Differences in sex hormones and brain morphology between females with offspring and nulliparous

Background: This study aims to investigate differences in sex hormone levels and brain morphology among women with offspring and nulliparous to explore the changes that the reproduction induces. Methods A total of 66 females of reproductive age range 20–40 years were enrolled, including 35 offspring women, and 31 nulliparous. Participants’ sex hormone levels were assessed. T1 structural images were obtained using a 3.0 Tesla MRI scanner, and voxel-based morphometry (VBM) was implemented to investigate gray matter changes between the two groups and extract brain volume including gray matter volume (GMV), white matter volume (WMV), cerebrospinal fluid (CSF). Results Analysis of sex hormones revealed no significant differences in E2 (z = − 0.28,p = 0.782), LH (z = − 0.62,p = 0.537), and P (z = − 1.34,p = 0.181), whereas significant differences were found in FSH (z = 3.86,p < 0.001), T (z = − 3.92,p < 0.001), and PRL (z = − 3.27, p = 0.018). Differences in brain volumes, including GMV (t = − 3.53,p = 0.001), CSF (t = − 2.39,p = 0.020), were observed. VBM analysis showed that compared with nulliparous women, those with offspring exhibited decreased cortical areas in the left superior frontal gyrus and right putamen, but no increased cortical areas were found. Conclusion Females of reproductive age in the 20–40 years group, compared with nulliparous female, sex hormones of female with offspring changed, and the volume of the cerebral cortex decreased, which indicated that females were developing in the direction of functional decline. Further research should explore the mechanism underlying these discrepancies, and their potential consequences for female health.