New Beginnings Doula Training

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Tuesday, September 20, 2011

Outside factors that may affect fetal oxygenation

While there is a lot going on with baby inside her body that helps her get the oxygen she needs, there are some outside factors that may affect on the babies ability to receive the oxygen she needs.

Uterine pressure is one of those.  During labor the pressure from the contractions lead to a temporary decrease or interruption of blood flow to the placenta.  In a healthy mom, the placenta provides more oxygen than the fetus needs.  This reserve allows the fetus to withstand the temporary decreases in blood flow and oxygenation.

The fetus is also able to resond to uterine blood flow by shunting more blood through the ductus venosus.  Maternal hemoglobin may increase and there may also be an increase in maternal hyperventilation.  As described in my last post, there are also various responses within the fetus that help increase oxygenation.

However, if uterine contractions  occur too often or the baseline resting tone increases, the fetus may need to compensate.  Along with this, if there are other factors that decrease blood flow and oxygenation(ie supine position, hypotension or pre-eclampsia), fhr changes can occur.

The umbilical cord being compressed may also alter the blood flow to the baby.  Compression is pretty common and usually tolerated well.  Compression may be associated with a wrapped cord, prolapse after the water breaks, oligohydraminos, and knots.  Problems may arise when there is also problems with the uterine blood flow at the same time.

Problems with the mom may also decrease oxygen to the fetus.  There is not a whole lot of research on the effect of stress during labor, but some research is showing that stress in the mom may cause changes in the fhr.  Other problems such as maternal smoking, anemai, and maternal respiratory problems also play a role.

Because of how the placena, fetus, and mom are designed, birth goes fine most of the time.  It's interesting to me to see how everything works to produce a good outcome.

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Birth is a Journey: Does it have to be life changing?

  • One woman might have to climb on an overfilled boat, risking her life and nearly dying as she escapes over the ocean to come to this land. This experience could certainly be life altering. It may very well color the rest of her life, positively or negatively. (I overcame this amazing struggle and here I am triumphant! OR Holy crap, that was SO hard I don’t know if I can go on! By the way, neither response is “right”. No one would judge the woman with the 2nd response.)
  • One woman may buy an airplane ticket, sit on a comfortable 747 and fly to America with a nice smooth flight and landing. She is happy to be in America. Those welcoming her are glad she is here safe and sound. She may only travel by plane 2-4 times in her life, so it is pretty memorable. But the journey itself probably wouldn’t be life changing; it would simply be a journey.
  • One woman may learn to fly an ultra-light plane to lead a flock of geese into America teaching them to migrate. This experience could certainly be empowering and life altering.