Background: Child undernutrition including stunting, underweight and wasting contribute for nearly half of all childhood mortality and the survivors are also liable to impaired physical growth and intellectual development. Stunting, which is a deficient height for age, is an indicator of chronic malnutrition. It mainly develop as a result of prolonged food deprivation or chronic disease or illness. Unintended pregnancy and unplanned birth can endanger the health of women and their families, and it also have negative impact on nutritional status of children.

Objective: This study was aimed to determine the effect of unintended pregnancy and other family and child characteristics on nutritional status of under five children.

Method: Community based unmatched case-control study was conducted among children aged 6-59 months in Wonago town, Gedeo Zone, South Ethiopia. Cases were randomly selected from stunted children and controls were randomly selected from non-stunted children. The sample size was determined using two population proportion formula and the total sample size is 302 i.e. 151 cases and 151 controls. Different characteristics of respondents were descriptively compared using chi-square and multivariable logistic regression was used to assess the effect of unintended pregnancy on stunting after controlling for the other variables at p-value of 0.05.

Result: The result revealed that unintended pregnancy is found to be among predictors of stunting where children from unintended pregnancy were about three times more likely to be stunted [AOR: 2.62, CI: (1.26, 5.45)]. The other predictors identified in this study were educational status of the father, wealth index of the household and daily meal frequency. From the finding, children from illiterate fathers [AOR: 3.43, CI: (1.04, 11.29)], children from poorer household economic status [AOR: 2.32, CI: (1.20, 4.49)] and children whom their daily meal frequency is below the recommended number of feeding [AOR: 4.50, CI: (1.31, 15.49)] were found to be more stunted.

Conclusion: From the result of this study, children delivered from unintended pregnancy were significantly at higher risk of stunting. The result also implies that parental education, households’ economic status and child feeding behavior have significant effect on child nutritional status. Hence preventing unintended pregnancy have great role in decreasing the risk of stunting among children.

Key words:  unintended pregnancy, stunting, under five, Wonago