Lithium Medication in Pregnancy and Breastfeeding-A Case Series

Lithium and endocrine disruption: A concern for human health?

Lithium is a key medication for the treatment of psychiatric disorders and is also used in various industrial applications (including battery production and recycling). Here, we review published data on the endocrine-disrupting potential of lithium, with a particular focus on the thyroid hormone system. To this end, we used PubMed and Scopus databases to search for, select and review primary research addressing human and animal health endpoints during or after lithium exposure at non-teratogenic doses. Given the key role of thyroid hormones in neurodevelopmental processes, we focused at studies of the neural effects of developmental exposure to lithium in humans and animals. Our results show that lithium meets the World Health Organization's definition of a thyroid hormone system disruptor - particularly when used at therapeutic doses. When combined with knowledge of adverse outcome pathways linking molecular initiating events targeting thyroid function and neurodevelopmental outcomes, the neurodevelopmental data reported in animal experiments prompt us to suggest that lithium influences neurodevelopment. However, we cannot rule out the involvement of additional modes of action (i.e. unrelated to the thyroid hormone system) in the described neural effects. Given the increasing use of lithium salts in new technologies, attention must be paid to this emerging pollutant - particularly with regard to its potential effects at environmental doses on the thyroid hormone system and potential consequences on the developing nervous system.

Where are the data linking infant outcomes, breastfeeding and medicine exposure? A systematic scoping review

INTRODUCTION

Information on the impact of medicines on breastfeeding and the breastfed infant remains scarce. The aims of this review were to identify databases and cohorts holding this information, and pinpoint current information and research deficits.

METHOD

We searched 12 electronic databases, including PubMed/ Medline and Scopus, using a combination of controlled vocabulary (MeSH terms) and free text terms. We included studies reporting data from databases with information on breastfeeding, medicines exposure, and infant outcomes. We excluded studies not reporting all three parameters. Two reviewers independently selected papers and extracted data using a standardised spreadsheet. Risk of bias was assessed. Recruited cohorts with relevant information were tabulated separately. Discrepancies were resolved by discussion.

RESULTS

From 752 unique records, 69 studies were identified for full review. Eleven papers reported analyses from ten established databases with information on maternal prescription or non-prescription drugs, breastfeeding and infant outcomes. Twenty-four cohort studies were also identified. No studies reported educational or long-term developmental outcomes. The data are too sparse to warrant any firm conclusions, beyond the need for more data. The overall picture hints at 1) unquantifiable, but probably rare, serious harms to infants exposed to medicines via breastmilk, 2) unknown long-term harms, and 3) a more insidious but more pervasive harm in terms of reduced breastfeeding rates following medicines exposure in late pregnancy and peri-partum.

IMPLICATIONS

Analyses of databases reporting on the full population are needed to quantify any adverse effects of medicines and identify dyads at risk of harm from prescribed medicines while breastfeeding. This information is essential to ensure 1) infants are monitored appropriately for any adverse drug reactions 2) inform breastfeeding patients using long-term medicines as to whether the benefits of breastfeeding outweigh exposure to medicines via breastmilk and 3) target additional support to breastfeeding patients whose medicines may affect breastfeeding. The protocol is registered with the Registry of Systematic Reviews, no.994.

Maternal LiCl exposure disrupts thyroid-cerebral axis in neonatal albino rats

This work aimed to elucidate whether maternal lithium chloride (LiCl) exposure disturbs the thyroid-cerebral axis in neonatal albino rats. 50 mg of LiCl/kg b.wt. is orally given for pregnant Wistar rats from gestational day (GD) 1 to lactation day (LD) 28. The maternal administration of LiCl induced follicular dilatation and degeneration, hyperplasia, lumen obliteration and colloid vacuolation in the maternal and neonatal thyroid gland at postnatal days (PNDs) 14, 21 and 28. Neuronal degeneration (spongiform), gliosis, nuclear pyknosis, perivascular oedema, and meningeal hyperaemia were observed in the neonatal cerebral cortex of the maternal LiCl-treated group at examined PNDs. This disturbance appears to depend on intensification in the neonatal cerebral malondialdehyde (MDA), nitric oxide (NO), and hydrogen peroxide (H₂ O₂ ) levels, and attenuation in the glutathione (GSH), total thiol (t-SH), catalase (CAT), and superoxide dismutase (SOD) levels. In the neonatal cerebrum, the fold change in the relative mRNA expression of deiodinases (DII and DIII) increased significantly at PNDs 21 and 14, respectively, in the maternal LiCl-treated group. These data suggest that maternal LiCl may perturb the thyroid-cerebrum axis generating neonatal neurodevelopmental disorder.