The director of Jewish education for the new Jewish Community Secondary School in Barnet will be away on maternity leave shortly after it opens in September.
Elaine Robinson - who was UJIA's head of Jewish social responsibility before joining JCoSS - is expecting her first child in October, but hopes to be working for the first few weeks of term.
She is in the process of finalising the school's Jewish curriculum arrangements.
A JCoSS spokesman said the school was "well into the process of arranging maternity cover".