Posts: 1,033. IVF under the NHS is now part of the 18 weeks rule. This means that you should wait no longer than 18 weeks from referral from consultant to starting treatment at fertility clinic.Now the rule is that 95% of referrals should fall under 18 weeks, so obviously, this means that up to 5% might fall outside and wait longer.hanel after gp referral i was seen by fs at hosp after i think 6-8 weeks. Then i had a lap 8wks later then left for 4 months to see if anything happened. It never so now we have been placed on the iui and ivf waiting lists.