Preconception Care Flashcards
Screening for sickle cell trait
Hb electrophoresis and CBC
A patient presents for prenatal testing. Her brother has sickle cell disease, but neither of her parents do. Her partner is from an ethnic group with a 1/10 prevalence of carrier status. What is the probability that their child will have sickle cell disease?
- Probability that the patient is a carrier: 2/3
- Probability that the partner is a carrier: 1/10
- Probability that a child of two carriers is homozygous: 1/4
- Net: 2/3 x 1/10 x 1/4 = 1/60
Patients taking valproic acid during pregnancy will have an increased risk of infants with ___.
Patients taking valproic acid during pregnancy will have an increased risk of infants with neural tube defects, hydrocephalus, and craniofacial malformations.
Patients with uncontrolled diabetes during pregnancy have an increased risk of having infants with ___.
Patients with uncontrolled diabetes during pregnancy have an increased risk of having infants with neural tube defects and congenital heart defects.
As part of preconception care, vaccinations should be offered to all women found to be susceptible to . . .
- Rubella
- Varicella
- Pertussis
- Hepatitis B
While there are a variety of tests for various diseases recommended for women dependent upon their history and background, ___ is recommended for all patients who are planning to become pregnant
While there are a variety of tests for various diseases recommended for women dependent upon their history and background, an HIV test is recommended for all patients who are planning to become pregnant
Choosing a dose of folate for a patient who plans on becoming pregnant
- 0.4 mg for most patients
- 4 mg for patients with a history of NTD pregnancy or are on a medication that interferes with folate metabolism (like topiramate)
Live vaccines and pregnancy
Pregnancy should be avoided within 1 month of receiving a live attenuated strain vaccine
How long does it take before the pregnant uterus becomes apparent on bimanual exam?
- 6 weeks estimated gestational age
Chadwick’s sign
- Genital tract finding of early pregnancy
- Congestion and bluish discoloration of the vagina and cervix
Hegar sign
- Genital tract sign of early pregnancy
- Softening of the cervix on pelvic exam
Quickening
Patient’s initial perception of fetal movement
Not usually seen before 16-18 weeks, often as late as 20 weeks in primigravid individuals.
LH and pregnancy tests
LH and hCG share a common alpha chain
Any pregnancy test that measure this alpha chain cannot discriminate between them, and these can thus yield false positives.
Standard laboratory urine pregnancy tests first become positive. . .
. . . approximately one month following the first day of the LMP.
ie, around when the first period is missed
Test characteristics of home pregnancy tests
Low false positive rate, but high false negative rate
All urine pregnancy tests should be performed upon. . .
. . . early morning urine specimens
Serum pregnancy tests measure. . .
. . . the beta chain
Therefore, they are all quite specific to hCG
With a traditional, nonelectronic, acoustic fetoscope, auscultaton of fetal heart tones first becomes possible at. . .
. . . 20 weeks eGA
This is almost always an indication of a viable pregnancy
eGA and “weeks” uterus
When the uterus grows in size so that it exits the pelvis and is at the level of the umbilicus (16-20 weeks gestation), the fundal height in centimeters represents the gestational age from that time to about 36 weeks.
After 36 weeks, the uterus generally moves downward into the pelvis a bit and the fundal height decreases.
Fundal height
After the uterus reaches the umbilicus (usually ~16-18 wks gestation), uterine size is assessed with use of a tape measure. The uterine fundus is identified and the distance from the pubic symphysis in the midline is taken.
Naegle’s rule
To calculate EDD given LMP
From LMP, add seven days, then subtract three months
___ date for EGA should take preference over ___.
Ultrasound-established date for EGA should take preference over history of LMP
How early ultrasound can detect pregnancy
- Abdominal: 5-6 weeks EGA
- Transvaginal: 3-4 weeks EGA
Month-by-month weight gain for a woman of normal BMI during pregnancy
3-4 lb per month is the expected rate
Significant deviation from this may require nutritional assessment
While prior to 34 wks eGA, breech, oblique, cephalic, and transverse presentations are all common, 95% of infants become ___ at term.
While prior to 34 wks eGA, breech, oblique, cephalic, and transverse presentations are all common, 95% of infants become cephalic at term.
Leopold maneuver
Allows the clinician to assess the presentation of the fetus
If breech presentation persists at 36-38 weeks, . . .
. . . external cephalic version should be discussed with the patient
This procedure involves turning the fetus from the breech position to the vertex position to allow vaginal rather than cesarean delivery.
It is contraindicated in the presence of multifetal gestation, uterine anomalies, or abnormal placentation.
The optimal time for single ultrasound examination in the absence of specific indications for first trimester exam
18-20 weeks gestation
Indications for first trimester ultrasound
- Confirmation of the presence of intrauterine pregnancy
- Determination of eGA
- Diagnosis and evaluation of multiple gestation pregnancies
- Confirm cardiac activity
- Evaluate for pelvic masses or abnormalities
- Diagnosis of chromosomal abnormalities (nuchal translucency)
- Adjunction to other procedure (chorionic villus sampling, embryo transfer, localization and removal of IUDs)
Universal screening for GBS / Streptococcus agalacticae
Performed at 35-37 weeks eGA
Third trimester glucose challenge test
Performed at eGA 24-28 weeks unless performed earlier in pregnancy (initial visit for obese, prediabetic patients)
If positive, a glucose tolerance test is performed
Third trimester repeat screenings
Repeat screening for anti-Rh (in Rh- patients) and for HIV (in all patients)
Large for gestational age
When fundal height measurement is significantly greater than expected
Considerations include incorrect eGA assessment, multiple pregnancy, macrosomia (large fetus), hydatidiform mole, and polyhydramnios
Small for gestational age
Fundal height measurement is significantly smaller than expected for eGA
Considerations include incorrect eGA assessment, hydatidiform mole, fetal growth restriction, oligohydramnios, or intrauterine fetal demise
Measures of fetal wellbeing
- Size/growth
- Fetal activity (kick counts)
- Fetal monitoring tests:
- Non-stress test
- Contraction stress test (aka oxytocin challenge test)
- BPP
- Ultrasonography of umbilical artery blood flow velocity
Non-stress test
Fetal heart rate, pattern, and accelerations are monitored for 20 minutes with an external transducer
“Reactive” if 2 or more fetal HR accelerations occur during this period (peaking at 15 bpm above baseline for at least 15 seconds)
“Nonreactive” if the above does not occur even in 40 minutes. This requires additional workup.
Contraction stress test / Oxytocin stress test
- During a uterine contraction, uteroplacental blood flow is reduced temporarily. A healthy fetus compensates for this by increasing HR.
- Tocodynamometer is used to measure for uterine contractions. If none occur, they may be induced by nipple self stimulation or by administration of exogenous oxytocin.
What do the non-stress test and contraction stress test measure?
NST: Measure fetal heart’s response to fetal activity
CST: Measures the fetal heart’s response to uterine contraction
Biophysical proflie (BPP)
- Series of five assessments of fetal well-being, each given a score from 0 (absent) to 2 (present)
- Includes:
- NST
- Fetal breathing movements
- Fetal movement
- Fetal tone
- Amniotic fluid volume
- 8-10 reassuring, 6 equivocal, 4 or less warrants further evaluation
Assessment of fetal maturity
Should always be performed when delivering a fetus preterm or electively in high-risk pregnancy
Many tests target the respiratory system, as this is the last organ system to mature in the fetus.
Common markers: Surfactant/albumin ratio, lecithin/sphingomyelin ratio, phosphatidylglycerol
Phosphatidylglycerol as a fetal maturation marker
Marker of complete fetal lung maturation present after 35 weeks gestation
Infants who are delivered prior to lung maturation are at risk for. . .
. . . respiratory distress syndrome of the newborn
Caused by lack of surfactant. Syndrome of grunting, chest retractions, nasal flaring, and hypoxia. May lead to acidosis and death.
Administration of synthetic surfactant results in improved outcomes, and administration of glucocorticoids in planned pre-term deliveries can hasten surfactant production in preparation for delivery.
Exercise in pregnancy
- In the absence of other medical complications:
- up to 30 minutes of moderate exercise per day on most or all days of the week is acceptable
- No supine exercises after the first trimester (avoiding IVC syndrome)
- NO WEIGHT BEARING OR CONTACT SPORTS
- NOTHING WITH RISK OF FALL OR TRAUMA
Hyperthermia in pregnancy
Teratogenic in the first trimester
Circumstances under which sexual activity is not advised for pregnancy
- Placenta previa
- Premature rupture of membranes
- History of or current pre-term labor or delivery
Tetracycline teratogenic effects
Yellow-brown discoloration of deciduous teeth
Sulfonamides teratogenic effects
Avoided near delivery due to risk of hyperbilirubinemia via displacement of bilirubin from albumin
Nitrofurantoin teratogenic effects
Theoretical risk in patients with G6PD deficiency
Quinolone teratogenic effects
Irreversible arthropathies and cartilage erosion in animal studies
Metronidazole teratogenic effects
Not teratogenic in the first trimester, but is later in pregnancy
Phenytoin teratogenic effects
May produce abnormal facies, cleft lip, cleft palate, microcephaly, growth deficiency, hypoplastic nails and distal phalanges
SSRI teratogenic effects
- Paroxetine specifically: Increased risk of ventral and atrial septal defects
- All other SSRIs: Exposure late in pregnancy associated with neonatal behavioral syndrome (increased muscle tone, irritability, jitteriness, respiratory distress)
Categories of abnormalities in fetal alcohol syndrome
- Growth restriction
- Abormal facies (shortened palpebral fissure, thin upper lip, low-set ears, midfacial hypoplasia, smooth philtrum)
- Central nervous system dysfunction (microcephaly, developmental delay, behavioral disorders like ADHD)
In a woman with OUD, ___ is a potential concern following infant delivery
In a woman with OUD, neonatal opioid withdrawal is a potential concern following infant delivery
Management of common pregnancy symptoms
- Headaches: Acetominophen, then if persistent and significant continue workup
- Lower extremity edema: Often no treatment, resolves on own, but monitor for this resolution and followup if none
- N/V: H1 blockers (promethazine)
- Heartburn: Behavioral counciling, antacids used judiciously
- Constipation: Psyllium wafers, docusate
- Leg cramps: Massage and rest
- Back pain: Massage, heat, limited analgesia
- Round ligament pain: More gradual movements, avoid analgesia
Round ligament pain
Patients will be 2nd or 3rd trimester and coming in rearding “sharp groin pain”, most often on the R side (since there is usually dextrorotation of the gravid uterus).
Reassure that pain represents stretching and spasms of the round ligament and is perfectly normal.
Treat w/ modification of activity, especially more gradual movement. Analgesics are rarely indicated.
Type I vs II diabetic pregnancies are at greatest risk for. . .
Type 1: IUGR
Type II: Macrosomia
