Fetal Growth & Development Flashcards
1
Q
Gestational Age
A
- from first day of LMP
- Precedes conception (happens 2wks later)
- approx. 280days/10lunar months/40wks
2
Q
Naegel’s Rule
A
LMP + 7days - 3months + 1year = EDD
3
Q
First 2 Weeks
A
- ovulation
- fertilization (12cell morula)
- Blastocyst (fluid filled sphere)
- Trophoblastic cell secretes HcG to maintain corpus luteum
- Corpus luteum secretes estrogen/progesterone to prevent menstruation - Implantation
- 2 flat layers of cells ——> First 3 germ layers
- Amniotic cavity, yolk sac & primitive Resp/GI system forms
4
Q
First thing that secretes HcG
A
Trophoblastic cell
5
Q
Day #5
A
Early blastocyst w/ ICM
6
Q
When does implantation of the blastocyst occur?
A
Day 8-9
7
Q
Embryonic Period = 3rd week
A
- All major internal/external structures established
- First missed day of period (Day#15)
- Trilaminar disc w/ 3 germ layers
- Ectoderm, Mesoderm & Endoderm
8
Q
What does the Etcoderm form?
A
- skin of ext genitalia
- Lower 1/3 of anal canal
- Nervous system primitive streak—-> Neural tube (spinal cord)
9
Q
Endoderm
A
- GI tract, epithelium
- bladder
- anorectal canal
- male/female urethra
- Vaginal epithelium/vestibule
- prostate gland
10
Q
Mesoderm
A
- gonads, ureters, reproductive ducts
- most muscle tissue & all connective tissue
- lymph tissue, spleen, blood cells
- Dermis of skin & teeth (except enamel=ectoderm)
11
Q
4weeks gestation
A
Heart starts beating Neural folds fuse into spinal cord Arm, Ears, & leg Buds form Facial & neck structures Otic pits = eye CR length 4mm
12
Q
Week 5
A
Brain development
Primitive mouth
13
Q
Week 6
A
Nose, mouth, palate
CR = 1cm (doubled)
14
Q
Week 7
A
Distinctly human form
But genital tubercle not formed yet = not a boy or girl
15
Q
Week 8
A
End of embryonic period & Beginning of Fetal period
—Boy or girl
-
16
Q
When can the fetus make respiratory Mets, urinate, swallow, move limbs, squint/frown & open mouth?
A
8 weeks
17
Q
What happens during week 13-15?
A
Rapid fetal growth
- nails/scalp hair pattern
18
Q
When does
- brown fat form
- skeleton ossifies
- vernix caseosa cover the skin
- uterus/primordial follicles
- testes descend
A
16-18wks
19
Q
When?
- lanugo
- fetus can hear sound
- REM
A
20-25wks
20
Q
When can fetus blink/startle
- Lungs secrete surfactant?
A
22-24wks
21
Q
When is Viability?
A
End of 24th week
22
Q
When do lungs mature?
A
Third trimester: 36 wks
23
Q
What are the 3 phases of normal growth?
A
- Cellular hyperplasia - first 16wks
- concomitant hyperplasia & hypertrophy - wks 16-32
- Cellular hypertrophy - 32wks-term
24
Q
Factors influencing growth rate
A
- poverty
- maternal age
- substances: drugs, EtoH, Nicotine
- Maternal nutrition
- Disease
- Psychological effects on pregnancy
- environmental toxins (metals/meds)
25
Cardiac activity establishes a GA of?
5.5-6wks
26
How to evaluate fetal growth after 20wks
- monitor weight gain
- measure uterine size/fundal ht @ each visit
- serial U/S
27
Ways to establish GA
- hx, LMP, early U/S, CRL
- cardiac activity
- head & ABD circumference
- femur length
28
Fundal height of navel
20wks
29
What can cause Size being larger than Date?
- Inaccurate dating
- Large for gestational age (LGA)
- Multiple gestation
- Polyhydraminos (too much fluid)
- Molar pregnancy
- Uterine anomaly (fibroid)
- Congenital anomaly (hydrocephalus)
30
What could explain Dates> Size?
- Intrauterine growth restriction
- Oligohydraminos (not enough fluid)
- Congenital anomaly
- Chronic maternal disease
- Viral Infection
- Inaccurate dating
31
LGA
Birth weight >90th percentile
>4000g or8lbs.13oz
Macrosomia grades 1-3
32
Which infants are at greatest risk of Perinatal morbidity/mortality?
LGA
33
What are the risk factors for LGA baby?
1. Moms who were LGA/obese/excessive wt gain
2. GDM
3. Post dates
4. h/o Large babies/previous macroscopic baby
5. Male sex
6. African American/Hispanic
7. Genetic ABNLs/syndromes
Beckwith-Wiedemann
34
LGA complications
1. Cephalopelvic disproportion (CPD)
2. Postpartum Hemorrhage
3. Stillbirth esp w/ grade 3 macrosomia
4. Neonatal complications
35
CPD = cephalopelvic disproportion
- labor/shoulder dystocia
- prolonged labor
- birth injuries
- Maternal soft tissue damage/lacerations
- Increased risk of C-section
36
What are neonatal LGA complications ?
- low APGAR score
- Hypoglycemia
- perinatal asphyxia
- Heme problems, polycythemia
- need mechanical ventilation
- respiratory distress syndrome (RDS)
37
Prenatal Mgt for LGA moms
- Screen for GDM
- US to r/o polyhydramnios/molar preg/fibroids
- Serial US to monitor growth
- Anticipate CPD & postpartum hemorrhage
- Offer delivery at 38wks if macrosomia
- Offer elective C/S
- Alert peds at delivery
38
Prognosis of LGA mom/baby
- increased risk of DM in kids
- risk of more LGA babies
- increased risk of obesity, insulin resistance, Hyperlipidemia, CV dz in kid
39
IUGR
Intrauterine growth restriction
Fetal growth restriction
Baby below 10th percentile
Usually caused by genetics or lack of nutrition
NOT SGA- small for gestational age
- Twin to twin transfer syndrome
40
IUGR Risk Factors
1. Poor nutrition/wt gains
2. Vascular dz/HTN
3. Renal dz
4. Infxn
5. Multiple gestation
6. Placental problems
7. Pregestational DM
8. Drugs/EtoH
9. Hypoxemia/Anemia
10. Late prenatal care
11. Low SES
12. ART
13. Prothrombin disorders (protein S, C, Factor V Leiden)
14. Genetic ABNL
41
Symmetrical IUGR = Global growth restriction
25%
Growth restricted in
- length, head circumference & weight
Caused by Torch Infxns, chromosomal ABLs or substance abuse
- higher risk of Permanent Neuro sequalae
42
Asymmetrical IUGR
70% of cases
* Decreased length & Weight BUT normal Head (Head sparing)
- Lack of fat
- Caused by HTN, Pre-eclampsia, Malnutrition
Normal growth in first 2 trimesters
43
Complications of IUGR
- fetal demise
- Meconium staining
- Perinatal morbidity/mortality
44
Causes of IUGR
1. Maternal
- Anemia
- Drugs/alcohol/smoking
- malnutrition/poor wt gain
- HTN
- GDM
- Celiac dz
2. Uteroplacental
- pre-eclampsia
- multiple gestation
- TTS: tein to twin transfer syndrome
- uterine malformations
- placental insufficiency
3. Fetal
- vertically transmitted infxns
- chromosomal ABNLS
45
IUGR Diagnosis
<2cm in 4wks = Suspicious (Should be 4cm)
2 US 4wks apart to confirm
- head & ABD circumference
AFI check to r//o Oligohydraminos
46
IUGR Management
1. Bed rest, limit activity
2. Nutrition
3. Stop smoking
4. Fetal surveillance
- repeat U/S every 4-6wks
- NST weekly
- BPP PRN
- Amniocentesis for lung maturity
5. Delivery the baby
47
Substrate deprivation/Uteroplacental insufficiency
Variable/asymmetric growth pattern
Normal anatomy
Low amniotic fluid
Fetal lung maturity testing
BPP score decreases
UAV shows vascular resistance
BPP & UAV
48
Fetus w/ structural and/or chromosomal ABNL or fetal infxn
Growth pattern markedly Below normal/symmetric
Anatomy usually ABNL
Hydramnios (too much fluid). Decrease w/ renal agenesis or urethral obstruction
Test for viral DNA/karyotype
BPP variable/normal UAV
49
Birth defects
- of medical, surgical or cosmetic
```
genetic & environmental factors
Maternal age >35yo
Illness
Drug use
Physical features of uterine involvement
```
50
Major congenital malformations
1. Skull
2. Eyes
3. Ears
4. Mouth/throat
5. Neck
6. Chest
7. Back
8. Abdomen
9. Genitalia
10. Extremities
- Hands & feet
11. Cardiovascular & great vessels
51
Birth Defect Etiology
65-75% unknown causes
Genetic
- single gene disorders-15-20% = mitochondrial/autosomal rec/dom
- chromosomal ABNLs -5%
Environmental disorders-10%
- maternal illness
- substance use
- infxn
- Drugs
- chemicals
- radiation
- Hyperthermia (fever)
- mechanical/physical constraints
52
Genetic disorders
>90% don’t survive to term, very early preg loss
Fragile X: long face big ears
Klinefelters
Trisomy 18/21
53
All or none period
Not susceptible to teratogens
First 2 wks after conception
54
Organogenesis (menstrual weeks 5-10)
Tissues differentiating
| Susceptible to teratogens
55
When is the fetus susceptible to teratogens?
Menstrual weeks 5-10
56
Which factors of teratogens influence effect on fetus?
Timing of exposure, dose & duration
57
Pregestational Diabetes
2-3 fold increase in congenital anomalies
*Esp Heart dz & spina bifida
- ABNL fetal growth
- newborn hypoglycemia
- still birth
58
Phenylketonuria
- microcephalic, MR, congenital heart dz
59
Androgen producing tumor
Virilization of girls
60
Autoimmune disease
SLE- fetal heart block
To of mom doesn’t always reduce effect on baby
61
Influenza
Cleft lip assoc w/ 2nd trimester
Congenital heart defects
Hydrocephalus
NTD
62
TORCH Infxns
Toxoplasmosis
Other-Syphilis & Parvovirus (slap cheek)
Rubella
CMV
Herpes/varicella (direct exposure at time of delivery
63
Toxoplasmosis
Syphilis
Rubella
1. Intracranial calcification
2. Hutchison teeth & Snuffles
3. Blueberry muffin baby
64
Non-specific signs on US that suggest fetal infection
- microcephaly
- cerebral or hepatic calcification
- IUGR
- HSM
- cardiac malformations, limb hypoplasia, hydrocephalus
- hydrops
65
Examples of Teratogens
- ionizing radiation
- SSRIs
- Ibuprofen, ASA, sulfa drugs at term, trimethoprim (bactrim)
- EtoH, tobacco, recreational drugs
- others: ACEI, iodine’s, lithium, accutane/isoretinoin, tetracycline, thalidomide, valproate, lead, rubella vaccine, anticonvulsants, antineoplastics
66
Factors that increase risk of fetal alcohol syndrome (FASD)
- maternal age
- high parity
- AA or Native American
- Genetics
67
FASD Exposure risk factors
- low SES
- smoking
- unmarried
- unemployed
- illicit drugs
- h/o sexual/physical abuse
- h/o incarceration
- fam member who drinks heavily
- Socially transient
- Psych stress/mental health disorder
68
FASD spectrum
- no effect/normal
- FAE, fetal alcohol effects
- ARBD, alcohol related birth defects
- FAS, fetal alcohol syndrome
69
Physical features of FASD
small eye opening
Smooth philtrum
Thin upper lip
70
The most important modifiable risk factor assoc with adverse outcomes
Smoking
71
Smoking
Directly impairs lung dev
Increased HR
Reduction of fetal breathing
ABNL gas exchange via placenta
72
Adverse effects of tobacco use
- infertility
- Low birth weight <2500g
- miscarriage
- stillbirth even 2nd hand smoke
- preterm premature rupture of membranes
- placental abruption/previa
- Preterm delivery
- Congenital malformations
- postnatal morbidity
- preeclampsia
- decreased milk production, postnatal morbidities
——> long term complications for baby: DMII, reduced sperm concentration, dyslipidemia, cancer
73
Smoking cessation in pregnancy
Ask, Advise, Assess, Assist, Arrange
Pharmacotherapy - lowest dose necessary—> NOT in first trimester (organogenesis)
CBT, hypnotherapy, acupuncture
Nicotine replacement: Wellbutrin
- Category C but benefits outweighs risks
74
Sxs of high risk chemical abuse
| Opiates
Late to prenatal care
Multiple missed appts
Impaired school/work performance
Past OB h/o SAB, IUGR, premature birth, placental abruption, stillbrth, precipitous delivery
Children w/neuro-dev problems
H/o drug ETOH problems
75
Opiate OB complications
Pre-eclampsia
Placental abruption
Premature labor/delivery
Placental insuff
3rd trimester bleeding
Malpresentation
Non reassuring fetal status
Meconium passage
Low birth weight
Perinatal mortality
Puerperal morbidity
76
OPiate Neonatal outcomes
Premature birth
Neonatal opiate withdrawal
Postnatal growth deficiency
Microcephaly
Neurobehavioral deficits - tremors, high pitched cry, excessive suck, hyper alertness, irritability
SIDS
77
Cocaine
Readily crosses the placenta
Vasoconstriction = major mechanism of fetal & placental damage
Shows up in baby pee 2days after delivery, Meconium positive for 3days, hair-months
78
Methamphetamine
- neurotoxic agent: damages brain cells w/ dopamine
| - SGA
79
Mgt of pregnant substance abuser
Screen for ETOH & drugs
Counsel about risks
Use behavioral therapy & pharmacotherapy
Assemble a team
Test for STIs
Schedule freq visits
Get an early US to confirm GA & get a baseline for growth
Begi antepartum fetal surveillance
Inform peds -may be withdrawal
No breastfeeding
Address incarceration, homelessness & malnutrition
Educate about nutrition & wt gain
Referrals- transportation, prenatal MVI, shelters, food assistance
Consult Anesthesia for pain mgt
