A healthy pregnancy is achieved by following a healthy regimen of diet, exercise and vitamins before, during and after the baby is born, reports the U.S. Department of Health and Human Services. Signs of healthy prenatal development can be measured in the three stages of the pregnancy during the 38 to 40 weeks of gestation. The weeks are grouped into trimesters, averaging about 13 weeks each.
First Trimester
The menstrual flow discontinues and hormonal changes begin to take place during the first 12 weeks of the pregnancy. Women can expect normal symptoms that can include nausea, tiredness and mood swings. Many women crave different foods or develop a dislike of other previously favorite foods during a healthy pregnancy. Heartburn, swollen breasts and constipation should be expected. Every woman does not experience drastic changes in food preferences and physical discomfort however. Some women may just gain a little weight, while others even lose a few pounds in the first trimester. Normal fetus development depends on a healthy first trimester, report doctors at the University of Virginia Medical Center. Most symptoms decrease or disappear in the second trimester.
Second Trimester
As most of the uncomfortable symptoms disappear in the 13th week, others take their place. In a healthy pregnancy, most women begin to show, with the abdomen expanding to accommodate the growing fetus. Body aches in the back, thighs and abdomen may be more pronounced. The skin around the nipples darkens and dark skin patches may appear on the forehead, cheeks, nose or upper lip. Carpel tunnel syndrome, characterized by a tingling sensation in the hands is a common symptom in a healthy pregnancy. Women should begin to feel movement from the growing baby during the second trimester.
Third Trimester
As the baby grows, putting additional pressure on the bladder, women find they must urinate more frequently during the third trimester. Breathing may become more labored as the fetus puts pressure on the chest as well. Heartburn is common and women should expect slight swelling in their feet and ankles. The breasts will become more tender and can emit a watery substance called colostrum. Most women at a healthy weight should expect to gain between 25 and 35 pounds by the third trimester, report doctors at the Mayo Clinic. During a healthy third trimester, the cervix will become softer and thinner and the baby may drop, all in preparation for birth.
