[Dynseli]

Serum Estrogen works on all Estrogen Receptors. Same for serum Progesterone activating all Progesterone Receptors.

Plant estrogens or progesterones usually work directly on one receptor subtype, but plant hormones can influence serum hormones which cause their respective full range of action.

Typically phytohormones used for NBE affect different subtype receptors than those for hips, unless as noted above. Prolactin herbs (usually breastfeeding herbs) and phytoprogesterones (of either subtype) during luteal phase are still relevant here. Aromatase is also relevant.

Bingo, according to The effect of relaxin on the musculoskeletal system, relaxin is involved in the bone remodeling process. Perhaps, it catabolizes bone so it can be rebuilt. It's a good read.

It suggests that (abnormal) high levels of relaxin during pregnancy is associated with hip problems (Congenital Dislocation) for newborns. Relaxin is also shown to weaken certain ligaments being a risk for injury. However, relaxin is part of a healing process of certain tissues.

It is important to cycle hormones, because some downregulate certain receptors when balance is needed.