Tocolysis should not be offered to any patient above 34 weeks. And the only reason for tocolysis is to give time for the admiration antinatal corticosteroids.
Tocolysis after 34 weeks should not be given. In women with GDM, it is too late to start with blood sugar control at 34 weeks to reduce the rate of macrosomia. Furthermore, tocolysis should only be given for 48h. Within this time interval a reduction of fetal complications due to GDM cannot be expected.
@Pro. Karl Oliver Kagan: But poor glycaemic control will limit fetal lung maturation, so I think it may be reasonable to give tocolysis to GDM women with poor glycaemic control after 34 weeks .
What will be your end point? If you are trying to get metabolic control in a short period of time (if you clinically think you can accomplish this) then maybe it is the right thing. In general, I do not use them at that GA.
All studies have shown that tocolysis for more than 48 hours don't work, so will not be able to prolong the pregnancy long enough after 34 weeks until you have a good glycaemic control.
There are benefits in the nursery to deliver a baby when the mother is under good glycemic control. We can accomplish that in 48 hrs or less. Now long term control if you dont deliver is another issue.
35 weeks with poorly controlled GDM needs delivery in a set up with well equipped NICU facilities. In that case, tocolytic is not needed. But if you are planning for in utero transfer, then stop gap cover can be given using nifedipine or atosiban.