Unit 2- Fetal development (teratogens, trimesters, fetal stages)

Pregnancy: ____ weeks

____ lunar months

____ trimesters

40

10

3

1st trimester (check)

12ish weeks (3 months)

• LMP to conception = 2 weeks (preconception)

2nd trimester (check)

13-27 ish weeks from LMP

3rd trimester (check)

28-40 ish weeks from LMP

teratogens definition

cell death; alter tissue growth

interfere with cellular differentiation

whats important of timing/dose of teratogen

• dose

• molecular weight

• timing

• host susceptibility

• interactions w environment

FDA category D teratogens

tetracyclines

cyclophosphamide

FDA category X teratogens

absolutely not safe

thalidomide

hormones (DES)

isotretinon (formerly Accutane)

coumadin

Lipitor

viruses and bacteria teratogens

TORCH, STIs, BBPs, Salmonella, Listeria

other examples of teratogens

xrays and radiation

chemicals/toxins

alcohol (FAS/FAE)

street drugs

household chemicals (paint, gasoline)

mercury in foods

Smoking & ETS (LBW, SGA, PTB, future childhood health risks like ear infections and respiratory disease)

end of embryonic stage ___”, ____ g

1.5”

2-3g

end of 1st trimester ___”, ____ g

3”

45g

sucking/swallowing and unfelt movements begin

13-16 wk

uterine fundus @ umbilicus

20 wk

Lanugo

hair on skin

(20wk)

Vernix caseosa

cheesy stuff on baby

(20wk)

Quickening

mom feels bby moving

(20wk)

2nd trimester rapid _____

growth in length

3rd trimester rapid growth in ______

weight rather than length

24 wks: ____ lb _____ oz or ______ g

1lb

10 oz

780g

Surfactant

slippery liquid fluid allows gas exchange

(24wks)

age of viability

24 wks

fetal breathing movements begin

24 wks

25-29 wks _____ lbs ___ oz

2 lbs

10 oz

beginning of CNS control of resp, body temp

25-29 wks

30-34 wks: ___ lbs

> 4lbs

35-38 wks: _____ lbs

6lbs

by 38 weeks, L/S ratio:

and

ratio 2:1

lung maturity

39-40.6 wks:

lbs and “

full term:

>7 lbs; 20”

heart beating by

4 weeks

heart visible on ultrasound by

6 weeks

heart audible w electronic fetoscope by

8-12 weeks

heart audible w conventional fetoscope or stethoscope by

16-20 wks

umbilical vein/arteries cut at

birth

_______ diverts blood from liver

ductus venosus

_______ diverts blood from lungs

ductus arteriosis

Foramen ovale

opening between atrium that allows blood flow from right atrium → left atrium