Really a tough judgement call here.
Hope below considerations help.
1. Spouse's salary enough to keep family afloat? At least half a year?
2. Emergency savings enough for 6 months or so?
3. Any big purchase pending?
Of course, SG Govt is helping a lot nowadays whereby u will lose the job...
That's a really terrible relatives u have there.
Indeed having children is more than just giving birth. If it is only about giving birth, humans are no more than animals :P