OB/GYN II Flashcards
What are the three developmental stages of teratology
- Resistant period
- Day 0-11
- killed by the insult or survive unaffected
- Maximum susceptibility
- day 11-57
- Lower Susceptibility
- After 57 days
- Growth retardation
- Reduction in organ size
What are the categories of structural defects and what is the associated time period that they occur
- Malformations
- 1st trimester
- morphologic defect of a body part or organ
- Deformation
- abnormal forms, shapes or positions of a body part
- 2nd or 3rd trimester
- Disruptions
- defects from interference with a normally developing organ system
- 2nd or 3rd trimester
What is the effect of ionizing radiation
- Time of effect (susceptible period)
- Dose effect
- Less than 10 rads (no effect)
- 10-25 rads some adverse
- greater than 25 classic fetal effects
What are factors effecting access of a drug or medication to the fetus
- Maternal absorption
- drug metabolism
- protein binding and storage
- molecular size
- electrical charge
- lipid solubility
how much alcohol is needed to cause fetal alcohol syndrome
as little as one oz per day
Dose response: the more drinks the more FAS that will present
What are the two most abused drugs in pregnancy
- Alcohol
- cocaine
What is a good predictor for fetal complications from maternal DM
Hemoglobin A1C
What are two types of malfomations found in the fetus of DM mothers
- Caudal regression syndrom with hypoplasia of the caudal spine and lower extremities
- CHD most commonly VSD
What is cretinism
the result of maternal, fetal, and neonatal thyroid hormone deficiency
usually in iodine poor areas
What is PKU
phenylketonuria
genetic d/o characterizeed by a deficiency of phenylalanine hydroxylase, a liver enzyme that catalyzes the conversion of phenylalanine to tyrosine. the resulting high levels of phenylalanine in maternal serum result in high levels in the fetus.
adverse effects:
- mental retardation
- microcephaly
- CHD
- low birth weight
what is arrhenoblastoma
virilizing tumor
What are the common abnormalities associated with epilepsy
Clift lip
cleft palate
CHD
Valproic Acid caries a 1-2% risk of NTD
Some studies suggest that the frequency of seizures is correlated with the degree of abnormality
What is the #1 cause of death during pregnancy
Thromboembolism
What is the teratogenic effect of benzodiazepines
less than 1% risk of cleft anomalies
What are the effects of fetal warfarin syndrome
- Flattened nasal bridge
- stippled bony epiphyses
- birth weight less than 10th percentil
- ocular defects
- extremity hypoplasia
- developmental retardation
- seizures
- scoliosis
- deafness/hearing loss
- CHD
- death
What is used for the treatment of HIT (heparin induced thrombocytopenia)
Argatroban
Hirudin / bivalirudin
What are the problems with a 1st trimester infection of rubella
- Neuropathologic changes
- microcephaly
- mental and motor retardation
- meninogencephalitis
- Cardiovascular changes
- PDA
- pulmonary artery stenosis
- Atrioventricular septal defects
- ocular defects
- cataracts
- microphthalmia
- retinal changes
- blindness
- inner ear problems
- IUGR
What are the problems associated with an early pregnancy infection of CMV
- Microcephaly and hydrocephaly
- chorioretinits
- hepatosplenomegaly
- cerebral calcification
- mental ratardation
- heart block
- petechiae
What are the associated problems with a 1st trimester infection of HSV-2
- IUGR
- Microcephaly
- Chorioretinits
- cerebral calification
- microphthalmia encephalitis
- miscarriage
What are the associated problems with inutero infection of VZV during the 1st 20 weeks
Several organ systems are effected
- Cutaneous
- Musculoskeletal
- Neurologic
What is the problem with an enterovirus infection such as coxsachie B
Serious or fatal illness (40%) in the fetus
surviving infants may exhibit cardiac malformations; hepatitis, pneumonitis, or pancreatitis or adrenal necrosis
What is substance use
involves taking low, infrequent doses of illicit substances fro experimentation or social reasons. damaging consequences are rare or minor
what is substance abuse
is the persistent or repeated use of a psychoactive substance for more than 1 month, despite the persistence or recurrence of adverse social, occupational, psychological or physical effects
what is substance dependence
WITHDraw IT mneumonic
what is the pharmacologic effect of cocaine
blocks dopamine and norepinephrine reuptake at the postsynaptic junction, thereby increasing CNS irritability
this leads to maternal and fetal vasoconstriction and tachycardia, as well as stimulation of uterine contractions
tocolytic agent of choice: Mag sulfate
Mag Sulfate can also be used to treat seizures
What are the effects of marijuana during pregnancy
no increase in congenital malformations
What are the fetal effects of heroin during pregnancy
no increase in congenital malformations
IUGR
Stillbirth
Prematurity
Increased perinatal death
What are the fetal effects associated with methadone
no increase in congenital abnormalities
associated with low birth weight
What are the fetal effects of tobacco
spontaneous abortion
abruptio placentae
PROM
preterm delivery
lower birth weight
What is placenta previa
implantation of the placenta over the cervical os
What are the three types of placenta previa
- Total placenta previa: placenta completely cover the internal os. Associated with the greatest risk and largest amount of blood loss
- Partial previa: placenta partially covers the os
- marginal previa: the placenta extends to the margin of the internal cervical os
What are the factors thought to cause placenta previa
- Previous placenta previa
- Previous C section
- Multiparity
- Advanced maternal age
- Smoking
- Asian and african descent
- Previous D & C
Placenta previa is associated with painful or painless bleeding
Painless bleeding
70% occurs at rest
Should you do a manual exam to determine placenta previa
NO
unless you are in the OR ready for emergency C section
Confirm placenta previa via ultrasound
What are the complication of PPH (post partum hemorrhage)
- renal damage from prolonged hypotension
- Pituitary necrosis (sheehans syndrome)
- DIC
What is placenta accreta
growth of the placenta into the myometrium or any of its variations due to the asence of decidua basalis
Placenta accreta should always be considered in the presence of placenta previa
What are the 3 types of placenta accreta
- Placenta Accreta: placenta is attached directly to the myometrium
- Placenta Increta: placenta invades the myometrium
- Placenta Percreta: placenta penetrates completely through the myometrium
What is abruptio placentae
premature separation of a normally implanted placenta after 20 weeks gestation.
It is initiated by bleeding into the decidua basalis, the bleeding splits the decidua, and the hematoma that forms causes further splitting. The process may be self limiting
What is the common triad of presenting symptoms associated with placenta previa
vaginal bleeding
uterine or back pain
fetal distress
What necessitates an immediate delivery with a placentae previa
- fetal heart rate tracing is nonreassuring and the gestational age is greater than 24 weeks
- maternal condition deteriorate regardless of gestational age
What is an Apt test
determination of a vasa previa
- blood from the vagina
- adding a small amount of tap water
- centrifuging the sample
- adding the pink supernatant to 1mL of NAOH solution
- Reading the treated sample in 2 minutes
- Pink color: presence of fetal hemoglobin
- Yellow-brown color: presence of adult hemoglobin
How does oxytocin effect labor
Levels of oxytocin increase with labor, but there is not a surge.
The greatest increase is in the number of oxytocin receptors
- Six fold increase in weeks 13-17 gestation
- 80 fold increase at term
- preterm labor has 2-3 times as many receptors than would be expected
How do prostaglandins assist in labor
Labor is associated with an increase in prostaglandins. this is likely the result of inflammation and not labor itself.
However, prostaglandins are believed to be important stimulatros of gap junctions
How is labor characterized
contractions that occur with increasing frequency and intensity, causing dilation of the cervix
What is the role of gap junctions in pregnancy
important cell-cell contacts that facilitate communication between cells via electrical or metabolic coupling
myometrial gap junctions, which are virtually absent during pregnancy increase in size and number before and during labor
Progesterone prevents gap junctions
Estrogen stimulates gap junctions
What are tocolysis agents and what is their functino
pharmacologic inhibition of uterine activity
- Antiprostaglandin agents
- indomethacin
- acetylsalicylic acid
- Calcium channel blockers
- nifedipine
- magnesium sulfate
- B-mimetic agents
- terbutaline
Discuss the stages of labor
- Stage 1
- Entails effacement and dilation. it begins when uterine contractions become sufficiently frquent, intense and long to initiate obvious effacement and dilation of the cervix
- Stage 2
- involves the expulsion of the fetus. it begins with complete dilation of the cervix and ends when the infant is delivered
- Stage 3
- involves the separation and expulsion of the placenta. It begins with the delivery of the infant and ends with the delivery of the placenta
What do contractions do to the uterus
upper segment of the uterus becomes thicker and as labor progresses and contracts down with a force that expels the fetus with each contraction
lower segment of the uterus passively thins out with the contractions of the upper segment, promoting efacement fo the cervix
What is effacement of the cervix
the shortening of the cervical canal from a structure of approximately 2 cm in length to one in which the canal is repalced by a more circlar orifice with almost paper thin edges
effacement occurs as the muscle fibers near tthe internal os are pulled upward into the lower uterine segment
What is the dilation of the cervix
involves the gradual widening of the verival os. must dilate to 10 cm to be considered completley dilated
What are the types of vertex presentations regarding position
Postion is named based on the occiput with in the birth canal (R or L and A or P) in an oblique fashion or
Occiput transverse or
Occiput anterior/posterior
What are the stations of engagement
Station 0 is the level of the ischial spine
Above the ischial spine in cm is the negative station
below the ischial spine in cm is the positive stations
+3 the presenting part is on the perineum
What does it mean if the fetal head is floating
when the fetal head is not engaged at the onset of labor and the fetal head is freely movable above the pelvic inlet
What are the 7 cardinal movements of labor and delivery
- Engagement
- Descent
- Flexion
- Internal rotation
- Extension of the fetal head
- External rotation
- Expulsion
What is engagement
the biparietal diameter of the fetal head, the greatest transverse diameter of the head in occiput presentations, passes through the pelvic inlet
What is associated with an increased risk of infection from ruptured membranes
time
greater than 24 hours regardless if labor has begun
On average how long should the first stage of labor last
12 hours primigravida
7 hours multigravida
What are the 2 phases of the 1st stage of labor
latent
- Prolonged is greater than 20 hours for primi or 14 hours multiparous
active
- prolonged is dlation less than 1.2cm/hour in primi or 1.5 cm/hour in multiparous
On average how long does the second stage of labor last
50 minutes in primigravida
20 minutes in multigravida
still common to last up to 2 hours
What is crowning
encirclement of the largest diameter of the fetal head by the vulvar ring
What are the two types of episiotomy
median
mediolater
episiotomy is easier to repair and heals better than a tear, shortens the second stage of labor, and spares the infants head from prolonged pounding again the perineum
On average how long is the 3rd stage of labor
5 minutes
What are the signs of placental separation
uterus becomes globular and firm
often a sudden gush of blood
umbilical cord protrudes farther out of the vagina
What is the main control of uterine hemostasis
vasoconstricion produced by a well contracted myometrium
May be assisted after the placenta has been delivered by:
Oxytocin
Ergonovine
prostaglandin F2a
Discuss the degrees of lacerations associated with birth
1st degree: invovle the fourchette, perineal skin and vaginal mucosa.
2nd degree: involve the skin, mucosa, fascia and muscles of the perineal body
3rd degree: extend throught the skin, mucosa, and perineal body and involve the anal sphincter
4th degree: are exensions of the third degree tear through the rectal mucosa to expose the lumen of the rectum.
What are the 2 types of fetal heart monitoring
External ultrasound device
Fetal scalp electrode
What is baseline fetal HR
the heart rate that occurs between contractions regardless of accelerations or decelerations
normal FHR is 110-160 and decreases gradually after 16 weeks gestation as the parasympathetic system develops
What are the causes of baseline fetal tachy
FHR greater 160
- hypoxia
- maternal fever
- chorioamnionitis
- prematurity
- drugs
- fetal stimulation
- fetal arrhythmias
- maternal anxiety
- maternal thyrotoxicosis
what are the causes of fetal bradycardia
FHR less than 110
- hypoxia
- drugs
- autonomic mediated reflex
- arrhthmias
- hypothermia
- maternal hypotension
is baseline FHR variability normal
yes
one of the best indicators of intact integration between the fetal CNS and the heart
How is FHR variability characterized
absent: undectable amplitude
minimal: detectable amplitude less than 5 bpm
moderate: amplitude of 6-25
marked: amplitude of more than 25 bpm
what are the two ways to measure contractions and there associated limitations
tocodynamometer: only determines the frequency and NOT intensity or strength
intrauterine pressure catheter (IUPC): measures both frequency and intensity
What define FHR accelerations
before 32 weeks: a peak of at least 10 bpm above baseline lasting 10 seconds or more
after 32 weeks: a peak of at least 15 bpm above baseline between 15 seconds and 2 minutes
what are the 3 types of FHR decelerations
- Early decelerations
- Variable decelerations
- Late decelerations
What determines if a deceleration is prolonged
decreases from baseline of 15 BPM or more and last 2-10 minutes
caused by vagus nerve discharge or fetal hypoxia
define early decelerations
begin with the onset of uterine contractions, reach their lowest point (never below 100 bpm) at the PEAK of contraction and return to baseline as the contraction ends
thought to be caused by local changes in cerebral blood flow which results in stimulation of the vagal centers
these decelerations are physiologic
define variable decelerations
abrupt decreases in fhr with a rapid reurn to baseline (onset of deceleration to nadir less than 30 seconds) that may occur before, during, or after contration
generally are caused by compression of the umbilical cord
What are the types of variable decelerations
mild: duration less than 30 seconds
moderate: Two types
1. Nadir of 70-80 with duration of more than 60 seconds
2. Nadir less than 70 duration 30-60 seconds
severe: nadir less than 70 with duration greater than 60 seconds