Alexis Hutchinson with Kamani. The army cook and single mother was arrested after failing to show up for her deployment. Photograph: Alexis Hutchinson/AP

A 21-year-old single mother serving with the US Army's 3rd Infantry Division is facing a possible court martial because she failed to turn up for deployment to Afghanistan, saying that she could not find anyone to care for her infant son.

Alexis Hutchinson, who serves as an army cook, was meant to have joined her division for a flight to Kabul on 5 November, but failed to show up. She was arrested and temporarily placed in custody while her 10-month-old child Kamani was put into a daycare scheme on her military base in Savannah, Georgia.

Hutchinson denies any suggestion that she was trying to avoid deployment, insisting that she was only acting out of concern for her boy. She had placed him in the care of her mother, Angelique Hughes, in Oakland, California, but after a couple of weeks Hughes found she was overburdened and unable to commit for a whole year looking after him.

"This is an infant, and they require 24-hour care," Hughes told Associated Press. "It was very, very stressful, just too much for me to deal with."

The case has highlighted the tensions within the US military, which has a policy of treating women personnel with children sensitively yet is under extreme pressure to maintain troop numbers in Afghanistan and Iraq. According to a report last month from the group Iraq and Afghanistan Veterans of America, more than 212,000 women have been deployed in the US military to the two war zones, making up 11% of the forces there. More than 120 have been killed, and 600 wounded. The deployments include some 30,000 women who are, like Hutchinson, single mothers.

Hutchinson's civilian attorney, Rai Sue Sussman, told the Oakland Tribune that her client had gone missing for a day at the time of deployment because she was afraid of what would happen to the child. The lawyer said that Hutchinson had been pressurised to get on the flight even though she had no satisfactory arrangement for his care.

Sussman said: "The day before she was forced to deploy, they told her you have a choice to make, but your duty is to get on that plane. She didn't have anyone to take care of her child. She thought they'd put her on a plane and take her child away."

An army spokesman said that Hutchinson's deployment has been put on hold while an investigation is carried out. Her child has now returned to Oakland to be with his grandmother.