PREGNANCY AND THE

TRIMESTERS

Conception – 4 weeks 8 weeks 12 weeks

FIRST TRIMESTER

SECOND TRIMESTER 16 weeks 20 weeks 24 weeks

THIRD TRIMESTER 28 weeks 32 weeks 36 - 38 weeks

FIRST TRIMESTERCONCEPTION – 4 WEEKS Less 1/10 inch long Beginning of spinal cord, nervous

system, heart, intestinal system and lungs

Amniotic Sac – clear fluid, in which the unborn baby floats and moves

FIRST TRIMESTER 8 WEEKS

Less than 1 inch Face forming – eyes, ears, mouth Arms and legs are moving Heartbeat detectable

FIRST TRIMESTER12 WEEKS 3 inches and weighs 1 oz Moving fingers and toes Finger prints Can smile, frown, swallow and urinate

SECOND TRIMESTER16 WEEKS 5 ½ inches long, 4 oz Strong heartbeat Thin skin Downy hair over body Fingernails and toe nails develop

SECOND TRIMESTER 20 WEEKS 10-12 inches Sucks thumb Hiccup Hair, eyelashes and eyebrows Rolls over fluid

SECOND TRIMESTER24 WEEKS 11-14 inches 1 ½ lbs Wrinkled skin Open eyes Strong grip

THIRD TRIMESTER 28 WEEKS 14-17 inches, 2 ½ - 3 lbs Adding body fat Very active

THIRD TRIMESTER 32 WEEKS 16 ½ - 18 inches, 4 – 5 lbs Sleep/awake Responds to sounds

THIRD TRIMESTER 36-28 WEEKS 19 inches 6lbs Skin less wrinkled Gaining immunities from mother

PERIOD OF PRENATAL DEVELOPMENT

Embryonic Period Occurs 2-8 weeks after conceptionRate increases of cell division, support

systems for the cells form, organs appear Germinal period

Takes place in first 2 weeks after conceptionCreation of zygote (fertilized egg), cell

division attachment of the zygote to the uterine wall

PERIOD OF PRENATAL DEVELOPMENT

Embryonic Period Occurs 2-8 weeks after conceptionRate increases of cell division, support systems

for the cells form, organs appearThe mass of cells attached to the uterine wall

forms three layers and is now called the embryo Endoderm – inner layer of cells will develop

into digestive and respiratory systems Ectoderm – outer layer of cells will become the

nervous systems and sensory receptors (ears, nose, eyes and skin)

Mesoderm – middle layer – will develop into the circulatory system, bones, muscle, excretory system and reproductive system

PERIOD OF PRENATAL DEVELOPMENT Fetal Period

2 months of conceptionLast for 7 monthsDevelopment is very dramatic