The phrase "a major adverse effect" is correct and usable in written English.
It can be used in contexts discussing the negative consequences or impacts of an action, decision, or event, particularly in fields like medicine, environmental science, or policy analysis.
Example: "The new policy could lead to a major adverse effect on the local economy, resulting in job losses and reduced investment."
Alternatives: "a significant negative impact" or "a serious detrimental effect."
It was widely recognized at the time that it had a major adverse effect on the economy, contributed to the impoverishment of southern Italy and was probably a contributor to emigration.
"The task force," the report said, "is particularly concerned that if Russian cooperation with Iran continues in a way that compromises nuclear nonproliferation norms, it will inevitably have a major adverse effect on continued cooperation in a wide range" of nonproliferation programs between the nations.
This paper argues that Hong Kong's floor area control mechanism has a major adverse effect on the development potential of private housing, and more importantly on the quality of living space.
If there is a cyber attack aimed at specific connected devices, the security vulnerability of mobile devices can bring about side effects that may even have a major adverse effect on a different industry [2].
Cardiomyopathy is a major adverse effect in patients treated with anthracyclines.
Shivering is both an anticipated consequence and, potentially, a major adverse effect of therapeutic hypothermia.
However, there is also a third condition, which is no more likely to feature than the other two: a health system that is sufficiently effective in its operation to be able to implement this scaling up in a satisfactory manner, without any major adverse effects.
Moreover, lasofoxifene shows a beneficial pharmacologic profile on bone, breast, and serum lipids, without any major adverse effects on the uterus.
No patient suffered a significant major adverse effect as a result of the treatment or their PWA studies during the observation period on the study.
In contrast, shivering, an anticipated consequence and potentially major adverse effect of TH, has been shown to be strongly associated with graded increases in systemic metabolism [ 16].
