NATIONWIDE — The Oklahoma State Department of Health is trying to reach a goal of 5,000 purple baby hats by October, and is asking knitters everywhere for their help.

Health officials are teaming up with the National Center on Shaken Baby Syndrome for the campaign Click for Babies, referring to the clicking sound that knitters make with their needles.

According to the center, the No. 1 trigger for shaking a baby is frustration with crying, during what the center refers to as the “PURPLE” period of crying.

Each letter of the word stands for scenarios that parents may experiencing with their infant. For example, the L stands for "long lasting"; babies may cry as much a five hours each day, according to the center's website.

The period of PURPLE crying, the center said, lasts from about 2 weeks of age to 3 to 4 months. Some babies experience it more severely than others, and it is often treated as colic.

Purple baby caps are accepted year-round. Only caps received by Oct. 1 will make it in this year’s hospital distribution.

Purple caps can be mailed to:

Oklahoma State Department of Health
ATTN: Maternal and Child Health
1000 NE 10th St
Oklahoma City, Ok 73117-1299

To obtain patterns for caps, guidelines and “CLICK for Babies” campaign details, visit clickcampaign.health.ok.gov.

To see if you can help more locally, a list of participating states/information how to launch efforts here