|MadSci Network: Medicine|
Amanda, everybody has different heart rates dearheart. You run up a flight of stairs your heart rate changes. For 25 years I've looked at boys and girls in uteruo with ultrasounds and never have found that boys or girls have consistantly higher or lower heart rates. You might argue that mamamals have slower heart rates as they get bigger. The mouse at 200 beats per minute (bpm) and the elephant at 30bpm, therefore since boys are usually bigger their heart rates should be slower. I've just never seen it when we were all 150mm in length. I see Obstetrical nurses that wish to tell the sex of a baby by its heart rate. First you have to find out what is the break point between fast and slow....usually 140bpm. My experience shows that half the nurses believe over 140bpm is a boy and the other half belief over 140bpm is a girl. Do this experement, write down all the heart rates of people in your classroom next to their name. Don't tell anyone their rate or let them see your record.... then at random pick a heart rate that you measured and "guess" the sex of the person with that number. You should get about half right which is better odds than we get here in LasVegas. I could go on and on but that's my story and I'm sticking to it. Keep asking questions. Mark Lawson, RDMS Diagnostic Medical Sonographer Texas, America 18Aug03 Lawson2k@juno.com
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