Our research revealed that the early manifestation of infant difficult behaviors increases the risk for continuation of problems during the first half-year of infancy. If a child demonstrates difficult behaviors at the age of 3 months the likelihood that these difficulties will persist through the age of 6 months increases by more than 5 times. However, the study demonstrated that the various forms of difficult behaviour vary with infant age. There is growing evidence of the persistence of problems experienced by very young children [22–24]. At the same time, it should be noted that infants during their first half-year still have the possibility to recover from such difficulties, as more than half of the infants characterized as having problems at age of 3 months were no longer characterized by their mothers as problematic at 6-months-of-age.
The present study showed that during the first half year of infancy, various psychosocial factors differ significantly with regard to their risk for development and persistence of infant difficult behaviors. According to the data, demographic and prenatal psychosocial factors including maternal age, emotional well-being and risk behaviors highly increased the risk for difficult infant behavior, but only at the age of 3 months. By the age of 6 months, the aforementioned factors became less important.
In this study, we had the opportunity to evaluate what factors are related to the persistence of infant behavioral difficulties between 3 and 6 months of age. The stability of infant difficulties was related to negative maternal and paternal emotional reactions (as reported by the mother) toward conception, low satisfaction with the couple's relationship before pregnancy, and rigid parent-centered maternal attitudes towards infant rearing. This suggests a strong significance of parent-related and family-related characteristics for an infant's development. Young families, especially those with poor relationships, low readiness for parenthood, and deficient child-oriented attitudes should therefore receive early prevention programs, which focus on teaching infant-rearing skills.
In general, it can be stated that the direct significance of some aspects of prenatal history (such as maternal emotional well-being) decrease during the first half year of infancy, while aspects of the postnatal child environment (such as maternal attitudes toward infant-rearing) become more significant. This could be explained by the complex interplay between a child and his or her environment over time, and the confounding effect of risk factors. Bidirectional effects of the child and of the environment are highlighted in transactional models  and are well-documented in various representative studies of experimental, quasi-experimental, and naturalistic design . However, our study also suggests that some negative aspects of prenatal history (such as poor quality of a couple's relationship before pregnancy and negative or ambivalent reactions toward conception) could potentially have long-lasting effects, increasing the risk of continuity of infant difficult behaviors. It can be assumed that these outward factors could also be interrelated with maternal emotional well-being and produce a combined effect along with the mother's long-lasting negative emotional state.
The results of this study also document the importance of maternal prenatal stress and emotional well-being in the emergence of infant difficult behaviors at 3 months of age, although it was not related with later infant problems. The effects of prenatal anxiety/stress on a child's difficulties developing in cognitive, behavioral, and emotional ways are documented in numerous studies . The prenatal stress associations with ADHD symptoms, externalizing problems, anxiety , and sleep disturbances  have already been highlighted by other researchers. Symptoms of depression, pregnancy-related anxiety, parenting stress, and job strain during pregnancy were also found to be associated with excessive infant crying . We did not find associations of the maternal depression and infant behavior, suggesting that maternal depression may have not direct associations with infant behavior. Some authors have found that maternal depression only explained infant problem behavior in high-risk samples; neither maternal depression nor medical complications in pregnancy predicted problem behaviors within low risk group categories .
Our study endorsed the importance of the paternal role in a child's development from the very beginning of pregnancy. Based on the study data, the quality of a couple's relationship before pregnancy and paternal emotional reactions toward conception could have long-lasting effects on infant behaviors and may be of greater significance than the quality of the couple's relationship later in time. Despite growing research interest and recognition of the importance of the father in a child's development, data on the influence of the fathers' role during the early stages of pregnancy and infancy are still lacking. Little attention is given to the relationships of couples before pregnancy; numerous studies exist about the effect of a couple's relationship on offspring development after childbirth or during pregnancy. It is proposed that marital conflict has an impact on the emotional arousal of children and the regulation of emotion and behavior within children . Data has shown, emotional security regarding the marital relationship mediates relations between marital conflict and child adjustment . However, some available data suggest that a poor relationship between the couple during early stages of pregnancy is linked with poor maternal emotional health, health problems, and poor newborn birth weight . A poor relationship between the couple before pregnancy, and the father's negative emotional reactions towards pregnancy, may also be very important factors influencing the emotional well-being of the pregnant mother, later family functioning, and childrearing.
The results revealed the significance of both maternal and paternal emotional response towards conception in respect of infant difficult behaviors. Negative emotional response to the fact that mother became pregnant increases the likelihood of continuation of infant difficult behaviors by about 4 times. Some earlier studies indicate that infants whose conception was unintended by their father are at an elevated risk for adverse health events . Fathers who did not want the pregnancy have been found less likely to exhibit paternal warmth following the birth . Some studies provide evidence that pregnancy unintendedness in women is associated with some disadvantages for prenatal child development, as women whose pregnancies were unintended were found to be more prone to unhealthy behaviors during pregnancy (cigarette smoking and insufficient vitamin intake) . However, a systematic review assessing the effects of unintended pregnancy (mostly studies classifying pregnancies as wanted, mistimed and unwanted) on the health of infants, children, and parents indicates that evidence on impact of unintended pregnancy on child outcomes is mixed and limited. The reviewed studies did not find the effects of pregnancy intention on maternal reports of child health, activity level, and overall development to be evident. Furthermore, if the effects of unwanted and mistimed pregnancies on child development were found, they mostly diminished once family-environment characteristics were included in the model . Thus, other authors underscore the importance of measuring not only how intentional pregnancy was (whether wanted, mistimed, etc.), but also the attitudes and feelings towards pregnancy . In our study, the emotional reactions of the mother and father towards woman conception were significant factors related with infant behavioral difficulties, while the same could not be said about the fact if pregnancy had been planned or not. These results also emphasize the importance to distinguish between pregnancy planning or intendedness, and pregnancy acceptance. The pregnancy intendedness mostly highlights maternal attitudes before conception, while pregnancy acceptance reflects emotional and cognitive response to the pregnancy after conception.
The study indicated that the continuation of infant difficult behaviors between the ages of 3 and 6 months is highly related to postpartum maternal attitudes toward infant rearing. Infants of mothers expressing more parent-centered and rigid attitudes towards infant-rearing had nearly three times of a greater risk for continual behavioural difficulties in comparison with mothers who expressed more flexible and infant-centered attitudes. Other studies provide evidence that mothers' self-reported attitudes correspond with their child rearing behaviors . The parental attitudes toward child rearing are also reported to be related with the parental response to infant crying. Parents characterized to have infant-centered child rearing attitudes had been found to respond to crying at an earlier point, to express greater sympathy, and to perceive crying as urgent . It has been found that infant fussing and crying was related with unresponsive maternal attitudes and behavior . The maternal emotional reactions to crying with anxiety or anger pose risk for subsequent attachment insecurity . The maternal attitudes are changeable factors, and the possibilities to reduce its negative effect on a child's development should be taken into account within various preventive programs.
However, we are considering that factors such as the emotional reactions towards conception and attitudes towards infant rearing are interrelated; perhaps they can be seen as a reflection of the parental acceptance of the child and preparedness to integrate him into the family system. Lack of emotional acceptance and preparedness at this stage might have a later effect on attachment to the child. Studies inspired by attachment theory highlight that the feelings and attitudes individuals have about parent-child relationships, even before they become parents, are predictive of the subsequent infant-mother attachment pattern and the emotional quality of their future parenting behaviors . However, the possible impact of parental emotional reactions toward pregnancy, as well as attitudes toward motherhood or parenthood, is lacking in the literature and requires greater attention.
Several limitations need to be addressed regarding the present study. Our decision to follow the development of full-term newborns (≥ 37 gestation weeks) could be mentioned not only as an advantage, but also a limitations of our study. Since our study was conducted only among low risk infants, the sample size was limited. The second limitation of the study was that all prenatal measures were collected post-natally during the first days after childbirth. The special emotional state of a recently delivered woman could influence responses to the questionnaire. In our study, all information about independent variables (psychosocial factors) and the dependent variable (infant difficult behaviors) were collected from mothers' reports. It was assumed that mothers acted as primary caregivers of infants, predisposing them to greater access to information about infant behavior than other family members. However, the fact that mothers were the only informants in our study may poorly reflect the real circumstances regarding infant behavior and family life; this is another important limitation of this study. Factors such as maternal personality and emotional state after childbirth could significantly influence the reports. This limited the possibility of obtaining more objective data. It is also important to note that information about the fathers' emotional reactions towards pregnancy, as well as the evaluation of the couple's relationship, was also obtained from mothers and could reflect more of the woman's evaluations about her husband/partner than the real feelings and emotions of the fathers. The results of our study, indicating important role of fathers' emotions and the parents' relationship quality on infant difficult behaviors, shows that these issues should be analyzed more comprehensively in further research, with an emphasis on collecting reports from fathers as well. Relatively low reliability scores using the Lithuanian version of the Women's perception of infant's difficult behaviors scale should also be noted as another methodological weakness of the present study. Thus, further empirical evaluations are needed.