The Importance Of Fertilization

Fertilization, is the penetration of an egg by the sperm and becoming one cell. This single cell is called: the Zygote.

Fertilization takes place in the fallopian tube.

The zygote starts dividing while moving through the fallopian tube until it reach the Uterus. Where it get implanted.

From implantation to week 8, the baby is called an embryo.

From week 9 to birth, the baby is called a fetus.

Gestational age: is the age of the pregnancy from the last normal menstrual period (LMP).

The development of pregnancy is counted from the first day of the last normal period, even though the development of the fetus does not begin until conception.

Conception occurs approximately 14 - 16 days after the first day of the last menstrual period (LMP).

The second trimester is week 14 to week 26 and consists of the 4th, 5th and 6th completed months.

The third trimester is week 27 to week 40 and is the 7th, 8th and 9th completed months of pregnancy.

When does life begins?

Preconception

Some religious community consider the sperm sacred since its has the ability of fertilize an egg and make a human being. So any interference with this process like condoms or birth control pills are prohibited.

Conception

Other religious community consider the moment of conception as the start of life. But there is variability in the definition of conception, some consider it the act of ejaculation, some consider it the process of fertilization, and some says it is the fusion of genetic materials.

All of these definitions are not an exact time that you can pin point. The time from ejaculation to fusion of genetic material could take from 2-3 days.

Gastrulation

Is the formation of the trilaminar embryo. The three germinal layers: endoderm, mesoderm and ectoderm. This happens after implantation.

It is arguably considered the start of life

It could be visible by ultrasound as early as 5 weeks.

Week 8

By the end of the eighth week, all major organs and body systems have begun to develop.

Some argues that with the beginning of brain development the fetus has the ability to react and think and that is the beginning of life.

Opponents to this theory argue that even though the brain is begun to develop but it is not functional yet.

Quickening

The first fetal movements are called quickening and are often described as flutters.

Some argues that this is the beginning of life since the fetus started voluntary movement and can react to external stimuli. This happens around 13 – 16 weeks.

Week 20

Some argues that the movements around 13 – 16 weeks are only reflexes and are not driven by higher cortical centers. Therefore, life should begin at week 20 when the thalamus is fully developed.

Fetal Viability

Around 23 - 24 weeks of gestation, the fetus reaches the age of viability, after which it has some chance of surviving out-side the uterus if it is born prematurely.

The chances of a premature baby’s survival increase significantly with each additional week it remains in the mother’s uterus.