Iodine contrast prior to or during pregnancy and neonatal thyroid function: a systematic review

Abstract

Objective: Thyroid dysfunction is a known side effect of iodinated contrast media. There is some evidence to suggest that iodinated contrast media administered to pregnant women may cause thyroid dysfunction not only in themselves but also in their offspring. Here, we systematically evaluated literature on the use of iodinated contrast media prior to or during pregnancy on the offspring’s thyroid function. Design: Systematic review of published literature. Materials and Methods: Relevant studies were identified by PubMed, EMBASE and The Cochrane Library up to June 5, 2020. All study designs, reporting on the fetal or neonatal thyroid function after exposure to iodinated contrast media prior to or during pregnancy, were included. We undertook random effects meta-analysis and pooled the estimates as proportions with 95% confidence intervals (CIs). Results: We identified 402 articles, of which 26 were included. Six studies reported (N=369) on exposure to iodinated contrast media prior to pregnancy by hysterosalpingography and 20 studies (N=670) on exposure to these media during pregnancy by amniofetography, urography or computed tomography. There was low to high risk of bias. The proportion of (transient) neonatal thyroid dysfunction was 0.0% (95%CI, 0.0-2.9%) for hysterosalpingography, 2.25% (95%CI, 0.03-6.55%) for amniofetography and 0.0% (95%CI, 0.0-0.02%) for computed tomography. There was a tendency towards an increased risk of thyroid dysfunction with higher amounts of contrast used. Conclusions: Exposure to iodinated contrast media prior to or during pregnancy may increase the risk of thyroid dysfunction in offspring. We recommend keeping the amount of contrast used as low as possible.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

“…After adaptation, the gland “escapes” from this block and resumes thyroid hormone synthesis. However, the immature neonatal thyroid gland may be unable to escape from the acute Wolff-Chaikoff effect, possibly making the fetus and infant more susceptible to iodine-induced hypothyroidism ( 122 , 147 ). Data in adults suggest that the susceptibility to excess iodine exposure may be higher in iodine-deficient populations compared to populations with otherwise adequate habitual iodine intake ( 98 ), but data in infants are limited.…”

Hysterosalpingography with Oil-Soluble Contrast Medium Does Not Increase Newborn Hypothyroidism

“…yroid safety of children conceived following OSCM HSG in the context of potential iodine excess remains unclear [24]. A Japanese study suggested an increased incidence of newborn thyroid dysfunction in offspring conceived immediately following an OSCM HSG [25].…”

Tubal Flushing Treatment for Unexplained Infertility

“…A systematic review evaluating the impact of iodinated contrast media prior to and during pregnancy on the offspring's thyroid function identified 26 studies. 95 The results of this review showed a risk of (transient) neonatal thyroid dysfunction of 0.0% (95% CI, 0.0-2.9%) for HSG. However, there was a tendency toward an increased risk of thyroid dysfunction with higher amounts of contrast used.…”