Obstetrics: Prenatal Diagnosis and Care Flashcards
Number of times a woman has been pregnant
what is this term?
Gravity
Number of pregnancies that led to a birth at or beyond 20 weeks
parity
categories in parity
- T – Term: >37 weeks
- P – Preterm: 20-37 weeks
- A – Abortion: all losses before 20 wks
- L – Living: any infant who lives > 30 d of life
a woman who currently is not pregnant and never has ever been pregnant
Nulligravida
a woman who currently is pregnant and has never been pregnant before
Primigravida
a woman who currently is pregnant and who has been pregnant before
Multigravida
a woman who has been delivered only once of a fetus or fetuses born alive or dead with an estimate length of gestation of >20weeks
Primipara
a woman who has completed 2 or more pregnancies to 20 weeks gestation or more
Multipara
how long are the 3 trimesters
- 1st Trimester: until 14 weeks gestation
- 2nd Trimester: from 15 weeks until 28weeks
- 3rd Trimester: from 29 weeks until 42 weeks
A set of interventions that aim to identify and modify biomedical, behavioral and social risks to a woman’s health or pregnancy outcome through prevention and management
pre-conceptional care
Most women do not realize they are pregnant till how many weeks after their first missed period
1-2 weeks
One of the most frequently used health services in the United States
prenatal care
what is Amenorrhea?
Abrupt cessation of menses in a healthy reproductive aged woman with previously spontaneous, cyclical, predictable menses
Not a reliable indicator until >10 d after expected menses
amenorrhea can have “____” from blastocyst implantation
implantation bleeding
Vaginal mucosa appears dark-bluish
red and congested is called what sign?
Chadwick sign
s/s of pregnancy
- chadwick sign
- cervical softening
- cervical mucus
- Hegar sign
- Breast changes - tenderness, presthesias, increased breast and nipple size, colorstrum production, areola pigmentation
- skin changes - increased pigmentation and straie
- fetal movement
Isthmus softening is called what sign?
Hegar sign
skin changes such as increased pigmentation and visual changes in abdominal striae can also be seen in women who take what med?
OCP
- Primigravida may not feel fetal movement till ? weeks gestation
- Multigravida may feel around ? weeks gestation
20 wks
16-18 wks
what testings are available for a pregnancy dx?
- B-hCG
- US - transvaginal US
what hormones have a similar structure as B-hCG
LH, FSH and TSH
B-hCG can be detect how?
blood & urine
Detectable ~8-9 days after ovulation depending on test sensitivity
False positive B-hCG are rare, how can it happen?
- Some women have circulating serum factors that may bind erroneously to hCG in an assay
- MC factors are heterophilic antibodies - Other rare causes:
- Exogenous hCG injection for wt loss
- Renal failure with impaired hCG clearance
- Physiological pituitary hCG
- hCG producing tumors = GI tract, ovary, bladder or lung
a woman tested positive b-hCG, but her urine test came back negative, what does this indicate?
false positive
heterophilic antibodies that bind erroneously to hCG
B-hCG doubles when (days)?
1.4-2 days
for a home pregnancy test, when should you take the test?
first urination of the day
what is the Gestational sac
small anechoic fluid collection within endometrial cavity
Seen around 4-5 weeks gestation
FIRST sonographic evidence of pregnancy
Gestational sac
Confirms with certainty an intrauterine location
brightly echogenic ring with an anechoic center
Yolk sac
Seen around 5-6 weeks gestation
what fetal anatomy should be seen after 6 wks on transvaginal US?
Fetal Pole/Embryo
This is when you measure from head to butt at 6 to 12 weeks is when it shows up best
Can be used up to 12 weeks to predict estimate due date
Accurate within 4 days
crown rump length
how to estimate the date of delivery (EDD)>
- Naegele’s Rule - LMP + 7 days - 3 months = EDD
- Assumes pregnancy to have begun 2 wks before ovulation - US
- 1st trimester crown rump length is the most accurate tool for gestational age assignment
Components of Initial Prenatal Visit
- History and Physical
- Lab Testing
- Patient Education
- Routine Care (indications for high risk management)
hx components of the initial prenatal visit
-
Obstetrical history
* Prior pregnancies – vaginal or C-section
* Prior complications
* Infertility components -
Menstrual history
* Interval between menses
* Contraceptive use -
Psychosocial history
* Depression/Anxiety
* Violence/Abuse
* Tobacco/Alcohol/Drugs
PE of the inital prenatal visit
- General - Heart, Lungs, etc
- Pelvic exam
- Speculum exam - Pap Smear (if >21yo); Chlamydia and Gonorrhea testing
- Bimanual exam - Uterine size, Cervical dilation, length, consistency, Bony pelvic architecture
during a bimanual exam you determine the uterine size is about the size of a large orange, how far long is this pregnancy?
8 wks
small orange - 6 wks
grapefruit - 12 wks - uterus will start to come out of the bony pelvis
possible lab testings done during 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 Cserology
- HIV serology
- Varicella serology (Ig) – if needed
- Hgba1c
purpose of CBC for prenatal visit?
Assess WBC, hemoglobin, hematocrit, platelet count
Helps monitor: Anemia, Thrombocytopenia
when is RhoGAM given?
- Rh- mother in 28 wks
- if vaginal bleeding or trauma prior to this time
- RhoGAM should be given postpartum if infant is Rh positive
what tests the amount of fetal red blood cells in the maternal circulation
Kleihauer-Betke
In cases of trauma or abruption, can perform test and administer additional RhoGAM if necessary
Common infectious cause of fetal growth restriction
Infection in the 1st trimester can cause abortion and severe congenital malformations
Rubella
Rubella fetal effects:
- Eye defects
- Congenital heart defects
- Sensorineural deafness (MC single defect)
- CNS defects - Microcephaly, developmental delay, mental retardation
- Hepatosplenomegaly and Jaundice
- Pigmentary retinopathy
management for rubella
- no specific tx
- Primary prevention is key!
- MMR vaccine should be offered to non-pregnant women of childbearing age
- Should be avoided 1 mo before or during pregnancy (live virus)
how is syphilis dangerous for the fetus?
Can cause preterm labor, fetal death, fetal growth restriction, neonatal infection
how to dx syphilis
- Venereal Disease Resarch Laboratory (VDRL)
- Rapid Plasma Reagin (RPR)
tx for syphilis
- PCN G
- allergy: oral stepwise PCN dose challenge or skin testing performed
- If allergy confirmed, PCN desensitization is recommended
prenatal counseling recommendations about prenatal vitamins
- Increased requirement of vitamins during pregnancy
- Should provide 400 μg of folic acid
- If Hx of child with neural tube defect should take 4mg folic acid per day
employment recommendations during prenatal counseling
- Most women can work until the onset of labor
- Some types of work can increase pregnancy complications
- Ex: physically demanding work = waitress, nursing, etc
wt gain recommendations during prenatal counseling
pregnant women should gain less weight
Obesity associated with multiple risks:
- Gestational hypertension
- Preeclampsia
- Gestational diabetes
- Macrosomia – big babies are hard to deliver
- Cesarean delivery
during pregnancy you require an additional ? kcal per day
100-300kcal/day
seafood recommendations during prenatal counseling
- Most fish and shellfish contain mercury which should be avoided in pregnant and lactating women
- Fish with potentially high mercury levels:
* Shark
* Swordfish
* King mackerel
* Tile fish - Recommend ingesting no more than 6oz of albacore or “white tuna” in a day
Recommend blood lead testing if risk factor is 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
seat belt recommendations during prenatal counseling
- Recommend wearing three point restraints throughout pregnancy while riding in automobiles
- Place lap belt under abdomen and across upper thighs
air travel recommendations during prenatal counseling
- Pregnant women can safely fly up to 35 weeks gestation
- Should ambulate hourly or consider wearing TED hose
dental tx recommendations during prenatal counseling
Pregnancy is not a contraindication to dental treatment including dental radiographs
sexual interocourse recommendations during prenatal counseling
- Usually not harmful in healthy women
- If threatened abortion, placenta previa or preterm labor occurs, should be avoided
caffeine recommendations during prenatal counseling
- Heavy intake (>5 cups of coffee per day) can increase abortion risk
- Moderate consumption of caffeine (< 200mg/d) does not appear to be associated with miscarriage or preterm birth
- 200mg = approximately 10 oz of coffee
exercise recommendations during prenatal counseling
- In general, healthy pregnant women do not need to limit exercise - Should not recommend exercise with significant health issues or obstetric complications
- encourage regular, moderate intensity physical activity for >30 mim/d
- Avoid activities with high risk of falling or abdominal trauma
- AVOID scuba diving due to decompression sickness
smoking recommendations during prenatal counseling
Person-to-person counseling shown to be most successful in achieving smoking abstinence
Example: 5 A’s of smoking cessation
alcohol recommendations during prenatal counseling
Should abstain from alcohol while pregnant
Potent teratogen that causes a fetal syndrome characterized by growth restriction, facial abnormalities and CNS dysfunction
who is most likely to drink while pregnant?
white, 35-44yo, college graduates, employed
Women who ___ are less likely to obtain prenatal care and if they do will not admit to this social hx
use drugs
Exclusive breast feeding is preferred until when?
6 months
Breastfeeding Benefits
- Decreased rate of common 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 as infants
- Decreased rate of necrotizing enterocolitis
- Decreased risk of sudden infant death syndrome
- Increased bonding between mother and infant
- Decreased rates of hypertension, hyperlipidemia, type 2 diabetes mellitus, and cardiovascular disease among women
- Decreased rates of ovarian and breast cancer in women
- Improved return to prepregnancy weight
- Improved birth spacing
CI for 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 the breast
Ethnic groups with Hisk Risk of Selected Disorders:
- African Americans = Sickle Cell
- Mediterranean = Beta thalassemia
- Asian = Alpha Thalassemia
- Jewish = Tay Sachs, Canavan Disease, Cystic Fibrosis
- North European Caucasians = Cystic Fibrosis
- Native Americans = Cystic Fibrosis
carrier screening should be provided to who?
every pregnant woman
ideally should be performed before pregnancy.
If an individual is found to be a carrier for a specific condition, what is the next step?
Individual’s reproductive partner should be offered testing in order to receive informed genetic counseling about potential reproductive outcomes
T/F: Prenatal carrier screening does not replace newborn screening, nor does newborn screening replace the potential value of prenatal carrier screening.
T
what is the Pregnancy and Lactation Labeling Rule?
System that would minimize misinformation and would better assist physicians and their patients in making evidence-based clinical decisions
timeline of subsequent prenatal visits
- Every 4 weeks until 28 weeks
- Every 2 weeks until 36 weeks
- Every week until delivery
High risk medical hx factors
- 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
high risk obstetrical hx factors
- Allomimmunization
- Prior or current fetal or structural abnormality
- Periconceptional exposure to known teratogens
- Infection
- Higher order multifetal gestation
- Severe disorders of amnionic fluid volume
At each return visit you should inspect what?
- Fetal heart rate
- Fetal growth
- Maternal BP and weight
- Sx – Need to ask at every visit - Leakage of fluid, Contractions, N/V, Pelvic pain, Bleeding
fetal Hr can be detectable by when by doppler?
10 wks
110-160 bpm
what is used to monitor fetal grwoth and amniotic fluid volume?
fundal height
Between 20-34 weeks, the height of the uterine fundus measured in centimeters correlates closely with gestational age
a basic scan for all the organ systems to make sure they are healthy
Anatomy ultrasound (around 18 weeks)
subsequent lab testings done
- Fetal Aneuploidy Screening
- Gestational Diabetes Screening - 24-28 weeks; 1st trimeter is high-risk
- CBC - repeat 28 wks
- Syphilis, HIV - Repeat around 28 weeks for high risk population
- Rh testing/Antibody testing - if Rh-, Repeat at 28-29 weeks = if antibody negative, give RhoGam
- Group B Streptococcal Infection - Vaginal/anal culture obtained between 35-37 weeks; PCN for prophylaxis if +cx
recommended vaccinations for the mother
- Hep A or B - Can be given to women at risk of exposure
-
Flu
- at any point in pregnancy
- Pregnant moms can die from flu during the pregnancy if not vaccinated -
tdap
- 3rd trimester so mom can pass immunity to the baby
- more for pertussis
N/V is common in what trimester
1st
tx for N/V
- Eating small meals
- BRAT diet
- Ginger
- Vitamin B6 with or without Doxylamine (Diplegis?)
- Prochlorperazine, Metoclopramide, Odansetron
what is Hyperemesis gravidarum
- Vomiting so severe that dehydration, electrolyte and acid-base disturbances and starvation ketosis occur
- Severe enough to produce weight loss
RF for backache during pregnancy
- increases with gestational age
- obesity
- hx of back pain
tx for back pain
- Squatting rather than bending down
- Avoiding high heeled shoes
- Using a pillow back support when sitting
- Belly band
- Physical therapy
- Tylenol or muscle relaxants when needed
hemorrhoid happen d/t?
increase in pelvic venous pressure, rectal vein varicosities occur
tx for hemorrhoids
Topical applied anesthetics
Warm soaks
Stool softeners
why do varicosities happen?
Femoral venous pressures in the supine pregnant women increase from 8mmHg to 24mmHg at term
Can result in mild cosmetic blemished to severe discomfort
tx for varicosities
Periodic rest with leg elevation
Elastic stockings
one of the most MC GI complaints
heartburn
Due to gastric content reflux in lower esophagus - upward displacement and compression of the stomach by uterus as well as relaxation of the lower esophageal sphincter
tx for heartburn
- Antacids - aluminum hydroxide, magnesium hydroxide
- H2 Blockers
- Proton pump inhibitors
Pica is associated with what other condition?
iron def
cause and tx for sleeping and fatigue complaints
- Increase in amount of sleep needed - Likely due to progesterone and associated discomforts
- Sleep efficiency declines with gestational age
- Tx - Benadryl, Daytime naps
cause of leukorrhea
increase vaginal discharge
Due to increased mucus secretion by cervical glands in response to increase in estrogen
Typically not pathological
all women before ? wks gestation should be offered major congenital abnormality screening
20 wks
Risk of fetal trisomy increases with maternal age, particularly after what age?
35yo
Second most common class of birth defect after cardiac anomalies
Neural Tube Defects
Neural Tube Defects
- Anencephaly
- Spina bifida
- Cephalocele
- Rare spinal fusion abnormalities
neural tube defects are associated with elevated levels of ? in maternal and fetal serum and amniotic fluid
alpha-fetoprotein (AFP)
AFP synthesized by fetal yolk sac and later by fetal GI tract and liver
RF for neural tube defect
- FHx
- MTHFR mutation
- Aneuploidy
- DM
- Hyperthermia
- Medications - esp seizure meds
how to screen for neural tube defect
Screen by measuring maternal serum AFP 15-18 wks gestation
- Measured in multiple of the median (MoM) of the unaffected population
- >2.0-2.5 MoM = neural tube defect
AFP can be affected by other factors than neural tube defects:
- Multifetal gestation
- Pilonidal cyst
- Chorioangioma of the placenta
- Placental abruption
- Oligohydramnios
- Preeclampsia
- Fetal growth restriction
what has a higher detection rate for NTDs
US
2nd-trimester fetal 2D US
Are screening tests such as for down syndrome diagnostic?
no - not 100% certain, they provide aneuploidy risk
what First Trimester Screening is available to screen for down syndrome and other aneuploidies
11-14 wks - Combined First screen
- Evaluates nuchal translucency and serum analytes (PAPP-A, hCG) to detect Down syndrome
- Nucal translucency = max thickness of subcutaneous translucent area between skin and soft tissue overlying the fetal spine at the back of neck
- nuchal translucency >3.5mm
With Down Syndrome, hCG is ___ and PAPP-A is
elevated, decreased
With Trisomy 18 and 13, both are lowered
this screen is more often used when patient presents for prenatal care later in pregnancy
second trimester screening
what is the triple test?
Evaluates hCG, AFP and unconjugated estriol
Down Syndrome = lower AFP, lower estriol, higher hCG
Trisomy 18 = all 3 markers decreased
not used a lot now
what is the quad screening?
- Evaluates hCG, AFP, unconjugated estriol and inhibin
- Down syndrome = elevated inhibin - Down syndrome detection of 80%
- More often used than triple test
what is the Combined First and Second Trimester Screening
Enhance aneuploidy detection rates
1. integrated screening
2. Sequential Screening
what is integrated screening in combined 1st and 2nd trimester screening
Combines results of 1st and 2nd trimester tests - Aneuploidy risk calculated from all parameters
what is the sequential screening in combined 1st and 2nd trimester screening
- Stepwise Sequential: Women with 1st trimester screen results that confer risk for Down Syndrome are offered invasive testing and the remaining women receive second trimester screening
- Women divided into high, moderate and low risk groups based on first trimester screening results
- Highest risk offered invasive testing
- Moderate risk offered 2nd trimester screening
- Low risk receive no further testing
A structural abnormality involving ____ or the presence of _____ in the same fetus can indicate high risk of fetal aneuploidy
a major organ
two or more minor structural abnormalities or dysmorphisms
Major anomalies that indicate for invasive testing:
- Cystic hygroma
- Hydrocephalus
- Cardiac defects
- Omphalocele
- Diaphragmatic hernia
- Omphalocele
- Gastroschisis
- Bladder outlet obstruction
- Club foot
- Single umbilical artery
- Duodenal atresia
Minor abnormalities include:
- Nuchal fold >6mm
- Pylectasis
- Hyperechogenic bowel
- Choroid plexus cyst
f/u with genetic testing because are at slightly higher risk of having genetic abnormality
cell free DNA can be done at ? wks?
9-10 wks
what is cell free DNA?
Fetal component of cell-free DNA is derived from placental trophoblasts that are released into the maternal circulation from cells undergoing programmed cell death
Most sensitive and specific screening test for the common fetal aneuploidies
cell free DNA
NOT equivalent to diagnostic testing
Most common procedure for diagnosis of fetal aneuploidy
Amniocentesis - Transabdominal withdrawal of amnionic fluid
Performed typically between 15-20 weeks gestation
indications for amniocentesis
- Assess fetal karyotype – MC
- Polyhydramnios- more than 25 ml of fluid in the mom can cause contractions
- Assessment of fetal anemia - Fallen out of favor
- Fetal lung maturity
- Evaluate Lecithin/Sphingomyelin ratio (L/S ratio)
- Lecitihin elevates after 32 wks while Sphingomyelin does not
- ratio >2.0 = low risk for rsp distress
complications with amniocentesis
- Pregnancy loss rate 1 per 300-500
- Amniotic fluid leakage
- Chorioamnionitis
- Needle injuries to fetus
what is Chorionic Villus Sampling (CVS)
chorionic villi bx
Performed 10-13 wks gestation
Can be performed transabdominal or transcervical
indication for CVS?
assess fetal karyotype
main advantage of CVS
done earlier allowing for earlier pregnancy termination if desired
relative CI of CVS
- Vaginal bleeding
- Active genital tract infection
- Extreme uterine ante- or retroflexion
- Body habitus precluding visualization
complications of CVS
- Pregnancy loss
- Limb-reduction Defects
- associated with procedure at 7 wks gestation; When >10 wks, occurs less - Vaginal spotting
- Infection
indications for Fetal Blood Sampling
- Fetal anemia – MC
- Assessment and treatment of platelet alloimmunization
- Fetal karyotype assessment
Usually performed near placental cord insertion site
complications of fetal blood sampling
- Fetal loss rate is about 1.4%
- Cord vessel bleeding
- Fetal-maternal bleeding
- Fetal bradycardia
To identify fetuses at risk of intrauterine death or other complications of intrauterine asphyxia and intervene to prevent adverse outcomes if possible
antepartum fetal assessment
indication for antepartum fetal assessment
Pregnancies at high risk of antepartum fetal demise
methods of antepartum fetal assessment
- Fetal movements
- NST
- BPP
- Doppler velocimetry
- AFI
Recommendations of antepartum fetal surveillance
- Begin testing around 32-34 weeks - higher-risk: start 26-28 wks
- Repeat testing q7d
Primigravida may not feel fetal movements till when?
Multigravida may feel around when?
- 20 weeks gestation
- 16-18 weeks gestation
Factors affecting fetal movement
- Amniotic fluid - Diminished amniotic fluid = diminished fetal activity
- Fetus has sleep-awake cycles - Can sleep for 20-75min at a time
- Gestational age - Near term, there is less space and activity may diminish
Diminished fetal activity could be indicator of impending fetal death
method of observing for fetal movements
- Begin counts around 28 weeks
- Patient should perceive 10 movements in up to 2 hours - Every baby is different
- Patient should count fetal movement for 1 hour a day
- Use this count daily and the count is reassuring if it equals or exceeds that baseline
Patient should report to hospital for fetal monitoring if abnml
what is the fetal HR NST?
- Under autonomic influences mediated by sympathetic or parasympathetic impulses from brainstem centers
- Based on hypothesis that the fetal HR that is not acidemic as a result of hypoxia or neurological depression will temporarily accelerate in response to fetal movement
- > 32 weeks - +15bpm lasting >15 seconds
- < 32 weeks - +10bpm lasting >10 seconds
if abnormal or nonreactive stress test, what is the next testing?
Can be seen with a sleeping fetus
Acoustic stimulation - used on maternal abdomen and a stimulus applied for 1-2seconds
- Can be repeated up to 3x; Reassuring response is a rapid appearance of accelerations
if fetus fails acoustic stimulation, what is the next testing?
biophysical profile (BPP)
components of BPP
Combines 5 fetal biophysical variables
0 - abnormal variables
2 - normal variables
- NST - ≥2 accelerations of ≥ 15 bpm for ≥ 15 sec within 20 mins
- Fetal Breathing (via US) - ≥ 1 episode of rhythmic breathing lasting ≥ 30 sec within 30 mins
- Fetal Movement (US) - ≥ 3 discrete body or limb movements within 30 min
- Fetal Tone (US) - ≥ 1 episode of extremity extension and subsequent return of flexion
- Amniotic Fluid Volume (US) - Pocket of fluid that measure at least 2 cm
interpretations for BPP
- 10 = normal, non-asphyxiated fetus
- 8 = normal, non-asphyxiated fetus
- If 8/10 for abnormal AFI, deliver - 6 = possible fetal asphyxia, repeat within 24h
- If normal fluid at >36 wks, deliver
- If repeat test ≤ 6, deliver
- If repeat test >6, observe (esp preterm) - 4 = probably fetal asphyxia, repeat or deliver
- 2 = DELIVER! Most likely fetal asphyxia
Modified BPP combines what two tests?
AFI and NST
Requires less time than BPP
what is doppler velocimetry?
Blood flow velocity measured by Doppler ultrasound reflects downstream impedance
what 3 fetal vasular circuits are evalused in doppler velocimetry
- Umbilical artery
- Middle cerebral artery
- Ductus venosus
abnormal findings in umbilical artery velocimetry
- Abnml = S/D ratio >95th percentile for gestational age
- Absent or reversed end diastolic flow = increased impedance to umbilical artery blood flow
Indications: Fetal growth restriction
indications for middle cerebral artery velocimetry
- Intrauterine growth restriction
- Isoimmunization
- Fetal anemia
