Objective: To examine the effect of a trunk exercise program on pain, quality of life (QoL) and physical health (PH) in the late pregnancy and post-partum periods as well as baby weight and size and delivery. Methods: 90 nulliparous women were allocated based on voluntarism to a training group (TG) or to a control group (CG). TG carried out a structured program with exercises for flexibility, balance and strengthening for the majority of skeletal muscles specifically for the spinal ones, between the 24th and 36th week of pregnancy. Both TG and CG were evaluated for pain at the beginning of the program (T1), at the end of the program (T2) and two months’ post-partum (T3). QoL was assessed at T1,T2 and T3, and PH at T1 and T3. Mann-Whitney test was utilized to compare TG and CG on each period and to compare the periods two by two. Results: At T1, no significant difference was found between the two groups in pain intensity (pain interference p = 0.317), QoL (p = 0.18) and PH (flexibility p = 0.06; walking p = 0.85). At T2, women of TG had a lower intensity of pain than CG (legs (p = 0.029), lower back (p < 0.0001), upper back (p = 0.022), pelvis (p = 0.017), groins (p = 0.043), lower pelvis (p = 0.009) and interference of pain (p < 0.0001)). At T3, TG had a lower intensity of pain than CG, in lower back and upper back (p < 0.0001) and interference of pain (p < 0.0001). Best scores of QoL were observed in TG compared to CG at T2 (p < 0.0001) and at T3 (p < 0.0001). PH in TG compared to CG was not different between the groups in T1 but was different in in T3 (flexibility p = 0.002, walking, balance, curling-ups and Ruffier p < 0.0001). TG were four times less likely to have a caesarean (p = 0.049) and had 4.5 h less of labor time (p < 0.0001). No difference was observed between the TG vs CG concerning the weight (p = 0.22) and the baby’s size (p = 0.11). Conclusion: Strengthening exercises centered on the trunk reduce pain, improve QoL and PH in late pregnancy and at two months in the post-partum period. Strengthening exercises also ease the delivery.