What is your approach to treating premenopausal woman with OI with a new compression fracture?

Young women with idiopathic premenopausal osteoporosis likely have low bone formation. I was not told her BMD but I will assume it is low.

An antiresorptive does not make much sense because she is producing enough estrogen to keep her cycles going. 

There has been some published data with the use of teriparatide in premenopausal women with OP and high risk for fx. I would consider an anabolic IF I could get it paid for!

After the anabolic, she may not need an antiresorptive but I would watch her BMD and maybe serum CTX to know when we should consider follow-up antiresorptive therapy.

Osteogenesis imperfecta (OI) is a heterogeneous group of inherited disorders of bone formation that results in low bone mass, bone fragility, and an increased predisposition to fracture. Most OI is caused by pathogenic variants in genes that encode type 1 collagen with an autosomal dominant pattern of inheritance.

Bisphosphonates (often given IV) together with adequate calcium and vitamin D remain the cornerstone of pharmacological therapy in moderate to severe forms of OI with a high risk of fractures.

There are reports of the use of anabolic agents (teriparatide), inhibitors of RANK ligand (denosumab), and the inhibitor of sclerostin (romosozumab) in patients with OI but their role, certainly as first-line agents, remains unestablished.

I would recommend the use of a bisphosphonate as first line pharmacological treatment in this premenopausal woman with OI who has developed a new compression fracture inspite of the lack of adequate data regarding long term safety of bisphosphonates in premenopausal women.