How long does the fertility-enhancing effect of hysterosalpingography with oil-based contrast last?

Neurodevelopmental outcomes of school-age children conceived after hysterosalpingography with oil-based or water-based iodinated contrast: long-term follow-up of a nationwide randomized controlled trial

STUDY QUESTION

Does preconceptional exposure to oil-based iodinated contrast media during hysterosalpingography (HSG) impact children's neurodevelopment compared with exposure to water-based alternatives?

SUMMARY ANSWER

Our study found no large-sized effects for neurodevelopment in children with preconceptional exposure to oil-based iodinated contrast media during HSG compared with water-based alternatives.

WHAT IS KNOWN ALREADY

HSG is widely used as a diagnostic tool in the female fertility work-up. Tubal flushing with oil-based iodinated contrast has been shown to enhance fertility outcomes in couples with unexplained infertility, increasing the chances of pregnancy and live birth compared with water-based alternatives. However, oil-based contrast contains higher doses of iodine and has a longer half-life, and concerns exist that iodinated contrast media can affect women's iodine status and cause temporary (sub)clinical hypothyroidism in mothers and/or foetuses. Considering that thyroid hormones are vital to embryonal and foetal brain development, oil-based contrast media use could increase the risk of impaired neurodevelopment in children conceived shortly after HSG. Here we examine neurodevelopmental outcomes in school-aged children conceived after HSG.

STUDY DESIGN, SIZE, DURATION

This is a long-term follow-up of the H2Oil trial in which oil-based or water-based contrast was used during HSG (Netherlands; 2012-2014; NTR3270). Of 369 children born <6 months after HSG in the study, we contacted the mothers of 140 children who gave consent to be contacted for follow-up. The follow-up study took place from January to July 2022 (NCT05168228).

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

The study included 69 children aged 6-9 years who were conceived after HSG with oil-based (n = 42) or water-based contrast (n = 27). The assessments targeted intelligence (Wechsler Intelligence Scale for Children), neurocognitive outcomes (computerized neurocognitive tests), behavioural functioning (parent and teacher questionnaires), and academic performance. Linear regression models, adjusted for age, sex, and parental educational attainment were employed to compare groups.

MAIN RESULTS AND THE ROLE OF CHANCE

School-aged children born to mothers after oil-based contrast HSG did not significantly differ from children born to mothers after water-based contrast HSG, in regards to intelligence, neurocognitive functioning, behavioural functioning, or academic performance, with the exception of better performance for visuomotor integration functions in children exposed to oil-based contrast preconception. After exploratory correction for multiple comparisons, none of the group differences was statistically significant.

LIMITATIONS, REASONS FOR CAUTION

The small sample size of this follow-up study limited statistical power. This study provides evidence for the absence of large-sized differences between preconceptional exposure to the two contrast media types but does not rule out more subtle effects on neurodevelopment compared to naturally conceived children without preconceptional exposure to HSG.

WIDER IMPLICATIONS OF THE FINDINGS

This study contributes to our knowledge about the long-term effects of different types of iodinated contrast media used in fertility work-up, indicating that choosing oil-based over water-based iodinated contrast media is unlikely to have major effect on the long-term neurodevelopmental outcomes of children conceived shortly after HSG. However, further research should focus on the overall safety of iodine exposure during HSG, comparing children conceived after HSG to those conceived naturally as both types of contrast contain high amounts of iodine.

STUDY FUNDING/COMPETING INTEREST(S)

The original H2Oil randomized controlled trial was an investigator-initiated study that was funded by the two academic hospitals now merged into the Amsterdam University Medical Centre. The current follow-up study (Neuro-H2Oil) is funded through a research grant awarded to the authors by the Amsterdam Reproduction & Development (AR&D) research institute. S.K. is funded by a AMC MD/PhD Scholarship from the Amsterdam UMC. S.K. reports holding voluntary roles in the civil society organizations Universities Allied for Essential Medicines and People's Health Movement. V.M. reports receiving travel and speaker fees as well as research grants from Guerbet, Merck and Ferring. K.D. reports receiving travel and speaker fees as well as research grants from Guerbet. BWM is supported by a NHMRC Investigator grant (GNT1176437) and reports consultancy, travel support and research funding from Merck, consultancy for Organon and Norgine, and holding stock from ObsEva. The other authors report no conflict of interest.

TRIAL REGISTRATION NUMBER

NCT05168228.

Corrigendum: Fertility-enhancing effect of oil-based contrast agents during hysterosalpingography and the variation of this effect within a 3-year follow-up period in infertile patients

[This corrects the article DOI: 10.3389/fmed.2022.948945.].

Comparison of fertility outcomes between oil‑based and water‑based contrast media during hysterosalpingography: A meta‑analysis

Water-based and oil-based contrast media are both widely used in clinical practice for patients receiving hysterosalpingography (HSG). However, minor controversy exists about whether the oil-based contrast medium has a superior fertility-enhancing effect during HSG. The present meta-analysis intended to comprehensively compare the fertility outcomes of patients receiving either an oil-based or a water-based contrast medium during HSG. Web of Science, PubMed, Excerpta Medica Database, Cochrane, China National Knowledge Infrastructure, Wanfang Data and China Science and Technology Journal Database were examined for literature comparing the fertility enhancement between oil-based and water-based contrast media during HSG up to November 10, 2022 and there was no cut off for studies published earlier than any given year. Data for clinical pregnancy, ongoing pregnancy, live birth, miscarriage and ectopic pregnancy were extracted and analyzed. A total of 11 studies with 2,462 patients receiving oil-based contrast medium and 2,830 patients receiving water-based contrast medium during HSG were included. Relative risks (RRs) and 95% confidence intervals (CIs) were presented for outcome assessment, and the random effects model was utilized for all analyses. Publication bias was analyzed using Egger's and Begg's tests. The results indicated that the rate of clinical pregnancy was increased using oil-based contrast medium compared with water-based contrast medium [relative risk (RR) (95% CI), 1.29 (1.07, 1.54); P=0.006]. In addition, the rate of ongoing pregnancy [RR (95% CI), 1.39 (1.22, 1.59); P#x003C;0.001] and live birth [RR (95% CI), 1.41 (1.07, 1.87); P=0.016] were also increased using oil-based contrast medium compared with water-based contrast medium. However, miscarriage [RR (95% CI), 1.06 (0.61, 1.86); P=0.833] and ectopic pregnancy [RR (95% CI), 0.66 (0.18, 2.36); P=0.518] were not affected by using oil-based or water-based contrast medium. Begg's test and Egger's test suggested that no publication bias of clinical pregnancy, ongoing pregnancy, live birth, miscarriage and ectopic pregnancy existed (all P>0.05), which indicated the stability of the present meta-analysis. In conclusion, the oil-based contrast medium enhances fertility outcomes compared with the water-based contrast medium in patients receiving HSG.