Introduction:
Maternal health remains a crucial public health phenomenon, with unplanned pregnancies and unsafe abortions contributing significantly to global maternal morbidity and mortality. Addressing the gap between reproductive intentions and contraceptive behaviours, therefore, remains vital towards empowering women to make informed reproductive health decisions. Our study aimed to identify patterns of pregnancy intentions, examine contraceptive behaviors, and investigate the association between pregnancy intentions and contraceptive behaviors. The study also examined determinants of contraceptive behaviors among postpartum women in Osun State, Nigeria.

Methods:
A descriptive, cross-sectional study was conducted among 377 women who were within six months postpartum and selected through a multistage sampling technique in Osun State, Nigeria. Data was collected using the intervieweradministered London Measure of Unplanned Pregnancy, while the Innovative Service Delivery Model provided the theoretical framework. Analysis was performed using SPSS software version 25 at univariate, bivariate, and multivariate levels. Chisquare and binary logistic regression analyses examined the association between dependent and independent variables, with a significance level set at p < 0.05.

Results:
Findings showed that 37.4% of postpartum women reported index pregnancies as unplanned, 27.3% had a negative attitude towards contraception, 66.0% reported non-use of any contraception, 57.8% made contraceptive decisions solely, while 22.5% made contraceptive decisions jointly with spouses. Contraceptive behaviour of 76.1% were considered ineffective, though no significant association was observed between pregnancy intentions and contraceptive behaviours, main predictors of contraceptive behaviours however include multiparity (P=0.04, OR =0.22, CI=0.805-0.95), positive attitude (P<0.001, OR=7.37, CI=2.68-20.24), length of postpartum period (P=0.004, OR = 3.88, CI=1.54-9.73).

Conclusions:
An innovative service delivery model that promotes a positive attitude towards contraception, encourages timely access and uptake of postpartum contraceptive services, and discourages higher-order parity through collaborative approaches remains essential for effective contraception, reducing unplanned pregnancies, and mitigating the risks and consequences of unsafe abortions in our study setting.