-
Period: to
weeks 1-2
none -
Period: to
weeks 3-4
zygote turns into blastocyst and travels down fallopian tubes
rapid cell division starts
blastocyst implants itself into uterus lining during week 4 and becomes an embryo -
weeks 5-6
neural tube closes
heart,organs and bones start to develop
develops head/trunk
brain starts to develop -
Period: to
weeks 7-8
brain and face shape begin growing
four-chamber heart
all major organs have formed
lips and nose have formed
trunk/neck begin to straighten -
Period: to
week 10
all body parts are present
eyes, ears,arms and legs are identifiable
head is half the size of the body -
Period: to
week 11
genitals develop
teeth buds form
baby is 2 inches long and weighs 1/3 of an ounce -
week 12
fingernails grow
face is more defined
intestines are in the abdomen -
Period: to
week 14
baby's sex becomes apparent
baby can swallow/make urine -
Period: to
week 16
baby is moving, mom can't feel it
baby is 4 1/2 inches long
weighs 4 ounces -
Period: to
weeks 18-19
baby begins to hear
digestive system works
vernix caseosa covers the baby -
weeks 20-21
regular sleep/wake patterns
breathing movements occur but are underdeveloped
covered in Lanugo
all organs/structures formed -
Period: to
week 22
has nails,fingerprints,eyebrows,lashes and possibly some hair
lowest limit of viability outside of mother
heartbeat heard with a stethoscope -
Period: to
week 24
wrinkly skin, translucent and pinkish red
lung development
8 inches long
1 1/3 pounds -
Period: to
weeks 28-29
eyes partially open/close
nervous system directs breathing and body temperature
baby kicks/stretches -
Period: to
weeks 31-32
finished most major development
rapid weight gain
lanugo starts to fall off -
week 34
responds to light
continues to grow fingernails and toenails
skin is pink/smooth
4 1/2 pounds -
Period: to
week 36-37
takes up most of amniotic sac
starts to turn head down for labor
will continue to gain 1/2 pound until week of delivery -
Period: to
weeks 38-40
brain,lungs and liver still developing
brain will double in size between weeks 35-40
weight gain helps with temperature control after birth
lung development during the last few weeks helps to decrease complications after birth