Radiotherapy during pregnancy
Radiotherapy in a pregnant patient should be carefully planned and discussed with the radiation oncologist and the radiophysicist in order to minimize direct and indirect sources of radiation to the fetus.
The fetal dose should not exceed 100 mGy. The specific risk of radiotherapy is associated with fetal gestation at the time of radiotherapy (Table 72.2).Even with proper shielding there is still the concern of so-called scatter and leakage radiation. Risks can be minimized by adequate shielding. Shielding of the uterus, especially in advanced pregnancy, can become quite challenging due to the heavy materials used for shielding. It may need to be adapted to gestational age and the size of the uterus. Some obstetric experts advise regular clinical and ultrasound examinations to determine the lie of the fetus to get the
Table 72.2 Risks of radiotherapy to fetus during pregnancy
| Gestational age (weeks) | Risk |
| Preimplantation (1) | Lethality |
| Organogenesis (2-7) | Lethality, gross malformations, growth retardation, sterility, cataracts, other neuropathology, malignant disease |
| Early fetal (8-15) | Lethality, gross malformations, growth retardation, intellectual disability, sterility, cataracts, malignant disease |
| Mid fetal (16-25) | Gross malformations, growth retardation, intellectual disability, sterility, cataracts, malignant disease |
| Late fetal (>25) | Growth retardation, sterility, cataracts, malignant disease |
position of the fetal head out of the potential field of radiotherapy, for example, in the case of chest radiotherapy, the fetus should be in the cephalic position and external cephalic version may be necessary.
More on the topic Radiotherapy during pregnancy:
- Arulkumaran S., Ledger W., Denny L., Doumouchtsis S. (eds.). Oxford Textbook of Obstetrics and Gynaecology. Oxford University Press,2020. — 928 p., 2020
- Treatment methods
- Endometrial carcinomas