Lectures of radiation and pregnancy

2021-03-19 12:00 AM

Organizational phase: This can last up to 12 weeks on the first day of your last menstrual period. This is a dramatic period, the fetus is extremely sensitive to X-rays

Effects of X-rays on pregnancy

In 1936, people used X-rays to cause miscarriage. This method was later abandoned because of low efficiency. X-rays have long been known to cause fetal malformations.

The effects of x-rays on pregnancy can be divided into three categories:

Immediately deformed.

Causes diseases such as cancer, leukemia.

Causes chromosomal mutations.

The degree to which x-rays affect pregnancy depends on two factors:

Gestational age when affected by X-rays.

How much x-ray will the fetus receive?

X-ray effects depend on age

It is divided into 3 different phases: the stage from conception to nesting stage, the stage of organizing and the stage of organizational completion.

The period from conception to implantation: in the vast majority of cases, the fetus dies. Very rarely, X-rays can cause major malformations of the central nervous system. It is not possible to determine the threshold for the causative dose.

Organizational phase: This can last up to 12 weeks on the first day of your last menstrual period. This is a dramatic stage, the fetus is extremely sensitive to X-rays, because organs are being formed, cells multiply very quickly. During this stage, a small dose of X-rays can cause many deformities in the central nervous system, in the eyes, in the bones, in the genitals, in the heart. The fetus can die in one third of cases.

The stage of organizational completion: X-rays no longer cause major deformities, but can cause mental retardation, behavioural disturbances, chromosomal mutations, especially in genital germ cells affecting for the next generation. It can also cause later diseases such as cancer, leucemi.

X-ray effects depend on dosage

Risk of deformity: over 50 Rad will definitely cause deformity. Under 5 Rad almost no risk of deformity. With the same x-ray dose, the greater the risk of malformations with the younger the fetus.

A recent study showed that with a low dose of 0.2 Rad (or 200 mRad) the rate of cancer later increased by 50%, with 3 Rad dose doubled the rate of blood cancer.

Amount of fetal x-rays received when applying diagnostic radiographs

Pregnancy is not in the irradiation field

In this case, the fetus receives about 100 times less X-rays than the fetus is in an irradiated field.

X-ray of the skull, spine, neck and abdomen with abdominal shield is estimated that the fetus will receive less than 10 mRad per film, except for thighs, the fetus can receive 100 mRad per film. Cardiopulmonary, fetal can receive from 5-25 mRad. Big fetuses will receive more because then the fetus is higher up.

In summary, when the fetus is not in the irradiation field and the abdomen is protected by a shield, the number of X-rays that the fetus receives may be ignored.

The fetus is in the irradiation field

The fetus receives a very large number of X-rays, which will increase with more films taken. Each scanned film can receive the fetus from 100 to 400 mRad. Hysteroscopy causes the fetus to receive the most x-rays.

If the isotope is used for diagnostic or therapeutic purposes, the fetus receives 50 mRad provided the half-life is less than 10 days.

X-ray diagnostic method

medium

Minimum

Max

Hysteroscopy - oviduct

Pelvic measurement

Abdominal imaging unprepared

UIV

Colon scans

Capture the groin, head on the femur

Lumbar spine capture

Breast scan

Take a close-up of the abdomen and pelvis

1270

620

300

590

870

240

410

< 20

1670

200

160

110

50

20

53

20

6700

4000

1600

4000

9200

1000

2900

Note: 1 Gy = 1 Gray = 100Rad

        1 cóy = 0.01 Gy = 1 Rad

        1 Rad = 100mRad

Management attitude towards an irradiated pregnant woman

If the woman already has a baby, we recommend suspending the pregnancy.

If the pregnant woman has not had a child yet, very much looking forward to a baby, we must base on many factors to decide:

Gestational age when visiting.

Gestational age when irradiated.

Irradiated dose.

For pregnancies, less than 12 weeks, the procedure to suspend pregnancy is relatively easy to use. If the dose of radiation is 1.5 Rad or more, a pregnancy suspension is required.

For pregnancies over 12 years old, irradiated with radiation from 5 Rad or more, it is mandatory to suspend the pregnancy.

To prevent fetal irradiation risk, all radiological examination must be done during the first 10 days of menstrual cycle for all women of childbearing age, except in emergency cases.