Some folks wonder whether this teaching of Jesus refers to the end of days or whether it was fulfilled in 70 C.E. when Jerusalem and its Temple was destroyed. Jesus speaks to both times in His discourse but Matthew’s account only deals with the end times and he constructs the account for this purpose. Luke, on the other hand, records both events in 21. 5-36. Luke does focus primarily on the end times also but inserts a section that covers the Jerusalem’s Temple destruction in 70 C.E. (vss.20-24).
The key to this understanding is to see the clause: “pregnant women and nursing mothers” referring to different sets of women, one in 70 C.E. and the other during the end.