Some things my midwife says she has noticed to keep babies in a breech position are:

Anterior placenta (and usually since its not a big deal, they dont even tell you that you have one. I would never have known had I not gotten my medical records and read my ultrasound findings). Mine is anterior again this time (4th time) and though it has only caused posterior babies in the past, this time since it was right in the middle as well, I think baby was having a hard time finding head down position. She would go from breech to transverse then back and then back again.

Also, bad posture and sitting and lounging habits. If you spend a lot of time reclined with knees above your pelvis, or other bad positions for lounging around in (dont remember which ones she said were bad for malpositioning babies).

sometimes you have a really active baby that gets the cord wrapped around their body a few times and then cant turn. That isn't something that is likely to repeat though beside coincidence and you said they didn't note anything unusual for your sections.

sedentary lifestyle or being on bedrest - this one is yet another "theory" that I dont remember if it was just suggested or if I actually read an article somewhere in my studies on it. Basically though the theory is that babies get head down because of gravity, the head being heaviest part of them. The more active we are, walking around and moving and wiggling, gives baby the chance to setttle into that preferred position whereas a mom who is very inactive say because of low thyroid function, anemia zapping all that engery, or being put on bed rest, that baby doesn't get settled into that position by gravity. Still, they may very well find that position on their own it being most favorable and a better fit but supposedly, it puts mama at higher risk of breech or other malpositions.

other than that, it was probably just a coincidence if no uterine fibroids are present, or other uterine anomolies.

 

Women who have one breech baby are more likely to have another (I think the repeat-rate is something like 5-10% if you've had one previously, versus 3-5% in general). Seems to be something about the pelvis shape, tension of ligaments on the uterus, and in some cases could be because of anomalies in the uterus anatomy (bicoronate or septum, etc). My first was breech at term, and my second, a planned VBAC, was breech at 31 weeks but flipped. I did try to be more proactive about good posture, doing some chiropractic for my achy hips etc with my second --- which I hadn't really done with my first. At the end of the day, generally baby's movements are random and since the head is the densest part and the uterus is "bowl" shaped at the pelvis, baby's random movements will usually cause the baby to flip to vertex unless there's something preventing baby from easily moving to that position.

 

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