In 2019, the Thailand Multiple Indicators Cluster Survey found that only 34% of mothers and babies initiated breastfeeding within one hour of birth. The exclusive breastfeeding rate of under-six-month-old infants was 14%. The proportions who were breastfed until one year and two years old, were 24% and 15%, respectively. These breastfeeding rates in Thailand were far lower than the 2030 Global Target for breastfeeding [1]; breastfeeding initiation of 70%; exclusive breastfeeding of 70%; and continued breastfeeding until one year and two years of age of 80% and 60% respectively [2].

Thailand has policies to protect, promote, and support breastfeeding. For instance, the Labour Protection Act B.E. 2541 states that working mothers are entitled to 98 days of maternity leave with full pay [3]. The Baby-Friendly Hospital Initiative (BFHI) has been implemented since 1992 in health facilities, particularly public hospitals, to deliver maternal-and-child health services following the “Ten Steps to Successful Breastfeeding” [3, 4]. Furthermore, Thailand adopted and implemented The International Code of Marketing of Breastmilk Substitutes (the Code) as a voluntary measure in 1981. However, there were no penalties for non-compliance by companies.

In 2010, the World Health Assembly (WHA) resolution 63.23 urged all member states to fully adopt the Code into national law [5]. A further resolution WHA 63.14 called for action to minimise the impact of unhealthy food marketing on children, by restricting such marketing, including in settings where children gather such as schools, without conflicts of interest [6]. Therefore, Thailand implemented the Control of Marketing Promotion of Infant and Young Child Food Act B.E. 2560 (the Act) in 2017. The Act prohibits the promotion of baby food such as advertising, cross-promotion, and direct contact with mothers. Furthermore, the Act has restrictions on baby food marketing in the health system, for example, through donations, sponsorship, and offering medical equipment. Most provisions of the Act follow the Code, but due to the interference from baby food industries, for example, lobbying, building relationships with policymakers, and seeking involvement in working groups, technical groups and advisory groups during the legislation process of the Act, some provisions of the Act are different from the Code, such as the scope of products. The Act does not include growing-up milks (GUM) and bottles and teats [7].

Since that time, the new Act implemented the Code in law in Thailand, although it has been illustrated as noted above that corporate political activities of baby food companies influenced the legislation process of the Act [7]. It has also been demonstrated that the companies did not comply with Thai law or the Code so that exposure of the public and new mothers to marketing of baby food products including GUM remains very high [8].

The World Health Organization (WHO) defines marketing as “any form of commercial communication or message that is designed to, or has the effect of, increasing recognition, appeal and / or consumption of particular products and services” [9]. Marketing activity includes various forms of promotion such as advertising and is conducted through different channels, such as via health facilities or electronic media. In 2016, technical guidance issued by the WHO confirmed that the definition of BMS included in the Code was “... any milks (or products that could be used to replace milk, such as fortified soy milk), in either liquid or powdered form, that are specifically marketed for feeding infants and young children up to the age of 3 years (including follow-up formula and growing-up milk)” [10]. As well, the guidance defined that promotion of food for infants and young children is inappropriate, if it interferes with breastfeeding [10].

As breastfeeding indicators improved in high-income countries [11] and regulations to restrict the marketing of BMS were strengthened, baby food marketing has increasingly focused on middle-income countries in Asia. There was a significant increase in global commercial milk formula (CMF) sales from 3.5 to 7.4 kg per child between 2005–19 [12]. A recent study [13] in upper-middle-income countries found that between 2000–19, there was a significant increase of 0.56 percentage points in the absolute average annual changes of formula consumption among infants up to six months. There was high consumption of CMF and CCF in Asian countries, for example, the percentage of prevalence of prelacteal feeding at discharge after delivery in Kathmandu Valley, Nepal was 55.9% in 2014 [14]. Second, in 2014, around 43% of Cambodian mothers of 0–5-month old infants reported they provided breastmilk substitutes to their child [15].

In such countries as Thailand market expansion possibilities are greater than in high income countries [16]. In Thailand, Euromonitor sales data indicates that households are increasingly purchasing milk formula. Between 2015–20 the percentage of volume growth of infant formula (for ages 0–6 months), follow-on formula (7–12 months), and growing-up formula (13–36 months) was 4, 5.3, and 11.3, respectively. Formula retail sales rose from 24,615.1 million Baht (USD$724.91million) in 2013, to 31,712.5 THB million (US$933.93million) in 2020 [17, 18]. Meanwhile, the percentage of exclusive breastfeeding in Thailand decreased from 23% in 2016 [19] to 14% in 2019 [1].

Inappropriate baby food marketing affects the feeding behavior of mothers because such marketing can positively change social norms and caregivers’ attitudes toward formula feeding. For example, A recent study in Indonesia showed that a high prevalence of marketing including through health systems was associated with perceived milk insufficiency, and mistaken maternal motivations for feeding BMS such as growth, intelligence and immunity. It was also associated with maternal employment outside the home. Such research findings highlight that as well as information and counselling, and marketing, broader social health system and employment environments are important for whether mothers’ intentions can be translated into infant feeding practice [20].

Furthermore, Social Cognitive Theory identifies the key factors relating to behaviour change. One is individual factors such as knowledge, and self-efficacy. Another is the existence of supportive factors or barriers in the environment such as family and community, and health system services [21, 22]. Likewise, the Theory of Planned Behaviour presents that infant feeding behaviour relates not only to attitude, intention and subjective norms but also to perceived behavioural control [21]. That is, unless the broader social and home environments support breastfeeding, women may not be enabled to give effect to their breastfeeding intentions.

Hence, apart from baby food marketing, maternal factors such as intention, knowledge, experience in, confidence, and self-efficacy of breastfeeding, also have sociodemographic associations with infant feeding practice. Previous studies in Asia and Africa showed that strong intention to breastfeed [23], and receiving breastfeeding information via counselling during pregnancy [24] were enabling factors of breastfeeding. However, those with low or no education [25, 26], or high income mothers who could afford to buy commercial baby foods rarely maintain exclusive breastfeeding [26].

Until recently little research has directly addressed the associations between baby food marketing and mothers’ infant feeding attitudes and behaviours, allowing companies to dispute their influence on breastfeeding despite enormous marketing expenditures on baby food marketing and promotion targeting mothers, and their families. This denial is a tactic employed by other industries such as the tobacco industry [27]. In 2015, Piwoz et.al presented a broad conceptual framework for the effect of BMS marketing on breastfeeding practices. This framework traced how baby food marketing links to positive attitudes toward baby food marketing and sub-optimal breastfeeding practice [28].

However, there is now growing evidence including from cross-sectional studies showing empirical data linking baby food marketing directly with behavior change. For example, in the Philippines, mothers who recalled formula advertising messages were shown to be more likely to give formula to their children than those who did not recall such messages [29]. Likewise, in the USA, mothers exposed to infant formula information from the media both offline and online were more likely to intend to use infant formula or use formula earlier compared with mothers who did not receive formula information [30]. Moreover, a 2015 study in Thailand found that mothers who more frequently perceived marketing of CMF, were more likely to have positive attitudes toward such marketing, and these mothers were more likely to feed CMF to their children [31].

There are multiple techniques used to market baby food. These include, for example, direct or indirect contact with pregnant or lactating women, digital marketing, and product packaging and labelling. Interestingly, many countries control marketing of infant and follow-on formula [32], but allow growing-up milk to be promoted. Therefore, baby food marketing increasingly uses cross-promotion techniques by promoting growing-up milk to link to infant or follow-on formula. Consequently, caregivers may confuse infant formula and growing-up milk. A study in Australia found that sampled women were not able to distinguish between advertising for infant formula and for GUM [33] There is strong recent evidence from Indonesia [34] and the US [34] showing that GUM contains sugar at levels of serious concern, and is unsuitable for inclusion in the diets of young children. Exposure to marketing claims increased parents’ intentions to give the product, increased its perceived healthfulness, and resulted in parents’ wrong perceptions that it had medical endorsement. Similarly in Vietnam, exposure to marketing of unhealthy commercial milk formula for pregnant women (CMF-PW), creating beliefs that such products were widely used and would make a child smart and healthy, were shown to be associated with greater use of such products [35].

This study, therefore, aimed to explore the associations between exposure to various types of baby food marketing on mothers’ opinions on formula and practices regarding formula feeding in Bangkok, Thailand three years after the new Thai law, in 2020.

It focused on mothers who live in Krung Thep Maha Nakhon (Bangkok), the capital city of Thailand, because baby food companies have more possibility to market their products in the capital city or big cities than other regions of countries [36]. Therefore, mothers in Bangkok may be more likely to have experienced baby food marketing. Moreover, the percentages of breastfeeding initiation and continue breastfeeding for two years of age in Bangkok were around 21%, and 4% respectively [1] which were lower than for other regions in Thailand.