Value of ultrasound at 35-37 weeks in the diagnosis of fetal abnormalities

Posted by Specialist Doctor I Nguyen Thi Mai - Doctor of Radiology - Department of Diagnostic Imaging - Vinmec Phu Quoc International General Hospital

Most fetal abnormalities are detected early in the first and second trimesters. Therefore, the detection of fetal abnormalities at 35-37 weeks is very rare. At this time, the fetus is almost mature, so the value of ultrasound will include anatomy and biometrics. Thereby, doctors can assess the development of the fetus before birth and some abnormalities that could not be detected in previous ultrasounds to improve the results by preparing well for life. delivery and early neonatal intervention.

After 35 weeks of pregnancy, the fetus has all parts of the body, although it may not be fully developed. At this time, the baby's skin becomes ruddy and smooth. The baby's limbs are chubby, leathery and fleshy.
Although there is not much room left in the uterus, this week your baby's weight continues to increase at nearly 5.5 pounds. Over the next few weeks, your baby's weight continues to increase at ~200g/week or more. During this time, the fetus is also in a stable position and moves lower in the mother's pelvis to prepare for birth.
During week 35 of pregnancy, most of the internal organs are complete, the baby's kidneys are fully developed and the liver is already able to process some waste products. At this time, your baby's length continues to increase at about 20 inches (about 50 - 51 cm).
Back to the second trimester of pregnancy when the baby's body is very small, only 2% of the body grows to an outstanding size (fat). Now that ratio has increased to 15% and at birth will double to 30% as the baby's organs gradually mature and magically fill in the gaps in the uterus.

The rate of fetal brain development continues to increase rapidly and will continue to do so throughout childhood. During this final trimester, your baby's brain weight increases by almost 10 times, and by the age of 12, that brain will be more than 3 times its size at birth.
For twins, the uterus will quickly become cramped, pregnant women will give birth earlier than those who are pregnant with one child (will give birth in the next few weeks). In fact, 37 weeks is considered a term for twins, so expectant mothers with twins should prepare for the upcoming labor.

Most (68%) of fetal abnormalities seen at 35 to 37 weeks' gestation were diagnosed during the first and/or second trimesters. The incidence of abnormalities first seen at 35 weeks 37 is 0.5%. This ultrasound includes ultrasound examination for fetal anatomy and fetal biometrics to assess fetal growth, fluid volume and Doppler measurements in the middle cerebral arteries of the uterus, umbilicus, and umbilicus. fetus. Predicts subsequent progression of preeclampsia and intrauterine smallness or growth retardation.
Besides, ultrasound at this week of pregnancy also detects new abnormalities of the fetus that could not be diagnosed in previous examinations, specifically:
Central nervous system abnormalities: Ventricular dilation , choroidal plexus cysts, microcephaly. Facial abnormalities: Lacrimation .

Cardiac Abnormalities: Of the cases of ventricular septal defect, 18.3% (22/120) were diagnosed for the first time in the third trimester and 4.2% (5/120) were diagnosed for the first time. postpartum prediction. Most cases of rhabdomyoma are first diagnosed during the third trimester. Some cases of aortic spasm, pulmonary or aortic stenosis, and tricuspid valve defects are first discovered during the third trimester and some are diagnosed only postpartum. Abdominal abnormalities: Ovarian cyst, renal dilatation, double kidney. A high proportion of fetal abnormalities are first detected during routine ultrasonography at 35-37 weeks gestation. Based on the results of this study, routine ultrasound at this time could help identify fetal malformations and potentially improve outcomes by adequate preparation for delivery and post-natal care. born.
If the ultrasound results at this week of pregnancy have problems, the pregnant woman will feel extremely worried. However, problems on ultrasound can range from large, obvious, serious abnormalities to minor problems. So when the ultrasound suspects a problem, you will be examined specifically to find out how to handle and prepare well during and after birth.

The entire process of pregnancy monitoring under the package Maternity care program at Vinmec International General Hospital is strictly implemented, limiting all problems of the fetus, especially those with can be treated right from the fetal stage, some have to wait until birth to be able to treat. At Vinmec, many difficult cases have been solved such as: placenta, knotted umbilical cord, pregnancy maintenance, etc. Accordingly, depending on detected abnormalities, doctors will plan a delivery for pregnant women. .
In addition to the accurate, scientific and quality antenatal checkup process, a number of other factors that make an important contribution are the modern medical equipment system at Vinmec. They can handle abnormalities during pregnancy and labor quickly so that the mother has the safest pregnancy.