In the Dunhuang archives I came across a series of images portraying six female spirits that protect children. Each image includes text which give the name of the spirit which appears to be phonetically transliterated from an Indian language. The text also provides a brief description of a vision of the spirit and a child which if seen in a dream would mean an offering to the spirit would be auspicious.
The catalogue does not provide a date for the manuscripts, but they are probably pre-9th century.
The art itself is interesting in that the spirits are anthropomorphic in quality being both animal and human. Note that the spirits are all painted with their breasts quite pronounced. As the text indicates these are female spirits (女神).
Click the images for larger views.
Such a religious practise as this would have indeed been desirable for mothers. Judging from the limited text, it seems to have been a simple matter of seeing the spirit in a dream with a child and making an offering. This would then prevent calamity from occurring.