Parental chest computerized tomography examination before IVF/ICSI has no impact on pregnancy and neonatal outcomes: a cohort study of 2680 fresh transfer cycles

BACKGROUND

Some concern has been expressed regarding the negative effects of low-level ionizing radiation exposure in the context of radiological evaluation prior to IVF/ICSI treatment, but the available evidence is limited and conflicting. The aim of this study is to evaluate pregnancy and neonatal outcomes of couples who did chest computed tomography (CT) prior to IVF/ICSI.

METHODS

This was a retrospective cohort study of 2680 IVF/ICSI fresh embryo transfer cycles conducted from January 2019 - August 2020. Fertility outcomes were compared between couples that had or had not undergone CT examination within 3 months prior to the date of oocyte retrieval and sperm collection. Miscarriage was the primary study outcome, while secondary outcomes included the number of oocytes collected, oocyte maturation, normal fertilization, number of good quality cleavage stage embryos, blastocyst formation, implantation, clinical pregnancy, ectopic pregnancy, live birth, multiple birth, Cesarean section rates, gestational weeks, maternal obstetric complications, birth weight, newborn sex ratio, and birth defect incidence. Propensity score matching was used to control for potential confounding variables.

RESULTS

Of the 2680 cycles included in this study, couples underwent CT examination in 731 cycles. After 1:1 propensity score matching, 670 cycles were included in each group. When comparing demographic and fertility-related variables between groups that had and had not undergone CT examination after propensity score matching, we detected no significant differences in miscarriage rates (16.99% vs. 15.77%, OR = 1.10, 95CI% = 0.74 to 1.68). Similarly, both groups exhibited comparable oocyte and embryonic development, implantation rates (41.99% vs. 40.42%, OR = 1.07, 95%CI = 0.87 to 1.31), clinical pregnancy rates (45.67% vs. 44.48%, OR = 1.05, 95%CI = 0.85 to 1.30), ectopic pregnancy rates (2.94% vs. 1.68%, OR = 1.78, 95%CI = 0.59 to 5.36), live birth rates (36.57% vs. 35.67%, OR = 1.04, 95%CI = 0.83 to 1.30), multiple birth rates, Cesarean section rates, gestational weeks, maternal obstetric complication rates, and neonatal outcomes.

CONCLUSIONS

Chest CT examination before IVF/ICSI has no impact on pregnancy and neonatal outcomes associated with fresh embryo transfer.

TRIAL REGISTRATION

Not applicable.

Mouse model of radiation-induced premature ovarian insufficiency reveals compromised oocyte quality: implications for fertility preservation

RESEARCH QUESTION

What is the impact of radiation exposure on oocyte quality and female fertility?

DESIGN

Prepubertal mice underwent whole-body irradiation with a single dose (0.02, 0.1, 0.5, 2, 8 Gy) of gamma- or X-rays. Oocytes were quantified in irradiated (n = 36) and sham-treated (n = 8) mice. After a single exposure to 2 Gy, formation of DNA double-strand breaks (n = 10), activation of checkpoint kinase (Chk2) (n = 10) and dynamics of follicular growth (n = 18) were analysed. Fertility assessment was performed in adult irradiated mice and controls from the number of pups per mouse (n = 28) and the fetal abortion rate (n = 24). Ploidy of mature oocytes (n = 20) was analysed after CREST immunostaining, and uterine sections were examined.

RESULTS

Radiation exposure induced a massive loss of primordial follicles with LD₅₀ below 50 mGy for both gamma and X-rays. Growing follicles survived doses up to 8 Gy. This difference in radiosensitivity was not due to a different amount of radio-induced DNA damage, and Chk2 was activated in all oocytes. Exposure to a 2 Gy dose abolished the long-term fertility of females due to depletion of the ovarian reserve. Detailed analysis indicates that surviving oocytes were able to complete folliculogenesis and could be fertilized. This transient fertility allowed irradiated females to produce a single litter albeit with a high rate of fetal abortion (23%, P = 0.0096), related to altered ploidy in the surviving oocytes (25.5%, P = 0.0035).

CONCLUSIONS

The effects of radiation on surviving oocyte quality question natural conception as a first-line approach in cancer survivors. Together, the data emphasize the need for fertility preservation before radiation exposure and call for reassessment of the use of cryopreserved oocytes.

Medical radiation exposure and risk of sporadic retinoblastoma

BACKGROUND

While there is evidence that parental exposure to medical radiation is associated with increased risk of sporadic bilateral retinoblastoma in offspring, this association has not been confirmed. Additionally, the relationship between paternal and maternal exposures and sporadic unilateral retinoblastoma has not been fully investigated.

PROCEDURE

Data were obtained from two large multicenter case-control studies of retinoblastoma. For the paternal analyses, 268 bilateral cases, 155 unilateral cases, and 358 controls were included. For the maternal analyses, 298 bilateral cases, 184 unilateral cases, and 404 controls were included. Logistical regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) to evaluate the associations between parental exposures to medical radiation and sporadic retinoblastoma, while adjusting for potential confounders.

RESULTS

Paternal exposure to medical radiation was not significantly associated with sporadic bilateral retinoblastoma in offspring. However, increasing paternal exposure to gonadal radiation was associated with increased risk of unilateral retinoblastoma (P-trend = .03). Maternal history of upper and lower gastrointestinal (GI) series was associated with bilateral retinoblastoma (OR = 1.9, 95% CI: 1.1-3.2 and OR = 6.9, 95% CI: 2.9-16.4, respectively). However, there was no association between maternal exposure to medical radiation and unilateral retinoblastoma in offspring.

CONCLUSION

Our investigation adds to the evidence that medical radiation exposure in fathers as well as mothers prior to pregnancy may increase the risk of germline alterations leading to the development of retinoblastoma in their offspring. However, our findings could point to a more complex etiological framework for this important pediatric malignancy.

Interaction between a single exposure and age in cohort-based hazard rate models impacted the statistical distribution of age at onset

OBJECTIVE

Statistical interaction between a single, instantaneous exposure and attained age (age during follow-up; attained age = age at exposure + time since exposure) is used in risk analyses to assess potential effect modification by unmeasured factors correlated with age. However, the impact of such interaction on the statistical distribution of age-at-onset of outcome (disease or death) is infrequently assessed. We therefore explored the impact of such interaction on the shape of the onset-age distribution.

STUDY DESIGN AND SETTING

We use for illustration age-at-onset of radiation-related early menopause in a cohort of female Japanese Atomic Bomb Survivors. The statistical distribution of age-at-onset was derived from a parametric hazard rate model fit to the data, assuming an underlying Gaussian onset-age distribution among nonexposed women.

RESULTS

Commonly used forms of exposure-by-age (attained age) interaction led to unnatural estimates of the age-specific rate function and unreasonable estimates of the onset-age distribution among exposed women, including positive risk of menopause before menarche.

CONCLUSION

We recommend that researchers examine the distribution of age-at-onset and exposure-age interaction when conducting risk analyses. To distinguish this from potential etiologic interaction between exposure and unmeasured factors represented by age as a surrogate, richer models or additional data may be required.