Whee, wonderful. Self-inflicted pain. Not.
At any rate, since we couldn't very well simulate an uterus contracting, Astrid asked us to hold out our arms horizontally and keep them up—and at some point or another, nearly everyone would feel pain.
This was an exercise for us to try to keep going, to deal with the pain. She said we could do anything we wanted: sing, curse, insult our partner, wave our arms around, walk up and down, whatever, as long as we left those arms up there and tried to endure it.
At first, I didn't feel pain as such; rather tension in my neck which later moved to my shoulders. But after a while, my upper arms started to hurt, and it was really uncomfortable, and I didn't know how to deal with it well. She said it was allowed to lift the arms up over your head, but I thought was chickening out—but I still did it once or twice to take the weight off those muscles.
After about six minutes, she said that was enough, and she asked each of us how we dealt with the pain. Answers included thinking about something else, moving around, concentrating on breathing, and other things. (You try this at home: hold your arms out for six minutes and see how you deal with it.)
Astrid said that distractions are good during early contractions but are rather less effective later on, where it can be more helpful to move your pelvis around a little, for example.
She also advised us not to panic at early contractions but to keep calm; most primiparous women come to the hospital quite a bit too early and often end up getting sent home again.
Next, we talked about the actual process of birth.
She opened a book and showed us a picture of a womb with a baby inside, its head downwards, its back on the right hand side (as we saw it from the front). She said that is the most common position, since head down is the best way for natural birth and the back tends to be on the mother's left because the mother's liver leaves less room for the baby to lie on the other side.
She talked about how nobody really knows what causes contractions to start, and that even though some hormones have been isolated and identified as playing a role, giving a woman those when she's not ready yet is much less effective than if "it has already started". Two major hormones in this connection are oxytocin and prostaglandin.
She described the contractions as starting at the top of the uterus and rolling down until the cervix at the end—a short channel which is about 3 cm (1¼ in) long normally but which gets shorter and shorter as time goes by. She compared this to putting on a turtleneck sweater where the turtle neck starts long but gets shorter the closer it gets to your head, until it can't get shorter and starts getting wider, which is what the mouth of the uterus does as well, dilating slowly until it's about 10 cm (4 in). (A decent time to enter hospital might be when it's about 3 cm (1¼ in) wide, she said.)
I wondered how the width is measured; can you see it from the outside? No, of course not, she said; but midwives have a "built-in tape measure" in their hands; if two fingers just fit inside, it's 3 cm in diameter; if they're a bit apart, 4 cm; a bit further, 5 and 6; and so on. And when you can only feel the top of the baby's head and no longer the cervix, then it's time.
She showed us with a model of a female pelvis and a newborn-sized doll how birth happens, which I found really interesting.
Most children start with their head downwards, the long axis (forehead to back of head) running from hip to hip of the woman, since the entrance of the pelvis is more or less oval shaped. However, the exit of the pelvis, defined by the two bones you sit on as well as the coccyx, is also oval shaped but at 90°, running from front to back, so the child has to turn its head to fit well and come through back-of-the-head first. This usually causes the nose to scrape along the coccyx, which is sometimes visible in the newborn :) But even though we can't move this part of our spine voluntarily, it's still movable, and the child can bend it away about 1 cm to make more room.
The top and back of the head comes out first, and the baby's head then makes a turn upward to reveal forehead and face; then the body turns through 90° to allow the shoulders through better.
However, some children who "think they know better" decide to turn their head the other way in order to fit through the exit, and come out forehead first. These are known as "stargazers", apparently, since if the mother were outside and giving birth at night in a sitting position, the first thing these children would see is the stars. But this journey is not optimal because the forehead is wider across than the back of the head and doesn't fit through the area below the symphysis quite as well.
Some also don't turn their head to enter the pelvis; if they can't get the child to turn (for example, by having the women position her pelvis higher than her shoulders to let gravity work, or by stopping contractions for a little while so the child can prepare a new "landing approach"), it has to get fetched by caesarian section. (I think this is what happened to my sister when my niece came along.)
Finally, there are breech babies, which can also be born normally—one of the women in the course was born that way and also gave birth to her first child like that.
It's a bit more difficult, since the pelvis of the child isn't as wide as the head and so doesn't expand things as much, but it's possible.
Where things can get critical, apparently, is when the legs and arms and body have come out and only the head is left; since the umbilical cord is running past the baby's neck and things are really tight there, it gets compressed and the child doesn't receive any oxygen, so has to be moved past this point quickly. (Normally, she says, the umbilical cord is not sensitive to pressure since it is well-padded, so even if it's wrapped around the neck three times, it need not be harmful. But in this position, there really isn't any room and so it will often get compressed and the flow of blood cut off.)
Since children in breech presentation are usually fetched by C-section, doctors aren't as experienced in the various techniques for assisting such births, she said, but there are some who do this well. But the mother has to want it and have confidence in it; doctors won't recommend a natural birth for a baby in breech presentation.
Finally, once the baby is out, it'll generally be put on the mother's stomach and covered with a blanket for warmth and dryness and left there for at least an hour.
I was a bit anxious when I heard about APGAR which is taken a few minutes after birth, but she assured me that that's something most midwives can check just by looking at you and nearly unconsciously since they know what to look for; I thought they had to pick the baby up or something to test its reflexes or whatever it is they do. But no, she says, it stays right with the mother during the first minutes of its life, ideally for an hour or until it has found the breast and nursed for the first time.
They also avoid sucking gunk from its lungs since it's usually not necessary since the pressure on the abdomen during passage through the pelvis expels it through the mouth during birth, and the first oral stimulation should be the mother's breast and not some plastic tubing.
Finally, we did some exercises where we tensed (on breathing in) and relaxed (on breathing out) various limbs, and also puckered our face on breathing in and relaxed it on breathing out. Apparently, the facial muscles are somehow connected to the pelvic floor muscles; many women felt their pelvic floor tensing when they puckered their faces. This was also important during childbirth: to learn to relax your pelvic floor muscles.
I asked where Kegel exercises were good to influence this, and she said yes, those were a forerunner of what's around now. (I feel so out-of-date: first Lamaze, now Kegel, are presented as "yeah, that's what they did twenty years ago, we have much better things now"…)