Hi Diane,  I don't think it is a very good question.  I think that the fetal hemoglobin is relatively weaker than the adult hemoglobin but the low oxygen environment of the fetus helps to draw oxygen from the placenta and the 2-3DPG helps to release oxygen from the adult hemoglobin on the maternal side of the placenta.  Ultimately what really matters is how well does the oxygen nourish the cellular level.
 
Fetal hemoglobin From Wikipedia, the free encyclopedia  

If you read down to the 5th paragraph, "Adult hemoglobin alone actually has a higher affinity for oxygen than its fetal equivalent, but the levels of 2,3-BPG reduce it." 
From what I remember about this topic, I  think that it is relative to the situation.  How oxygen is released or attacted is affected by many different factors that are explained by the oxygen-hemoglobin dissociation curve.   This curve can also shift right or left.
 
Oxygen-haemoglobin dissociation curve
From Wikipedia, the free encyclopedia
  (Redirected from Oxygen-hemoglobin dissociation curve)
 

"The oxyhemoglobin dissociation curve is an important tool for understanding how our blood carries and releases oxygen.
 The amount of oxygen bound to the hemoglobin at any time is related, in large part, to the partial pressure of oxygen to which the hemoglobin is exposed. In the lungs, at the alveolar-capillary interface, the partial pressure of oxygen is typically high, and therefore the oxygen binds readily to hemoglobin that is present. As the blood circulates to other body tissue in which the partial pressure of oxygen is less, the hemoglobin releases the oxygen into the tissue because the hemoglobin cannot maintain its full bound capacity of oxygen in the presence of lower oxygen partial pressures.
 
 
In contrast, the curve is shifted to the left by the opposite of these conditions. This leftward shift indicates that the hemoglobin under study has an increased affinity for oxygen so that hemoglobin binds oxygen more easily, but unloads it more reluctantly.
 
Fetal hemoglobin (HbF) is structurally different from normal hemoglobin (Hb). The fetal dissociation curve is shifted to the left relative to the curve for the normal adult. Typically, fetal arterial oxygen pressures are low, and hence the leftward shift enhances the placental uptake of oxygen. At the placenta there is a higher concentration of 2,3-DPG formed. This binds more readily to adult hemoglobin but not to fetal heamoglobin. This causes the adult Hb to release more oxygen at the placenta to be taken up by the fetus. Fetal Hb is made up of gamma chains not beta ones, and 2,3-DPG does not bind readily to gamma chains, hence it does not give up its oxygen."> Date: Thu, 15 Jan 2009 14:58:47 -0500> From: Diane Wiessinger <[log in to unmask]>> Subject: fetal hemoglobin and oxygen> > I was sent this e-mail note from an IBCLC friend studying for the exam. => Everything *I* found on-line disagreed with R&A. Does anyone know for => sure?> > Diane Wiessinger, MS, IBCLC, LLL Leader, Ithaca, NY USA> www.normalfed.com> > Question (from Study Guide for BF & Human Lactation by Riordan & => Auerbach) :> Fetal hemoglobin> a. picks up oxygen poorly.> b. has a high affinity for oxygen> (c & d were quickly eliminated)> > The correct answer was given as "a" with this explanation from the book:> > Riordan & Auerbach's BF & Human Lactation...> Fetal hemoglobin is well adapted to assisting the fetus in the => low-oxygen environment of the uterus. It has a low affinity for oxygen; => therefore, it picks up oxygen less well than does adult hemoglobin => (which has more need for it). However, it also is better able to release => the oxygen to peripheral tissue, thus enabling the fetus to live and => grow in a relatively low-oxygen environment.> It previously explained that fetal hemoglobin takes up oxygen poorly, so => more hemoglobin is needed. The normal, full-term baby is born with a => relatively high level of red blood cells containing a high level of => fetal hemoglobin.=20> > One of my study-mates had checked on line and found this conflicting => statement re: fetal hemoglobin and its affinity for oxygen as compared => to the adult hemoglobin...> > http://en.wikipedia.org/wiki/Fetal_hemoglobin> Fetal hemoglobin, or Foetal haemoglobin in British English, (also => hemoglobin F or HbF) is the main oxygen transport protein in the fetus => during the last seven months of development in the uterus and in the => newborn until roughly 6 months old. Functionally, fetal hemoglobin => differs most from adult hemoglobin in that it is able to bind oxygen => with greater affinity than the adult form, giving the developing fetus => better access to oxygen from the mother's bloodstream.> > What's your take on this...does fetal hemoglobin have a low or high => affinity for oxygen and why?
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