Fetal deformities

The first trimester of pregnancy is crucial for embryonic growth and development. According to Brent, the average dose of radiation in a typical diagnostic procedure is 5 rad. Studies show that an increased risk of fetal deformity does not occur until radiation exposure reaches 20 rad up to week 8 and 30 rad between weeks 8 to 15. Brent states that fetal deformities do not occur from radiation exposure after week 20, since the fetus is fully formed at that point (International Commission on Radiological Protection, 2003)

Cancer risks later in life

Exposure to radiation before birth in high amounts can increase the chance that a fetus will develop cancer later in life; however, according to the Centers for Disease Control (CDC), the risk for those exposed to equal to 500 chest x-rays or less have only two percent more chance overall of developing cancer than a person without prenatal radiation exposure (according to perinatology.com) this risk is not dependent on the stage of pregnancy when radiation exposure occurred. (Bushong, 2001).

Aim of work

The study aims to observe and detect the effect of radiation on pregnancy.

A total of 20 animals were collected from September to December, 2012. Samples were collected in healthy condition and transported to the Diagnostic Radiology Department, Faculty of Applied Medical Science, Hail University. Each sample was examined by the following methods.

Advanced x-ray machine

Two groups of samples were exposed to x- rays. The first group was exposed randomly as all population when they need to be exposed to radiation on emergency or medical examination. The second group of samples was exposed to x- rays continuously as radiation workers, they are exposed to radiation or they do not use the protections tools from radiation (www.radiologyinfo.org/en/safety/index.cfm?pg=sfty_xray#part6).

Thermo luminous dosimeter (TLD)

 This was employed to measure the accumulative radiation dose (National Council on Radiation Protection and Measurements, 1998).

A total of 20 samples were examined. Out of them, 10 animals (50%) were sensitive for radiation as observed by the different exposure stages in pregnancies. The effects of low-dose, long term irradiation in utero can include:

1. Death of fetus, congenital deformity, cancers, impairment of growth and genetic effect. After maturity, radio-sensitivity increases with age. It begins to decrease with age at the end of child bearing age.

2. Within the first two weeks after fertilization the most pronounced effect of a high radiation dose is fetal death which is manifested as a spontaneous abortion.

3. During the 2nd to 10th weeks two effects may occur. Early in this period, skeletal and organ abnormalities can be induced. As organs continue to develop, central nervous system abnormalities may develop. If the abnormalities are severe enough, the effect will be fetal death.

4. After a dose of 200 rad, nearly 100% of the fetuses suffered significant abnormalities. In 80%, it was sufficient to cause death.

5. A dose of 10 rad during organogenesis is expected to induce congenital abnormalities by 1% above natural occurrence.

In utero irradiation has been associated with childhood malignancy. Fetal death when the abnormalities are severe enough.

Everyone is exposed to radiation every day. People are continuously exposed to low-level radiation found in food, soils, building materials, and the air and from outer space.  All   of   this   radiation  originates   from  naturally occurring sources. For example, bananas contain naturally occurring radioactive potassium-40 and air contains radon, a radioactive gas. The average natural background radiation dose is about 3.0 mSv (300 mrem) each year, in comparison with the study of Kevin et al. (1999).

Maternal illness during pregnancy is not uncommon and sometimes requires radiographic imaging for proper diagnosis and treatment. The patient and her physician may be concerned about potential harm to the fetus from radiation exposure. In reality, however, the risks to the developing fetus are quite small. The accepted cumulative dose of ionizing radiation during pregnancy is 5 rad, and no single diagnostic study exceeds this maximum. For example, the amount of exposure to the fetus from a two-view chest x-ray of the mother is only 0.00007 rad. The most sensitive time period for central nervous system teratogenesis is between 10 and 17 weeks of gestation. Non-urgent radiologic testing should be avoided during this time. Rare consequences of prenatal radiation exposure include a slight increase in the incidence of childhood leukemia and, possibly, a very small change in the frequency of genetic mutations. Such exposure is not an indication for pregnancy termination. Appropriate counseling of patients before radiologic studies are performed is critical. Observed in atomic bomb survivors has been an increase in mental retardation. This involved very high exposure rates. It is known that radiation does retard growth. Irradiation particularly during organogenesis has been associated with microcephaly (small head) and retardation. Human data from atom bomb survivors and residents of the Marshall Islands exposed to fall out from atom bomb tests demonstrated impaired growth in children. In addition to natural background radiation, the Pt may be exposed to radiation from medical x-rays and medical radiation tests or treatments, if the Pt think, or there is a possibility, that the female may be pregnant and need a medical x-ray or radiation procedure.

Radiation effects vary depending on the fetal stage of development and the magnitude of the doses that indicates that there is a threshold below which negative effects are not observed. According to the American College of Radiology (2010), routine x-rays of a mother’s abdomen, back, hips, and pelvis are not likely to pose a serious risk to the child. However, certain procedures (such as a computerized tomography [CT scan]) or a lower GI fluoroscope exam) to the mother’s stomach or hips may give higher doses. Most standard radiological tests and treatments produce radiation doses below 50 mSv (5,000 millirem). The National Council on Radiation Protection and Measurements (1998) and the American College of Obstetricians and Gynecologists (2013, 2014) both agree that the potential health risks to the fetus are not increased from most  standard  medical  tests  with  a radiation dose below 50 mSv. Potential health risks, however, may increase for a few medical tests or combinations of tests that result in radiation doses that exceed 50 mSv, depending on the dose and on the stage of pregnancy.

The sensitivity of a developing fetus to radiation can vary with the stage of development, the magnitude of the dose, and the length of time of the total exposure (minutes, hours, days, or weeks). The most radio sensitive period appears to be between 8 and 15 weeks after conception.

The effects of low-dose, long term irradiation in utero can include: death of fetus, congenital deformity, cancers, impairment of growth and genetic effect. These abnormalities are based upon exposure of greater than 10 rad in animal experiments (rabbits). There is no evidence that diagnostic levels of radiation exposure currently experienced occupationally or medically are responsible for any such effects on fetal growth or development. Ultrasonography is safe to perform during pregnancy.

1. Keep the time of exposure to radiation as short as possible.

2. Maintain a large distance as possible between the source of radiation and the exposed object.

3. Insert shielding material between the radiation source and the exposed person.

4. ALARA stands for “As low as reasonably achievable” and is the corner stone of radiation safety policies and procedures.

5. During pregnancy we should be considering having an abdominal/pelvic x-ray or medical test.

6. Determine if the procedures can be delayed until after birth or whether another medical procedure, such as an ultra-sound or MRI, could be used instead.

7. When pregnancy and abdominal x-rays are scheduled without consultation with doctor, we should inform the person performing the exam of our pregnant state. As a precaution, you should inform a person performing any type of x-ray or radiation procedure that you are pregnant. Ultrasonography is safe to perform during pregnancy.

Authors have none to declare.