatment after birth, and prior to surgery, medications such as digoxin tablets, furosemide tablets, or spironolactone tablets may be used under medical evaluation to alleviate symptoms.

4. Detecting Limb Developmental Abnormalities

This ultrasound can clearly visualize the shape, length, and skeletal development of the fetal limbs, helping identify abnormalities such as polydactyly, syndactyly, or limb shortening. Correctable limb abnormalities can be surgically corrected after birth, and postoperatively, medications such as amoxicillin-clavulanate potassium for oral suspension, cefaclor for oral suspension, or azithromycin for oral suspension may be used to prevent infection, depending on the clinical situation.

5. Identifying Gastrointestinal Tract Malformations

The structure of the fetal gastrointestinal tract can be observed to detect malformations such as esophageal atresia or duodenal atresia in a timely manner. If diagnosed, surgical intervention should be performed as early as possible after birth. Prior to surgery, nutritional support and maintenance of fluid and electrolyte balance should be conducted under medical guidance, and intravenous fluids such as glucose injection, sodium chloride injection, or potassium chloride injection may be administered as necessary to replenish fluids and electrolytes.