Jane Evans: Mechanisms of Breech Birth

First Amsterdam Breech Conference, Day 2

Jane Evans

Mechanisms of (Upright) Breech Birth

Jane Evans is an independent midwife in the U.K. Other posts about Jane Evans include: Physiological Breech Birth and Cardinal Movements of the Breech Baby (Heads Up! Breech Conference, D.C., 2012)

This conference summary is best understood when watching Jane Evans demonstrate the cardinal movements in person. Fortunately, she gave me permission to film her at the Heads Up! Breech Conference in D.C (2012). Although you cannot see the video footage she had playing in the background, you can still follow the baby's journey as she demonstrates on a doll & pelvis.

I also recommend reading Jane's article Understanding Physiological Breech Birth (PDF) in Essentially MIDIRS Feb 2012 (pages 17-21).



Jane's goal today was to recap what to look for and and what is normal is in a breech birth, particularly when the woman is upright. She has been studying breech for over 20 years. British midwife Mary Cronk first piqued her interest in breech and set up a study day in 2003 after the TBT came out. About 30% of breeches are still undiagnosed at the start of labor, so you’ll need to know how to assist a breech birth: how not to panic, how to help if the baby needs help.

The optimal position for a baby to be in, for breech, is RSA as it drops into the pelvis. In her studies, 55% of breech babies enter RSA while 45% of the babies enter LSA. More babies that come in on the left don’t rotate. Use that observation as a little flag.

As the baby comes into the pelvis--because of the architecture of the bony pelvis, muscles, and ligaments--the baby comes in RSA, comes onto the pelvic floor, and then rotates to RSL or RST. The baby comes down in a straight line. The posterior buttock comes into contact with the mother’s sacrum, and that triggers a lateral flexion of the baby’s hips, which brings the posterior shoulder onto the back and upmost bit of the muscles in the pelvic brim.

That then triggers the baby's rotation back to RSA and continues round to direct sacrum anterior. At the top of the pelvis, that rotation brings the shoulders into line with the widest part of the pelvis. You’ll see the baby’s bum and lower part of the torso.

The body descends and the legs seem to go on forever. The baby is extending its spine. It’s very tempting to flick out the legs, but if you do that the baby won’t have to extend its pelvis so far around the mother’s symphysis pubis, which means the baby will have a harder time bringing its shoulder and head past the sacral prominence. So please don’t flick out the legs!!

As soon as you can see the baby, you won’t be able to hear the heartbeat as easily. Look at the color of the baby. Once the parts are out, look at the tone. Then look at the vitality of the cord. The knees look a bit inside out as the legs are emerging, but that’s normal for newborn anatomy. That facilitates the legs being born. The legs flick out on their own and the shoulders come into the pelvis. You’ll see the “valley of the cord.”

You’ll see a crease in the chest (or "cleavage") indicating that the arms are close to the head and not to worry about. You’ll see the baby siting on the floor/birth bed. Don’t lift the mother’s buttocks and push the mother up at this point!

Sometimes women sit down a bit; this opens the pelvis and flattens the perineum, helping the baby come down. What’s happening inside the woman's body when she does this? At the top, this helps the baby’s head to flex. Do NOT push the mother's bottom up at your peril! (Unless you really need to get the baby out). Sometimes women will move, put a leg up, etc—let her do this.

Now the baby's legs are out and the shoulders are coming in. You’ll see the cord going up through the valley of the cord and going over the shoulder. The cord is quite protected and the baby is not pressing on the mother’s vena cava--another advantage of being upright.

Now with the shoulders, the baby continues to rotate to LSA, and that releases what was the posterior arm (now the anterior arm) under the symphysis pubis. The baby has done its own Loveset maneuver! That allows the posterior arm to drop down. With that, the head drops down into the pelvis. This is where you might get some cord compression.

Then, at this point, Jane and her colleagues had been watching women drop forwards (placing their heads near the floor/bed) and didn't know why. As they were watching photos and videos, they realized that babies are doing a “tummy tuck” at this moment. Often the baby's arms and legs move together, flexing and tucking. If this doesn’t happen at all, you might need to help the baby out. The baby lifts its tummy and arms, tucking its legs, and this movement brings the baby’s chin onto its chest and rolls the occiput onto the mother’s symphsis pubis. It doesn’t hurt the women, but they all say at this moment: “I had to move.” They drop their torso around forward and roll their pelvis around the baby.

Now all that’s holding the baby in is the pelvic floor muscles and the perineum. Plomp! Out comes baby.

Once the baby is born, follow the curve of the mother's sacrum and pass the baby through the mother's knees to the mother. Then, if needed, you can assess the baby from the other side.

The first Apgar score is taken at 1 minute. That can be a long time to wait. Breech babies are a bit like waterbirth babies. Leave them there. Don’t cut the cord! You still have the circulation going from the placenta. The babies will often lie there, quite happily, nice and pink, and then suddenly open up and breathe.

When the baby comes down LSA (about 45% of breeches), what you should be seeing for normal is mostly the same but on the left rather than on the right.