Period of Organogenesis
Most Critical
1st Trimester
> Fetal Heart tone begins/heard
> CNS develops
> GIT and URT remains a single tube
> Insulin decrease
1st Month
> All Vital organs are formed
> Placenta developed
> Sex organ developed
2nd Month
> Placenta is complete
> Kidneys are functional so fetus begins to swallow amniotic fluid
> Buds of milk teeth appear
> Sex is distinguishable
> FHT audible via doppler at 10-12 weeks, but as early as 8 weeks
3rd Month
Period of Continous G & D
FOCUS: Length of Fetus
2nd Trimester
> Lanugo appears
> Buds of permanent teeth appears
4th Month
> Lanugo covers the body
> FHT is audible by steth 18-20 weeks
> Actively swallow amniotic fluid
> Fetus: 19-25 cm
> Quickening
Primi: 18-20 weeks
Multi: 16-18 weeks
5th Month
> Skin is red and wrinkled.
> Vernix covers the body
> Eyelids open
> Sense of hearing develops
> startle reflex
6th Month
Period of Most Rapid Growth
FOCUS: Weight of Fetus
Third Trimester
> Surfactant develops
Male: testes descends into scrotum
Female: clitoris is prominent and labia majora are small and do not cover minora
7th Month
> Active moro reflex
> Lanugo begins to disappear
> SQ fat deposits
> Nails extends to fingers
8th Month
> Lanugo and vernix begins to thin
> Sole of foot has creases
> Birth position usually assumed
9th Month
> Bone
ossification of fetal skull
10th Month
37 - 42 weeks
266 - 280 days
280/28
10 lunar months
280/30
9.7 calendar months
