Millie Smith and Lewis Cann found out they were having twin girls, but only one of them would survive.

Smith gave birth to identical twins Callie and Skye on April 30, following a high-risk pregnancy that lasted 30 weeks. Skye only lived for three hours.

Without her sister, Callie spent the night in the NICU incubator under the watchful eyes of her adoring and distraught parents.

An exhausted mother of healthy newborn twins told Smith, in all candor, that she was “so lucky” not to have two infants.

The statements devastated the new mother, and she was at a loss for words. Then she saw the purple butterfly and knew that Skye’s legacy was to comfort other bereaved parents.

Millie Smith and her partner, Lewis Cann, welcomed their first child in November 2015.

Smith, who is expecting a pair of daughters and whose family includes many sets of twins, reported a “gut feeling” that she was carrying more than one baby.

The British parents were shocked to find out that their unborn child had a deadly disease less than two weeks after they found out they were expecting twins.

“During the scan, the doctor didn’t say anything. I was very excited and loved seeing the little babies, but she was silent. Both Lewis and I immediately knew there must be a problem,” Smith said.

The CDC reports that approximately 1 in 4,600 newborns in the United States are born with anencephaly; thus, the doctors broke the news that one of the babies had the condition.