Growth of the Baby During Pregnancy

Growth of the baby during pregnancy

Pregnancy is divided into three phases, or trimesters. All the important organs in a human being are formed during the embryonic stage (from fertilization until about six weeks).

The length of a pregnancy is calculated methodically from the first day of the last menstrual period. On the 14th day of a normal 28-day cycle, which is the time of fertilization, the pregnancy is said to be already two weeks old. The embryo is said to be eight weeks old at six weeks after fertilization.

The Placenta

It is the lifeline between mother and baby. It first exists as a thick, spongy layer of cell. The cells burrow deeper and deeper as the embryo develops, drawing on the maternal blood to meet its increased nutritional demands. They were the first cells to reach into the maternal tissues for nourishment.


The Umbilical Cord

It carries blood from baby to and from the placenta. This is where the exchange of wastes for nutrients in favor of the baby takes place.

Amniotic Fluid

This fluid cushions the baby from shock and from the pressures of the uterine wall. The fetus also drinks from it.

From Embryo to Infant

Much of the hard work of the growth of the baby during pregnancy takes place from conception until about twelve weeks (that is, 10 weeks after fertilization). They continue to mature throughout the pregnancy.

Week 2 – This is day zero. The one fertilized cell, which is the largest cell in the body shows that life has begun.

Week 3 – 64 cells now exist

Week 4 – The amniotic sac is starting to form. A primitive placenta has taken shape.

Week 5 – The newly formed amniotic sac has the embryo that is starting to take shape.

Week 6 – The urine test is now positive. Pregnancy sac can now be seen by ultrasound scan. The human embryo at this stage looks more like a fish than a human.

Week 7 – A brain develops. The nose and cheeks are forming. The arms and legs can be seen.

Week 8 – The embryo is now visible using ultrasound. The formations of all the major internal organs are now completed. Shoulders, elbows, hips and knees are becoming visible.

Week 9 – The formation of eyes are completed. The nose becomes visible. The spine has movements, but is not apparent to the mother.

Week 10 – The umbilical cord is formed and functioning. Ankles and wrists become visible. The inner ear is formed.

Week 11 – This is the baby’s development’s milestone. All his essential organs are completed and the baby is now less vulnerable to external disturbances.

Week 12 – A complete and vigorously moving fetus can be seen on the ultrasound screen.

Week 13 – The baby now looks like a baby. The baby can hear a great deal from now on. The finger prints appear. The rest of the pregnancy is where the baby grows and matures.

Week 16 - The baby’s sex is now apparent.

Week 20 – The mother can now feel the baby’s movements

Week 24 – The baby’s arms and legs have all the normal muscles.

Week 28 – The baby might now have a chance of sustaining life outside the uterus (with some difficulty) if delivered.

Week 32 – The baby’s lungs can now support life independently. His head should be settling into the head-down position (cephalic or head presentation), under normal circumstances.

Week 36 – The baby’s finger nails now reach the end of his finger tips. If this is the mother’s first baby, the baby’s head passes through the inlet and into the pelvis to become engaged. The mother will notice less pressure in the upper part of the abdomen. There is no need for anxiety if the baby's head has not engaged by thirty-seven weeks.

Week 40 – On average, a pregnancy lasts 40 weeks from the first day of the last menstrual period. The pregnancy is now at full term. Babies born between 37 – 42 weeks are considered term babies. A healthy and normal term baby weighs around 2.5 kg to 3.8 kg.


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