Babies born in winter start crawling earlier than babies born in the summer, a new study finds.
The study was conducted by researchers from the University of Haifa in Israel. They noted that babies born between December and May start crawling much earlier than babies born in between June and November.
Researchers observed 47 healthy babies and divided them into two groups. The first group titled "summer fall" had babies born from June to November. This group had 16 babies. The remaining 31 babies belonged to the second group titled "winter spring," comprising babies born between December and May. The study included motor observations in the babies' homes when they were 7 months old, and a follow-up session when they began to crawl. Parents were asked to record the stages in their babies' development before and between the observations. The researchers used the Alberta Infant Motor Scale (AIMS) to track the babies' development. The scale is based on four positions: prone (on the stomach), supine (on the back), sitting and standing.
Researchers noted that the average age at which children started crawling was 31 weeks. Babies in the "winter spring" group started crawling within an average age of 30 weeks while babies in the other group started doing so at an average age of 35 weeks. No difference in when they started crawling or the initial style of crawling was observed between girls and boys.
"The difference in crawling onset of four weeks constitutes 14 percent of a 7-month-old's life and is significant," the researchers noted in a press statement. "Documenting the trend by comparing the results of a standard evaluation scale strengthens the findings and points to a significant seasonal effect in the Israeli context."
The researchers also stated that AIMS scores were higher among winter babies. They also found that the score for movement in the prone position, the scale most meaningful in connection with crawling, was significantly higher for the babies in the winter group.
"Although the winter in Israel is comparatively mild compared to other places in the world, it turns out that it nonetheless influences the motor development of babies because of the differences between summer and winter in Israel," the researchers said. "The season influences the babies' experiences in a number of ways, including layers of clothing that are worn; the opportunities babies are given to spend on the floor on their stomachs, and the hours of activity and daylight. Awareness of the seasonal effect is important so that parents will give their babies proper movement and development opportunities in the winter as well."
