Obstetrics Flashcards
(139 cards)
1
Q
What is gravity?
A
Number of times a woman has been pregnant
2
Q
What is parity
A
Number of pregnancies that led to a birth at or beyond 20 weeks
3
Q
What is considered term?
A
Born after 37 weeks
4
Q
What is considered preterm?
A
Born after 20 weeks but before 37 weeks
5
Q
What is abortion?
A
All pregnancy losses prior to 20 weeks
6
Q
What is living?
A
Any infant who lives beyond 30 days of life
7
Q
Define nulligravida
A
A woman who is not pregnant and has never been pregnant
8
Q
Define primigravida
A
A woman who currently is pregnant and has never been pregnant before
9
Q
Define multigravida
A
A woman who currently is pregnant and who has been pregnant before
10
Q
Define primipara
A
A woman who has delivered only once of a fetus or fetuses born alive or dead with an estimated length of gestation >20 weeks
11
Q
Define multipara
A
A woman who has completed 2 or more pregnancies to 20 weeks gestation or more
12
Q
What is considered the first trimester?
A
Until 14 weeks gestation
13
Q
What is considered the second trimester?
A
From 15 weeks until 28 weeks
14
Q
What is considered the 3rd trimester?
A
From 29 weeks until 42 weeks
15
Q
What is the goal of pre-conceptional care?
A
- Identify and modify biomedical, behavioral, and social risks to woman’s health or pregnancy outcome throuhg prevention and management
16
Q
What percentage of all pregnancies are unplanned?
A
Up to half
17
Q
What are symptoms of pregnancy?
A
- Amenorrhea (not reliable until 10 days after expected menses)
- Breast tenderness and paresthesias
- Maternal perception of fetal movement (20 weeks primigravida or 16-18 weeks multigravida)
18
Q
What are signs of pregnancy?
A
- Chadwick sign
- Cervical softening
- Change in cervical mucus due to progesterone
- Uterine isthmus softening –> hegar sign
- Increase in breast size and nipple size
- Breasts produce colostrum
- Areola becomes more deeply pigmented
- Increased pigmentation and visual changes in abdominal striae
19
Q
What are tests for pregnancy?
A
- BhCG
- Ultrasound
20
Q
What is bhCG?
A
- heterodimer with similar subunit to LH, FSH, and TSH
- Produced by syncytiotrophoblasts after implantation
- Detected in blood and urine approx 8-9 days after ovulation
- Prevents involution of corpus luteum (supports pregnancy)
21
Q
What are causes of false positive b hCG?
A
- Circulating serum factors ie heterophilic antibodies bind to hCG, urine would be negative still
- Exogenous hCG injection for weight loss
- Renal failure with impaired hCG clearance
- Physiological pituitary hCG
- hCG producing tumors of GI tract, ovary, bladder, or lung
22
Q
How should the bhCG value change over the course of early pregnancy?
A
Should double every 1.4-2 days
23
Q
What is seen on a transvaginal ultrasound?
A
- Gestational sac –> anechoic fluid collection within endometrial cavity
- Yolk sac –> echogenic ring with anechoic center
- Fetal pole/embryo after 6 weeks
- Crown rump length –> head to butt at 6-12 weeks
24
Q
What is the first sonographic evidence of pregnancy seen around 4-5 weeks gestation?
A
Gestational sac
25
Why would it be reassuring to see a yolk sac?
Confirms intrauterine location
26
When is yolk sac first seen? Fetal pole/embryo?
Yolk sac: 5-6 weeks
Fetal pole/embryo: after 6 weeks
27
When would you measure crown rump length?
6-12 weeks
Used up to 12 weeks to predict due date
Accurate within 4 days
28
What are ways that you can estimate date of delivery?
* Naegele's rule
* Ultrasound (first trimester crown rump length)
## Footnote
Crown rump length is most accurate tool for gestational age assessment
29
What is Naegele's rule?
LMP + 7 days - 3 months = EDD
Assumes pregnancy to have begun 2 weeks before ovulation
30
What are components of the initial prenatal visit?
* History and physical
* Lab testing
* Patient education
* Routine care
31
What are important historical components of the initial prenatal visit?
* Obstetrical history: prior pregnancies (C section or vaginal), prior complications, infertility
* Menstrual history: interval between menses, contraceptive use
* Psychosocial history: depression/anxiety, violence/abuse, tobacco/alcohol/drugs
32
What are components of the initial prenatal physical exam?
* General physical --> heart, lungs, etc
Pelvic exam
* Speculum exam: pap smear (if >21) and chlamydia and gonorrhea testing
* Bimanual exam: uterine size, cervical dilation, length, consistency, and bony pelvic architecture
33
What size uterus is a small orange? Large orange? Grapefruit?
* 6 weeks
* 8 weeks
* 12 weeks
34
What lab testing is done at the first prenatal visit?
* CBC
* Blood type and Rh factor
* Antibody screening
* Pap smear
* Urine protein and culture
* Rubella serology
* Syphilis serology
* Gonococcal screening
* Chlamydial screening
* Hepatitis B and C serology
* HIV serology
* Varicella serology- if needed
* Hgba1c
35
What are you assessing on the prenatal CBC?
* WBC, hemoglobin, hematocrit, platelet count
* Monitor anemia, thrombocytopenia
36
What are you looking for with Rh status?
* Lacking Rh or D antigen
37
If a mom is lacking Rh or D antigen, what would you do?
* Give RhoGAM at 28 weeks to prevent Rh alloimmunization
* Give RhoGAM if vaginal bleeding in trauma prior to this time
* Give postpartum if infant is Rh positive
38
What is Kleihauer Betke?
* Tests amount of fetal red blood cells in maternal circulation
* Can test if trauma or abruption and administer additional RhoGAM
39
Why is rubella important to screen for in pregnancy?
* Cause of fetal growth restriction
* Infection in 1st trimester can cause abortion and severe congenital malformations
* Fetal effects: eye defects, congenital heart defects, sensorineural deafness, CNS defects (microcephaly, developmental delay, mental retardation), hepatosplenomegaly and jaundice, pigmentary retinopathy
40
How is rubella diagnosed?
Serology
41
How do you treat/prevent rubella?
* Treatment: no specific treatment
* Prevention with MMR vaccine for non-pregnant women of childbearing age, avoid 1 month before or during pregnancy (live virus)
42
What does maternal syphilis lead to?
* Preterm labor
* Fetal death
* Fetal growth restriction
* Neonatal infection
43
How is syphilis diagnosed?
* Venereal Disease Research Laboratory (VLDR)
* Rapid Plasma Reagin
44
What is the treatment for syphilis?
* Penicillin G
* Women with allergy should have oral penicillin dose challenge or skin testing and penicillin desensitization if confirmed allergy
45
What counseling should be provided to patients prenatal regarding vitamins, occupation, and weight?
* Prenatal vitamin with 400 ug of folic acid
* Can work until onset of labor, depending on type of work (some increase pregnancy complications)
* Weight gain of 1 lb/week in 2nd/3rd trimester if normal weight or underweight and .6 lb/week if overweight, .5 lb/week if obese
46
What are risks of obesity during pregnancy?
* Gestational hypertension
* Preeclampsia
* Gestational diabetes
* Macrosomia- big babies hard to deliver
* Cesarean delivery
47
How much weight gain in obese women has the lowest rate of complications?
Less than 15 lbs
48
What is counseling regarding diet to provide to patients prenatally?
* Require additional 100-300 kcal per day
* avoid fish and shellfish
* Definitely avoid shark, swordfish, king mackerel, tile fish (high mercury levels)
* No more than 6 oz albacore or white tuna in a day
49
When would you do lead testing prenatal?
If risk factor identified
* Recent immigrant
* Living near lead source
* Using lead glazed pottery
* Eating non-food substances (pica)
* Using imported cosmetics
* Remodeling home with lead hazards
* Consuming lead contaminated drinking water
* Living with someone identified with an elevated lead level
50
How should a patient wear a seat belt while pregnant?
* Place lap belt under abdomen and across upper thighs
51
How should a patient be counseled prenatal on air travel? Dental treatment? Sexual intercourse?
* Air travel: can safely fly up to 35 weeks but should ambulate hourly or consider wearing TED hos
* Dental treatment: can still receive dental treatment and dental radiographs
* Sexual intercourse: usually not harmful. If threatened abortion, placenta previa, or preterm labor should be avoided
52
How should a patient be counciled prenatally on caffeine?
* Heavy intake (>5 cups of coffee) increases abortion risk
* Moderate consumption of caffeine (less than 200 mg per day/10 oz coffee) does not seem to be associated with miscarriage or preterm birth
53
What are guidelines for exercise during pregnancy?
* Healthy pregnant women do not need to limit
* Do not recommend if significant health issues or obstetric complications
* Encourage regular, moderate intensity physical activity for 30 mins a day
* Avoid activities with high risk of falling or abdominal trauma
* Avoid scuba diving due to decompression sickness
54
What is recommended regarding smoking during pregnancy?
Quit smoking
Person to person counseling is most successful
1. Ask about tobacco use
2. Advise to quit
3. Assess willingness to quit
4. Assist in quit attempt
5. Arrange follow up
55
Who is most likely to drink while pregnant?
* White
* 35-44 yo
* College graduates
* Employed
56
Why should you abstain from alcohol during pregnancy?
* Fetal alcohol yndrome
* Growth restriction
* Facial abnormalities
* CNS dysfunction
57
What are recommendations regarding breast feeding?
* Exclusive breast feeding preferred until 6 months (most term newborns feed 8-12 times daily for 15 mins at a time
58
What are breastfeeding benefits?
* Decreased childhood infections, such as diarrhea and ear infections, which results in decreased parental absenteeism from work
* Decreased rates of childhood obesity in children who were breastfed
* Decreased necrotizing enterocolitis
* Decreased risk of SIDS
* Increaesd bonding between mother and infant
* Decreased hypertension, hyperlipidemia, type 2 diabetes, and cardiovascular disease
* Decreased ovarian and breast cancer in women
* Improved return to prepregnancy weight
* Improved birth spacing
59
What are contraindications to breastfeeding?
* Use of street drugs or uncontrolled alcohol intake
* infant with galactosemia
* HIV
* Hepatitis C with cracked nipples or broken skin
* Active tuberculosis
* Certain medications
* Women undergoing breast cancer treatment
* Active herpes lesions on breast
60
What ethnic groups have high risks of selected genetic disorders that may need to be screened for prenatally?
* African american --> sickle cell
* Mediterranean --> beta thalassemia
* Asian --> alpha thalassemia
* Jewish --> Tay Sachs, canavan disease, cystic fibrosis
* North european caucasians --> cystic fibrosis
* Native americans --> cystic fibrosis
61
What should be provided to every pregnant woman and ideally performed before pregnancy?
* Carrier screening
* If individual found to be carrier, reproductive partner offered testing
* Obtain family history of patient
62
How are medications rated for pregnancy?
Pregnancy and Lactation Labeling Rule
63
After the initial prenatal visit, how often are subsequent prenatal visits?
Every 4 weeks until 28 weeks
Every 2 weeks until 36 weeks
Every week until delivery
64
What are high risk medical histories for pregnancy?
* Cardiac disease
* Diabetes mellitus with end organ damage or uncontrolled hyperglycemia
* Personal or family genetic abnormalities
* Hemoglobinopathy
* Chronic hypertension if uncontrolled or renal/cardiac disease
* Renal insufficiency
* Pulmonary disease if severe restrictive or obstructive
* HIV
* Prior PE or DVT
* Severe systemic disease
* Bariatric surgery
* Epilepsy if poorly controlled
* Cancer
65
What are high risk obstetrical history considerations?
* Allomimmunization
* Prior or current fetal or structural abnormality
* Periconceptional exposure to known teratogens
* Infection
* Higher order multifetal gestation
* Severe disorders of amnionic fluid volume
66
What is done at each prenatal return visit?
* Fetal heart rate by doppler US at 10 weeks
* Fetal growth
* Maternal BP and weight
* Symptoms: leakage of fluid, contractions, nausea and vomiting, pelvic pain, bleeding
* Lab tests
67
What is the fetal heart rate range?
110-160
68
How is fetal growth measured?
* Fundal height
* 12 weeks: emerging from bony pelvis
* 16 weeks: between pubic symphysis and umbilicus
* 20 weeks: at umbilicus
* 20-34 weeks: uterine fundus measured in cm correlates with gestational age (ie 25 weeks 25 cm)
Can also do dating ultrasound and anatomy ultrasound is performed around 18 weeks for all organ systems
69
What lab tests are performed during return visits?
* Fetal aneuploidy screening
* Gestational diabetes: 24-28 weeks, 1st trimester if family history or risk factors, 1 hour glucola testing
* CBC: repeat around 28 weeks and monitor for anemia
* Syphilis, HIV: repeat around 28 weeks in high risk pop
* Rh testing/antibody testing: if patient Rh negative repeat at 28-29 weeks and if negative give RhoGAM
* Group B streptococcal
70
When is group B cultured and prophylaxis given?
* Vaginal/anal culture at 35-37 weeks
* Antibiotic prophylaxis in labor if culture positive
71
What are recommended vaccines during pregnancy?
* Hepatitis A or B: given to women at risk of exposure
* Flu vaccine: given at any point in pregnancy (pregnant women can die from flu if not vaccinated!)
* Tetanus, diptheria, and pertussis: given in 3rd trimester to pass immunity
72
What are common complaints during pregnancy?
* Nausea and vomiting
* Backache
* Hemorrhoids
* Varicosities
* Heartburn
* Pica
* Sleeping and fatigue
* Leukorrhea
73
When is nausea and vomiting most common?
1st trimester, lasts on average 35 days
74
What is treatment for nausea and vomiting in pregnancy?
* Eating small meals
* BRAT diet
* Ginger
* Vitamin B6 with or without doxylamine
* Prochlorperazine, metoclopramide, ondansetron
75
Vomiting so severe that dehydration, electrolyte and acid-base disturbances and starvation ketosis occur. Severe enough to produce weight loss
Hyperemesis gravidarum
76
When is backache more common in pregnancy?
With gestational age
More prevalent in obese women and those with history of back pain
77
How can backache during pregnancy be reduced?
* Squat rather than bend down
* Avoid high heels
* Use pillow back support when sitting
* Belly band
* Physical therapy
* Can try tylenol or muscle relaxants when needed
78
What causes hemorrhoids during pregnancy?
* Increase in pelvic venous pressure
79
What is treatment for hemorrhoids during pregnancy?
* Topical applied anesthetics
* Warm soaks
* Stool softeners
80
What can result from increased femoral venous pressures?
Varcosities
81
How are varicosities treated?
* Periodic rest with leg elevation
* Elastic stockings
82
Why does heartburn occur in pregnancy?
* Gastric content reflux in lower esophagus
* Upward displacement and compression of stomach by uterus and relaxation of lower esophageal sphincter
83
What are treatments for heartburn in pregnancy?
* Antacids --> aluminum hydroxide, magnesium hydroxide
* H2 blockers
* PPIs
84
What is pica associated with?
Severe iron deficiency
85
Why does sleeping and fatigue increase during pregnancy and what can you do?
* Increase in amount of sleep needed due to progesterone and discomfort
* Sleep efficiency decreases with gestational age
* Treatment: benadryl and daytime naps
86
What is leukorrhea?
Increase in vaginal discharge due to increased mucus secretion by cervical glands in response to increase in estrogen
87
All women before 20 weeks should be offered screening for what?
Congenital abnormalities
88
Science of identifying malformations, disruptions, chromosomal abnormalities, and other genetic syndromes in fetus
Prenatal diagnosis
89
The risk of what condition increases with maternal age, particularly after 35
Trisomy
90
What neural tube defects can occur?
Anencephaly
SPina bifida
Cephalocele
Rare spinal fusion abnormalities
91
What are neural tube defects associated with?
* Elevated levels of alpha-fetoprotein in maternal and fetal serum and amniotic fluid
92
What are risk factors for neural tube defects?
* Family history
* MTHFR mutation
* Aneuploidy
* Diabetes
* Hyperthermia
* Meidcations --> specifically seizure medications
93
How are neural tube defects screened for?
* Screen maternal serum AFP between 15-18 weeks gestation
* Measured in multiple of median of unaffected population with >2.0-2.5 MoM indicative of neural tube defect
* Refer for additional screening and diagnostic test
* Second trimester fetal anatomy ultrasonography has higher detection rates
## Footnote
can have false positive, should refer for additional testing
94
What factors can impact AFP other than neural tube defects?
* Multifetall gestation
* Pilonidal cyst
* Chorioangioma of placenta
* Placental abruption
* Oligohydramnios
* Preeclampsia
* Fetal growth restriction
95
What are ACOG recommendations for genetic screening and diagnostic testing for down syndrome and other aneuploidies?
* Discuss and offer to all pregnant women regardless of maternal age or risk of chromosomal abnormalities
* Each patient can then pursue or decline
96
What should you do for women with family or personal history of aneuploidy?
Refer to genetic counseling
97
How is down syndrome and other aneuploidies screened in first trimester?
* 11-14 weeks- combined first screen
* Nuchal translucency and serum analytes to detect down syndrome
98
What is nuchal translucency?
* Maximum thickness of the subcutaneous translucent area between the skin and soft tissue overlying the fetal spine at the back of the neck
99
What should be done if nuchal translucency >3.5 mm?
Patinet offered targeted sonography with or without fetal echocardiography and fetal karyotyping
100
What happens to serum analytes in down syndrome? Trisomy 18?
* hCG elevated and PAPP-A decreased with down syndrome
* Trisomy 18 and 13: both hCG and PAPP-A decreased
101
What screening for down syndrome and other aneuploidies is done in the second trimester?
* Triple test
* Mostly used if patients present for prenatal care later
* Evaluates hCG, AFP, and unconjugated estriol
* Quad screen: evaluates hCG, AFP, unconjugated estriol, and inhibin --> used more often
## Footnote
Quad screen has higher down syndrome detection of 80%
102
What happens to hCG, AFP, and unconjugated estriol on triple test in down syndrome and trisomy 18? What happens on quad screen in down syndrome?
* Down syndrome: lower AFP, lower estriol, higher hCG
* Trisomy 18: all 3 markers decreased
* (Quad): down syndrome: elevated inhibin
103
What is a combined first and second trimester screen?
* Enhance aneuploidy detection rates
* Combines first and second trimester tests
* Aneuploidy risk calculated from all parameters
104
What is a stepwise sequential?
* 1st trimester screen results with risk for Down syndrome offered invasive testing and remaining receive second trimester screening
105
What is sequential screening for down syndrome and aneuploidies?
* Women divided into risk groups (high, moderate, low) based on first trimester screen
* Highest risk offered invasive testing
* Moderate risk offered 2nd timester screening
* Low risk receive no further testing
106
All positive screens should be referred for what?
* Genetic counseling
* Definitive fetal chromosome analysis (CVS, amniocentesis)
* Cell free DNA
107
What ultrasound result can indicate high risk of fetal aneuploidy?
* Presence of two or more minor structural abnormalities or dysmorphisms in same fetus
108
What are major anomalies?
* Cystic hygroma
* Hydrocephalus
* Cardiac defects
* Omphalocele
* Diaphragmatic hernia
* Gastroschisis
* Bladder outlet obstruction
* Club foot
* Single umbilical artery
* Duodenal atresia
## Footnote
Indication for invasive testing
109
110
What are minor abnormalities on ultrasound?
* Nuchal fold >6 mm
* Pyectasis
* Hyperechogenic bowel
* Choroid plexus cyst
## Footnote
Should be followed up with genetic testing because at higher risk of genetic abnormality
111
What is cell free DNA?
* Test done at 9-10 weeks
* Fetal component of cell-free DNA from placental trophoblasts released into maternal circulation from cells undergoing programmed celld eath
* Most sensitive and specific screening test for common fetal aneuploidies
* Not equivalent to diagnostic testing
112
What invasive testing can be performed as a follow up on possible aneuploidy?
* Amniocentesis
* Chorionic villus sampling
* Fetal blood sampling
113
What is amniocentesis?
* Transabdominal withdrawal of amnionic fluid
* Most common procedure for diagnosis of fetal aneuploidy
* Performed typically between 15-20 weeks gestation
* 20 mL fluid collected for chromosomal analysis
## Footnote
can be performed for polyhydramnios for comfort
114
What are complications of amniocentesis?
* Pregnancy loss rate 1 per 300-500
* Amniotic fluid leakage
* Chorioamnionitis
* Needle injuries to fetus
115
What are indications for amniocentesis?
* Assess fetal karyotype
* Polyhydramnios (more than 25 mL fluid can cause contractions)
* Assessment of fetal anemia
* Fetal lung maturity (evaluate lecithin/sphingomyelin ratio)
## Footnote
Lecithin elevates after 32 weeks while sphingomyelin does not, if ratio >2 risk of respiratory distress is low
116
What is chorionic villus sampling?
* Biopsy of chorionic villi performed between 10-13 weeks gestation
* Indication: fetal karyotype assessment
* Primary advantage over amniocentesis is that can be done earlier allowing for earlier pregnancy termination if desired
* Can be transabdominal or transcervical
117
What are relative contraindications for chorionic villus sampling?
* Vaginal bleeding
* Active genital tract infection
* Extreme uterine ante-or retroflexion
* Body habitus precluding visualization
118
What are complications of chorionic villus sampling?
* Pregnancy loss (overall 2%)
* Limb-reduction defects: found to be associated with perfomance of CVS at 7 weeks gestation; 1/1000 if done at >10 weeks
* Vaginal spotting
* Infection
119
What is fetal blood sampling used for?
* Fetal transfusion of red blood cells
* Anemia MC
* Assessment and treatment of platelet alloimunization
* Fetal karyotype assessment
## Footnote
Performed near placental cord insertion site
120
121
What are complications of fetal blood sampling?
* Fetal loss rate about 1.4%
* Cord vessel bleeding
* Fetal-maternal bleeding
* Fetal bradycardia
122
What is the goal of antepartum fetal assessment?
* Identify fetuses at risk of intrauterine death or other complications of intrauterine asphyxia
* Intervene to prevent adverse outcomes if possible
* based on idea that fetus responds to hypoxemia in predictable manner
123
What are indications for antepartum fetal assessment?
* Pregnancies at high risk of antepartum fetal demise
124
What are methods for assessment of antepartum fetal assessment?
* Fetal movements
* NST
* BPP
* Doppler velocimetry
* AFI
125
What are examples of indications for antepartum fetal surveillance?
* Diabetes
* Hypertensive disorders
* Prior fetal demise
* Post term pregnancy
* Decreased fetal movement
* SLE
* Sickle cell
* Isoimmunization
* PPROM
* Oligohydramnios or polyhydramnios
126
What are recommendations for antepartum fetal surveillance?
* Begin testing around 32-34 weeks (those at greatest risk can begin at 26-28 weeks)
* Repeat testing every 7 days
127
How is fetal movement measured?
Maternal perception of fetal movement
Begin to feel around 20 weeks (primi) or 16-18 (multi)
* Begin counting around 28 weeks
* Should perceive 10 movements in up to 2 hours
* Patient should count fetal movement for 1 hour a day
* Report to hospital for fetal monitoring when abnormal
128
What factors affect fetal movement?
* Amniotic fluid --> decreased amniotic fluid decreased fetal activity
* fetus has sleep awake cycles (20-75 mins at a time)
* Gestational age (near term less space and activity may diminish)
129
What are expectations regarding a healthy fetal heart rate?
* Fetus >32 weeks, acceleration is 15 bpm change in baseline that lasts 15 sec or longer
* Fetus <32 weeks, acceleration is 10 bpm change in baseline that lasts 10 sec or longer
* Normal is 2 or more accelerations in 20 minute time span
130
What can cause a abnormal or nonreactive stress test and what should be done?
* Sleeping fetus --> apply acoustic stimulator on abdomen for 1-2 seconds, can repeat up to 3 times
* Should evaluate further with BPP if no acceleration
131
What are components of BPP?
Combines 5 fetal biophysical variables
* NST (>2 accelerations of >15 beats/min for >15 sec within 20 minutes)
* Fetal breathing (>1 episode of rhythmic breathing lasting 30 sec within 30 min)
* Fetal movement (>3 discrete body or limb movements within 30 minutes)
* Fetal tone (>1 episode extremity extension and return to flexion)
* Amniotic fluid volume (pocket of fluid at least 2 cm)
## Footnote
Score of 0 for abnormal variables and 2 for normal variables
132
What is the interpretation of BPP?
* 10 --> normal, non-asphyxiated fetus
* 8 --> normal, non-asphyxiated fetus; if 8/20 for abnormal AFI, deliver
* 6 --> possible fetal asphyxia, repeat within 24 hrs and if normal fluid at 36 weeks, deliver and if repeat test <6 deliver
* 4 --> probably fetal asphyxia, repeat or deliver
* 2--> deliver, most likely fetal asphyxia
133
What is a modified BPP?
* COmbination of just AFI and NST
* Requires less time than BPP
134
Blood flow velocity measured by Doppler ultrasound reflects downstream impedance
Doppler velocimetry
135
What vascular circuits are evlauated by doppler velocimetry?
* Umbilical artery
* Middle cerebral artery
* Ductus venosus
136
What makes abnormal umbilical artery velocimetry?
* S/D ratio >95th percentile for gestational age
* Absent or reversed end diastolic flow signifies increased impedance to umbilical artery blood flow
137
When is umbilical artery velocimetry indicated?
fetal growth restriction
138
What are indications for middle cerebral artery velocimetry?
* intrauterine growth restriction
* isoimmunization
* fetal anemia
139
