Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Obstetrics > Fetal Growth and Development > Flashcards

Fetal Growth and Development Flashcards

1
Q

gestational age

A
  • Dated from first day of last menstrual period (LMP)
    • Precedes conception, which occurs approx 2 weeks later
  • Gestation takes approx 280 days or 10 “lunar” months or 40 weeks
    • Can quickly estimate using Nagle’s rule: +7 days to the LMP date, - 3 months = EDD
    • Only 4% of women deliver on their due date
  • Divided for convenience into trimesters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

first trimester

A
  • The first 12 weeks from LMP (roughly 10 wks from conception)
  • 4 weeks gestation
    • CR length 4mm
    • Heart starts beating, neural folds fusing
    • Disc becomes cylindrical
    • Buds of arms, ears, legs and facial/neck structures
    • Otic pits form
  • Week five
    • Brain development, head large relative to truck
    • Primitive mouth
  • Week six
    • Nose, mouth and palate, CR=1cm
  • Week seven
    • Neck, eyelids, genital tubercle (not differentiated yet
    • Distinctly human form
  • Week eight
    • End of embryonic period, fetal period begins
    • Has or male female characteristics
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the first 2 weeks

A
  • Ovulation
  • Fertilization
    • Formation of zygote (fusion of female and male pronuclei)
    • Division of zygote into blastomere cells, then 12 cell morula
  • Formation of blastocyst (fluid filled sphere)
    • Trophoblastic cell secretes hCG to maintain corpus luteum, which secretes estrogen/progesterone to prevent menstruation
  • Implantation – upper endometrial epithelium
    • Embryonic laminar develop, start of amniotic cavity and yolk sac, the primitive respiratory/digestive system
    • 2 flat layers of cells
    • The first of 3 germ layers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

embryonic period

A
  • Starts at third week – beginning of all major internal/external structures established
  • Day 15: first missed day of expected period
  • Trilaminar disc
    • 3 germ layers
  • Ectoderm
    • Skin of ext genitalia
    • Lower 1/3 of anal canal
    • Nervous system primitive streak->neural tube
  • Mesoderm
    • Epithelium of gonads, ureters, reproductive ducts
    • Most muscle tissue, all connective tissue
    • Lymph tissue, spleen, blood cells
    • Dermis of skin, teeth (except enamel)
  • Endoderm
    • GI tract, epithelium
    • Urinary bladder, anorectal canal
    • Male urethra, prostate gland
    • Female urethra, vaginal epithelium, vestibule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

second trimester

A
  • Weeks 13 through 27
  • 13-15 weeks: rapid fetal growth, nails, limb movements, scalp hair pattern, head erect, eyes in position on face
  • 20-25 weeks: lanugo, eyebrows, hair, fetus hears sounds, REM, substantial weight gain, by 25 weeks, lean but well proportioned fetus. Weight 600g at 24 weeks
  • 16-18 weeks: CRL 4.5-6 inches, skeleton ossifying, 200cc amniotic fluid, brown fat forms, vernix caseosa covers skin, uterus/primordial ovarian follicles, testes beginning to descend
  • 22-24 weeks: Blink/startle responses, lungs secrete surfactant
  • Viability is reached by end of 24th week with approx. 50% survival
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

third trimester

A
  • Weeks 28 through 40
  • 26-29 weeks: eyelashes, descent of testes, weight 1050g, 37cm, lungs capable of breathing but surfactant low, survival 90% at 28 weeks.
  • 30-34 weeks: pupils respond to light, skin smooth and pink. 1700g at 32 weeks
  • 35-38 weeks: fetus orients to light, and has a firm grasp. 36 weeks – lungs mature, skin loses wrinkled appearance, head/abdomen circumferences equal, fetus start to get “plump”
  • 40 weeks – “Term” fetus averages 50 cm and 3200-3500g. Chest is prominent, breast tissue protrudes slightly. BPD 9.5 cm (hence the need for cervical dilation to 10 cm) Full term considered 37-42 weeks.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

normal growth

A
  • Reflects the interaction of the fetus’ genetically predetermined growth potential and it’s modulation by the health of the fetus, placenta and mother
  • 3 phases
    • Cellular hyperplasia (first 16 weeks)
    • Concomitant hyperplasia and hypertrophy (weeks 16-32)
    • Cellular hypertrophy (32 weeks to term)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

factors influencing growth rate

A
  • Poverty
  • Maternal age
  • Substances – drugs, EtoH, nicotine
  • Maternal nutrition
  • Disease
  • Psychological effects on pregnancy
  • Environmental toxins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

evaluating fetal growth

A
  • Establish GA as early as possible
    • Using hx, LMP, early US (CRL more accurate than gestational sac diameter, yolk sac visible at 5 weeks)
    • Cardiac activity establishes GA of 5.5-6 weeks
    • Head circumference, femur length, abd circumference
    • Use of multiple markers for gestational age most accurate
    • Biometric images MOST useful for obtaining EDD in FIRST 20 weeks of pregnancy
    • After 20 weeks:
      • Monitor weight gain
      • Measure uterine size/fundal height at each visit
      • Serial US as needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

size-dates discrepancy

A
  • S>D
    • Inaccurate dating
    • Large for gestational age (LGA)
    • Multiple gestation
    • Polyhydramnios
    • Molar pregnancy (1st tri)
    • Uterine anomaly (fibroid)
    • Congenital anomaly
  • S<d>
    <li>Inaccurate dating</li>
    <li>Intrauterine growth restriction (IUGR)</li>
    <li>Oligohydramnios</li>
    <li>Congenital anomaly</li>
    <li>Chronic maternal disease</li>
    <li>Viral infection</li>
    </d>
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

large for gestational age (LGA)

A
  • Birth weight >90th percentile, over 4000g (8lbs 13oz) (usually above 97th percentile, reflecting infants with greatest risk of perinatal morbity/mortality. ACOG suggests >4500g
  • Macrosomia – grades 1-3 (birth weight >4000g)
  • Incidence – about 7% American babies (2008)
  • Risk factors
    • Mothers who were LGA/obese/excessive wt gain
    • GDM
    • Postdates
    • H/o large babies/previous macrosomic infant
    • Male sex
    • Race (Hispanic/African American)
    • Genetic abnormalities/syndromes (Beckwith-Wiedemann)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

LGA complications

A
  • Cephalopelvic disproportion (CPD)
    • Labor dystocia/prolonged labor
    • Shoulder dystocia, birth injuries
    • Maternal soft tissue damage/lacerations
    • Increased C/S
  • Postpartum hemorrhage
  • Stillbirth, esp with grade 3 macrosomia (5000g)
  • Neonatal complications
    • Low Apgar, need for mechanical ventilation, RDS
    • Hypoglycemia, perinatal asphyxia
    • Hematologic abnormalities/polycythemia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

prenatal managment and prognosis of LGA

A
  • Prenatal Management
    • Screen for GDM if not already done
    • US to r/o polyhydramnios, molar pregnancy, fibroids
    • Serial US to monitor growth
    • Anticipate cephalopelvic disproportion (CPD) and sequelae
    • Anticipate shoulder dystocia
    • Anticipate postpartum hemorrhage
    • Offer delivery at 38 wks if possible macrosomia
    • Offer elective C/S
    • Alert peds at delivery
  • Prognosis
    • Risk of subsequent LGA baby
    • Increased risk of diabetes eventually in child
    • Neonatal complications and sequelae
    • Increased risk of obesity, insulin resistance, hyperlipidemia, CV disease? in child
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

IUGR

A
  • Intrauterine Growth Restriction/FGR (Fetal Growth Restriction)
    • Impaired or restricted intrauterine growth
    • Significant because there is an inverse relationship between fetal/neonatal weight percentile and perinatal mortality
    • Not to be confused with small-for-gestational age (SGA)
      • Neonatal diagnosis of size below the 10th percentile
        • Usually genetic or due to inadequate nutrition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

IUGR risk factors

A
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

IUGR: symmetrical, asymmetrical, complications

A
  • Symmetrical (20-25%) “global growth restriction”
    • Compromised growth in length, head circumference and weight
    • More likely to have permanent neuro sequelae
    • TORCH infections
    • Chromosomal abnormalities
    • Substance abuse
  • Asymmetrical (70%)
    • Decreased length and weight, but normal head circumference aka head-sparing (lack of fat, normal growth first 2 trimesters)
    • HTN, malnutrition, Pre-eclampsia
  • Complications
    • Increased risk fetal distress
    • Meconium staining
    • Increased perinatal morbidity and mortality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

IUGR causes

A
  • Maternal: Poor weight gain, anemia, drugs/EtoH, smoking, HTN, GD, celiac disease, poor nutrition
  • Uteroplacental: Pre-eclampsia, multiple gestation/Twin to twin transfusion syndrome (TTTS), uterine malformations, placental insufficiency
  • Fetal: vertically transmitted infections, chromosomal abnormalities
18
Q

IUGR diagnosis and management

A
  • Diagnosis
  • Careful menstrual/medical/OB hx
  • Accurate dating/early ultrasound
  • Monitor for adequate weight gain
  • Carefully evaluate fundal height changes
    • Watch for “progressive” growth
    • <2cm in 4 wks is suspicious
    • If possible, single, consistent examiner
  • 2 U/S 4 wks apart to confirm
    • Esp head and abdominal circumference
    • AFI check to r/o oligohydramnios
  • Management
    • Limit activity/bed rest
    • Nutrition
    • Cessation of smoking
    • Fetal surveillance
      • Repeat U/S q 4-6 wks
      • Non Stress Tests (NST) weekly
      • Biophysical Profiles (BPP) prn
      • Amniocentesis for lung maturity
    • Delivery of compromised fetus
19
Q

birth defects/congenital malformations

A
  • A major birth defect is one of medical, surgical or cosmetic significance
    • Prevalence 2-4% among live born infants
    • May be isolated or multiple, major or minor
    • Genetic and environmental factors play a role
    • Maternal age
    • Illness
    • Drug use
    • Physical features of uterine environment
20
Q

etiology of birth defects

A
  • Unknown causes (65-75%)
  • Genetic
    • Single gene disorders (15-20%)
    • Chromosomal abnormalities (5%)
  • Environmental exposures (10%)
    • Maternal illness, substance use, infection, drugs, chemicals, radiation, hyperthermia, mechanical/physical constraints
21
Q

genetic disorders

A
  • >90% do not survive to term
  • Multiple organ systems tend to be involved
  • Longevity and fertility of these individuals tend to be reduced
  • Chromosomal Abnormalities
    • Affect 1 in 200 newborn infants
    • Nondisjunction, unequal recombination, inversions, deletions/duplications, translocations
  • Single gene disorders
    • Autosomal dominant/recessive, X-linked
  • Non-Mendelian patterns of inheritance
    • Unstable DNA, fragile X syndrome, imprinting, mitochondrial inheritance, etc.
22
Q

teratogens

A
  • Study of malformations - teratology
  • Genetic (single gene and chromosomal abnormality) 20%
  • Environmental factors 10%
  • Unknown 70%
  • Timing of exposure, dose and duration all influence effect on fetus
  • First two weeks after conception known as “all or none period”
  • Organogenesis (menstrual weeks 5-10) – tissues are differentiating, susceptible to teratogenic effects
  • causes:
    • Ionizing radiation
    • Other meds: ACE inhibitors, chloramphenicol, warfarin/
      • anticoags, DES, toluene, iodides, lithium, accutane/iso-retinoin, tetracycline, thalidomide, valproate, lead, rubella vaccine, anticonvulsants, antineoplastics
    • SSRIs
    • Avoid: ibuprofen, ASA, sulfa drugs at term, trimethoprim
    • Always check drug class
      • A, B, C usually OK, especially if benefit outweighs risk
    • EtoH, tobacco, recreational drugs
23
Q

maternal illness

A
  • Pregestational diabetes -2-3 fold increase in congenital anomalies (esp heart disease, spina bifida)
    • Abnormal fetal growth
    • Newborn hypoglycemia
    • Stillbirth
  • Phenylketonuria
    • Microcephaly, MR, congenital heart disease
  • Androgen producing tumors - Virilization of female fetuses
  • Autoimmune diseases - Same or different toxicity to fetus
    • SLE – fetal, not maternal heart block
    • Treatment of mother does not always reduce effects on fetus
  • Influenza – 2nd trimester assoc. w/cleft lip, NTD, congenital heart defects, hydrocephaly
24
Q

infectious teratogens

A
  • Infections (TORCH) can cause malformations/congenital infections, disability and death
    • Toxoplasmosis
    • Other (syphilis and parvovirus)
    • Rubella
    • Cytomegalovirus (CMV)
    • Herpes/varicella
25
Q

nonspecific sonographic signs suggestive of fetal infection

A
  • Microcephaly
  • Cerebral or hepatic calcifications
  • IUGR
  • HSM
  • Cardiac malformations, limb hypoplasia, hydrocephalus
  • Hydrops – edema of the baby
26
Q
A
27
Q

alcohol

A
  • 60% of women have at least 1 drink per year
  • Of those who drink 13% have more than 7 drinks per week
  • 7.6% of pregnant women in US use EtoH and 1.4% admit to binge drinking (2010 CDC)
  • Non pregnant women – 52% use EtoH, 15% admit to binging
  • NO AMOUNT OF ALCOHOL IS CONSIDERED SAFE IN PREGNANCY (US Surgeon General and Secretary HHS)
28
Q

alcohol use in pregnancy

A
  • There is no exact dose-response relationship between the amount of EtoH consumed during the perinatal period and the exact damage caused by EtoH to the infant
  • Binge drinking exerts a potentially greater negative effect than comparable consumption of EtoH over several days
  • Other factors that effect outcome and increase risk of fetal alcohol syndrome (FASD)
    • Maternal age
    • High parity
    • Being African-American or Native American
    • Genetics
  • EtoH freely crosses the placenta
  • 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
  • EtoH is a teratogen with the potential to cause deleterious effects at all stages of gestation, the most severe being fetal alcohol spectrum disorder (FASD) and stillbirth.
29
Q

exposure risk factors

A
  • The following increase the risk of FASD:
  • Low economic status
  • Smoking
  • Unmarried
  • Unemployed
  • Illicit drug use
  • H/o sexual or physical abuse
  • H/o incarceration
  • Family member who drinks heavily
  • Socially transient
  • Psychological stress/mental health disorder
30
Q

etoh effects on fetus

A
  • Fetal alcohol spectrum disorder (FASD) describes the broad range of adverse sequelae
    • No effect, normal
    • Fetal alcohol effects (FAE)
    • Alcohol related birth defects (ARBD)
    • Fetal alcohol syndrome (FAS)
31
Q

tobacco use in pregnancy

A
  • The most important modifiable risk factor associated with adverse outcomes
  • Estimated that cessation during pregnancy could prevent:
    • 10% of perinatal deaths
    • 35% of low birth weight infants
    • 15% of preterm deliveries
32
Q

pathophysiology of tobacco use in pregnancy

A
  • Impaired fetal oxygen delivery
    • Placentas of smokers show structural changes that may contribute to abnormal gas exchange
  • Carbon monoxide exposure
    • Carboxyhemoglobin clears slowly from fetal circulation and diminishes tissue oxygenation
  • Direct damage to fetal genetic material, genetic susceptibility varies
  • Direct toxicity form more than 2500 substances found in cigarettes, up to 100,000 compounds in tobacco smoke!
  • Directly impairs lung development
  • Sympathetic activation leads to accelerated heart rate/ reduction in fetal breathing movement
33
Q

adverse effects of tobacco use in pregnancy

A
  • Infertility (maternal)
  • Low birth weight (LBW) <2500g
  • Miscarriage
  • Stillbirth, including from second hand smoke
  • Preterm premature rupture of membranes
  • Placental abruption/previa
  • Preterm delivery (1.3-2.5 times more likely)
  • Congenital malformations, likely
  • Postnatal morbidity
  • Preeclampsia
  • Decreased milk volume production, postnatal morbidities (SIDS, respiratory infections, asthma, atopy…)
  • ?long term implications for offspring: DMII, reduced sperm concentration, dyslipidemia, cancer
34
Q

smoking cessation in pregnancy

A
  • Pregnancy provides a unique opportunity for medical intervention for smoking cessation because of the frequency of prenatal visits
  • The five As: Ask, Advise, Assess, Assist, Arrange
  • 800-QUIT-NOW, CBT, hypnotherapy, acupuncture
  • 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.
  • Lowest dose necessary, avoid in first trimester
  • Nicotine replacement therapy and bupropion (Cat C) are first line
35
Q

opiates

A
  • 50% of US women who use drugs are of childbearing age
  • 25% of these use heroin
  • Some exposure risks are same for pregnant and nonpregnant women
    • Infection, psychological stress, violence
36
Q

s/sx of high-risk chemical abuse

A
  • Late to prenatal care
  • Multiple missed appointments
  • Impaired school/work performance
  • Past OB h/o SAB, IUGR, premature birth, placental abruption, stillbirth, precipitous delivery
  • Children w/ neuro-developmental problems
  • H/o drug/EtoH problems
37
Q

obstetrical complications from opiate use in pregnancy

A
  • Preeclampsia
  • Placenta abruption
  • Premature labor/delivery
  • Placental insufficiency
  • Third trimester bleeding
  • Malpresentation
  • Nonreassuring fetal status
  • Meconium passage
  • Low birth weight
  • Perinatal mortality
  • Puerperal morbidity
38
Q

neonatal outcomes from opiate use

A
  • Premature birth
  • Neonatal opiate withdrawal
  • Postnatal growth deficiency
  • Microcephaly
  • Neurobehavioral deficits- tremors, high pitched cry, excess suck, hyper-alertness, irritability
  • SIDS
  • Post natal effects – difficult to ascertain long-term effects due to confounding variables (psychosocial factors, exposure to other drugs prenatally, prematurity, IUGR)
39
Q

cocaine use in pregnancy

A
  • Less women than men use the drug but numbers are growing
    • Especially with crack cocaine use
  • Effects related to dose and stage of pregnancy
    • Decreased birth weight, length and head circumference
    • Increased risk prematurity, placental abruption, SAB, fetal death
    • Readily crosses placenta
  • Major mechanism of fetal and placental damage is vasoconstriction
  • Teratogenic effects not definitely established
    • possibly intestinal atresia, brain anomalies
  • Cognitive development of children exposed in utero controversial
  • Maternal cocaine use tests positive in neonatal urine within 2 days of delivery and is excreted within 12-24 hrs
    • Meconium stays positive for 3 days and hair for months
40
Q

marijuana use in pregnancy

A
  • Most commonly used illicit substance taken during pregnancy
  • Impact unknown
    • Not significantly related to any growth measures at birth, prematurity or congenital anomalies
  • May be associated with EtoH and cigarette use
  • In a retrospective study of 417 mothers who reported ONLY marijuana use in pregnancy, there was no association between MJ use and prematurity or congenital anomalies
  • Heavy users had a trend toward a slight decrease in birth weight
41
Q

methamphetamine use during pregnancy

A
  • 10 million Americans have tried methamphetamine at some point in their lives
    • A neurotoxic agent that damages ending of brain cells containing dopamine
    • 3.5 times more likely to be SGA
    • No fetal structural abnormality has been associated definitively with perinatal amphetamine exposure
42
Q

management of pregnant substance user

A
  • Screen all pregnant women for EtoH and substance use
  • Counsel regarding risks of specific substance used
  • Use behavioral therapy and/or pharmacotherapy to treat addiction
  • Assemble a multidisciplinary team of providers (including social workers and peds) to comprehensively assess the patient and her baby
  • Test for STIs and treat
  • Schedule frequent visits to monitor maternal and fetal status
  • Obtain early US to confirm GA and establish accurate baseline for growth
  • Begin antepartum fetal surveillance if there is evidence of pregnancy complications
  • Inform peds of possibility of neonatal withdrawal
  • Discourage breastfeeding in women who continue to take illicit drugs
  • Address the needs of poorly nourished, homeless and or incarcerated pregnant substance abusers
  • Education about nutrition and weight gain
  • Referral to food assistance programs, shelters, vouchers for transportation, prenatal multivitamins
  • Consult anesthesia prior to delivery to develop pain management plan (opioid use assoc. with more pain sensitivity, may require higher doses, difficult venous access

Obstetrics (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions