Introduction: The long return of menstruation in postpartum mothers is strongly influenced by the exclusive breastfeeding behavior. In Indonesia is still relatively low compared to other countries, where the median return of menstruation in postpartum mothers in Indonesia is 2 months. The purpose of this study was to look at the influence of exclusive breastfeeding on lactation amenorrhea. Methode: This research is a quantitative research with cross sectional research design with research samples are women who have married aged 15-49 years, amounting to 10,143 people. This study uses SDKI data in 2017 with survival analysis. The results of this study do show the influence of exclusive breastfeeding on lactation amenorrhea after being controlled by confoding variables in the form of education, age, parity, residence and the use of birth control (p value 0,048 with an HR value of 2,32 (95% CI=1,98 – 2,49).  The recommendation of this study is the need to increase KIA method related to the intensity and frequency of breastfeeding from mother to baby.

The number and sex composition of children are important for some married couples in Indonesia. Having sons in the family is considered as a must since they are argued to be the successor of the family lineage. The presence of daughters is expected to help with household chores and care for their elderly parents. The sex preference for children by the married couples can affect their number of children. This study aims to assess the relationship between the number and sex composition of children, contraceptive use, and the desire to have more children among women in Indonesia. The study employed the data from the 2017 Indonesian Demography and Health Survey (IDHS), with the unit of analysis of currently married women aged 15-49 who have at least one living children. The results show that women with two or more children of the same sex had a higher tendency to have additional children and no use of contraceptives. The Family Planning program's campaign of similar values shared between son and daughter is still hardly accepted, hence, sex preference still exists. It is necessary to reformulate an effective concept for proper socialization of these values as an effort to control the fertility rate in Indonesia.

Although the fertility rate in East Nusa Tenggara Province has decreased over the last 10 years, the birth rate is still higher than other provinces in Indonesia. Interestingly, the infertility index for breastfeeding in East Nusa Tenggara Province is the lowest compared to other provinces in Indonesia, which means that women of childbearing age in East Nusa Tenggara Province breastfeed their children with the longest breastfeeding period. Therefore, this study aims to determine the fertility decomposition and characteristics of breastfeeding mothers in East Nusa Tenggara Province in 2017. The data source of this study uses the results of the 2017 Indonesian Demographic and Health Survey (IDHS) using women of childbearing age who have given birth. The analysis used in this study included fertility decomposition analysis and continued with univariable, bivariable, logistic regression analysis. The results of this study indicate that breastfeeding as a proxy for infertility towards fertility in the province of East Nusa Tenggara has an index value (Ci) of 0.72 and after controlling for maternal characteristics variables, age, education and work status of mothers are the factors most related to breastfeeding behavior in East Nusa Tenggara in 2017. Promotion of good breastfeeding techniques and the benefits of breastfeeding needs to be improved in order to improve the quality of life of infants, spacing pregnancies and reduce the incidence of tengkes (stunting).