Originally Posted by rhiandmoi
Usually when people say a placenta has "worn out" they mean that it has calcified. The more calcification, the less healthy placenta tissue is supplying oxygen and nutrients to the baby or babies. This is happens as a normal part of the placenta aging, and usually doesn't get to a point where it adversely affects the baby or babies, but it can cause problems if the placenta calcifies too much too soon. It can also be a sign that something else is going on, such as PreE if excessive calcifications are visible on ultrasound.
Yes, this is also my understanding--and one time saw such a placenta (birth at 43wks) and the baby had clearly lost a little weight in the final days. She and mom were both fine, btw--baby was big enough to handle a few ounces lost, and mom's milk came in very fast (24hrs) so all was well from birth onward.
I'm sorry I don't have links to share, but in a discussion on a mw forum a few years back, this very issue of optimal twin gestation came up. One mw had lost one twin in the past, at 40+wks gestation, and had done extensive study of the topic. According to her, the general surveys of twin health compared to gestational age showed that 37-39wks was optimal. Now, this was all based on research from hospital births/OB care, and when I asked about homebirth twin studies there was no response. I have to assume that we just don't have sufficient numbers for good studies w/respect to homebirth--and this is also true for hbac. But there is no doubt that in general, natural-minded/hb/UC mamas are, as a group, more attentive to things like diet and lifestyle matters that impact pregnancy health--more attentive than the average OB or average OB patient. I kind of assume--with things like twins, hbac, pre-e, GD, some other higher-risk situations--that there is most often a real and highly positive difference in outcomes made by diet/self-care efforts.. And these are not things so well promoted by most OBs; and they also deal with a more 'average' population of women--and a broader range of women, including crackheads and so forth--so of course, their statistics and assumptions are going to be skewed in the direction of 'least common denominator': in this case, the basic common factor of twins, without any other factors weighed in.
So, for the twin mom who IS taking good care of herself, and paying good attention to her own signs and her babies' signs too, gestational age at birth is not so critical a factor as seems to be implied by the 37-39wk limit deduced from the med research on twins.
If that makes sense!