Radiography

A healthy birth weight is crucial to the life of a newborn. The typical pregnancy lasts approximately 40 weeks, starting from the first day of the last menstrual period of the mother. During the pregnancy, the fetus grows to an average weight at birth of approximately 7.5 pounds. Babies born less than 5.5 pounds are considered low birth weight babies.¹ Many low birth weight infants face serious health problems with an increased risk of long-term disabilities, including breathing troubles, bleeding in the brain, heart conditions, intestinal problems leading to feeding difficulties, and lack of enough body fat to maintain a normal body temperature.¹

IS RADIATION RELATED?

In 2004, a study was published that linked low birth weight babies with exposure of the mother to dental radiation during pregnancy. The complete results of this study were published in the Journal of the American Medical Association.² Researchers from the University of Washington conducted it and analyzed the pregnancies of nearly 6,000 women. The results found that those who received dental radiation were over three times more likely to deliver a low birth weight baby at term. One theory for this finding is that radiation exposure might cause subtle changes in the functioning of the thyroid gland of the mother (previous studies found a link between low birth weight babies in women with mild thyroid disease.² The authors state that more research is necessary to determine if dental radiation alone was truly the cause of the birth weight since it was unclear how dental radiation might affect the unborn child.

In dentistry, the beam of radiation is not typically directed at the reproductive organs, the uterus, or the developing fetus. However, radiation can interact with several organs that might affect pregnancy, including the thyroid gland in the neck and the hypothalamus and pituitary gland in the brain. Any effect on pregnancy could be indirect through these areas. The thyroid hormone of the mother is important for the baby’s physical and mental growth and a dose of radiation to the thyroid gland may result in a lower metabolism for the fetus and low birth weight.

This study reinforces the importance of relieving potential dental problems before pregnancy occurs. And while this study reveals a relationship between low birth weight babies and exposure to dental radiation, it does not mean that dental radiation causes low birth weight babies. The lead author of this study reiterates that the results of this research should not prevent pregnant women from having diagnostic dental x-rays if they are suffering from a dental problem.

THE ROLE OF DENTISTRY

In addition to radiography, other areas of dentistry have also been studied in relationship to pregnancy, premature delivery, and low birth weigh babies. Premature birth, with its subsequent morbidity and mortality, is the leading perinatal problem in the United States.³ Periodontal disease is a possible risk factor for premature delivery and low birth weight babies.⁴ Pregnant women who have periodontal disease may be seven times more likely to have a baby that is born too early and too small.⁵ Biochemical markers specifically found in periodontitis are the same chemicals that mediate uterine contractions, cervical dilation, and labor. This can result in a premature delivery, low birth weight, and possibly morbidity of the infant.⁶ In addition, some pregnant women experience gingival problems for the first time due to the hormonal changes in the body, which can lead to pathological conditions, such as a pyogenic granuloma. Untreated dental infections, abscesses, or endodontic problems can also pose a risk to the fetus. Research states that any maternal infection may be considered a risk for both the mother and unborn child.⁷

REDUCING EXPOSURE

Bear in mind that every effort is made to reduce the amount of radiation for the patient—pregnant or not—during radiographic dental procedures. The importance of patient protection during radiographic procedures cannot be overemphasized. This includes the proper ordering of radiographs, proper equipment and processing, operator technique, and the use of a leaded apron and thyroid collar for all patients. Digital imaging is also recommended since radiation exposure for digital imaging systems is 50% to 80% less than is required for traditional film-based radiography.⁸

Good dental health is critical for many reasons and dental treatment may be necessary to maintain the health of the mother and unborn child. Women should inform their dentists if they are pregnant, might be pregnant, or are planning to become pregnant. The American Dental Association (ADA) recommends that pregnant women postpone elective dental radiation procedures until after they give birth.⁹ However, occasions may occur when a radiograph is required during pregnancy to help the dental professional diagnose and treat the oral disease. The ADA also advises that pregnant women eat a balanced diet, brush their teeth thoroughly with an ADA-accepted fluoride toothpaste at least twice daily, floss at least once a day, and schedule regular dental appointments.

REFERENCES

1. Quick references and fact sheets. Low birthweight. Available at: www.marchofdimes.com/professionals/14332_1153.asp. Accessed January 17, 2006.
2. Hujoel PP, Bollen AM, Noonan CJ, del Aguila MA. Antepartum dental radiography and infant low birth weight. JAMA. 2004;291:1987-1993.
3. Gibbs RS. The relationship between infections and adverse pregnancy outcomes: an overview. Ann Periodontol. 2001;6:153-163.
4. Scannapieco FA, Bush RB, Paju S. Periodontal disease as a risk factor for adverse pregnancy outcomes: a systemic review. Ann Periodontol. 2003;8:70-78.
5. Baby steps to a healthy pregnancy and on-time delivery. Available at: www.perio.org/consumer/ pregnancy.htm. Accessed January 17, 2006.
6. Jared HL. Periodontitis and pregnancy outcomes. Dimensions of Dental Hygiene. 2005;3(11):14-18.
7. Protecting oral health throughout your life. Available at: www.perio.org/consumer/women.htm. Accessed January 17, 2006.
8. Haring JI, Jansen L. Dental Radiography: Principles and Techniques. 3rd ed. Philadelphia: Elsevier Health Sciences; 2005:343-354.
9. Berthold M. JAMA dental radiography study bolsters ADA Recommendations. Available at www.ada.org/prof/resources/pubs/adanews/adanewsarticle.asp?articleid=853. Accessed January 17, 2006.

From Dimensions of Dental Hygiene. February 2006;4(2):32, 34.