A Tommy's spokesperson said an interview with a national newspaper was being negotiated, and celebrity weekly and parenting press would be covering the story.
The T-shirt was designed by maternity label Séraphine and features a print of an ultrasound scan on the front. The campaign's success means the charity is already planning to commission a design for a new garment next year.
Tommy's is aiming to raise £50,000 through selling the long-sleeved T-shirt at £29. It said that the money will go towards research programmes into the prevention of premature birth, miscarriage and stillbirth.