Fetal Development Trimester and Size

Fetal Development Trimester

Fetal Development Trimesters consist of three trimesters. A trimester is a period of three equal periods; each one consists of three months. The first trimester consists of 0-13 weeks, the second trimester is 14- 27 weeks,occour during these trimesters. and the third trimester is 28-40 weeks. Several changes occur during this trimester. Each trimester has a distinct developmental character for the fetus, and different physical changes occur in the pregnant person.

 

First Trimester.

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The first trimester consists of 0-13 weeks.

0 – 3 Weeks.

  • Pregnancy begins after the first day of the last menstrual period (LMP).
  • The body prepares for pregnancy.
  • Zygote divides and forms a blastocyst, which implants in the uterine lining.
  • Size 1/16 of an inch long.
  • The Embryo looks like Pinhead.

 

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4 – 5 Weeks.
  • A home pregnancy test should display a positive result.
  • The ball of cells formed during Fertilization has developed into an embryo in the uterus.

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  •  Size 1/ 8 of an inch long.
  • They resemble a poppy seed.
6 – 7 Weeks.
  • An embryo’s major systems and structures, e.g., the brain and spinal cord, develop.
  • The neural tube closes, and the heart beats at a regular rhythm.

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  • Size 1/4 of an inch long.
  • The size looks like a Pea or a Blueberry.
8 – 9 Weeks.
  • The embryo is now called a Fetus.

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  • All key body parts are present.
  • The brain continues to grow, and the lungs begin to form.
  • The size is 1/2 inch long.
  • The fetus roughly looks like a Raspberry to a Strawberry.
10 – 11 Weeks.
  • The critical part of the body develops completely.

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  • Tissues, the kidney, the brain, the liver, and the intestine are beginning to function.
  • The size is 1  1/4 inches long.
  • The size resembles a Caterpillar.
12 – 13 Weeks.
  • The fetus is able to swallow, the kidneys make urine, and reflexes have developed, but are still developing.

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  • External genitals have formed.
  • Fingernails are formed.
  • The skin is thickening, and small hair starts to appear.
  • Vocal cords are formed.
  • Some babies may start sucking their thumbs.
  • The size is over 2 inches long.
  • The size is roughly that of a Plum or a Peach.

Second Trimester.

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The second trimester consists of 14 to 27 weeks

14 – 15 Weeks.

  • The fetus develops Lanugo, a fine, downy hair all over its body.
  • Lanugo helps the fetus retain body heat until it accumulates fat.
  • The neck is more developed, and the head is more erect.
  • Facial features are becoming more defined.
  • Limb movements are becoming.
  • The placenta is fully developed
  • The size is 3  1/2 inches long.
  • They resembled Naval Orange.
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16 – 17 Weeks.
  • The fetus doubles in size and weight, and fetal movements called Quickening may be felt.

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  • The eyes are moving slowly, and eyelashes are beginning to form.
  • The size is 4 1/2 inches long.
  • They look like the size of an Avocardo.
18 – 19 Weeks.
  • Fetal organs and structures have been formed.

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  • Ultrasound may reveal the sex of the fetus.
  • The nervous system is rapidly developing.
  • The size is about 5 1/2 inches long.
  • The fetus’s size is between Bell Paper and Mango.
20 – 21 Weeks.
  • This is the halfway point of pregnancy.

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  • The fetus is now covered in a chees like coating, called Vernix caseosa, which protects skin.
  • The fetus is developing its senses.
  • The mother may feel flutters or kicks as the fetus moves around.
  • The size is 10 inches long.
  • The fetus looks like the size of a Banana.
22 – 23 Weeks.
  • Fetal facial features are more distinct.

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  • Developing blood vessels are visible.
  • The eyelids are still closed, but the eyes are moving behind them.
  • The size is 11 inches, 1 lb.
  • The size looks like roughly a Papaya or a Sweet Potato.
24 – 25 Weeks.
  • The brain is growing rapidly.

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  • Taste buds and the lungs are developing.
  • The baby’s face is almost fully formed.
  • Facial muscles are developing.
  • The size is 12 inches long.
  • A fetus is roughly the size of a full ear of corn.
26 – 27 Weeks.
  • The lungs are developing surfactant, the substance that allows the lungs to inflate.

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  • The fetus begins to inhale and exhale, practicing breathing movement.
  • The baby is starting to look more like a newborn.
  • The size is 14 inches, 2 lbs.
  • The fetus looks like the head of a Cauliflower or Cabbage.

Third Trimester.

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They consist of 28 – 40 weeks or till birth.

28 – 29 Weeks.

  • The lungs are almost fully developed.
  • Breathing movement and body temperature are now controlled by the central nervous system.
  • The hair on the body is longer.
  • The baby’s bones continue to harden.
  • The baby can now blink their eyes.
  • The baby’s skin is becoming smoother and less wrinkled.
  • The size is 15 inches, 2.2 lbs.
  • The size is almost an extra-large Cauliflower.
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30 – 31 Weeks.
  • Major fetal development is complete.

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  • The fetus begins to rapidly gain weight.
  • The baby’s skin is smoother as the lanugo starts to shed.
  • The size is 16 inches, 3.5 lbs.
  • The size is almost like a Coconut.
32 – 33 Weeks.
  • The fetus’s bones are hardening, though the skull remains soft.

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  • The baby is putting on fat.
  • The baby is also still moving around, though less freely.
  • The size is 16.7 inches, 3  3/4 lbs.
  • The size looks like a Pineapple.
34 – 35 Weeks.
  • The kidneys are fully developed, and the liver can process some waste products.

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  • The fetus continues gaining fat, which helps regulate body temperature after birth.
  • Fetal movement may be felt as rolls or shifts.
  • Finger nails have reached the fingertips.
  • The size is 18 inches, 4  3/4 lbs.
  • Size comparison of a cantaloupe or Honeydew melon.
36 – 37 Weeks.
  • The fetus gains about an ounce a day, and fat develops under the skin.

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  • The baby’s head is now more in proportion to its body.
  • Fingernails have reached the end of their fingers.
  • The baby’s digestive system is ready, but it has not been used yet.
  • The baby’s size is 18.5 inches, 5.5 lbs.
  • Roughly the size of a head of romaine lettuce or a Papaya.
38 – 39 Weeks.
  • The lanugo is mostly shed.
  • The fetus has accumulated fat all over to keep warm after birth.

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  • The baby’s organs are fully developed and ready for life,
  • The baby’s skin is thicker and no longer transparent.
  • The baby’s head may have engaged in preparation for birth.
  • The size is 19.5 inches, 6.8 lbs.
  • The size looks like a mini watermelon.
40 Weeks.
  • The fetus is completely developed.
  • The due date arrives, but just an estimate; it is normal to give birth before or after this date.

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  • All major organs and systems are fully functional.
  • The size is 20 inches, 7.5 lbs.
  • The size is almost that of a Pumpkin or Watermelon.

 

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