Lam 3:22 The steadfast love of the LORD never ceases;
his mercies never come to an end;
23 they are new every morning;
great is your faithfulness.
24 "The LORD is my portion," says my soul,
"therefore I will hope in him."
25 The LORD is good to those who wait for him,
to the soul who seeks him.
It seems that lately we have had more than a few couples who have miscarried. Teresa and I have not had to go through that, but I do have a sister who lost 2 at 5 months and my oldest sister was in a car wreck and lost her first son at 8-1/2 MONTHS. While that was so difficult to understand at the time, God who is always true to His Word, used that for His glory. My brother in law came to Christ as a result of the loss.
While our friends are struggling with God's timing, I can say personally that God certainly knows what we need and when we need it. His Word is true and we can rest in His promises. He gives us new mercies everyday; they can't be kept for tomorrow and there will always be exactly the right amount.
I don't understand how He does it, but He does and we can rest and rejoice in that promise.