Apart from the fact that preterm babies less than 35 weeks were not included in the sugar babies study and also possibly may have swallowing issues, is there any other reason why glucose gel is not being used for preterm infants less than 35 weeks and is anyone of you recommending the use in preterm infants less than 35 weeks and upto what gestational age in case you are using?.

The reason we use gel in term babies is to avoid admissions and transiently support feeds. On the other hand preterm <35wks is by default admitted to nicu so it doesn't make any sense to use gel in them plus you have to start IV D10w or formula NG feeds so gel has no role. 

Moreover gel is not 100% effective in preventing hypoglycemia same as vaccines are not 100% guaranteed. Having said that we use gels in terms because they have more glycogen reserves as compared to preterm and sustainability is more attainable in terms as compared to preterm.

I agree with the rationale put fw by @rehman_naveed. We have though used gel sometimes in well preterm infants solely on enteral feeds and with sugars in the range of ~1.8-2.0 mmol/L, and where we have tested gel firstm before starting glucose iv. Usually succesfully. I recall the lowest gest-age to be 33+ weeks.

Certainly I agree with @Stefan Johansson on the exception to the rule stated by @rehman_naveed.  I have never done it, but I've at times wondered if I wouldn't give glucose gel a try in a situation where there was some difficulty obtaining access, just to get the sugar up a bit while I put in an umbilical line.

https://www.ncbi.nlm.nih.gov/pubmed/29579758

We are using it for 34 weeks and above