Scrooge-like regulations are being blamed and with Harriet Harman, the Social Services Secretary, already cutting benefits, teachers are not optimistic of reform. Conceive in the spring and suffer financially in the new year is the tough festive reality.

The teacher, who does not want to be named, is being backed by the Scottish Secondary Teachers’ Association. She will receive the basic Pounds 54.55 a week during maternity leave and not the several hundred pounds she would have been entitled to had her baby been born at another time of year.

Barbara Clark, the union’s assistant secretary, said women on temporary contracts who give birth during November, December and January have their maternity assessment on the eight-week summer holiday when they receive no pay.

Mrs Clark said the teacher was “very angry” but her authority said it was bound by national regulations. The teacher knew of at least four women in a similar plight.

The teacher has 26 continuous weeks’ service and is paid the same rate as a permanent teacher. But because she is unpaid during the summer she misses out.

Permanent staff are entitled to full salary for 13 weeks, followed by five weeks on the basic rate of Pounds 54.55. Teachers on temporary contracts who qualify for maternity pay receive 90 per cent of salary for six weeks followed by the basic rate for the remaining period of the 18-week statutory leave. But a teacher who starts her family in the heady days of spring will come a cropper later because of the stringent regulations on qualifying periods.

Mrs Clark said: “This shows the inflexibility of the law. It was surely never the intention to deprive mums of statutory maternity pay. The whole idea was to help mums have healthy pregnancies, to return to work afterwards and to help families suffer as little loss of income as possible.”