A woman’s pregnancy starts as soon as sexual intercourse has occurred and the sperm has reached the egg (conception.) The period after conception is made, is referred to as gestation. The time of gestation (on average) will last around 40 weeks. Although some pregnancies can end early 36 weeks or last up to 42 weeks.
Since every woman ovulates and the exact date and time of fertilization cannot always be exactly determined, obstetricians use a general guideline decided by the date of the woman’s last menstrual period.
Pregnancy (the gestation period) has been broken down by medical experts into phases, milestones, and more as the baby grows and becomes functional enough to enter this world healthy.
The 3 Phases of the Human Gestation Period
The phases or milestones of the human gestation are broken down into 3 unique trimesters: (the first trimester, the second trimester, and the third trimester.
Human Gestation Period: The First Trimester
The first trimester begins on the last day of a woman’s menstrual period. It lasts up until the 13th week of the beginning of her pregnancy. The sperm has no fertilized the egg- from there the fetus becomes implanted into the uterus (womb.) A woman is usually 4-6 weeks along in her pregnancy before she skips her period and realizes she may be pregnant.
Pregnancy symptoms will begin to be noticeable such as nausea, fatigue, and frequent urination. It is in the first 4-6 weeks that alcohol or used of medications or illegal drugs can adversely impact the health of the unborn baby. This trimester is also the time that problems with the pregnancy can cause the woman to miscarry.
Human Gestation Period: The Second Trimester
The second trimester begins on the 14th week since the woman’s last menstrual period and lasts to the end of the 27th week..The second trimester is often reported as the easiest as nausea sue to hormonal changes has subsided. Additionally it is during this trimester about the 18-21st week that a woman can feel her baby move in small “fluttering’ types of sensations. It is also around this time that a mother can decide if she wants to know the sex of her baby. Ultrasounds performed from 18-22 weeks typically can identify whether the baby is a boy or a girl.
During the second trimester it is also vital as the baby is growing and changing. It can hear sounds, and its eyes can see. It can also feel different sensations. Sometimes if a baby is born after 24 weeks it can be saved by machines, medication, and modern neonatal science.
Human Gestation Period: The Third Trimester
The third trimester is the last trimester of the pregnancy which begins on the 28th seek since the woman experienced her last normal period of menstruation.The fetus is now growing leaps and bounds & can expand from 3lbs to 8lbs on average in this time period. It is constantly growing and moving as its mother’s belly grows in size as well. As weeks 36-40 approach the baby may move less as it begins to get less roomy in the womb.
The mother may have to urinate frequently, may experience practice contractions, her feet may swell, and she may get tired very easy in this last trimester of pregnancy. From the last weeks of pregnancy a mother may experience more contractions, she may be effacing as the cervix opens and stretches to prepare for childbirth,
Labor begins differently for each woman and it should be anywhere from 38-42 weeks from the woman’s last menstrual period. However, each woman is unique. In some cases if a woman is at risk for other things that may harm her or the baby a doctor will schedule a c-section (surgical birth) or will induce labor early by giving the mother medication that expedites the process of the beginning of labor.