It seems important, and definitely worth unpacking. But the meaning isn't clear. The woman doesn't elaborate or explain what she means by spiritual. Furthermore, I hardly ever hear someone describe her birth experience as "religious." If I were conducting an ethnographic study, I would ask these women what they mean. There are a few things I think might characterize this spiritual experience. 1) The perception that it is extremely important or ultimate. 2) The perception that it is transformative; the experience changes the woman. 3) Going along with the first one, the perception that it is set apart and special, i.e. sacred. 4) The perception that the experience transcends the body or physical world.
It fascinates me that many women who identify as atheist or agnostic describe their birth experiences in these terms. I found a 2002 study called "'Being Religious' or 'Being Spiritual' in America: A Zero-Sum Proposition?" The study asks, is there a difference between being religious and being spiritual? Can you be one but not the other? What do religiousness and spirituality mean? In every survey the study cited, the majority of people said they were both religious and spiritual. But after that, the next biggest group were those who said they were spiritual, but not religious.
Overall, the study concluded that "being religious" and "being spiritual" were most often seen as distinct but interdependent concepts. Surprisingly, most religious people also tend to be the most spiritual people. This finding combats the notion that the United States is becoming more spiritual and less religious, or that religiousness and spirituality are mutually exclusive. There are a few common characteristics of those who describe themselves as spiritual but not religious. Some scholars call these people "seekers." Seekers tend to be agnostic, not attend church, and to be independent (from a religious group). They also tend to "experiment with New Age or Eastern practices."
That being said, the birthing women to whom I refer do not describe themselves as spiritual, but rather describe their births as spiritual. The study is still helpful, because it shows that most people associate religiousness with external institutions. It makes sense that women would call birth spiritual but not religious, if "religious" connotes church or some other organized structure. Now I understand why birth is not always considered religious, but I have yet to understand fully what it means for birth to be spiritual.