Laboratory

Question.before the lockdown i was advised by my OB to have CAS and OGTT and i was just 23weeks that time.i was able to do the CAS however,since the lockdown i was not able to do the OGTT laboratory and im on my 28th weeks now.i cant contact my OB since the clinic im having a checkup with doesnt give out doctors number and they are close as of the moment. Does someone has an idea until what weeks can i have an OGTT test?thanks for the answer