I used it 4 years ago for the birth of my first son (took the class one month before my due date) and had a great experience. Painfree 18 hour hospital labor.
You can read my story in this thread
Tell me more about HypnoBirthing
I was a nervous wreck about birth the first time. I was afraid if I hired a Doula and SHE couldn't help me, I'd be screwed. So I was desperate to find
something to help me. I was really afraid to be in the position so many women are. THey are determined to go natural. Then they get into labor and after X amount of hours, ask for the epidural. No judgement at all, I just didn't want that to be me.
When I found out about HypnoBirthing, I was

thrilled. I signed up.
I ended up not needing
anybody coaching me through labor. I was relaxing just fine on my own. But I was very determined to 1) go all natural (no drugs) so I practiced a lot and 2) DH wasn't really into it, so I practiced alone.
My 2nd labor was not completely pain free. I felt a little twinge of discomfort, but it was totally manageable. On a scale of 1-10 pain, it was a 2. It was there, but very minimal. This last time I was a nervous wreck with my "what if, what if..." doubts so that's what I KNOW contributed to it.
And as far as it not working at all for some people there are a variety of reasons:
1) not a good in-person instructor
2) not enough diligent practice
3) letting yourself fall asleep during the tapes (some say it's OK and that the subconscious is taking it anyway. Phooey. I didn't trust that.)
4) still lots of self-doubt during and after the course (you are supposed to check that at the door.)
5) Interestingly, my practioner told us NOT to watch anymore Baby Story. Why? Because it introduces more FEAR to the mom. And it gives a mental picture to the mom what Labor/Birth looks like (women in pain, unable to cope, getting meds). That's what at all what a HypnoBirthing labor looks like. The mom is very relaxed and centered.
I personally feel that my success the first time around was due to the fact I had a great instructor who told true life success stories of HER OWN clients. Those stories (and watching videos of real HypnoBirthing mother) during labor is what helped give me the incredible self-confidence I felt. (And of course, I practiced every freakin' day. It was harder to do that with a 4 yr old this time.)
That's why I think * ideally* you can take a class. Personally, *I* do better in a class. I'm a very visual person. And having someone explain it to me, walk me through stuff, etc... helped.
There are two self-study courses:
www.Hypnobabies.com and
www.Hypbirth.com
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