Understanding how reproductive knowledge and perceptions shape family size decision-making among couples in southwestern Nigeria

Family size decision-making is shaped by multiple individual and contextual factors, including knowledge of family planning, perceptions of family size, reproductive preferences and the ability to translate reproductive intentions into practice. In Nigeria, where fertility remains relatively high, understanding how couples' knowledge and perceptions relate to family-size practices is important for strengthening reproductive health interventions. This study examined reproductive knowledge and perceptions and their relationship with family-size practices among couples in Abeokuta South Local Government Area, Ogun State, Nigeria. A descriptive cross-sectional study was conducted among 440 respondents selected through multistage sampling from Abeokuta South Local Government Area. Data were collected using a structured questionnaire developed from relevant literature and the PRECEDE-PROCEED framework. Descriptive statistics, including frequencies, percentages, means and standard deviations, were used to summarize respondents' knowledge, perceptions and family-size practices. Chi-square analysis was used to examine the relationship between knowledge and family-size practices at a 0.05 level of significance. Respondents demonstrated a generally high level of knowledge of family planning and family-size concepts, with a mean knowledge score of 12.77 ± 1.73. Perceptions toward family size and reproductive decision-making were generally favourable, with a mean score of 24.94 ± 3.56, and 90.7% of respondents’ demonstrated positive perceptions. Family-size practices were predominantly moderate, with 82.5% of respondents classified as having moderate practices, 10.2% low practices and 7.3% high practices. Knowledge of family planning was significantly associated with family-size practices (χ² = 2.106, df = 2, p = 0.009), whereas perception of family size was not significantly associated with family-size practices (χ² = 1.864, p > 0.05). The findings suggest that adequate reproductive knowledge is relevant to family-size practices, but favourable perceptions alone may not necessarily translate into corresponding reproductive practices. Strengthening family planning education should therefore go beyond information provision to support couples in translating knowledge into informed and sustained family-size decisions.