Night shifts
A. Regulation 17 of The Management of Health and Safety at Work Regulations 1999 deals with the situation of a new or expectant mother who works at night.
Someone who is in that position should seek a certificate from her GP or midwife that she should not be working at night at all.
On receipt of that certificate, the employer should suspend your member while the risk to her health and safety persists.
Alternatively, under section 67 of the Employment Rights Act 1996, the employer can provide her with suitable alternative work. The terms and conditions for any suitable alternative work do not have to be identical. However, they must not be substantially less favourable than her pre-existing ones.