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- $Unique_ID{BRK01560}
- $Pretitle{}
- $Title{Does the Heart of the Mother Change While She is Pregnant?}
- $Subject{heart size Pregnancy Childbirth Mother Pregnant rate rates Blood
- pressure pregnancies cardiac output aorta ventricle ventricular circulatory
- system circulation pressures ventricles circulation}
- $Volume{K-3,G-3}
- $Log{}
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- Copyright (c) 1991-92,1993 Tribune Media Services, Inc.
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- Does the Heart of the Mother Change While She is Pregnant?
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- QUESTION: Since there are many apparent changes in a woman's body during
- pregnancy, I wondered if her heart might also be affected by the pregnancy.
- Does the heart of the mother change while she is pregnant?
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- ANSWER: It most certainly does. During normal pregnancy, labor and delivery,
- a good many changes take place, providing physicians with a special
- opportunity for observing important cardiac adjustments during a temporary
- state of high stress.
- To begin with, heart rate increases up to fifteen beats per minute above
- nonpregnant levels, with the most significant increases occurring before the
- eighth week of pregnancy. Blood pressure can either increase or decrease,
- depending on the woman's age and whether she's had previous pregnancies.
- Levels appear to increase with advancing age and decrease if previous
- pregnancies existed.
- In addition, cardiac output (the amount of blood the heart pumps out) at
- rest increases during pregnancy, from 30-50 percent above normal, peaking at
- the end of the second trimester. It is believed that the increased heart rate
- is responsible for this change in cardiac output, as well as the increased
- stroke volume (amount of blood that is pumped out with each beat of the
- heart). The resistance to blood flow in the arteries of the body decreases
- during pregnancy, and together with the increased cardiac output, blood flow
- to various organ systems is altered as well. Uterine and kidney blood flow
- markedly increase, as well as blood flow to breasts, skin, limbs, and mucous
- membranes.
- One of the most significant changes, however, involves the left
- ventricle, or lower left chamber of the heart which pumps oxygenated blood out
- through the aorta to all the tissues of the body. Left ventricular volume and
- chamber size gradually increase throughout pregnancy resulting in the
- enlargement of the heart's cavities and wall mass. This enlargement
- contributes to the increased cardiac output. However, despite the dimensional
- changes, the heart's function and wall stress remain normal. Within five
- weeks after delivery, all blood flow, structural, and functional changes are
- back to pre-pregnancy values, indicating that the heart is a remarkably
- adaptive organ which can respond to the changing demands placed upon it by
- the needs of the pregnancy. Physicians are hopeful that these findings will
- one day lead to insights concerning possible treatment for the problems of an
- ailing heart, and the need for it to adjust to stress.
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- The material contained here is "FOR INFORMATION ONLY" and should not replace
- the counsel and advice of your personal physician. Promptly consulting your
- doctor is the best path to a quick and successful resolution of any medical
- problem.
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