Private companies that exploit pregnant women courtesy of NHS staff and services have long made me sick. Companies with commercial agendas dressed up as philanthropy – such as Emma’s Diary and Bounty – are promoted to pregnant women via their appointments with midwives or GPs and after childbirth in NHS hospitals.

They dangle free gift incentives in front of women, encouraging them to sign up to mailing lists and baby clubs that will share their data (thanks to carefully worded privacy statements) with a wide range of firms – from pharmaceuticals to cars. These firms will go on to bombard them with marketing materials at a time of financial and emotional strain. And now we know that some of the data collected by one company was used for political purposes.

The Information Commissioner’s Office (ICO) revealed today that Emma’s Diary, which provides weekly emails during pregnancy, magazines and a bundle of goodies if you sign up to its app, is potentially in breach of data protection regulation and may face a £140,000 fine. (Emma’s Diary says the ICO findings contain “significant factual inaccuracies”, which they contest.)

The news serves as a signifier for the sometimes shady, usually dysfunctional relationship that society and industry have with motherhood. I already worry about the focus on buying things as opposed to preparing emotionally for the opportunities and challenges of parenting; there is a more sinister aspect to the way motherhood and commerce interact here.

At a time often underscored by money worries, pregnant women have signed up to Emma’s Diary, a seemingly benign service that offers them items such as a pack of nappies and £200 of Argos vouchers in exchange for due dates, dates of birth of existing children and interaction with an app or ads that further profiles them. The particularly nasty twist highlighted by the ICO is that the data collected has subsequently been used by the Labour party for political campaigning and analytics. Emma’s Diary told the ICO that usage of mothers’ data was fully outlined in its privacy policy at the time. The company later amended its privacy policy to make explicit the potential for customer data to be sold for political purposes.

To get to women in the first place, companies such as Emma’s Diary and Bounty (which provide information packs, vouchers and photography services) have exploited the underfunding of antenatal resources and education to provide much-needed online and printed materials, giving a mouthpiece to important health information from midwives and doctors but only on the commercial interest’s terms. For legitimacy and access, the companies have developed partnerships with the Royal College of General Practitioners or the Royal College of Midwives and have permissions that stagger me to distribute their materials using NHS staff as couriers and, in Bounty’s case, by having representatives inside NHS hospitals.

Putting aside possible unlawful data use (which feels like the final straw in this story), private companies having access to pregnant women or those recovering from childbirth feels objectively wrong. And if something feels this wrong to so many (more than 60,000 people signed a petition to ban Bounty reps from maternity wards), that is often because it is wrong.

This is an industry that relies on access to women, granted by state-funded services, at moments of peak physical and emotional vulnerability. I’ve supported women who felt aggrieved by a Bounty rep visiting them within the first hours after birth and delivering a sales pitch. It seems particularly upsetting in the many cases where women’s partners or supporters were sent home shortly after birth (due to visiting-hour policies) and new mothers found themselves alone on understaffed wards, sometimes unable to access food, water or shower facilities.

The selling of data for political purposes also feels like a violation – albeit a different one. Pregnant women and new mothers often talk to me about how infantilised they feel within maternity services and in conversations about their bodies, health and decisions. Any misrepresentation of how data will be collected and the deliberate positioning of these brands as friends when they might be foes is offensive and speaks to the wider lack of respect women encounter on the road to motherhood.

Products, services, information and support can be essential tools to smooth the path to parenting. But opaque and misleading commerce has no place inside the NHS.

• Rebecca Schiller is the director of the childbirth charity Birthrights