The aim of this study was to investigate the effect of dietary fibre on reproductive performance during the first two parities. Gilts were randomly allocated to receive three fibrous diets from days 1–90 of gestation, including low fibre [low fiber (LF), 10.8% neutral detergent fiber (NDF), n = 132], middle fibre [middle fiber (MF), 15.8% NDF, n = 132] and high fibre diet (HF, 20.8% NDF, n = 135), until completion of the second parity. Response criteria included backfat measurements, litter size and pig weight at parturition and day 22 of lactation, weaning-oestrus-interval, oestrus rate, sow farrowing and culling rate, uniformity of newborns and relative organ weights. The results showed sows fed LF diet in parity 1 gained more backfat (p < 0.05) during gestation but lost more (p < 0.05) during lactation than sows fed HF diet. Furthermore, sows fed LF diet farrowed more pigs (+0.7–1.1 pigs, p < 0.05) and pigs born alive (+1.0 pigs, p < 0.05) relative to sows fed HF diet. Likewise, sows fed LF and MF diets had greater litter weights at parturition (both p = 0.06) and day 22 after lactation (both p < 0.05). In parity 2, yet, it was MF diet to increase both total pigs born and pigs born alive (+0.9–1.1 pigs, p < 0.05) and litter weight (p = 0.05) relative to other diets. After 22 d of lactation, intriguingly, sows fed HF diet had most pigs alive (p < 0.01–0.07) and heavier litter weight (p = 0.07 or 0.2). Feeding HF diet also increased internal organs weight of newborns (p < 0.05). Collectively, feeding LF and MF diets had beneficial effects on litter weight at parturition and day 22 of lactation in parity 1, and feeding MF diet until parity 2 was able to improve litter size and weight at parturition, but this positive effect disappeared after 22 days of lactation, instead feeding HF diet showed the optimal litter performance.