Pregnancy has three trimesters, each of which is marked by specific fetal
developments. A pregnancy is considered full-term at 40 weeks; infants delivered
before the end of Week 37 are considered premature. Premature infants may have
problems with their growth and development, as well as difficulties in breathing and
digesting.
First Trimester (0 to 13 Weeks)
The first trimester is the most crucial to your baby’s development. During this period,
your baby’s body structure and organ systems develop. Most miscarriages and birth
defects occur during this period.
Your body also undergoes major changes during the first trimester. These changes
often cause a variety of symptoms, including nausea, fatigue, breast tenderness, and
frequent urination. Although these are common pregnancy symptoms, every woman
has a different experience. For example, while some may experience an increased
energy level during this period, others may feel very tired and emotional.
Second Trimester (14 to 26 Weeks)
The second trimester of pregnancy is often called the “golden period” because many of
the unpleasant effects of early pregnancy disappear. During the second trimester,
you’re likely to experience decreased nausea, better sleep patterns, and an increased
energy level. However, you may experience a whole new set of symptoms, such as
back pain, abdominal pain, leg cramps, constipation, and heartburn.
Somewhere between 16 weeks and 20 weeks, you may feel your baby’s first fluttering
movements.
Third Trimester (27 to 40 Weeks)
You have now reached your final stretch of pregnancy and are probably very excited
and anxious for the birth of your baby. Some of the physical symptoms you may
experience during this period include shortness of breath, hemorrhoids, urinary
incontinence, varicose veins, and sleeping problems. Many of these symptoms arise
from the increase in the size of your uterus, which expands from approximately two
ounces before pregnancy to two and a half pounds at the time of birth.