@bondo We’ve had similar problems.
1st thing - has your girl had her iron level checked ? Our son was anemic and it was messing his sleep up terribly. This possibility is increased if the mom has had a history of anemia. This may not be your issue, but we spoke to our pediatrician 5 times about the sleep thing and she always had some version of “it’s normal” and on our 6th visit, she was out for the day, and her replacement said “hey have you had his iron checked ?”
Me: “sure haven’t why would we do that ?”
Her: “ oh well low iron is a very common cause of sleep disturbance in infants “
F*+[sup]ing[/sup] great. Thanks pediatrician, we’ve been begging you to help us explain why our kid is writhing in apparent agony at night for months, and you haven’t offered any explanations, other than “it’s teething” or “it’s sleep regression” or 3 other normal things….
Anyhow our son was in the lowest 5% of iron Ferritin in his blood. Huge consequences for this, but the fix was simple , iron supplements until his iron came to normal , now he gets enough iron in the solids he eats… not perfect sleep by any means , but he was way better within 10 days of starting the iron supplement.
Hope this helps. The same pediatrician also stated that the co sleeping can keep the baby from developing their own coping mechanisms when they wake, but there’s obviously mixed schools of thought on this
Best of luck