There are guidelines on lactation following maternal analgo-sedative exposure, but these do not consider the effect of maternal fasting, nor fluid abstention on human milk macronutrient composition. We therefore performed a structured search (PubMed) on ‘human milk composition’ and screened title, abstract and full paper on ‘fasting’ or ‘abstention’ and ‘macronutrient composition’ (lactose, protein, fat, solids, triglycerides, cholesterol). This resulted in 6 papers and one abstract related to religious fasting (n=129 women) and observational studies in lactating women (n=23, healthy volunteers, fasting). These data reflect two different ‘fasting’ patterns: an acute (18-25h) model in 71 (healthy volunteers, Yom Kippur/Ninth of Av) women and a chronic fasting (Ramadan) model in 81 women. Changes were most related to electrolytes and were moderate, with almost no changes in macronutrients during acute fasting. We therefor conclude that neither short term fasting nor fluid abstention (18-25h) affect human milk macronutrient composition, so that women can be reassured when this topic were raised during consulting. Besides the nutritional relevance, this also matters as clinical research samples – especially to estimate analgo-sedative exposure by lactation - are commonly collected after maternal procedural sedation, associated with maternal fasting and physiology-based pharmacokinetic (PBPK) models assume stable human milk composition.

The objectives were to identify conditions under which mothers may be willing to use telelactation and explore associations between participant characteristics, willingness, and beliefs regarding telelactation use. Mothers 2-8 weeks postpartum were recruited from two Florida maternal care sites and surveyed to assess demographics, breastfeeding initiation, and potential telelactation use. Analyses included descriptive statistics and logistic regression models. Of the 88 participants, most were white, married, earned less than $50,000 per year, had access to technology, and were willing to use telelactation if it was free (80.7%) or over a secure server (63.6%). Fifty-six percent were willing to use telelactation if it involved feeding the baby without a cover, but only 45.5% were willing if their nipples may be seen. Those with higher odds of willingness to use telelaction under these modesty conditions were experienced using videochat, white, married, and of higher income. Mothers with security concerns had six times the odds of being uncomfortable with telelactation compared to mothers without concerns. While telelactation can improve access to critical services, willingness to use telelactation may depend on conditions of use and sociodemographics. During the COVID-19 pandemic and beyond, these findings offer important insights for lactation professionals implementing virtual consultations.

Milk is a complex liquid, and the concentrations of many of its components are under genetic control. Many genes and pathways are known to regulate milk compositon, and the purpose of this review is to highlight how the discoveries of quantitative trait loci (QTL) for milk phenotypes can elucidate these pathways. The main body of this review focusses primarily on QTL discovered in cattle (Bos taurus) as a model species for lactation biology, with occasional references to other ruminant species, and some comparisons with human milk composition are also presented. The following section describes a range of techniques that can be used to help identify the causative genes underlying QTL when the underlying mechanism involves the regulation of gene expression. As genotype and phenotype data bases continue to grow and diversify, new QTL will continue to be discovered, and, although proving the causality of underlying genes and variants remains difficult, these new data sets will further enhance our understanding of lactation biology.

Vitamin A and E are important during pregnancy, the neonatal period, and childhood. The objective of this study was to assess whether maternal RRR-a-tocopherol supplementation affects serum and breast milk retinol. Serum was collected at baseline and twenty days later, and breast milk, at baseline, and on days 1, 7, and 20 after delivery. After the baseline serum collection, the supplemented group (n=16) received a single 400 IU of RRR-α-tocopherol. The control group (n=18) was only performed collections. Retinol and alpha tocopherol levels were determined by liquid chromatography. Serum retinol and alpha tocopherol at baseline and 20 days after delivery indicated proper vitamin A (> 20 µg/dL) and E (> 516 μg/dL) statuses in the control and supplemented groups (p > 0.05). Colostrum retinol levels on days 1 and 7 after delivery were significantly higher in the supplemented group (p = 0.018 and p = 0.012, respectively). Maternal vitamin E supplementation increased colostrum retinol by 52.23% and 111.2%, 24 hours and 7 days, respectively. However, retinol in mature milk did not differ between the groups (p > 0.05). In conclusion, the supplementation with 400 IU of RRR-α-tocopherol improved vitamin A bioavailability in breast milk.

The aims of the study are: a) Describe the reactogenicity of WHO-approved two mRNA (Pfizer-BioNTech, Moderna) and two non-RNA vaccines (Oxford-AstraZeneca, Sinovac) among lactating mother and baby pairs; and b) compare and contrast the reactogenicity between mRNA and non-mRNA vaccines. A cross-sectional, self-reported survey was conducted amongst 1784 lactating women who received COVID-19 vaccinations. The most common maternal adverse reaction was a local reaction at the injection site; the largest minority of respondents, 43.7% (780/1784), reported experiencing worse symptoms when receiving the second dose compared to the first dose. There were no major reported adverse effects or behavioural changes in the breastfed infants. Among the respondents who received non-mRNA COVID-19 vaccinations, a majority reported no change in lactation but those who did more commonly reported an increase in milk supply, decrease in milk supply and pain in the breast. The more commonly reported lactation changes (fluctuations in breastmilk supply and pain in the breast) for the non-mRNA vaccines were similar to that of respondents who received mRNA vaccines. Our study, with a large cohort and wide geographical and racial mix, further augments earlier reported findings that COVID-19 vaccines are safe for breastfeeding mothers and her children.

There is a need to assess the knowledge of healthcare providers on the use of maternal analgesics during lactation, while a valid instrument is not yet available. This study aimed to develop a valid and reliable questionnaire on the knowledge of analgesics (acetaminophen, ibuprofen, aspirin, tramadol, codeine, oxycodone) during lactation, using a prospective, stepwise approach. To generate a pool of item subgroups, literature was assessed as first step. This preliminary version was subsequently reviewed in two focus groups [midwives (n=4), pediatric nurses (n=6)], followed by an expert panel (n=7, 2 rounds) to confirm content validity [item-level and scale content validity]. This resulted in a instrument consisting of 33 questions, and 5 clincial case descriptions specific for both disciplines. Based on known-groups validity between midwives and pediatric nurses (assuming an a priori difference related to their curricula), high construct validity was subsequently demonstrated in a pilot e-survey (86 midwives, 73 pediatric nurses). We therefore conclude that an instrument to assess knowledge on lactation-related exposure to analgesics was generated, that can be further developed and validated. Furthermore, pilot findings suggest suboptimal knowledge for both professions, so that adaptations in their curricula and postgraduate training are warranted.

This study aims to quantify carotenoids and tocopherols in human milk from healthy Chinese women, and to explore their associations with region, lactation stage, and maternal socio-economic and obstetric factors. Human milk was obtained from 509 healthy mothers and the compounds of carotenoids and tocopherols were analyzed by high-performance liquid chromatography after mild saponification and solvent extraction. Socio-economic and obstetric characteristics of the mothers and their dietary intakes through a single 24-hour dietary recall were evaluated. The median content of each component [μg/100mL, median (interquartile range)] in colostrum and mature milk was, respectively, β-carotene 8.0 (4.7-15.2) and 1.8 (1.4-2.7), β-cryptoxanthin 6.2 (2.4-12.9) and 1.8 (1.1-3.4), lutein 5.7 (2.9-10.2) and 3.4 (1.5-6.0), lycopene 6.3 (4.0-9.9) and 1.4 (1.1-2.0), zeaxanthin 1.0 (0.6-1.5) and 1.0 (0.6-1.4), α-tocopherol 645 (388-1176) and 211 (131-321), γ-tocopherol 68 (48-121) and 77 (45-120). The levels of all those vitamins presented regional differences, and decreased as lactation stage increased except for zeaxanthin and γ-tocopherol. Associations of carotenoid contents with maternal education, delivery mode, and present body mass index were found in multivariate analyses. These results suggest that some region, lactation stage, obstetric and socio-economic factors are associated with human milk concentrations of carotenoids and tocopherols in healthy Chinese mothers.