Background Children’s breast preference, feeding from one breast more than the other, has been thought to be common. It may develop spontaneously in absence of known risk factors. We know of no study that explores characteristics of spontaneous children’s breast preference (BP).

Objective To establish characteristics of spontaneous BP among children aged 2–24 months.

Design/methods We conducted this cross-sectional study through self-administered survey in 8 primary healthcare centres in Al-Ahsa area, Saudi Arabia. A convenience sample of 500 mothers who brought their 2–24 months old children for vaccination was recruited during 3 months of 2013. The survey consisted of two parts: part 1 was general demographic questions and part 2 explored more about BP. The survey was validated by 2 lactation consultants and tested in a pilot sample of 20 mothers. Surveys with nonresponses on presence or absence of BP question were excluded whereas other nonresponses were replaced by multiple imputation.

Results A total of 480 mothers answered the question on presence or absence of BP (response rate 96%). Out of this, 127 (26%) mothers reported that their children had BP. Prevalence of spontaneous BP was 14% (67/480). Self-reported causes of BP differed significantly (Chi-Square goodness-of-fit p < 0.001): spontaneous BP constituted 53% of the causes; small nipple 19%; less milk production 17%; various medical/surgical pathologies 6%; mothers’ preference 5%. Mothers observed that spontaneous BP began at a median of 1 month (interquartile range: 1 day-3 months, maximum: 9 months). No significant sex predominance was noted (binomial p = 0.50). Proportion of children preferred right or left breast were similar (42% vs 58% binomial p = 0.50). Spontaneous BP was the main or ancillary reason for 21% of formula milk usage within the first six months of life. Nineteen mothers were worried from spontaneous BP; however, only 7 of them sought medical advice.

Conclusions Spontaneous BP was the most common cause of BP in children aged 2–24 months with prevalence of 14% and with no sex or side predominance. It started at very early in life and negatively impacted exclusive breastfeeding. Further study is warranted to confirm these results in other populations and ascertain biological causes and the best intervention, as this could help to improve exclusive breastfeeding.