美國還是加拿大？

https://www.nextsource.com/2015/05/14/the-laws-of-pregnancy-and-contractual-labor/

你自己看這篇文章，就知道你沒有說清楚很多事實。

On appeal, the court found that only the primary employer, (Perma-Temp) was responsible for compliance with leave according to the FMLA.  Yet, the court ruled that the secondary employer (Keppel) did bear a conditional burden.  The secondary employer was obligated to accept a returning FMLA employee, provided they continued to engage the same staffing firm to fill that position. In this case, since the secondary employer replaced Cuellar without using Perma-Temp to fill the position, neither entity was found to have broken their FMLA obligations.

也就是說，你的孕婦身份主要是你的直接雇主（小老板）保護。在你的產假期間，你的合同雇主（大老板）可以用別的合同公司的人來替代你的合同。

但是如果你的合同雇主（大老板）用你的直接雇主（小老板）的其他人來代替你的合同，而且如果你的直接雇主（小老板）執意把你送回原職位，你的合同雇主（大老板）必須接受你回去。