In O'Neill v Buckinghamshire County Council, the EAT holds that, for an employer to fall under a duty to conduct a risk assessment for a pregnant worker, these preconditions must be met:
(a) the employee notifies the employer in writing that she is pregnant;
(b) the work is of a kind which could involve a risk of harm or danger to the health and safety of the expectant mother or her baby;
(c) the risk arises from either processes, working conditions or physical, chemical or biological agents in the workplace.
There is no more general obligation to carry out a risk assessment for a pregnant worker. In discharging its risk assessment obligations, where they arise, there is nothing in either the Pregnant Workers Directive or the Management of Health and Safety at Work Regulations 1999 to indicate that a meeting with the worker is required before the obligation to carry out a risk assessment is satisfied. But an employer must provide her with comprehensive and relevant information on the identified risks to her health and safety.
The EAT also provides tentative support for the proposition first adopted by the EAT in Hardman v. Mallon  IRLR 516 and considered in Madarassy v Nomura  IRLR 246, that, if an obligation to carry out a risk assessment, and a failure to carry out that risk assessment is established, then discrimination results.
Proof of detriment is not necessary. Employers, accordingly, need to be astute to carrying out risk assessments where the preconditions are met.