LONDON—Almost all parents and pregnant women in China, Vietnam, and the UK are exposed to “aggressive” formula milk marketing campaigns that breach global rules set up after scandals more than 40 years ago, according to a new report. The marketing techniques can push women away from breastfeeding and include everything from giving free samples, to executives setting up or joining “mums’ groups” on popular messaging apps, the report from the World Health Organization (WHO), UNICEF, and M&C Saatchi said. Health workers are also targeted, with gifts, funding for research, and even commission from sales, all practices that are banned under international guidelines for the marketing of formula milk. The WHO recommends exclusive breastfeeding for newborns, where possible, as the healthier option. The report’s authors and several external experts said it was time to reform the International Code of Marketing of Breast-milk Substitutes. The code was set up by WHO in …