Open Access
Original Article, Biomed Biopharm Res., 2022; 19(1):19-30
doi: 10.19277/bbr.19.1.276; pdf version [+] Portuguese html version [PT] 


Factors influencing breastfeeding duration among Portuguese mothers

Mariana Z. de Oliveira 1, Cíntia Ferreira-Pêgo 2*

1School of Sciences and Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Lisboa, Portugal

2CBIOS – Universidade Lusófona’s Research Center for Biosciences & Health Technologies, Campo Grande 376, 1749-024 Lisboa, Portugal.

*corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



Breastfeeding is extensively associated with significant benefits for maternal and child health. The World Health Organization recommends that infants be breastfed up to 24 months. The decision to breastfeed is affected by many factors. The present study aimed to assess the factors contributing to the duration of breastfeeding. An online questionnaire was applied to 351 Portuguese mothers of infants under five years old to collect data on socioeconomic, obstetric, and breastfeeding factors. Conditions that contribute to the duration of breastfeeding were information and education about the topic (p≤0.001), residence area (p≤0.001), number of children (p=0.002), duration of pregnancy (p=0.015), previous experience with breastfeeding (p≤0.001), and difficulties during breastfeeding (p=0.035). In conclusion, among the modifiable barriers which influence breastfeeding cessation, breastfeeding education and information is essential to improve breastfeeding rates.


Keywords: Breastfeeding, duration of breastfeeding, literacy, infant nutrition, Portugal

Received: 31/12/2021; Accepted: 12/03/2022



Breastfeeding is a birthright and crucial for the newborn's survival and is the most effective way to meet the baby's nutritional, immunological and psychological needs (1). Breastfeeding is extensively associated with the reduction of infant morbidity and mortality, as well as with significant benefits for maternal and child health (1–3). In Azores (Portugal), breastfeeding acted as a protective factor for childhood obesity (4). Exclusive breastfeeding also seems to have a potential protective influence on postpartum depression among women with prenatal depression, according to Portuguese researchers (5). Therefore, breastfeeding can be an effective, simple, and affordable tool (4), reducing public health costs by decreasing the use of services (6,7). The promotion and support of breastfeeding is a public health issue (2) and should not be seen as the exclusive responsibility of the woman and her family.

The current official recommendation is for breastfeeding exclusivity for the first six months of life, and to be accompanied by solid foods for at least two years, or for as long as mother and baby wish (9).

The worldwide prevalence of breastfeeding is lower than the recommendations of international organizations, especially in high-income countries, since the prevalence of breastfeeding at 12 months is lower than 20% in these countries (8). However, even in low-income and middle-income countries, only 37% of infants younger than 6 months are exclusively breastfed (8). In the United States of America and Australia only half of the mothers breastfeed their babies until they are six months old and, in the UK, only one-third do so (8,10). In Portugal, according to the Registry of Breastfeeding (Registo do Aleitamento Materno or RAM), in 2013, 98.6% of mothers started breastfeeding in the postpartum hospitalization, but only 76.7% continued the practice after being discharged from the hospital. The records from Primary Health Care show that exclusive breastfeeding between the fifth and sixth week was 88.1%; this percentage drops to 22.1% for five-month-old infants (11). Another publication refers that in Portugal in 2014, the prevalence of exclusive breastfeeding at 3, 4, and 6 months of age was 55.9, 48.5, and 30.3%, respectively (12).

Several factors contribute to the success of breastfeeding; these are described within a complex structure, which includes biological, psychological, and social factors that are linked together at various levels (8). The difficulties experienced by the puerperal woman during breastfeeding contribute significantly to the early interruption of breastfeeding and make mothers less likely to breastfeed a second child (13). However, to have more information about the barriers which mothers face when choosing to breastfeed their children is of great interest to health professionals to improve support and expand the assistance at a community level (14). In a pilot study developed in a region of Portugal, breastfeeding women receiving intensive support during the first 120 days postpartum showed promissory results in improving ‘perception of breastfeeding self-efficacy’ compared to conventional care, favoring breastfeeding duration and exclusivity, and cumulative breastfeeding competence of women/families (15).

For all these reasons, this study aimed to assess the factors which contribute to the prevalence of breastfeeding, namely the information available and education about this topic, support and difficulties which puerperal women may experience, and which of these factors influence early breastfeeding abandonment.


Sample and methods

Study design and population

A cross-sectional study was conducted, including a final sample of 351 volunteers. The inclusion criteria consisted of being mothers of children under five years old and having official residence in Portugal. No other non-inclusion criteria were established.

Data collection

Data collection was performed using an online questionnaire through the Google-Forms platform and all the data was self-reported. The questionnaire consisted of five groups of questions. The first group was sociodemographic characterization, namely age at motherhood, marital status, academic degree, occupation, residence, and income. In the second group of questions, obstetric data were collected, including duration of pregnancy, type of delivery, obstetric violence, and number of children. The third group was composed of fifteen questions to measure knowledge about breastfeeding, adapted from the breastfeeding scale (16). The fourth group of questions referred to personal experience with breastfeeding, previous experience, breastfeeding method, duration of breastfeeding, and introduction of infant formula. The fifth and final group of questions referred to the difficulties experienced during the breastfeeding period. The questionnaire was shared on different social networks, mainly Facebook, Instagram, and WhatsApp.

Breastfeeding knowledge scores

The cut-off points of maternal knowledge concerning breastfeeding were made by identifying percentiles. Knowledge was considered “very poor” up to the 25th percentile (0 to 4 points), “poor” above the 25th percentile (5 to 8 points), “moderate” above the 50th percentile (9-11 points), and “good” above the 75th percentile (scores from 12 to 15).

Ethical Considerations

Before data collection, all individuals agreed to participate in the study, giving their informed and written consent to participate. Consent was obtained on the first page of the questionnaire, which included all the information of a “standard” informed consent. Only after reading all the information and selecting the option “I read and agree to participate in the present study” did participants have access to the remainder of the questions. If an individual selected the option “I read the information, and do not agree to participate in the present study,” she was sent to the end of the questionnaire with no access to any question. All the data was confidential and anonymous, and no other information about the participating individuals was collected. The objective of the study, the variables to be evaluated, and the maintenance of anonymity of the data were made available to the participants at the beginning of the questionnaire. The present study was performed following the ethical standards as outlined within the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Statistical analysis

The distribution of characteristics between groups was compared using Pearson χ2 tests for categorical variables, where the units were expressed in % (n). To analyze the relationship between different variables influencing the duration of breastfeeding, four analysis groups were created: <6 months, 6-12 months, 12-18 months, 18-24 months, and > 24 months. Statistical analysis was performed using IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp. All statistical tests were two-tailed and the significance level was set at p<0.05.



Sociodemographic data

Most of the participants were mothers between 31-35 years old (39.6%), married or living in cohabitation (92%), graduated (50.4%), and working (91.7%), with a monthly income of between €1,000 and €3,000 (71.8%), who lived in the metropolitan area of Lisbon (42.2%) and had only one child (55.8%) (Table 1).

Breastfeeding results

According to the breastfeeding knowledge questionnaire, none of the women presented a “very poor” score (0-4 points), 9% had their knowledge qualified as “poor” (5-8 points), 33% were qualified with “reasonable” knowledge (9-11 points) and 58% had a “good” qualification according to the questionnaire (12-15 points) (Figure 1). Table 1 summarizes the characteristics of the study population according to questionnaire score. The breastfeeding knowledge questions and the percentages of correct/incorrect answers for each are displayed in Table 2. The question with the highest number of incorrect answers was “Women who breastfeed should avoid potential allergens” (51.9%), and the statement with the highest number of correct answers was “Formula milk is a better source of nutrients than breast milk” (99.4%). 57% of the population in this study no longer breastfed their children, while 43% of participants were still breastfeeding their babies at the time of the survey. (Figure 2). Among women who were no longer breastfeeding, 49% had breastfed their children for more than 24 months and 29% for less than 6 months. (Figure 3). The most frequent problems with breastfeeding reported were nipple (skin) cracking and pain during breastfeeding (28% and 27%, respectively) (Figure 4).

The main factors influencing the duration of breastfeeding were residence area, the number of children, duration of pregnancy, previous experience with breastfeeding, information and education about breastfeeding, and difficulties during breastfeeding (Table 3).



The present work was one of the first studies to look into which factors influenced the duration of breastfeeding according to World Health Organization guidelines (9) in Portuguese women with children younger than 5 years old.

The main results show a significant association between maternal information about breastfeeding and the duration of breastfeeding. Women who breastfed their children for more than 2 years also presented higher scores on the breastfeeding information questionnaire, while women who breastfed their children for less than 6 months showed lower scores. Similar results were also observed by different authors (17,18). Thereafter, we demonstrated that the highest level of knowledge about breastfeeding is a protective factor against the early cessation of breastfeeding. According to the percentages of incorrect answers, 47% of mothers are not informed about the recommendation (9) “Breastfeeding should be maintained until, at least, 2 years old; before that age, it is considered premature cessation”. Furthermore, 49.3% of them are unaware that “Formula-fed babies have an increased risk of becoming obese in adulthood” according to the last evidence (19). This performance shows that mothers who choose not to breastfeed may not be fully informed about the consequences of this choice. Over 50% of participants believe that “Lactating mothers should avoid potential allergens”, which do not correspond with the most recent published literature (20). A study conducted in Poland shows similar performance among participants, where 44.6% of the participants also believed they should avoid these foods. According to the same study, the authors conclude that the difficulties of a restrictive diet can be one of the causes for the early interruption of breastfeeding (21). This mechanism could be one of the explanations for the premature cessation of breastfeeding of our sample.

The difficulties during breastfeeding also have a significant relationship with the abandonment of breastfeeding. The problems reported by the participants in this study were registered in literature as transitory (13,22), which reinforces the need to provide more information about the management of these difficulties, so that they can be overcome and, consequently, not compromise the continuity of breastfeeding.

The number of children and the previous experience with breastfeeding seem to be two important factors that correlate and influence the duration of breastfeeding. It has been reported that the highest rates of early abandonment are of women who are breastfeeding for the first time, consequently, a previous positive experience and the knowledge acquired during a first breastfeeding experience are protective factors of the longest duration of breastfeeding (13,14).

The duration of pregnancy was also a non-modifiable factor that significantly influenced breastfeeding. In the present analysis, women who had their labor induced had the highest rates of early breastfeeding cessation. However, the scientific literature has not reached a consensus about the topic, since some authors claim that the form of birth influences breastfeeding duration (23), however, other authors found contrary results (14,24).

In conclusion, breastfeeding must be widely encouraged, due to its countless benefits for maternal-infant health and also for the whole society (2,25,26). Since the information about breastfeeding obtained by women comes mostly from health professionals (17), it is important to increase the awareness, commitment, and training of these professionals for the management of modifiable barriers that prevent the optimal duration of breastfeeding, so that they can implement the support which improves the practice.

Limitations of the study

Regarding the limitations of this study, it is important to mention the self-reported data collection, as the results may be subject to social desirability. The sample is composed mostly of married women or women within a stable union, presenting an average socioeconomic level, and the large number of women who breastfeed their children for more than 2 years might not be representative of the Portuguese population. The fact that the questionnaire was not previously validated nor a pre-test performed are also important limitations that should be assumed. We could also mention the memory bias; however, the literature sustains that maternal memory of the duration of breastfeeding is a reliable and valid estimate (27). Finally, it is important to refer that the cross-sectional design of the study is an important limitation as it is not possible to establish a cause-effect relationship.

Practical implications

After identifying the factors that influence early cessation of breastfeeding, we could conclude that knowledge is a modifiable factor which has a high impact on the duration of breastfeeding. For all these reasons, education is a fundamental part of public health; with knowledge, it is possible to understand the difficulties associated with breastfeeding, as well as clarify doubts that may prevent the beginning and continuation of breastfeeding. Training health professionals and having their commitment to the dissemination of breastfeeding recommendations are essential in the process of encouraging prolonged breastfeeding (28). Therefore, it is crucial to educate women and promote public health policies encouraging breastfeeding.

Directions for future research

Additional studies should be conducted to identify the population at risk and to know which educational resources are the most effective to increase knowledge among the population. Future public health campaigns, as well as the presence of a breastfeeding consultant regularly close to the new mother, should be encouraged in a way to increase breastfeeding duration.



In conclusion, the main factors contributing to the duration of breastfeeding in the present analyses were residence, the number of children, duration of pregnancy, previous experience with breastfeeding, information and education about breastfeeding, and difficulties during breastfeeding.


Author’s Contributions Statement

M.O.: conceptualization and study design; experimental implementation; data analysis; figures and graphics; drafting; C.F.-P.: editing and reviewing; supervision and final writing.



Cíntia Ferreira Pêgo is funded by Foundation for Science and Technology (FCT) Scientific Employment Stimulus contract with the reference number CEEC/CBIOS/NUT/2018. This work is funded by national funds through FCT - Foundation for Science and Technology, I.P., under the  UIDB/04567/2020 and UIDP/ 04567/2020 projects.



The authors thank all the participants of this study.


Conflict of Interests

The authors declare no conflict of interest.



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