A babysitter accused of administering potentially harmful medications to two baby girls under her care had been prescribed the drugs later found in the infants' bodies.

They included sleeping drug zolpidem as well as alprazolam and diazepam, which are used to treat anxiety disorders.

Court documents did not state why freelance nurse Sa'adiah Jamari, 38, had these drugs prescribed in November and December 2016.

On Dec 29 that year, items including an empty pack of zolpidem, a handkerchief and a milk bottle were found in her Hougang flat. Diazepam was later detected on the handkerchief and traces of zolpidem on the bottle.

Sa'adiah, a Singaporean, is accused of two counts of administering poisons to the babies with the intention of hurting them. One of the infants was five months old while the other was 11 months old. They are not related to each other.

The 22-year-old mother of the older child testified in court on the third day of the trial yesterday. She told the court that in December 2016, she posted on a Facebook group that she needed somebody to look after her baby on Christmas night.

Sa'adiah responded to the message and the mother took her child to Sa'adiah's flat as planned.

Her boyfriend picked up the baby at around 6am the next day, and she noticed that her infant seemed tired.

The mother told District Judge John Ng: "Even after she woke up, she was so drowsy. She could not walk. After one hour... still the same thing... Her head kept moving round and round."

The baby was taken to KK Women's and Children's Hospital that day and admitted.

A urine sample from the child was later found to contain substances including alprazolam and diazepam. She was discharged on Jan 1, 2017.

The 29-year-old mother of the younger baby who testified in court on Tuesday also said that her daughter was hospitalised for several days after she was found to be "very drowsy" and "cranky".

She took the baby to Parkway East Hospital in December 2016 when she had misgivings about her daughter's condition, and later received a medical report listing multiple substances detected in her.

They included the sleeping drug temazepam, the antihistamine chlorpheniramine, and alprazolam. Both women cannot be named to protect their children's identities.

Sa'adiah is out on bail of $10,000. Her trial will resume next Thursday.