My Mother was also in one of these homes in the late 1950s. Her experience was not good. She still finds it upsetting to recall her time there. It was so bad that she wrote home and pleaded with them to get her out of there. She also said that she could see that the babies were not well treated and was desparate not to leave me there.
Luckily she was able to leave and go elsewhere, but her short stay there left a big impression. She described it as "a big house, a miserable place where the expectant mothers were made to scrub floors on their hands and knees every day". She said that "the atmosphere was oppressive and the mothers were made to feel like they were worthless people". When she had to go for examinations she said they treated her "as if she was a prostitute".
I have located where I think the building was. It is no longer a home, but offices now, and has changed quite a bit externally. My mother was not sure from the photos I took if it was the same place, but several of the features of the building that she had described seemed to fit. She is usually quite open about discussing events, but it is clear that this home was a very damaging place to be, and not somewhere she wishes to think about.
After my birth (not in the above home) my mother had to supply a layette and powered milk for me. A older lady my mother had stayed with later in her pregnancy had knitted clothes for "the baby" not realising the circumstances. The lady asked to see "the baby" after the birth and an elaborate story had to be made up by my mother about how "the baby" had to go straight home from hospital so was not able to be taken for a visit to the lady's house. My mother had to stand in a queue, about 6 days after my birth, after having had to leave me at the hospital, to buy the required powered milk - she said she was crying her eyes out at the time.... and the registrar gave her a hard time when she had to go and register the birth, again just after she had left me.
The whole set up seemed to be particularly brutal, appearing to be designed as some sort of punishment for an awful wrongdoing. No empathy, no support for the mother and then the mother was expected to go home and get on with normal life as if nothing had happened, to maintain the elaborate illusion, because, of course, no one was supposed to know about any of it.
So, I think I'd go easy when approaching the subject with your mother. Your mother's experience may not have been as bad, but maybe better to err on the careful side. Of all the subject I've discussed with my mother, this is by far the most upsetting for her, and I felt uneasy asking her to remember, but the issues surrounding this were part of my life too, and I felt I needed to know, to understand the full picture. We've both ended up in buckets of tears talking about this period of her life together, but I think they are healing tears now, and being able to share the feelings and experiences, which she could not do with anyone else, has maybe, I hope, helped a little to put some of the hurt and pain to rest.