Patient's question:
I am 28 weeks pregnant and have had four ultrasound scans in total. I am worried about the potential impact on the baby. There were reasons for having four ultrasounds: the first one was for confirmation, the second one was because I was sick and feared it might affect the fetus, which I did under the doctor's advice. The third and fourth scans were both recommended by the doctor for color ultrasounds. Later, when I did antenatal care at the community hospital, the doctor said that there would still be one more scan at seven months, and prenatal care would also be required. He also mentioned that big hospitals only care about making money and doing unnecessary scans, which made me regret it deeply. Can I skip it? Will these many ultrasounds affect the baby? I am worried...Doctor's answer:
Hello:For a long time, it has been widely believed that ultrasound is a non-invasive examination that does not cause harm to the examined individual. In fact, ultrasound is also a form of energy. When a certain dosage is reached, biological effects may occur in the examined individual's body, causing damage to local cells that experience these effects. In most human organs, damaging a few cells is insignificant. However, if germ cells or embryos in a sensitive developmental stage are damaged, the consequences can be severe.
Someone once used lymphocytes from newborn umbilical cord blood to conduct a "sister chromatid exchange" test, abbreviated as "SCE" test. Comparisons were made of SCE frequencies in umbilical cord blood of newborns who had undergone their first obstetric ultrasound examination during the first three months of pregnancy, those who had undergone obstetric ultrasound examination between the fourth and sixth months of pregnancy, and those who had undergone obstetric ultrasound examination between the seventh month and full term, as well as newborns who had not undergone any obstetric ultrasound examination after pregnancy. The results showed that the SCE frequency in umbilical cord blood of newborns who had undergone obstetric ultrasound during early pregnancy was higher, while there was no significant difference in SCE frequency between newborns who had undergone obstetric ultrasound examination in the second and third trimesters and newborns who had never undergone B examination during pregnancy.
An increase in SCE is a warning signal that the body has been affected by harmful environmental factors, reflecting the survival of cells whose genetic material has been damaged. Early pregnancy is the most dangerous stage for embryos to be affected by teratogenic, mutagenic, and carcinogenic factors. If an ultrasound examination during this stage increases SCE frequency, it suggests that the fetus's DNA may be damaged. Therefore, obstetric ultrasound examinations during early pregnancy should be used with caution.
However, it is still unclear whether a single ultrasound examination will affect the fetus, or how long an examination would need to last to have an impact on the fetus. Currently, there is no definitive answer.