New parents (at least those who were trying to become parents and are happy to be in this role) are understandably smitten with their offspring while simultaneously overwhelmed by the responsibilities of caring for a dependent, helpless, miraculous being. Life has been changed forever, in a wonderful way.
A baby fills a parent's time and thoughts so completely, there is little else to talk about, and adds, as one of my friends put it after the birth of her first baby, a whole new dimension of love to one's life. You want to share the experience with your friends. Most of these friends can relate because they are themselves parents.
But what happens when a close friend struggles with infertility? How do you share your life, consumed by a baby, without causing pain or even jealousy? The unfortunate answer is that you can't. Not freely. Not without keeping your friend's loss and pain in the front of your mind and heart.
Then you would listen and not mention running, or swimming or biking, even to complain about an injury or report a win. You would continue this sensitive communication for as long as your friend needed support from you. You wouldn't drop the friendship, hopefully, but would view it as an opportunity to show compassion—the same kind of compassion you'd want if the situation were reversed.
There are many people with whom you can share parenting questions and stories. Let your circumstance of mother- or fatherhood make you acutely aware of the loss in not having and desperately wanting a child. If baby talk isn't painful to your friend, she can tell you, and then you can share more freely. My suspicion, though, is that it will be, whether she admits it to you or not, so don't open the floodgates, even with permission: Talk about your baby with restraint.
2. Don't make assumptions (good or bad): "No need to worry. You'll get pregnant. I refuse to believe you won't, and we can have playgroups and go on vacations together. We'll have fun!" It's easy to be cheerful when life is good. Refrain from imposing breezy predictions on a distressed friend who finds it difficult to share your hope. She'll feel like she's alone in a cold ocean, drifting away on a wedge of dislodged ice, and that you cannot possibly understand the realities of her situation: She may never become pregnant or give birth. She may not be able or willing to adopt.
And not: "Oh no, another setback? I want you to tell me about it, but right now I have to take care of something that will be difficult for you to hear. I need to change the baby." C'mon, really? Would you say to the paralyzed friend, "I do want to hear how your electrically stimulated exercise is going, but (I realize this is difficult for you to hear) I need to meet someone to go running now"?