indian baby names
share page mobile version translate page
Pregnancy Trimester

Note: Information provided on this page is for general education only, please seek medical assistance when in doubt

First trimester begins at day 1 of your last menstrual cycle till week 12. During the first trimester of pregnancy, the woman undergoes many physiological and hormonal changes, including cardiovascular, hematologic, metabolic, renal and respiratory changes. This changes occurs in your body to ensure the fetus is provided for blood sugar, breathing and cardiac output. Levels of progesterone and oestrogens rise continually throughout pregnancy, suppressing the hypothalamic axis and subsequently the menstrual cycle. Hormonal changes affect almost every organ system in your body.

Other noticeable changes you may experience:
  • Extreme tiredness
  • Tender and/or swollen breasts, your nipples might also stick out.
  • Upset stomach with or without throwing up (morning sickness)
  • Cravings or distaste for certain foods
  • Mood swings
  • Constipation (trouble having bowel movements)
  • Need to pass urine more often
  • Headache
  • Heartburn
  • Weight gain or loss
With changes in your body, you might need to make changes to your daily routine, such as going to bed earlier or eating frequent small meals. Fortunately, most of these discomforts will go away as your pregnancy progresses.

Baby growth in First Trimester
At 4 weeks:
  • Baby's brain and spinal cord have begun to form.
  • Heart begins to form.
  • Arm and leg buds appear.
  • Your baby is now an embryo and one-twenty-fifth inch long.

At 8 weeks:
  • All major organs and external body structures have begun to form.
  • Baby's heart beats with a regular rhythm.
  • Arms and legs grow longer, and fingers and toes have begun to form.
  • Umbilical cord is clearly visible.
  • Eyes have moved forward on the face and eyelids have formed.
  • Sex organs begin to form.
  • At the end of eight weeks, baby looks more like a human nearly 1 inch long and weighs less than one-eighth ounce.

At 12 weeks:
  • The nerves and muscles begin to work together.
  • Your baby can make a fist.
  • Eyelids close to protect the developing eyes; however eyelids do not open until the 28 th week.
  • External sex organ shows up and boy or girl baby is distinguishable.
  • Growth of head has slowed, and your baby is now much longer about 3 inches long, and weighs almost an ounce.
  Next Trimester ► 

Fetal Growth in ...
1st month 2nd month 3rd month 4th month
5th month 6th month 7th month 8th month
9th month 10th month

Fetal Growth in ...
Week 1 Week 2 Week 3 Week 4 Week 5 Week 6
Week 7 Week 8 Week 9 Week 10 Week 11 Week 12
Week 13 Week 14 Week 15 Week 16 Week 17 Week 18
Week 19 Week 20 Week 21 Week 22 Week 23 Week 24
Week 25 Week 26 Week 27 Week 28 Week 29 Week 30
Week 31 Week 32 Week 33 Week 34 Week 35 Week 36
Week 37 Week 38 Week 39 Week 40 Beyond 40 weeks

Also See:
  Due Date Calculator
  Ovulation Calculator (When is Ovulation)
  Fertility Calculator
  Safe Period Calculator
  Fetal Growth Calculator
  Fetal Size Calculator
  Pregnancy Calendar (Pregnancy Chart)
  Fetal length and weight chart
  Pregnancy Weeks (Pregnancy week by week)
  Pregnancy Months (Pregnancy month by month)
  Pregnancy Trimester
    -  First Trimester
    -  Second Trimester
    -  Third Trimester
  How to get Pregnant
  Pregnancy Overview
  Signs or Symptoms of Pregnancy
  Pregnancy Tests
  When to test for pregnancy
  Embryonic period in human pregnancy
  What is Ovulation
  When does Ovulation occurs
  What is fertile period
  When is safe period
  IVF (In vitro fertilization)