The maternity protection will apply to the employee as long as she has served her employer for at least 3 continuous months.
If your employer terminates your employment without sufficient cause while you are pregnant, or retrenches you during your pregnancy, they must pay the maternity benefits you would have been eligible for.
If your employer did not confirm your probation with reason that you did not meet expectation. You can report to MOM and request your employer to provide proof to support their assessment.
http://www.mom.gov.sg/faq/maternity-leave/if-the-contractual-probation-period-is-longer-than-the-3-months-minimum-qualifying-period-will-the-employee-enjoy-maternity-protection
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