Factors Associated To Breastfeeding Cessation Before 6 Months

Roig, Antoni Oliver; Martínez, Miguel Richart; Cabrero García, Julio; Pérez Hoyos, Santiago; Laguna Navidad, Ginesa; Flores Álvarez, Juan Carlos; Calatayud Pujalte, María del Mar; García de León González, Ricardo Fatores associados ao abandono do aleitamento materno durante os primeiros seis meses de vida Revista Latino-Americana de Enfermagem, vol. 18, núm. 3, 2010, pp. Tela 79-Tela 86 Universidade de São Paulo São Paulo, Brasil


Introduction
Breastfeeding (BF) benefits mothers' and infants' health in the short and long terms and is the most adequate option to feed infants.The World Health Organization recommends exclusive breastfeeding during the first six months of life and combined with complementary foods until the age of two years or older, but only a minority of European infants, including the Spanish, are breastfed in accordance with these recommendations (1) .

Specific
professional support and peer interventions (7) , adequate information access (6) and the implementation of the 10 steps of the Baby-Friendly www.eerp.usp.br/rlae Hospital Initiative (BFHI) (8) in hospitals in general have shown their efficacy to improve BF rates.
Most Spanish research about factors related to BF duration resulted from cross-sectional data (4,9) or focused on factors determining BF prevalence at concrete moments during follow-up (6) and do not use definitions of BF types based on the classification proposed by WHO (10) , which impairs the adequate interpretation and comparison among results.Only one pilot study (2) carried out in Spain complies with these two conditions.
This research aims to determine the independent effect of factors related to the duration of Full BF (FBF) and Any BF (ABF) during the first six months of life in a Spanish population.

Participants
The study population included the mother-infant pairs in Elda (Spain The remaining 24% include, besides cases with some exclusion criterion, mothers who did not consult the midwife or who did during the replacement period of one of the participating midwives.

Methods
After obtaining informed consent, a six-month follow-up was carried out.Antecedent variables included information about socioeconomic characteristics and maternal antecedents like age, marital status, education level and family social class.To determine the family social class, the highest value for the class was obtained, based on the mother's and her partner's occupation, using the 1994 National Classification of Occupations and registering the equivalent to the British classification of social classes (11) .
The following were also included as antecedent food is based on the definitions proposed by WHO (10) .
The duration of FBF was considered to be the time until the introduction of IF or complementary feeding (CF) and duration of ABF as the time during which the infants received any quantity of mother's milk.

Data analysis
Variables were subject to descriptive analysis, calculating proportions, means and standard deviations (SD).
To detect differences in antecedent variables between the sample with complete follow-up and the sample with censored data before the age of six months, Student's t-test was used for continuous variables and χ 2 for categorical variables.
To obtain the explanatory models for FBF and ABF and univariate Cox regression for continuous variables.
In the multivariate models, all variables associated with FBF or ABF were included, with p<0.05 in bivariate analysis.
Cox regression models were developed to determine associated variables, independently of the duration of FBF and ABF, using a sequential stepwise backward model, selecting the optimal set of variables by means of the likelihood ratio test.The existence of possible confounding factors or multiplicative interactions was discarded by observing a significant change in the likelihood logarithm after introducing the factor or interaction into the models (manual method).To confirm the supposed proportionality of hazards, the significance of including the term of each variable's interaction with the logarithm of follow-up time was contrasted.
The "expected BF time" variable was not included in the models as this factor does not influence the decision to cease BF but is part of the decision itself (12) .The introduction (not occasional) of IF or complementary feeding was not included as a factor either, since it cannot be considered a risk factor for the abandonment of ABF, as it is an intermediary step necessary for the complete cessation of BF.
The effect of the antecedent variables was described as the Hazard Ratio (HR).Confidence intervals were calculated for a 95% confidence level.Stata/SE for Windows v. 9.0 was used for calculations.

Bivariate and multivariate analysis
The results of the bivariate analysis are shown in Table 1.
No relation was found between FBF or ABF cessation and the mother's age or the baby's birth weight.

Discussion
This study reveals an independent effect of the mother's education level, earlier BF experience, participation in maternal education groups and use of pacifiers or breast milk substitutes in the postpartum period on the early cessation of FBF or ABF.The influence of the mother's valuation of earlier ABF experiences had not been mentioned in other similar research yet.
In the sample, the duration of FBF and ABF remains far below the mothers' own expectations and international recommendations.Data for duration of ABF are similar to other studies showing results for ABF duration in groups of Spanish mothers who breastfed since birth (6,13) .
The positive influence of the mother's higher education level on the duration of BF has been identified in countless studies (2,4,6,9) .The education level is a good proxy of social class (11) and a higher social status has been related with better BF rates (14) .In the analysis, the education level shows to be a more powerful variable than social class based on the mother's occupation, with a view to detecting intergroup BF differences.
The variables related to the mothers' earlier experience exert the strongest independent effect on the duration of FBF and ABF in the sample.The results support the hypothesis about a positive relation between the duration of earlier and current BF, as mothers who did not breastfeed an earlier child ceased ABF or FBF faster than those who breastfeed for four months or less, and the latter faster than mothers who breastfed longer.
In another Spanish research, previous breastfeeding experience for more than four months was described as a protective factor of BF (2) .
The positive association between the mother's valuation of earlier BF and the duration of current BF had not been studied to date.Mothers who valued the earlier experience as less possible may have faced more difficulties during the earlier BF experience and, hence, ceased the current BF more easily when new problems arose.Further research is needed to expand on this aspect.
The positive effect of participation in prenatal education sessions has been described earlier (15)(16) and another research carried out in Spain had associated the duration of BF with the information professionals offer during pregnancy (6) .
In different observation studies, the relation between BF duration and occasional bottles (6,9,15) or pacifier use (5,17) in the postpartum period has been observed, although its direct causal effect on the duration of BF still remains unclear and its use could actually be a symptoms of the appearance of initial BF difficulties (5,18) .
Generalization of these study results should be done cautiously, as it cannot be determined whether the mothers who participated in midwifery consultations and were included in the sample were more predisposed to self-care for their health or if they participated in the consultations for other reasons.
The absence of a relation in the sample between FBF or ABF cessation and variables identified in other studies, such as maternal age (2,6,15) , delivery type (2,4,6) and the infant's birth weight (4) could be explained by the sample's characteristics or size, which makes it difficult to identify risk factors with a lesser impact on BF duration.On the other hand, the variables identified in other studies that were not controlled for in the sample, such as maternal obesity (15) , smoking (2,5) , mother's attitude towards ABF (5) and situations after birth, such as BF problems (3,5,17) could also influence the duration of ABF or FBF.

Conclusion
In conclusion, it is highlighted that (i) the success Data were collected through a personal interview during the midwifery consultation upon the mother's first postpartum visit (antecedent variables), during the infant's first month of life, and through telephone interviews at four and six months postpartum (outcome variables) for mothers who continued ABF during the last contact.Moreover, during the fourth month postpartum, information was collected about the type of maternity leave chosen, return to the paid job and satisfaction with family cooperation in housework during the first month postpartum.
of BF is closely linked with the existence of a positive previous experience, which is why prioritizing professional support resources should take into account the group of mothers without earlier BF experience or with a negative earlier experience; (ii) Adequate information supply can be a protective factor of BF and should be accessible, especially for mothers with a lower education level or more difficult access to the necessary information; and, (iii) postpartum interventions to support BF should include the control of hospital routines, such as the use of pacifiers and not medically indicated breast milk substitutes that can influence the early cessation of BF.

Table 1 ,
sample characteristics are shown.

Table 1 -
Total duration of FBF and ABF according to antecedent variables c Did not know/answer 2 Continue... www.eerp.usp.br/rlae
a Statistical significance of intergroup difference for FBF cessation (ns=not significant); b Statistical significance of intergroup difference for ABF cessation (ns=not significant); c Log Rank Test; d Breslow Test; e Managers, freelancers, supervisors, management support); f Manual and unqualified workers; g People <5 years or disabled who depend on woman's care (without counting the last child)

Table 2 -
Factors Associated with FBF and BF cessation before 6 months (n=246)* After the stepwise method, the final model was developed taking into account the following potential confounding variables: social class, mother's age, parity, delivery type, moment of skin-to-skin contact postpartum, gender and weight of infant and hospital routines like rooming-in practice, professional breastfeeding help, pacifier use, breast milk substitutes and limitation of breastfeeding duration and frequency.
a Full Breastfeeding b Any Breastfeeding; b Adjusted Hazard Ratio; c Confidence Interval 95%, "ns" indicates non-significant differences in the model when including the variable.*