Fetal, Newborn and Early Childhood Growth & Development

At what embryonic age does implantation begin and what is the embryo called?

Around 6 days post-conception; the embryo is a blastocyst.

Which weeks define the embryonic period of human development?

Fertilization through the end of week 8.

What major event marks the beginning of the fetal period?

The completion of organ rudiments at the end of week 8 and transition into rapid body growth starting week 9.

By which week is the face recognizably human?

Week 10.

During which weeks do primitive alveoli begin to form and surfactant production start?

Weeks 20-24.

How much do fetal weight and length increase during the third trimester?

Weight roughly triples and length about doubles.

When does the neural plate first appear in embryogenesis?

During the 3rd week.

What process forms the central and peripheral nervous systems from the neural plate?

Infolding into a neural tube (CNS) and neural crest (PNS).

When does myelination of the nervous system begin?

At mid-gestation (around 20 weeks) and continues for years.

Which gestational week marks completion of neuronal migration to the six cortical layers?

By the sixth month (~24 weeks).

What fetal behaviors appear at 13-14 weeks’ gestation?

Breathing and swallowing motions.

At what gestational age does the grasp reflex first appear?

Around 17 weeks.

When do fetal