New York ( CNN ) -- New York police have detained a 20-year-old woman they say left a baby in a stroller on a subway platform Monday . A witness told police she saw a woman , described as between 20 and 30 years old , push a stroller from a subway car onto the platform when the doors opened . The woman did n't get off the train , instead letting the doors slide closed and continuing on , according to the witness . After waiting 20 minutes with the baby on the platform to see if the caretaker or mother would return for the child , the witness alerted police . The 7-month-old girl is in stable condition at nearby St. Luke 's Hospital . She was not malnourished , though she suffers from a bit of eczema , police said . Early Tuesday morning , police announced they had detained a woman for questioning . They did n't release her name but said she was the baby 's mother . 'Baby hatch ' inundated with abandoned , disabled children . Texas jogger finds child abandoned in bushes after car theft . CNN 's Julie Cannold contributed to this report .
A witness sees a woman push a stroller from a subway car after its doors open . Hide Caption 2 of 7 Photos:Photos: Police say the baby girl is in stable condition and not malnourished . New York police have detained a 20-year-old woman , say she 's the baby 's mother .