The phrase "a significant challenge because" is correct and usable in written English.
You can use it when explaining the reasons or factors that contribute to a particular challenge or difficulty in a situation.
Example: "The project faced a significant challenge because of the limited resources available to the team."
Alternatives: "a major obstacle due to" or "a considerable difficulty as a result of".
Getting to five represented a significant challenge because, as he pointed out, the bigger you get, the harder it becomes to keep the growth trajectory going.
However, high temperature operation remains a significant challenge because of severe electrochemical side reactions.
Peptide oral delivery is still a significant challenge because of two major impediments, low absorption efficiency and instability in gastrointestinal tract.
Evaluating their success poses a significant challenge because appropriate counterfactuals (what would have happened in the absence of the mine) are often unavailable.
However, the underwater ignition of nEMs is a significant challenge because water perturbs the reactants prior to ignition and also quenches the subsequent combustion reaction of nEMs upon ignition.
However, identifying clear ecological responses to flow alteration can be a significant challenge, because of the complexity of river systems and the other factors which may confound the response.
A significant challenge arises because scientists, and indeed all stakeholders, need to switch between a) being autonomous actors, and b) being multi-disciplinary team members, depending on the task being undertaken (Janssen et al. 2010).
The cervical thoracic junction represents a significant challenge for stabilization because of anatomical constraints.
"That's a significant challenge for residents because it results in higher garbage rates," Mr. Barnes said.
"Understanding the shared concepts and patterned behaviours of a culture is a significant challenge," she writes, "because cultural norms tend to be hidden.
Such measurement poses a significant challenge in mice because blood volume is smaller and the heart rate is much higher in mice than in larger animals or humans.
