Is there a limit on how many children a working woman may have without compromising her job status?

Someone really dear to me was terminated from her job, because she was expecting her third child. In Malaysia, the federal constitution guarantees that a working mother be accorded full maternity benefits without losing her job up to 5 surviving children. However, her employers Malaysia Airlines enforces a collective agreement that was signed by the Airline's union to only 2 children!
Further previously terminated stewardesses have lost their cases in Malaysian Courts because of this technicality! It seems that in the eyes of Malaysian Law, the Federal Constitution is not applicable to contracts between two private individuals/entities.
In other words, Malaysia Airlines can continue to abuse the rights of these mothers, so long as it feels the need to wihtout contravening Malaysian Laws! This sounds absurd to me.
I would like to know if such law exists in any other countries?

The collective agreement is illegal because it is violative of the constitution. The employees should file a case in court against the Malaysian Airlines to invalidate the law.

move to the u.s.a you can have as many as you like.
I know that in the past, a woman in China was legally not allowed to have a 2nd child.

But other than China, I can't imagine any other country enforcing an agreement like that!
There are laws here, it all depends who you work for. 30 years ago I was fired because I stayed home when my 2 kids were sick. My boss told me that I either worked for the railroad or I was a mother. I had to chose. I chose motherhood, but I shouldn't have had to chose. A lot of women are mothers and work, some out of need. It should make no difference. Things have come a long way since then, thank God.
that is because she violated the offer letter contract she signed! why signed in the first place if it is unfair?