Your baby's heart will beat quite fast, at between 110 and 160 beats every minute. Even after birth, your baby's heart will continue to beat at this speed. It will be several years before the heart rate is 70 or so beats per minute, the same as an adult.
If you imagine the lung as a tree, then the windpipe or "trachea" is the trunk of the tree. This then forms several branches or "bronchi," which divide several times, like twigs, to then produce the most delicate structures: the alveoli or leaves of the tree. It is within the alveoli that gas exchange will take place.
The alveoli began to develop at 24 weeks but they continue to increase in number throughout the pregnancy. The alveoli contain surfactant-producing cells to keep them open and these now become fully functional.
Maintaining muscular strength, stretching, and doing gentle exercise right up until you give birth will help your posture-minimizing backaches, reducing stress on your skeleton, and making you feel more energized and relaxed.
As long as you feel good and adhere to the guidelines set out on page 18, you can continue with your activities.
Most importantly, at this time you should use common sense and listen to your body. If you're in pain, feel fatigued, or have dizzy spells, see your doctor immediately and stop exercising. You'll be feeling tired carrying around all that extra weight so adjust your activities accordingly. This could mean that you lower the intensity of your exercise and exercise for a shorter time, but if you feel good don't stop exercising entirely.
Look at the routines on pages 90 and 250, but don't do any exercises at this stage that require you to lie on your back.
Toward the end of pregnancy, there are some circumstances when you may need to be admitted into the hospital for bedrest.
Excerpted from Pregnancy Day by Day.
Copyright ©2009 Dorling Kindersley Limited.
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