FETAL DEVELOPMENT Flashcards
When do centers of ossification appear?
12 wks
When do skin and nails develop?
12 weeks
When are fingers and toes differentiated?
12 weeks
When do eye movements begin?
16 weeks
When does midbrain maturation begin?
16 weeks
When do eyes open?
26 weeks
When does subcutaneous fat deposit?
36 weeks
When does vernix caseosa form over skin?.
28 weeks
When does vaginal canalization begin?
16 weeks
When does testes descend?
20 weeks
When does canalicular development complete?
24 weeks
When is the fetal liver and spleen the sites of hematopoiesis
28 weeks
When does type ii pneumocytes begin to secrete surfactant?
24 weeks
When does downy lanugo cover the body?
20 weeks
When does fetal uterus form?
16 weeks
When do fingers and toes differentiate?
12 weeks
When is the bone marrow the major site of hematopoeisis?
28 weeks
What significant fetal changes occur during 36 weeks?
Subcutaneous fat deposition
Body becomes rotund
Face becomes fuller
What significant fetal changes occur during 28 weeks?
Vernix caseosa
Bone marrow for hematopoiesis
What significant fetal changes occur during 24 weeks?
Skin wrinkles, fat deposits begin
Head enlarged
Canaliculra kung devt nearly complete
Surfactant begins
When does brown fat form?
20 weeks
What significant fetal changes occur during 20 weeks?
Testes descends
Brown fat forms
Downy lanugo
What significant fetal changes occur during 16 weeks?
Eye movement
Midbrain maturation
Uterus
Vaginal canalization
What significant fetal changes occur during 12 weeks?
Centers of ossification
Skin and nails
Fingers and toes
What significant fetal changes occur during 4-5 weeks?
Ureteric bud from mesonephric duct will become the kidney
What significant fetal changes occur during 7 weeks?
Cloaca divides into rectum and urogenital sinus
What are the three parts of the urogenital sinus
Cephalad (vesicle): bladder
Middle (pelvic): urethra
Caudal (phallic): lower vagina, batholins and paraurethral glands
What significant fetal sex changes occur during 10th week?
Uterus is formed by union of mullerian ducts in the middle
What significant fetal sex changes occur during 16th week?
Primordial follicle begin to form which contain oogonia
What significant fetal sex changes occur during 20th week?
Final uterine cavity formed
Vaginal canalization is complete (begins at 16 weeks)
Three fetal shunts
Ductus venosus
Foramen ovale
Ductus arteriosus
What are the 3 umbilical vessels
AVA
2 arteries
1 vein
Trace flow of blood from placenta
Oxygenated - Umbilical vein - Portal v (liver) - Ductus vein (IVC) Mixed blood - IVC - Right atrium - foramen ovale - left atrium - left ventricle - aorta - common iliac (2) - hypogastric a (2) - umbilical a (2)
Functional closure
Ductus arteriosus
10-12 hours
Functional closure
Foramen ovale
Few mins
Functional closure
Ligamentum venosum
10-96hours
Closure
Ligamentum teres
3-4 days
Closure of umbilical ligament
3-4 days
Anatomic closure
Ductus arteriosis
2-3 weeks
Anatomic closure
Foramen ovale
1 yr
Anatomic closure
Ligamentum venosum
2-3 weeks
Fetal lung development Pseudoglandular stage (1st): growth of intrasegmental bronchial tree
5-17 weeks
When can chest wall movements be detected sonographically?
11 weeks
Fetal lung development
Canicular lung development is nearly complete by
24 weeks
Type II pneumocytes begin to secrete surfactant by
24 weeks
Terminal sac stage (3rd) by?
25 weeks
Which stage of fetal lung development involves growth of intrasegmental bronchial tree?
A. 1st - Pseudoglandular stage
B. 2nd - canalicular stage
C. 3rd - terminal sac stage
A. Pseudoglandular stage (1) at 5-17 weeks
Which stage of fetal lung development involves alveoli giving rise to pulmonary alveoli and extracellular matrix development
A. 1st - Pseudoglandular stage
B. 2nd - canalicular stage
C. 3rd - terminal sac stage
C. Terminal sac stage (3) at >25 wks
Which stage of fetal lung development involves bronchial cartilage plates extending peripherally (terminal bronchiole > several respiratory bronchioles > multiple saccular ducts)?
A. 1st - Pseudoglandular stage
B. 2nd - canalicular stage
C. 3rd - terminal sac stage
B. Canalicular stage (2) at 16-25 weeks
When does fetus begin to engage in respiratory movement?
16 weeks
Source of amniotic fluid in early pregnancy
Maternal plasma as ultrafiltrate
Source of amniotic fluid in 2nd trimester pregnancy
ECF diffused through fetal skin
Source of amniotic fluid at over 20 weeks
Fetal urine
Removal and regulation of amniotic fluid
Fetal swallowing
Fetal aspiration
Exchange through skin and fetal membranes
Severe oligohydramnios mechanism
Renal agenesis
Bladder obstruction
Causes of polyhydramnios
Esophageal atresia
Pulmonary hypoplasia
Skin has no pores *rare
Causes nephrotoxicity and ototoxicity in oreterms
Aminoglycosides
Gentamycin or streptomycin
Gray baby syndrome
Chloramphenicol
Is chloramphenicol teratogenic?
No
If used in 1st tri, causes hypoplastic left heart syndrome, microphthalmia, anophthalmia, clefts and ASD
Nitrofurantoin
If used in 1st tri, causes anencephaly, left ventricular outflow tract obstruction, choanal atresia, diaphragmatic hernia
Sulfonamides
If used over 25 weeks AOG, causes yellowish brown discoloration of deciduous teeth
Tetracycline
Causes cleft
Corticosteroids
Miscarriage and ear defecte
Mycophenolic acid
hypoplastic T shaped uterine cavity,
Cervical collars,
Breast cancer
Diethylstilbestrol
Embryopathy (6th to 9th week)
Warfarin
Clover-leaf skull
Methotrexate
Wide nasal bridge Lowset ears Micronathia Limb abnormalities Skull abnormalities
Methotrexat
Irreversible hypothyroidism
Radioiodine
Fetal growth and behavioral abnormalities
Lead
Epididymal cysts, hypospadia, cryptorchidism
Diethylstilbestrol
Disturbances in neuronal cell division and migration
Mercury
Sources of mercury
Shark, swordfish, king mackerel, tilefish, albacore tuna
Most potent teratogen
Isotretinoin
Amount of retinol that can cause defects
> 10000 mIU/day
Neonatal behavioral syndrome (drug that causes it)
SSRI/SNRI
Fluoxetine
Sertraline
Citalopram
Neonatal behavior syndrome (characteristifs)
Jittery, irritable Hyper or hypotonia Feeding abnormalities Vomiting Hypoglycemia Thermoregulatory instability Respiratory abnormalities
ASD and VSD
Paroxetine (SSRI)
Ebstein anomaly
Lithium
Condition with apical displacement of tricuspid valve
Ebstein anomaly
Near delivery exposure causes Hypothyroidism Diabetes insipidus Cardiomegaly Bradycardia Ecg abno Cyanosis Hypotonia
Lithium
Risk of thyroid cancer
Radioiodine
Causes childhood developmental delay, microcephaly and severe brain damage
Mercury
Fetal renal damage
ACEi
NTDs
Antiseizures
Valproate ate the folate
Fetal hydantoin syndrome
Phenytoin
Stippling of vertebrae, nasal hypoplasia
Choanal atresia
Warfarin
Abnormal EP muscle movements
Antipsychotics (not a teratogen) Haloperidol Chlorpromazine Fluphenazine Clozapine Olanzapine Risperidone
Neonatal hypoglycemia
Oral hypoglycemic agents
Neonatal dependence
Barbiturates
Clear cell adenoCA (vagina)
diethylstilbestrol
Craniofacial abnormalities
Isotretinoin
Congenital hypothyroidism
Iodide
Fetal alcohol syndrome
Ethanol
Warfarin in 1st tri
Chondrodysplasia
Warfarin in 2nd tri
CNS abno
Warfarin in 3rd tri
Bleeding diathesis
Mobius sequence
Misoprostol
Withdrawal Agitation Abno muscle tone Tremor Sleepiness Feeding difficulty Respiratory abno
Antipsychotics (not a teratogen) Haloperidol Chlorpromazine Fluphenazine Clozapine Olanzapine Risperidone
Tetracycline
Yellow teeth
Cutis laxa
Penicillamine
Phocomelia
Thalidomide
Smoking
IUGR
Streptomycin
Ototoxicity
Aplasia cutis congenita
Methimazole
Kernicterus
Sulfonamides
Cartilage damage
Fluoroquinolone
Trisomy 21
Down
Trisomy 18
Edward
Trisomy 13
Patau
45 XO
Turner
47 XXY
Klinefelter
Microdelete
Cri du chat
Most common non lethal trisomy
Downs
Strawberry shaped cranium
Edward
Abnormal laryngeal development
Cri du chat
Most common sex chromosome abnormality
Klinefelter
Holoprosencephaly
Patau
Only monosomy compatible with life
Turner syndrome
