Clin: Normal Pregnancy and Prenatal Care - Moulton Flashcards
what should be started at least 1 month prior to conception to reduce the risk of neural tube defects?
folic acid
- if no history of NTD, 0.4mg folic acid
- if hx of previous child with NTD, increase to 4mg folic acid
what should diabetics be counseled on preconception?
adequate glucose control before and throughout pregnancy can decrease maternal morbidity, SAB, fetal malformations, fetal macrosomia and IUFD
what is FPAL?
Full term: 37-42 weeks
Preterm: 20-36+6 weeks
Abortions: all pregnancy loses prior to 20 weeks (<500g)
Living
what is the GP of a woman who has given birth to 1 set of twins at term and both are living?
G1P1002
the number of pregnancies that led to BIRTH at or beyond 20 weeks, or an infant weighing more than 500 grams
parity
what is the GP of a woman who has given birth to one term infant, one set of preterm twins, and has had 1 miscarriage, and 1 ectopic pregnancy. She has 3 living children
G4P1123
ectopic pregnancy and miscarriage in same spot
- systolic murmurs, exaggerated splitting and S3
- palmar erythema
- spider angiomas
- linea nigra (darkened areolas)
- striae gravidarum (stretch marks)
- chadwicks sign (bluish hue of vagina/cervix)
- malasma/chalasma (red “mask” over cheeks ad nose)
normal finding associated with pregnancy
- CBC
- blood type and screen
- Rubella (vaccinate postpartum if not immune)
- Syphilis
- Heb BsAg
- HIV
- cervical cytology, gonorrhea and chlamydia
- diabetes screen based on risk factors
- urine culture
prenatal labs done at 1st visit
what common lab value will increase during pregnancy?
fibrinogen (pregnancy is a hyper-coagulable state), plasma, amylase, leukocytes
- most other lab values will decrease
when is the most important time to get an US?
1st trimester, gives most accurate estimation of gestational age and due date
when can hCG first be detected in serum?
6-8 days after ovulation
- less than 5 IU/L = NEGATIVE
- level above 25 IU/L = POSITIVE
- level of about 100 is reached by time of expected menses
what level do most urine pregnancy tests detect?
hCG at about 25 IU/L
in the first 30 days of a normal pregnancy, what happens to the hCG level?
it doubles every 2 days (used to evaluate for early IUP vs ectopic pregnancies)
when can a gestational sac be seen on transvaginal ultrasound?
5 weeks
- mean hCG of 1500-2000 IU/L
when can a fetal pole be seen on transvaginal ultrasound?
6 weeks
when can cardiac activity be seen on transvaginal ultrasound?
7 weeks
what is Naegels rule?
estimates gestational age/due date
- LMP - 3 months + 7 days = EDD
- useful ONLY for patients with regular 28 day cycles
when can crown rump length (CRL) be used to measure due date?
between 6-11 weeks, can determine due date usually within 3-5 days
when can US be used to measure femur length, biparietal diameter and abdominal circumference to determine due date?
12-20 weeks, can determine due date within 10 days
- advanced maternal age (35+)
- previous child/family history of birth defect
- previous child with undiagnosed mental retardation
- previous baby died in neonatal period
- multiple fetal losses
- abnormal serum marker screening
- consanguinity (marrying cousins)
- exposure to teratogens
- abnormal uS findings
recommend genetic counseling
what are the most common chromosomal disorders?
sex chromosome aneuploidy: Turners (45XO), Kleinfelters (47XXY), balanced Robertsonian translocations
what are moms over 35 at an increased risk for?
autosomal trisomies (13, 18, 21) or sex chromosome abnormalities
what is the risk that a couple who previously has had a child with Downs syndrome has another affected child with chromosomal abnormality?
1%
what causes 95% of cases of Down syndrome?
meiotic nondisjunctional events leading to 47 chromosomes with an extra copy of chromosome 21
what should be done on couples after 3+ SAB?
karyotyping
- 3-5% of these couples will be dx with balanced translocation
- those couples should receive counseling regarding possibility of having a child with an unbalanced translocation and therefore be offered prenatal diagnosis (chorionic villus sampling/amniocentesis)
what is the most common autosomal trisomy?
trisomy 16
what are the examples of autosomal dominant disorders that Moulton mentioned?
tuberous sclerosis, achondroplasia, muscular dystrophy
what are the examples of AR disorders that Moulton mentioned?
Tay-Sachs, sickle cell, alpha and beta thalassemia, cystic fibrosis
what is the most common gene carried in North American whites, with a frequency of 1 in 25?
cystic fibrosis
- genetic counseling is important for CF screening because 15% of carriers are undetected
- should offer CF screening to all pregnant women
what are the examples of sex-linked disorders that Moulton mentioned?
- Duchenne muscular dystrophy
- Fragile X syndrome most common form of inherited mental retardation, and second most common form of mental retardation after trisomy 21
how are sex linked disorders diagnosed prenatally?
by chorionic villus sampling or amniocentesis
cleft lips or palates, congenital heart defects, pyloric stenosis and neural tube defects are examples of what?
multifactorial disorders
what is the recurrence rate of multifactorial disorders?
3%
which screening includes:
- maternal age
- fetal nuchal translucency (NT) thickness (echo-free area at the back of the fetal neck between 10-14 weeks)
- maternal serum b-human chorionic gonadotropin (b-hCG)
- pregnancy associated plasma protein-A (PAPP-A)
first trimester screening
what is an elevated b-hCG and low PAPP-A associated with?
Down’s
- first trimester screen has detection rate of 79%
- addition of nasal bone assessment (absence of) to nuchal translucency measurement and serum biochemistry can increase the Down syndrome detection rate to 93%
b-hCG, estriol, and maternal serum alpha fetoprotein (AFP)
- between 16-20 weeks
- 70% detection rate of trisomy 21
triple screen (second trimester screening)
b-hCG, estriol, AFP and inhibin A
quadruple screen (second trimester screening) - 80% detection rate of trisomy 21
- 9-10 weeks
- tests cell free fetal DNA, thought to be derived apoptosis of trophoblastic cells that have entered the maternal circulation
- does NOT test for open neural fetal defects
noninvasive prenatal testing, cell-free fetal DNA
when would you order a cell-free fetal DNA?
ONLY in high risk patients, including one or more of the following
- advanced maternal age
- history of prior pregnancy with a trisomy
- family history of chromosomal abnormalities
- fetal ultrasound abnormalities suggestive of aneuploidy
- positive serum screening test including first trimester, triple or quad screen
what’s the next step if cell-free fetal DNA comes back positive?
proceed with invasive diagnostic test to confirm results
- amnoicentesis or chronic villus sampling (CVS)
which second trimester screen is performed at 16-20 weeks, and has a 0.3% miscarriage rate?
amniocentesis
which second trimester screen is performed during the 11th week, and has a 1% miscarriage rate?
chorionic villi sampling
- can still do D&C at 11 weeks, less traumatic
what is the study of abnormal fetal development?
teratology
what does thalidomide cause?
phocomelia (flipper babies)
what is risk factor category X?
the use of the product is contraindicated in women who are or may become pregnant
what changed the content and format for information presented in prescription drug labeling to assist health care providers is assessing benefit vs. risk of medications?
Pregnancy and Lactation Labeling Rule (PLLR)
which subsection of PLLR includes pregnancy exposure registry risk summary, and clinical considerations?
pregnancy (8.1) subsection
which subsection of PLLR provides information about the use of drugs while breastfeeding, such as amount of drug in breast milk and potential side effects to breastfed infants?
lactation (8.2) subsection
which subsection of PLLR includes information about the need for pregnancy testing, contraception recommendations, and information about infertility as it relates to the drug?
females and males of reproductive potential
efficacy of a teratogen is dependent on the genetic make-up of a mother and fetus as well as on a number of factors related to maternal-fetal environment (multifactorial)
fetal susceptibility
what period is known as organogenesis?
day 17-56 post conception, is the most vulnerable stage
from the fourth month to the end of gestation, what goes development consist of?
increasing organ size
- with the exception of brain and gonads - teratogenic exposure after the 4th month usually results in delayed growth and not into malformation
what is the most common teratogen to which a fetus is exposed?
alcohol
exposure to what medication has been associated with a four fold increase in severe congenital anomalies?
anti-anxiety meds: meprobamate (D) or chlodiazepoxide (D)
what is the drug of choice for anxiety and depression during pregnancy?
fluoxetine
what two drugs are known folic acid antagonists and have been established as teratogens?
anti-neoplastic meds: aminopterin (X) and methotrexate (D)
- exposure before 40 days is lethal to embryo
- later exposure causes IUGR, craniofacial abnormalities, mental retardation, miscarriage, stillbirth and neonatal death
what anticoagulant crosses the placenta and should NOT be used during pregnancy?
- *coumadin**
- causes spontaneous abortion, IUGR, central nervous system defects like mental retardation, stillbirth and craniofacial features known as fetal warfarin syndrome
which anticoagulants do NOT cross the placenta and CAN be used during pregnancy?
herapin and lovanox
craniofacial abnormalities, limb reduction defects, prenatal onset growth restriction, mental deficiency, and CV anomalies
fetal hydantoin syndrome (FHS)
- caused by diphenylhydantoin (Dilantin)
what other anticonvulsants were mentioned as causing spinal defects?
valproic acid and carbamazepine
what can cause the masculinization of female external genitalia?
highly androgenic progestins
what malformations can retinoids (accutane) cause?
- central nervous system (hydrocephaly, facial nerve palsy, cortical blindness)
- cardiovascular
- craniofacial defects (microcephaly with severe ear abnormalities)
NOTE: rate of SAB is 50% if retinoids taken in first trimester
which miscellaneous agent is dose dependent
- interferes with fetal growth - weight, length, and head circumference
- increases risk of SAB, fetal death, neonatal death and prematurity
tobacco
what is the critical period for radiation exposure?
between 2-6 weeks postconception
what happens if exposure is before 2 weeks?
either lethal, or no effect at all
what is the rule of thumb for radiation exposure?
less than 5 rads of exposure = no risk
what causes constipation in pregnancy?
decrease in colonic activity
- tx: dietary changes, increase water, fiber, fruits, vegetables, stool softener
what causes hemorrhoids in pregnancy?
increase in venous pressure in the rectum
- tx: rest, stool softeners, sitz baths, elevation of legs, avoid constipation
how often should a woman been seen during pregnancy?
- every 4 weeks until 28 weeks
- every 2 weeks from 28 to 36
- weekly until delivery
what happens at prenatal visits?
BP, weight
- urine protein
- measurement of uterine size
- fetal heart rate (doppler at 12 weeks, fetoscope 18-20 weeks)
when does the first sensation of movement usually happen?
quickening occurs on average at 20 weeks
what routine screening should be done at 20 weeks?
fetal survey US
what routine screening should be done at 28 weeks?
gestational diabetes and repeat hemoglobin and hematocrit
- Rhogam injection
- Tdap
what routine screening should be done at 36 weeks?
screening for GBS with vaginal culture
- if positive, treat in labor
what is considered normal fetal movement?
10 movements in 2 hours
what is a reactive NST?
2 accelerations of at least 15 beats above baseline lasting at least 15 seconds during 20 minutes of monitoring
- if nonreactive, further evaluation is warranted (contraction test, biophysical profile)
what is a contraction stress test (CST)?
give oxytocin to establish at least 3 contractions in a 10 min period
- if late decelerations are noted with the majority of contractions, the test is POSITIVE and delivery is warranted
