Young mothers
In accordance with previous studies, the results indicate that giving birth at a young age is associated with symptoms of postpartum depression. Several factors might be of importance for this finding. Firstly, an adolescent mother faces the challenge of her own developmental tasks besides the challenge of taking care of a newborn. Secondly, early motherhood is associated with lower degrees of education and lower income [22]. As shown in this study, school drop-out was the most influential factor for postpartum depression symptoms. Moreover, adolescent pregnancy has previously been shown to be linked to other factors increasing the risk for mental health problems, factors such as lower family SES and aggressive and delinquent behaviors [23].
Young mothers reported more emotional and behavioral problems in their children, as has been noted previously [2]. However, it has to be taken into consideration that maternal mental health could influence how the mother perceives and reports on behavior in her child, which could explain part of the increased risk for child behavioral and emotional problems. This in turn, could influence parenthood through anxiety or frustration and create a downward spiral for family wellbeing.
No association was found between young maternal age and the physical and mental development of the child as assessed at the routine medical examination at age 3, which could be interpreted as a promising sign. However, as discussed earlier, a detrimental environment during pregnancy and the first years in life when brain development is intense, could have effects on behavior and stress response apparent later in life [24].
Single mothers
Quite contrary to findings in the majority of previous studies, mothers who were single at childbirth did not report symptoms of postpartum depression to a greater extent than cohabitating mothers. Since the reason for single status of the women in the present study is not known, one can only hypothesize that this group might be more heterogeneous than the divorced women usually included in this type of studies. Living arrangements were not specified in the present study, and it is likely that the mother’s social network is of importance. Likewise, the quality of contact with the father has been shown to impact child wellbeing [25], but was not controlled for in the present study.
Women who were single at childbirth did not report emotional or behavioral problems in their children to a greater extent than cohabitating mothers. Increased rates of depression and anxiety have been shown earlier in school-aged children of divorce [26], however, the separation in itself might be the stress triggering behavioral and emotional problems [27]. Likewise, an association between single motherhood and externalizing problems have previously been reported in older children [12]. Almost 2/3 (n = 22) of the women who were single at baseline, reported cohabitation at the 3-year follow-up, which has to be taken into account when interpreting the results. These families are maybe less likely to experience lower SES due to the structural inequalities of one parent households, however, the children might be subjected to a major life event of family restructuring.
Sociodemographic factors
Low SES is known to be linked to both early and single motherhood. The present study controlled for unemployment, profession, and lack of completion of compulsory or upper secondary school; the latter was shown to be more influential on depressive symptoms than both young age and single status. Just as researchers have argued previously, risk factors for mental health problems tend to coexist due to structural inequalities that tend to reproduce between generations [15]. Health care workers need to be aware of the increased risk for mental health problems especially in young mothers, and to continuously follow up on mental health and development in these families. Societal support for young mothers is needed to enable them to continue their education, but also to support parenthood and wellbeing and facilitate the transition from childhood to adulthood when it involves parenthood.
An important observation is that parental unemployment increased the risk for adverse outcomes in all models, including child development (CWC score). Most likely, mediating factors play a role in this association. Moreover, the relationship could be bidirectional, for example, developmental delays in a child could impact the possibility of parental labor.
Limitations
First, reports on mental health and child behavior came from the mothers, and no clinical assessment of mental health was obtained The CWC score included behavior, but as only one of five domains where the focus was general development. Previous research has raised concerns about biased reports on child behavior in mothers who suffer from mental health problems [28]. However, others say this does not impact the results to a great extent [29]. Furthermore, one can argue that it is reasonable to believe that the wellbeing of a small child is best known by the primary caregiver.
Despite the use of a large population based cohort, the numbers of mothers in the index groups were small. Thus, the results should be interpreted with caution due to the low number of observations in each combination of variables. Moreover, the young mothers did not participate in the follow-up to the same extent as mothers age 21 and above. This can possibly cause an underestimation of the risks of being a young mother, since the overrepresentation of loss to follow-up was extra prominent in the variables internalizing and externalizing problems. Low income, unemployment and low educational status are factors known to increase the dropout rate in longitudinal studies [30], and from the results of the present study it is obvious that young mothers are a vulnerable group. Likewise, mothers of foreign origin did not participate in the follow-up to the same extent as mothers born in Sweden. While there is support in the literature for similar levels of internalizing and externalizing problems reported by immigrant and non-immigrant mothers [31], immigrants might not dispose the same resources (SES, language, social network etc) as Swedish-born parents. The families who dropped out might thus be burdened and would have made an interesting contribution to the follow-up results. The SESBiC cohort was followed further through childhood, but at age 12 the retention rate was too low to carry out multivariate analyses on sub groups.
Another limitation of the present study is the lack of data on quantity and quality of contact with the child’s father and other family and social network contacts. For a young mother living with her parents, or for a single mother to have the child’s father or other person especially close to the mother, sharing the responsibility for the child, the stress is likely to be reduced. This kind of support is possibly a mediating factor which could affect the outcome of mental health and behavior, and is suggested here as an issue for future studies.
In conclusion, the study is strengthened by the use of a birth cohort and not a specifically burdened population. The aim of the study was not to stigmatize young mothers and single mothers, but to pinpoint associated risks for these families, and in conclusion to illuminate the need for societal support.