How can I get across the true awfulness of this film, which is based on the equally bad self-help book? It takes Hollywood trash to a whole new level. For a while, I wondered if it was meant to be a parody, but then I decided it wasn't intelligent enough.

We follow five couples as they come to terms with having a baby; beyond that, the storylines are virtually non-existent. The product placement is constant. In one superfluous scene, we see an expectant mother pick up a leaflet about the collection of umbilical cord blood: a procedure that's incredibly expensive but, to the best of my knowledge, has never helped anyone. The film's clearly conceived as a money-making machine; we can take comfort from the fact that I don't think it's making any. The cinema I saw it in was almost empty.

I suppose we could say the film reflects the fact that pregnant women do worry about breast-feeding and uncomfortable bodily changes. There's also an attempt to tackle the serious issue of miscarriage, but no woman I know has ever miscarried while looking perfectly made up and beautiful in a pristine hospital bed. In fact, all the women look perfect all the time, which is worryingly misleading: any pregnant woman watching this would come out feeling completely inadequate.

The most devastating thing, however, is the complete lack of understanding on the part of any of the future parents that this isn't a game they're playing – but the creation of another human being. At the National Childbirth Trust, where I'm chief executive, we take this aspect of pregnancy very seriously: we see so many expectant parents reach that moment of realisation about the huge responsibilities of parenthood. It can be frightening, but also very moving.

I came out of the cinema crying – whether from laughter at how bad the film was, or sadness at how much harm it could do, I can't say.