Second Trimester Month 4 - Month 6

By: Mallory Ammons

Month Four 12 weeks sexual differentiation

  • Sperm carries X or Y chromosome.
  • Developed during the fourth week.
  • Male fetus- analog

Month Four Development

  • Fetus is 3 inches long
  • Face looks more human like
  • Eyelids form but remained close until the 7 month
  • Amniotic Sac protects the baby
  • The baby breathes Amniotic Fluid
  • Oxygen received from moms placenta
  • 2,000 to 2,700 calories a day
  • increase protein,iron and calcium
  • whole grain
  • veggies
  • lean meat
  • milk

Month 5

  • During the fifth month the outer ear has developed but not fully. It won't fully develop until birth
  • Ultrasound- Helps visualize defects of the head, chest and limbs
  • Fetus is 9 inches long
  • Fluttering can be felt my the mom
  • movements happen more often
  • nervous system is more developed
  • Sleep and wake like a new born. This is called (Sleep Cycle)

Month 6


  • 13 inches long
  • baby will gain 1/2 pound per week
  • fingernail formed and growing
  • Lanugo forms due to vernix
-Helps fight infection and aids in delivery

Amniotic Fluid

  • Keeps baby warm
  • provides lubrication so you won't have webbed feet or hands
  • Allows baby to move easily
- Exercise muscles


  • Protects baby
  • Amniotic Fluid is 98% water and 2% salt
  • Baby aids to Fluid by urinating in it, drinks it's urinates again baby consumes 13oz of fluid a day

Month 6 Twins

  • Twins only occur in 1% of all pregnancies
-Identical-30%

-Fraternal-70%

-Identical twins development is not explained

-Fraternal twins development is due to the mother

Identical Twins

  • Fertilized by one single sperm
  • Splitting occurs during first week
  • stage will split and determines how twins will implant

Fraternal Twins

  • Non-identical twins develop from two fertilized egg cells.