Summary Almost a quarter of patients with PAO will sustain a subsequent fracture; patients need to be informed about potential risks before deciding for further pregnancies. Introduction Pregnancy and lactation-associated osteoporosis (PAO) is a severe type of premenopausal osteoporosis which predominantly occurs in the last trimester of pregnancy or immediately postpartum. Long-term follow-up data including subsequent fracture risk have yet to be reported. Methods This single-center prospective cohort study investigated the subsequent fracture risk of all 107 patients with PAO who were referred to our institution. Results Overall, 107 presented with at least one fracture. Each patient sustained on average four fractures most commonly at the thoracolumbar spine. During a median of 6 years of follow-up, 26 (24.3%) of patients who had a fracture at baseline reported a subsequent fracture. Overall, 30 PAO patients (28%) reported a further pregnancy. In subsequent pregnancies, 6 (20%) of patients reported a subsequent fracture. Patients with up to 1 vs. > 1 fracture at time of diagnosis showed a 3 (10%) and 25 (27%) subsequent fracture rate, respectively ( p  = 0.047). There was a significant correlation between the number of fractures at time of diagnosis and subsequent fracture risk ( N  = 26, p = 0.56, p  = 0.003). Conclusions Almost a quarter of patients with PAO will sustain a subsequent fracture, and this fracture risk correlates with the number of fractures at time of diagnosis. Patients with PAO need to be informed about their potential subsequent fracture risk before deciding for further pregnancies.