fetal growth and development Flashcards
1
Q
role of the placenta
A
secretion of peptides
steroid secretion
helps protect the fetus from rejection
2
Q
gestational age
A
dated from the last day of LMP
precedes conception (occurs 2 weeks later)
3
Q
Nagle’s rule
A
+7 days to the LMP date, - 3 months = EDD
4
Q
how many woman deliver on their due date
A
Only 4% of women deliver on their due date
37 weeks -42 weeks
more of a window
5
Q
changes in the placenta over time
A
stops doing gas exchange as well
becomes more calcified
6
Q
first trimester is how many weeks from conception
sxs of 1st trimester improve around
A
first trimester 1
10 weeks from conception
fatigue
nausea
low energy
improves by 12 weeks
7
Q
Fertilization
A
Formation of zygote (fusion of female and male pronuclei)
8
Q
Division of zygote into ____ cells, then 12 cell ______
A
Division of zygote into blastomere cells, then 12 cell morula
9
Q
formation of a blastocyst leads to the..
A
Trophoblastic cell secretes hCG to maintain corpus luteum, which secretes estrogen/progesterone to prevent menstruation
10
Q
implantation occurs at the day___ of the cycle and at this location
A
upper endometrial epithelium
day 8 or 9
can have light bleeding
11
Q
on the 5th day of fertilization the morula becomes a
A
blastocyst
12
Q
implantation and development
A
Embryonic laminar develop, start of amniotic cavity and yolk sac, the primitive respiratory/digestive system
b. 2 flat layers of cells
c. The first of 3 germ layers
13
Q
embryonic period begins at the ____ week of gestation
A
week three
14
Q
3 germ layers
A
- Ectoderm
- Mesoderm
- Endoderm
15
Q
ectoderm develops into
A
- Skin of ext genitalia
- Lower 1/3 of anal canal
- Nervous system primitive streak->neural tube
16
Q
Epithelium of gonads, ureters, reproductive duct develops from
A
• Mesoderm
17
Q
•Lower 1/3 of anal canal develops from
A
ectoderm d
18
Q
Most muscle tissue, all connective tissue develops from
A
• Mesoderm
19
Q
GI tract, epithelium develops from
A
• Endoderm
20
Q
Urinary bladder, anorectal canal develops from
A
• Endoderm
21
Q
Skin of ext genitalia develops from
A
• Ectoderm
22
Q
Nervous system primitive streak->neural tube develops from
A
• Ectoderm
23
Q
Lymph tissue, spleen, blood cells develops from
A
• Mesoderm
24
Q
Dermis of skin, teeth (except enamel) develops from
A
• Mesoderm
25
Epithelium of gonads, ureters, reproductive ducts develops from
• Mesoderm
26
CR length 4mm at ___ weeks gestation
v. 4 weeks gestation
27
4 weeks gestation 4 developmental milestones
2. Heart starts beating, neural folds fusing
3. Disc becomes cylindrical
4. Buds of arms, ears, legs and facial/neck structures
5. Otic pits form
28
Brain development, head large relative to truck
week fiver
29
Neck, eyelids, genital tubercle (not differentiated yet)
Week seven
30
Nose, mouth and palate, CR=1cm
week six
31
Distinctly human form by
week seven
32
primitive mouth seen at
week five
33
, fetal period begins at
characterized by
week 8
Has or male female characteristics
34
by end of first trimester, fetus
can make respiratory movements, urinate, swallow, move limbs, squint and frown and open mouth
Beginnings of all structures present
35
13-15 week land marks
rapid fetal growth, nails, limb movements, scalp hair pattern, head erect, eyes in position on face
36
CRL at 16-18 weeks
CRL 4.5-6 inches,
37
rapid fetal growth, nails, limb movements, scalp hair pattern, head erect, eyes in position on face
• 13-15 weeks
38
fetus heart sounds
20-25 weeks
39
vernix caseosa
• 16-18 weeks
40
lanugo, eyebrows, hair
20-25 weeks
41
testes beginning to descend
• 16-18 weeks
42
can hear sounds at
20-25 weeks
43
typical weight at 20-24weeks
600g
24 weeks in viability here
44
lungs secrete surfactant
22-24 weeks
45
Blink/startle responses
22-24 weeks
46
REM sleep begins at
20-25 weeks
47
demands of the pregnancy are highest during ___ and result in
3rd trimester
we see gestational DM here
48
eyelashes, descent of testes
• 26-29 weeks
49
26-29 weeks weight and length
weight 1050g, 37cm
50
26-29 weeks we see lung development and survival here
lungs capable of breathing but surfactant low, survival 90% at 28 weeks.
51
30-34 weeks development
pupils respond to light, skin smooth and pink. 1700g at 32 weeks
52
35-38 weeks last things to develop
fetus orients to light, and has a firm grasp. 36 weeks – lungs mature, skin loses wrinkled appearance,
53
head and abdomen circumference around 35-38 weeks
head/abdomen circumferences equal, fetus start to get “plump”
54
BPD stands for
bi parietal diameter
usually in newborns at term BPD 9.5 cm (hence the need for cervical dilation to 10 cm)
55
normal growth is dependent on
genetically predetermined
modulation by
the health of the fetus, placenta and
mother
56
first 16 weeks growth is mainly
Cellular hyperplasia (first 16 weeks)
57
weeks 16-32 growth looks like
Concomitant hyperplasia and hypertrophy (weeks 16-32)
58
32 weeks to term growth looks like
Cellular hypertrophy
59
7 factors that directly influence growth
1. Poverty
2. Maternal age
3. Substances – drugs, EtoH, nicotine
4. Maternal nutrition
5. Disease
6. Psychological effects on pregnancy
7. Environmental toxins
60
how can you determin
• Using hx, LMP, early US
(CRL more accurate than gestational sac diameter, yolk sac visible at 5 weeks
61
Cardiac activity establishes GA of _____
Cardiac activity establishes GA of 5.5-6 weeks
62
how do we measure fetal growth
• Head circumference, femur length, abd circumference
63
naval height of fundus
20 weeks
grows about a cm a week
64
after 20 weeks ow do we monitor growth
* Monitor weight gain
* Measure uterine size/fundal height at each visit
* Serial US as needed
65
reasons for the size being bigger than the date
Inaccurate dating
Large for gestational age (LGA)
Multiple gestation
Polyhydramnios – too much amniotic fluid
Molar pregnancy (1st tri)
Uterine anomaly (fibroid)
Congenital anomaly
66
if the size is smaller than the date (6)
Inaccurate dating
Intrauterine growth restriction (IUGR)
Oligohydramnios – not enough amniotic fluid
Congenital anomaly
Chronic maternal disease
Viral infection- think TORCH
67
Birth weight >90th percentile
over 4000g (8lbs 13oz)
ACOG suggests >4500g
68
Macrosomia
grades 1-3
(birth weight >4000g)
this usually means a edematous
69
incidence of macrosomia
iii. Incidence – about 7% American babies (2008)
70
RF for macrosomia
1. Mothers who were LGA/obese/excessive wt gain
2. GDM
3. Postdates
4. H/o large babies/previous macrosomic infant
5. Male sex
6. Race (Hispanic/African American)
7. Genetic abnormalities/syndromes (Beckwith-Wiedermann)
71
CPD complications
Cephalopelvic disproportion (CPD)
Labor dystocia/prolonged labor
Shoulder dystocia, birth injuries
Maternal soft tissue damage/lacerations
Increased C/S
72
LGA complications other than CPD
2. Postpartum hemorrhage
3. Stillbirth, esp with grade 3 macrosomia (5000g)
4. Neonatal complications
73
Neonatal complication
a. Low Apgar, need for mechanical ventilation, RDS
b. Hypoglycemia, perinatal asphyxia
c. Hematologic abnormalities/polycythemia
74
prenatal management of LGA
1. Screen for GDM if not already done
2. US to r/o polyhydramnios, molar pregnancy, fibroids
3. Serial US to monitor growth
4. Anticipate cephalopelvic disproportion (CPD) and sequelae
5. Anticipate shoulder dystocia
6. Anticipate postpartum hemorrhage
7. Offer delivery at 38 wks if possible macrosomia
8. Offer elective C/S
9. Alert peds at delivery
75
PROGNOSIS of LGA
1. Risk of subsequent LGA baby
2. Increased risk of diabetes eventually in child
3. Neonatal complications and sequelae
4. Increased risk of obesity, insulin resistance, hyperlipidemia, CV disease? in child
76
IUGR
| what is it and why is it significant
Intrauterine Growth Restriction/FGR (Fetal Growth Restriction)
i. Impaired or restricted intrauterine growth
ii. Significant because there is an inverse relationship between fetal/neonatal weight percentile and perinatal mortality
77
how os SGA different
SGA is
Neonatal diagnosis of size below the 10th percentile
Usually genetic or due to inadequate nutrition
Baby that is around a 1000g has much less risk of mortality
78
IUGR RF
* Poor nutrition/weight gain
* Vascular disease/HTN
* Renal disease
* Infection
* Genetic abnormality
* Multiple gestation
* Placental problems • Pregestational diabetic
* Drug use/smoking/EtoH
* Hypoxemia/anemia
* Late onset prenatal care
* Low SES
* Prothrombotic disorders
* ART (in vitro)
79
types of IUGR and which is more serious, which is more common
symmetric and asymmetrical
symmetric is more serious but less common
80
picture os symmetric IUGR
20-25% . of IUGR
1. Compromised growth in length, head circumference and weight
2. More likely to have permanent neuro sequelae
3. Often d/t TORCH infections
4. D/t Chromosomal abnormalities
5. Substance abuse
81
asymmetrical IUGR picture
MORE COMMON b/c head size is preserved but body can be small
1. Decreased length and weight, but normal head circumference aka head-sparing (lack of fat, normal growth first 2 trimesters)
a. D/t reduction in nutrients
2. HTN, malnutrition, Pre-eclampsia
82
complications with IUGR
1. Increased risk fetal distress
2. Meconium staining
3. Increased perinatal morbidity and mortality
83
complications specifically with meconium staining
a. When baby is stressed, they let go of their bowel
| b. The sticky bowel doesn’t let the lung inflate and causes respiratory distress
84
maternal causes of IUGR
Poor weight gain, anemia, drugs/EtoH, smoking, HTN, GD, celiac disease, poor nutrition
a. Mom should be gaining about 1 lb per week
85
Uteroplacental causes of IUGR
Pre-eclampsia, multiple gestation/Twin to twin transfusion syndrome, uterine malformations,
```
placental insufficiency (abruption life threatening)
anemia
SSD
toxins
single uterine atery
```
86
fetal etiology of IUGR
vertically transmitted infections, chromosomal abnormalities
87
DX IUGR
1. Careful menstrual/medical/OB hx
2. Accurate dating/early ultrasound
3. Monitor for adequate weight gain
4. Carefully evaluate fundal height changes
5. 2 U/S 4 wks apart to confirm
88
Carefully evaluate fundal height changes involves
what is suspiciously slow growth look like
a. Watch for “progressive” growth
b <2cm in 4 wks is suspicious
c. If possible, single, consistent examiner
89
ULS tracking of IUGR
a. Esp head and abdominal circumference
| b. AFI check to r/o oligohydramnios (not enough fluid)
90
oligohydramnios causes
most fluid is from the fetal kidneys
renal issues can cause low fluid levels
91
management of IUGR in mom
1. Limit activity/bed rest so that the mom is not using extra calories and it can go to the baby for growth
2. Nutrition
3. Cessation of smoking
4. Fetal surveillance
5. Delivery of compromised fetus
92
Fetal surveillance looks like
a. Repeat U/S q 4-6 wks
b. Non Stress Tests (NST) weekly – monitor of fetal well being
c. Biophysical Profiles (BPP) prn
d. Amniocentesis for lung maturity if felt induction is necessary
93
etiology of birth defects
Unknown causes (65-75%)
Genetic
1. Single gene disorders (15-20%)
2. Chromosomal abnormalities (5%)
Environmental exposures (10%)
94
Single gene disorders
1. Autosomal dominant/recessive, X-linked
95
vi. Non-Mendelian patterns of inheritance
1. Unstable DNA, fragile X syndrome, imprinting, mitochondrial inheritance, etc.
96
all or none period
First two weeks after conception known as
97
Organogenesis occurs at
this period is important because
menstrual weeks 5-10
tissues are differentiating, susceptible to teratogenic effects
98
Pregestational diabetes causes increase in
2-3 fold increase in congenital anomalies (esp heart disease, spina bifida)
1. Abnormal fetal growth
2. Newborn hypoglycemia
3. Stillbirth
99
complications of mom with PKU
1. Microcephaly, MR, congenital heart disease
100
Androgen producing tumors in mother
Virilization of female fetuses
101
SLE can lead to
SLE – fetal, not maternal heart block
| Treatment of mother does not always reduce effects on fetus
102
influenza in mother can lead to
– 2nd trimester assoc. w/cleft lip, NTD, congenital heart defects, hydrocephaly
103
Infections (TORCH) can cause malformations/congenital infections, disability and deat
1. Toxoplasmosis
2. Other (syphilis and parvovirus)
3. Rubella
4. Cytomegalovirus (CMV)
5. Herpes/varicella
104
slap cheek disease caused by the
parvovirus
105
hutchinson's teeth
syphilis
106
saddle nose, short maxilla, protuberant mandible.
syphilis
107
Non specific sonographic signs suggestive of fetal infection seen on ULS (6)
1. Microcephaly
2. Cerebral or hepatic calcifications
3. IUGR
4. HSM
5. Cardiac malformations, limb hypoplasia, hydrocephalus
6. Hydrops
108
hydrops fetalis
hydrops fetalis refers to abnormal fluid collections in fetal soft tissues and serous cavities.
109
common teratogenic Rx
ACE inhibitors, chloramphenicol, warfarin/anticoags, DES, toluene, iodides, lithium, accutane/iso-retinoin, tetracycline, thalidomide, valproate, lead, rubella vaccine, anticonvulsants, antineoplastics
SSRIs
ibuprofen, ASA, sulfa drugs at term, trimethoprim
110
fetal BAL reach maternal levels within
Fetal BAL approach maternal levels within two hours of maternal intake
Elimination relies on maternal metabolic capacity, which varies – this explains why similar amounts of EtoH result in wildly varying phenotypic presentations in infants
111
4 classification for pregnancy
evidence of CNS impairment
growth deficiency
typical features
hx of alcohol exposure in prengnacy
112
]The most important modifiable risk factor associated with adverse outcomes
tobacco
113
cessation could prevent
a. 10% of perinatal deaths
b. 35% of low birth weight infants
c. 15% of preterm deliveries
114
Pathophysiology for tobacco
a. Impaired fetal oxygen delivery
b. Carbon monoxide exposure
c. Direct damage to fetal genetic material, genetic susceptibility varies
d. Direct toxicity form more than 2500 substances found in cigarettes, up to 100,000 compounds in tobacco smoke!
e. Directly impairs lung development
f. Sympathetic activation leads to accelerated heart rate/ reduction in fetal breathing movement
115
Adverse effects of tobacco use in pregnancy
a. Infertility (maternal)
b. Low birth weight (LBW) <2500g
c. Miscarriage
d. Stillbirth, including from second hand smoke
e. Preterm premature rupture of membranes
f. Placental abruption/previa
g. Preterm delivery (1.3-2.5 times more likely)
h. Congenital malformations, likely
i. Postnatal morbidity
j. Preeclampsia
k. Decreased milk volume production, postnatal morbidities (SIDS, respiratory infections, asthma, atopy…)
l. ?Long term implications for offspring: DMII, reduced sperm concentration, dyslipidemia, cancer
116
5 A's
Ask, Advise, Assess, Assist, Arrange
117
Pharmacotherapy
women who are otherwise unable to quit or heavy smokers (>10day) – In this population, the benefits of quitting with pharmacotherapy outweigh the potential risks of pharmacotherapy and continued smoking.
