Marriage is an important social, cultural, and biological aspect of human life but is often affected by societal changes leading to differences in family formation and reproductive behaviour. Changes in marital patterns are component of transformations in a society’s social structure. Variations in marriage patterns exist within and across countries and over time. We examine the trends and spatial patterns of marital statuses among women of reproductive age (15–49 years) in Nigeria and further determine the associated factors based on the country’s north–south divide. Data were sourced from the Nigeria demographic and health survey conducted in 2003, 2008, 2013, and 2018, and the marital patterns were classified into four categories: never married, married, cohabiting, and formerly married. A Bayesian multinomial spatial model that simultaneously estimates parameters of different forms through a geo-additive predictor was adopted, and inference was based on Markov chain Monte Carlo. Findings reveal a north–south divide in marriage patterns. Women in the northern part of the country have a higher likelihood of being in marital union, while those in the south have a higher likelihood of cohabitation. A somewhat east–west divide was obtained for formerly married. Religion and ethnicity were found to be the major factors that account for differences in marital patterns across the divide and based on rural and urban residency. Cultural practices dictated by these variables would, therefore, continue to shape marital patterns and, by extension, fertility in Nigeria. The factors are hence important to be considered in marriage related policy formulation.

婚姻是人类生活的一个重要的社会、文化和生物学方面，但经常受到社会变化的影响，导致家庭形成和生殖行为的差异。婚姻模式的变化是社会结构转型的组成部分。婚姻模式在国家内部和国家之间以及随着时间的推移而存在差异。我们研究了尼日利亚育龄妇女（15-49 岁）婚姻状况的趋势和空间格局，并根据该国的南北差异进一步确定相关因素。数据来源于尼日利亚2003年、2008年、2013年和2018年进行的人口和健康调查，婚姻模式分为四类：从未结婚、已婚、同居和曾经结婚。采用贝叶斯多项空间模型，通过地理可加预测器同时估计不同形式的参数，并基于马尔可夫链蒙特卡罗进行推理。调查结果揭示了婚姻模式的南北差异。该国北部地区的妇女结婚的可能性较高，而南部地区的妇女同居的可能性较高。对于以前已婚的人来说，存在某种程度的东西向分歧。研究发现，宗教和种族是造成农村和城市居住地婚姻模式差异的主要因素。因此，这些变量决定的文化习俗将继续影响尼日利亚的婚姻模式，进而影响生育率。因此，这些因素在制定婚姻相关政策时必须予以考虑。