Lisa McKay had expected morning sickness, weight gain and strange food cravings when she found out she was pregnant with her first child in 2011. But she didn't expect a nagging ambivalence over being pregnant to persist into her third trimester.

She had trouble shaking the feeling that her horizon was narrowing, that what she stood to lose was more tangible than the joys coming her way, she wrote in a blog post at seven months pregnant.

Pregnancy had already taken its toll as sleep deprivation, morning sickness and fatigue sapped her energy and ability to concentrate. She mourned the impending loss of "long, lazy dinner conversations" with her husband and the luxury of spending time as she pleased to write or pursue consulting projects as a psychologist in Laos, where she and her husband live.

In addition to concerns about labor and delivery, she was worried about juggling identities she had spent her adult life forming -- writer, psychologist, wife, friend -- to include mother, sure to be the largest role.

"I knew I wanted a family, but I was also wary of the huge change (and, frankly, the sacrifices of time and energy) that I knew a baby would bring," McKay said in a CNN iReport.

"Dominic's very existence completely reordered my priorities. I had changed significantly, and not all of those changes felt fun. They felt miraculous, and I wouldn't undo my decision to become a mother if given the choice, but they didn't all feel fun."

McKay and other CNN iReporters shared stories of lessons learned from pregnancy in the wake of some recent high-profile baby announcements. Among the thicket of blessings, nightmares and unforeseen medical complications, a few common themes emerged, chief among them that pregnancy rarely goes as planned.

Throw out the playbook

"Have an open mind, and expect the unexpected," said Renee Governale, a 47-year-old executive assistant from Charlotte, North Carolina. "I went into it thinking I was going to have a perfect birth with lots of support, music playing, and holding my baby right after he was born. It didn't go that way for me. Nothing I planned went the way I wanted it to, but my son was born healthy and I survived, and that is all that really matters."

For instance, Governale did not anticipate losing weight while she was pregnant. But after developing gestational diabetes, she started exercising one hour a day and changing her eating habits so she could avoid taking insulin shots.