Relationship of the type of breastfeeding in the sexual function of women*

Objective: to relate the type of breastfeeding in the women’s sexual function. Method: a cross-sectional study conducted with 150 women in the postpartum period registered in the Family Health Strategy of a large Brazilian municipality. Two instruments were used: one for characterizing sociodemographic, obstetric and breastfeeding variables, and the Female Sexual Function Index for the sexual function. Descriptive data analysis was performed, comparing the variables of interest using the Analysis of Variance, Brown-Forsythe and Tukey tests. Results: there was statistical significance between the groups that practiced different types of breastfeeding in the vaginal lubrication domain (p = 0.015), with the mothers in mixed or partial breastfeeding presenting a higher score for this domain (3.8). Conclusion: there is a difference in the female sexual function between different types of breastfeeding. Women who presented better vaginal lubrication belonged to the mixed breastfeeding group.


Introduction
As a social and multidimensional practice, breastfeeding involves several aspects of the woman's life, the mother-child binomial, the family and the couple, including sexual behavior (1) . Like breastfeeding, sexual response results from complex interactions between biological and psychosocial factors, which vary among cultures, individuals, depending on time, environment and circumstances (2) .
S o m e c o u p l e s c a n e x p e r i e n c e s e x u a l i ty concomitantly with breastfeeding in a positive or negative way, according to the sexual response and possible interaction between the couple. Sexual dysfunctions are frequent during breastfeeding and are defined as disorders related to obtaining sexual desire and satisfaction (3) .
There is limited information on the incidence and prevalence of female sexual dysfunction (4) . The available data differ due to variations in the definitions of sexual dysfunction, composition of the samples in the research studies, methods of data collection, and the way the instruments were validated (4) . In this sense, the studies show a wide prevalence of female sexual dysfunction, which has been obtained in different ways. Considering the variety of existing assessment methods, there is international consensus that the prevalence of female dysfunction, regardless of age, is 40% to 50% (2,5) . When considering the pregnant puerperal cycle, recent studies show a high prevalence of sexual dysfunction ranging from 41% to 83% in the first three months (6) and around 60% in the first postpartum year (3,7) .
Thus, the perinatal period is characterized by a decline in sexual activity (3) , in which there are reports of higher levels of sexual dysfunction and reduced sexual desire. Breastfeeding women report sexual inactivity or dysfunctional problems more often (8) . During breastfeeding, hormonal changes occur that involve the secretion of prolactin and androgen receptors, suppressing the libido and interfering with the sexual response phases (9) . Other aspects of motherhood, such as night sleep deprivation and baby care, may come to interfere with the woman's sexual response cycle.
These physical, hormonal, and social changes involved in breastfeeding are well described in the literature.
However, it was sought to know if the time and type of breastfeeding influence the woman's sexual function.
Despite the significant impact on life, the sexual function of women after childbirth is often neglected by the health professionals (4) . Perceiving that the female sexual response suffers hormonal and emotional interference in the postpartum period, which can manifest itself in sexual dysfunctions, and recognizing that sexual dysfunction can influence early weaning, is of paramount importance for the nurses who assist nursing mothers.
This study aims to relate the type of breastfeeding to women's sexual function.

Method
This is an observational study with a cross-sectional The participants were selected according to the following inclusion criteria: women between three and six months postpartum, who were breastfeeding, who had a sexual partner, and who had resumed sexual activity after delivery. The exclusion criteria were as follows: women with any health condition that contraindicated sexual activity, women from seven months postpartum, and women who use drugs or other psychoactive substances, with a history of psychiatric illness or chronic diseases, such as cancer and neurological diseases, as these factors negatively interfere in one or more phases of sexual response (10) .
The calculation of a simple random sample was performed based on the prevalence of exclusive breastfeeding in children under six months of age in the municipality, obtained from the II National Survey on the Prevalence of Breastfeeding in the Brazilian Capitals and the Federal District, of 34%. A tolerable sampling error of 5% was considered, as well as a 95% confidence level, and an expected loss of 10%. The calculated sample was 150 participants.
Two instruments were used for data collection.

Results
Of the 150 women investigated, age ranged from  (Table 1). and 72 (48.0%) underwent cesarean section as a way to resolve the last pregnancy.
At the time of data collection, the breastfeeding groups found were exclusive, predominant, complemented and mixed breastfeeding. Regarding the Table 1 -Distribution of the participants according duration and type of breastfeeding practiced (n=150). Maceió, AL, Brazil, 2017 As for the breastfeeding time, no association was found between the occurrence of female sexual dysfunction and the duration of breastfeeding, even when each domain was analyzed separately (p>0.05). Table 2 shows the type of breastfeeding and its influence on the female sexual function.   Multiple comparisons were also made between the breastfeeding groups and the vaginal lubrication domain, as shown in Table 3.

Discussion
This study was conducted to assess postpartum sexual function among women who practiced different types of breastfeeding. In the sample studied, the tendency to compromise sexual function was observed, with identification of low mean FSFI scores (<26.55), regardless of the type of breastfeeding, similarly to other studies (13)(14) .
The highest mean score of sexual function (22.7 ± 4.0) was detected in the group of women who practiced mixed breastfeeding. These findings differ from an Iranian study, which detected a higher mean score of sexual function (23.6 ± 5.3) in women who practiced exclusive breastfeeding, in the period of four months after delivery (13) .
Breastfeeding causes different sensations and feelings in women in relation to their sexuality (15) . The positive effects of breastfeeding on the maternal sexual function are reported (13,16) , possibly due to increased breast sensitivity and increased oxytocin levels (14) . However, there are reports of negative effects of breastfeeding on the female sexual function, including fewer sexual relationships, low sexual desire, and low sexual satisfaction of women and their partners (15,(17)(18) .
It was identified that the women on mixed breastfeeding had more vaginal lubrication (3.8 ± 0.6) than those who practiced other types of breastfeeding; while another study detected greater lubrication in women on complementary breastfeeding (3.5 ± 1.0) (13) .
Contrary to the findings of this study, a recent study on breastfeeding and sexual function, in primiparous women, found a significant relationship between low vaginal lubrication, dyspareunia and low desire in sexual activity www.eerp.usp.br/rlae 6 Rev. Latino-Am. Enfermagem 2021;29:e3438.
in the presence of breastfeeding, in relation to the women who did not breastfeed, in the six-month period after delivery (19) . Considering the FSFI domains, it is noted that breastfeeding affects the desire, excitement, lubrication and pain domains (14) . In Italy, a study conducted with 269 women also measured sexual function through the application of the FSFI questionnaire and identified that those who were breastfeeding presented lower vaginal lubrication (8) . However, these studies do not specify the type of breastfeeding practiced.
When data between breastfeeding and nonbreastfeeding women are compared, the results show that those who are breastfeeding are more likely to experience pain during intercourse and poor vaginal lubrication (6,15) .
A possible justification for the low vaginal lubrication in breastfeeding women can be the physiological absence of the estrogen hormone during breastfeeding (6) .
In the case of women who are on mixed breastfeeding, other foods are offered for the baby, which increases the interval between feedings, induces ovarian cycles and the resumption of a woman's hormonal physiology outside the pregnant-puerperal cycle, increasing the libido and vaginal lubrication. In fact, a higher sexual function score is observed in breastfeeding women who have resumed ovarian cycles, compared to women in lactational amenorrhea (16) . In addition to breastfeeding, among other factors associated with the lack of vaginal lubrication, dissatisfaction with body image stands out, especially in relation to overweight and obesity, reducing sexual interest (19) .
The influence of breastfeeding on the female sexual function must be considered, with the possibility of decreased vaginal lubrication, in addition to other changes, which can cause discomfort for the woman and consequently favor the reduction in the rate of exclusive breastfeeding. It was observed that exclusive breastfeeding up to six months, recommended by the World Health Organization (20) , was not practiced by part of the study participants, with interruption of breastfeeding at less than four months in 60 (40%), as well as early initiation of mixed or partial breastfeeding in 60 (40%), which reinforces the innumerable challenges for nurses and other health professionals, in order to implement public breastfeeding policies in the national territory and pro-breastfeeding practices (21) .
The importance of Nursing interventions is highlighted, with care centered on women (19) and with the development of health education strategies in prenatal care, in order to discuss and contextualize the exercise of sexuality in the pregnancy-puerperal cycle, and its relationship with breastfeeding (14) . In addition, the participation of the partners in the puerperal consultations must be stimulated, in order to guide them in this regard, and the participation of the partner in prenatal care is also very important (15,22) .
Positive effects on the marital relationship were found in women who breastfed, for up to four months or for a period equal to or greater than five months, in relation to those who never breastfed, indicating that breastfeeding increases the levels of quality in the marital relationship throughout time, from the woman's perspective. However, the duration of breastfeeding did not have the same influence for the partners. The results suggest that the improvement in the quality of the intimate relationship can be another psychosocial benefit experienced by the nursing mothers (23) .
Lack of information leads women to feel guilty and responsible for the loss of sexual interest (19) . The lack of sexual interest in the puerperal period, especially in the child's first year of life, is a common event and occurs due to the transition from parenting and the definition of new roles, with a significant impact on family dynamics (19) .
During the breastfeeding phase, the woman dedicates more time to the child and the perception of her body is directed as a source of nutrition, to the detriment of pleasure (15) . for the development of advanced Nursing practices (24) , for promoting, protecting and supporting breastfeeding and the sexual and reproductive health of breastfeeding women. In this context, the Nursing workforce must be valued, as it has the capacity to fill gaps and unmet needs for care, especially in the context of primary health care (25) , with an impact on improving the health indicators of the population.
As this is an intimate forum issue, it is possible that some women did not fully report the truth about their sexuality, which is a limitation of the study. To reduce the bias, the interviews were conducted at the participants' homes, a place that the women know and where they feel more comfortable, in a private and timely manner, according to her preferences and availability, and by prior appointment. The subjectivity of the term "vaginal lubrication" also stands out, which, during the application of the questionnaire, had a greater chance of www.eerp.usp.br/rlae 7 Holanda JBL, Richter S, Campos RB, Trindade RFC, Monteiro JCS, Gomes-Sponholz FA.
personal interpretations, as to its meaning; to facilitate the approach to this question, popular terms were used for a better understanding of the aspect to be evaluated.
The evaluation of the woman during the gestational period, as well as at different points of observation in the puerperium, could provide a more detailed view regarding the study question. To advance this knowledge, it is recommended to carry out other studies, with a longitudinal approach, as well as the evaluation of women who do not breastfeed.

Conclusion
There was a difference in the female sexual function between different types of breastfeeding. The highest sexual