Radiation hazards in pregnancy and methods of prevention

Impact of Ionizing Radiation Exposure on Placental Function and Implications for Fetal Programming

Accidental exposure to high-dose radiation while pregnant has shown significant negative effects on the developing fetus. One fetal organ which has been studied is the placenta. The placenta performs all essential functions for fetal development, including nutrition, respiration, waste excretion, endocrine communication, and immunological functions. Improper placental development can lead to complications during pregnancy, as well as the occurrence of intrauterine growth-restricted (IUGR) offspring. IUGR is one of the leading indicators of fetal programming, classified as an improper uterine environment leading to the predisposition of diseases within the offspring. With numerous studies examining fetal programming, there remains a significant gap in understanding the placenta's role in irradiation-induced fetal programming. This review aims to synthesize current knowledge on how irradiation affects placental function to guide future research directions. This review provides a comprehensive overview of placental biology, including its development, structure, and function, and summarizes the placenta's role in fetal programming, with a focus on the impact of radiation on placental biology. Taken together, this review demonstrates that fetal radiation exposure causes placental degradation and immune function dysregulation. Given the placenta's crucial role in fetal development, understanding its impact on irradiation-induced IUGR is essential.

Absence of Depressive and Anxious Behavior with Genetic Dysregulation in Adult C57Bl/6J Mice after Prenatal Exposure to Ionizing Radiation

The exposure of ionizing radiation during early gestation often leads to deleterious and even lethal effects; however, few extensive studies have been conducted on late gestational exposures. This research examined the behavior al effects of C57Bl/6J mouse offspring exposed to low dose ionizing gamma irradiation during the equivalent third trimester. Pregnant dams were randomly assigned to sham or exposed groups to either low dose or sublethal dose radiation (50, 300, or 1000 mGy) at gestational day 15. Adult offspring underwent a behavioral and genetic analysis after being raised under normal murine housing conditions. Our results indicate very little change in the behavioral tasks measuring general anxiety, social anxiety, and stress-management in animals exposed prenatally across the low dose radiation conditions. Quantitative real-time polymerase chain reactions were conducted on the cerebral cortex, hippocampus, and cerebellum of each animal; results indicate some dysregulation in markers of DNA damage, synaptic activity, reactive oxygen species (ROS) regulation, and methylation pathways in the offspring. Together, our results provide evidence in the C57Bl/6J strain, that exposure to sublethal dose radiation (<1000 mGy) during the last period of gestation leads to no observable changes in behaviour when assessed as adults, although some changes in gene expression were observed for specific brain regions. These results indicate that the level of oxidative stress occurring during late gestation for this mouse strain is not sufficient for a change in the assessed behavioral phenotype, but results in some modest dysregulation of the genetic profile of the brain.

Maternal Chronic Disease and Congenital Anomalies of the Kidney and Urinary Tract in Offspring: A Japanese Cohort Study

RATIONALE & OBJECTIVE

Several maternal chronic diseases have been reported as risk factors for congenital anomalies of the kidney and urinary tract (CAKUT) in offspring. However, these investigations used case-control designs, and cases with isolated genitourinary CAKUT were not distinguished from cases in which CAKUT were present with extrarenal congenital anomalies (complicated CAKUT). We examined the association of maternal diseases with isolated and complicated CAKUT in offspring using data from a prospective cohort study.

STUDY DESIGN

A nationwide prospective birth cohort study.

SETTING & PARTICIPANTS

100,239 children enrolled in the Japan Environment and Children's Study between January 2011 and March 2014 at 15 research centers. Physicians' diagnoses in mothers and children were collected from medical record transcripts and questionnaires.

EXPOSURES

Medical histories of maternal noncommunicable diseases, including obesity, hypertension, diabetes mellitus, kidney disease, hyperthyroidism, hypothyroidism, psychiatric disease, epilepsy, cancer, and autoimmune disease.

OUTCOMES

CAKUT diagnosed during the first 3 years of life, classified as isolated or complicated.

ANALYTICAL APPROACH

Multivariable Poisson regression with generalized estimating equations accounting for clustering by clinical center.

RESULTS

Among the 100,239 children, 560 (0.6%) had CAKUT, comprising 454 (81%) isolated and 106 (19%) complicated forms. The risk of isolated CAKUT was increased in children of mothers who experienced kidney disease (adjusted risk ratio [RR], 1.80 [95% CI, 1.12-2.91]) or cancer (RR, 2.11 [95% CI, 1.15-3.86]). Furthermore, the risk of complicated CAKUT was increased in children of mothers with diabetes mellitus (RR, 3.04 [95% CI, 1.64-5.61]).

LIMITATIONS

Lack of standardization or prespecification of clinical definitions, diagnostic criteria, measurements, and testing. Genetic testing was not performed.

CONCLUSIONS

Isolated CAKUTs and complicated CAKUTs were associated with different maternal diseases. The results may inform clinical management of pregnancy and highlight potential differences in the genesis of isolated and complicated forms of CAKUT.

Diagnostic Imaging of Pregnant Women and Fetuses: Literature Review

Healthcare providers have acknowledged the dangers of radiation exposure to embryonic and fetal health, yet diagnostic imaging of pregnant women is increasing. Literature that pertains to the topic of interest was reviewed to collect tertiary data. The purpose of this literature review was to present the various radiation risks for pregnant women and the fetus depending on the gestational age of the pregnancy. The specific effects of radiation on pregnant women and the fetus, X-ray risks depending on the gestational age of the pregnancy, and other potential health effects when performing diagnostic imaging procedures on pregnant women were discussed in this review. In addition, ethical issues have been considered by improving overall communication to minimize unnecessary radiation exposure to pregnant women and fetuses.

Commercial Air And High-Altitude Travel by Pregnant Women: A scientific review commissioned by the European Board and College of Obstetrics and Gynaecology (EBCOG)

Air travel and long distance travel may have adverse effect on the pregnancy-induced physiology and these effects are more marked among those with pre-existing medical conditions. There are significantly increased risks of deep venous thrombosis, inflight transmission of infections, preterm labour, and other significant obstetric and medical complications that may be exacerbated by the flight and may require emergency care. Transient changes in cardiotocographic tracings during third trimester of pregnancy have been reported following air travel. It has been suggested that pregnant members of the flight crew may be at a slightly higher risk of spontaneous miscarriages. There are no contra-indications for healthy pregnant women on air travel. Those with underlying medical conditions should only embark on long distance travel following consultation with their obstetrician. Pregnant women should be advised to familiarise themselves with the healthcare system in the country/region they will be visiting and draw up an emergency plan of how they will contact the healthcare system at their destination.

Ionizing radiation and toll like receptors: A systematic review article

Ionizing radiation, including X and gamma rays, are used for various purposes such as; medicine, nuclear power, research, manufacturing, food preservation and construction. Furthermore, people are also exposed to ionizing radiation from their workplace or the environment. Apart from DNA fragmentation resulting in apoptosis, several additional mechanisms have been proposed to describe how radiation can alter human cell functions. Ionizing radiation may alter immune responses, which are the main cause of human disorders. Toll like receptors (TLRs) are important human innate immunity receptors which participate in several immune and non-immune cell functions including, induction of appropriate immune responses and immune related disorders. Based on the role played by ionizing radiation on human cell systems, it has been hypothesized that radiation may affect immune responses. Therefore, the main aim of this review article is to discuss recent information regarding the effects of ionizing radiation on TLRs and their related disorders.

Radiotherapy in Pregnancy-Associated Breast Cancer

Breast radiotherapy during pregnancy is a matter of debate as both the efficacy of treatment and the safety of the developing fetus should be considered. Currently there is not enough data to support the safety of in-utero exposure to radiation even with modern radiotherapy techniques. So it is highly recommended that breast radiotherapy is postponed to after delivery, though it might be considered in very selected patients according to risk-benefit assessment.

Feasibility and performance of catheter ablation with zero-fluoroscopy approach for regular supraventricular tachycardia in patients with structural and/or congenital heart disease

Patients with structural heart disease (SHD) are more difficult to ablate than those with a structurally healthy heart. The reason may be technical problems. We compared periprocedural data in unselected patients (including SHD group) recruited for zero-fluoroscopy catheter ablation (ZF-CA) of supraventricular arrhythmias (SVTs).Consecutive adult patients with atrioventricular nodal reentry tachycardia (AVNRT), accessory pathways (AP), atrial flutter (AFL), and atrial tachycardia (AT) were recruited. A 3-dimensional electroanatomical mapping system (Ensite Velocity, NavX, St Jude Medical, Lake Bluff, Illinois) was used to create electroanatomical maps and navigate catheters. Fluoroscopy was used on the decision of the first operator after 5 minutes of unresolved problems.Of the 1280 patients ablated with the intention to be treated with ZF approach, 174 (13.6%) patients with SHD (age: 58.2 ± 13.6; AVNRT: 23.9%; AP: 8.5%; AFL: 61.4%; and AT: 6.2%) were recruited. These patients were compared with the 1106 patients with nonstructural heart disease (NSHD) (age: 51.4 ± 16.4; AVNRT: 58.0%; AP: 17.6%; AFL: 20.7%; and AT: 3.7% P ≤ .001). Procedural time (49.9 ± 24.6 vs 49.1 ± 23.9 minutes, P = .55) and number of applications were similar between groups (P = 0.08). The rate of conversion from ZF-CA to fluoroscopy was slightly higher in SHD as compared to NSHD (13.2% vs 7.8%, P = .02) while the total time of fluoroscopy and radiation doses were comparable in the group of SHD and NSHD (P = .55; P = .48).ZF-CA is feasible and safe in majority of patients with SHD and should be incorporated into a standard approach for SHD; however, the procedure requires sufficient experience.

Vascular Type of Ehlers-Danlos Syndrome: A Case Report of an Aortic Dissection During Pregnancy

BACKGROUND Vascular type of Ehlers-Danlos syndrome (vEDS) is a rare connective tissue disorder associated with a high prevalence rate of aortic dissection (AD). The coexistence of a pregnancy raises these rates and the diagnostic complexity of the situation. In this article, we present a different initial diagnostic approach to an acute aortic syndrome. CASE REPORT A young pregnant woman (29th week gestation) with vEDS was admitted to our clinic due to sudden tearing back pain radiating to the left arm. Four years ago, the same patient underwent a surgical aortic valve reconstruction and replace of the ascending and proximal arch of the aorta because of an acute Standford A AD. The clinical, laboratory as well as transthoracic echocardiographic findings did not reveal any objective signs of an acute aortic syndrome. Due to the relative contraindications against computed tomography imaging due to pregnancy, we conducted a transesophageal echocardiography which revealed acute progress of pre-existing AD. A follow-up computed tomography could verify our findings,showing a Standford B dissection, which was treated conservatively. After 2 weeks, due to a distal progression of dissection, our patient underwent a cesarean section. In absence of new clinical findings, the young patient was discharged the following week. CONCLUSIONS Patients with vEDS are at high risk of an AD and other life-threatening complications, especially during pregnancy. According to the guidelines of European Society of Cardiology (ESC), vEDS-patients should be thoroughly screened. In the case of pregnancy, physicians should consider frequent follow-up examinations and be prepared for diagnosis and treatment of the potential complications.

Current standards for assessing pregnancy status before surgery are subjective and should be replaced with definitive, objective evidence

We report a case of a young woman admitted electively for laparoscopic Nissen fundoplication, and again three days post-operatively as an emergency with profuse vomiting and abdominal pain. She underwent diagnostic laparoscopy, and a small gastric perforation was found at the site of the fundoplication and this was suture-repaired. On both admissions, she was “screened” for pregnancy as per current guidelines. On the second admission, following a CT scan, she was found to have a gravid uterus with a foetus of 16–18 weeks’ gestation. In the opinion of the authors, this case highlights that current National Institute for Health and Care Excellence guidelines may be insufficient and could lead to unnecessary harm either to mother or foetus pre-, peri- or post-operatively.

Monte Carlo Simulation of Radiotherapy for Breast Cancer in Pregnant Patients: How to Reduce the Radiation Dose and Risks to Fetus?

This study estimated the fetal dose and risks from radiotherapy for breast cancer with 6 MV X-rays. Breast irradiation was simulated with the MCNP code using two mathematical phantoms corresponding to patients in the early and middle periods of pregnancy. Monte Carlo simulations were performed to determine the appropriate fetal shielding. For a 50-Gy tumor dose, the unshielded fetal dose reached up to 133.1 mGy. Fetal protection with a lead shield of dimensions 30 × 30 × 5 cm3 placed besides the treatment couch resulted in maximum doses of 22.0 and 70.3 mGy at the first and second trimesters of gestation, respectively. These shielded fetal doses may be associated with a fatal cancer risk during childhood up to 0.42% and a maximum probability for the appearance of heritable effects of 0.17%. The use of fetal shielding ensures the absence of deterministic effects from radiotherapy during the first 24 weeks of gestation.

A mini review on pregnant mothers with cancer: A paradoxical coexistence

The diagnosis of cancer during pregnancy at least in the Western world is a rare phenomenon, but this might be raised into the future due to late pregnancies in the modern societies. The coexistence of pregnancy and cancer implicates numerous medical, ethical, psychological and sometimes religious issues between the mother, the family and the treating physician. Breast, cervical cancer, melanoma and lymphoma are the most common malignancies diagnosed during pregnancy. Diagnostic or therapeutic irradiation requires careful application, whereas systemic chemotherapy is not allowed during the first trimester of pregnancy due to lethal or teratogenic effects as well as to congenital malformations. In some gestational cancers, tumor cells can invade the placenta or the fetus.