STAGES OF PRENATAL

DEVELOPMENT

PRENATAL• The term prenatal means the period of time

before delivery. • Today we are going to talk about the prenatal

development of the baby in utero (in the uterus).

Period One: the Zygote• Period One is the ZYGOTE stage which lasts from

fertilization to two weeks.• The fertilized egg reaches the uterus or womb

where it attached to the lining of the uterine wall.• The main activity in this stage is cell division.• At the end of this period the baby is the size of a

pin head.

Period two: the Embryo• The EMBRYO becomes fully attached to the

uterine lining.• The placenta forms between the uterus and

the embryo.• Nourishment and oxygen are carried to the

embryo by the umbilical cord which is filled blood.

• Any wastes or toxins are also eliminated through the cord.

• The embryo is surrounded by amniotic fluid.• This period lasts 2-8 weeks.

Period three: the Fetus• A human baby can be recognized (arms,

legs and internal organs have developed.• At 5 months there is movement. • The baby begins to curl into the “fetal

position”.• At 7 months the baby can live outside the

womb.• At the beginning of the 9th month the fetus

moves into the birth position by lowering into the birth canal.

• This period lasts from 8 weeks to Birth.

Pregnancy• Pregnancy lasts 40 weeks full term.

Miscarriages

• Most likely to happen in the first three months.• Reasons that a miscarriage might happen:– Deformed egg – Placenta failure – the fetus does not get enough

oxygen– Weak cervix– Trauma to the mother or child – accident, breathing

in poisonous chemicals– Age (over 35)– History of miscarriages– Trouble getting pregnant