UWise - Objectives 20-24 Flashcards
List 2 clues of twin gestations.
- Elevated AFP (roughly double that of singleton pregnancies)
- Fundal height exceeding gestational age in weeks
List 7 causes of elevated maternal serum AFP.
- Neural tube defects
- Multiple gestation
- Fetal abdominal wall defects
- Fetal death
- Pilonidal cysts
- Cystic hygroma
- Sacrococcygeal teratoma
List 4 U/S markers suggestive of dizygotic (non-identical) twins.
- Dividing membrane thickness >2 mm
- Twin peak (lambda) sign
- Different fetal genders
- 2 sparate placentas (anterior and posterior)
Discuss the difference between di/di, di/mono, and mono/mono placentation.
Diamniotic dichorionic placentation occurs with division prior to the morula state (within 3 days post-fertilization). Diamniotic monochorionic placentation occurs with division between days 4 and 8 post-fertilization.
Monoamniotic monochorionic placentation occurs with division between days 8 and 12 post-fertilization.
What happens with division of the zyogte at or after day 13?
Conjoined twins
Discuss the risks related to twin gestations with ARTs.
- Twin infant death is 5x higher than that of singletons.
- Risk for development of cerebral palsy in twin infants is 5-6xx higher than that of singletons
- Twins had a higher incidence of IUGR than singletons.
- 58% of twins delivery prematurely; 12% deliver very prematurely
The incidence of ___ anomalies is increased in twins, particularly monozygotic twins, compared to singletons. Note that the majority of twin pairs in which an anomaly is present will be discordant for this anomaly.
Congenital anomalies
True or false - twin gestations tend to deliver later than singleton gestations.
False - twin gestations tend to deliver earlier than singleton gestations with the average length of twin gestation being 35-37 weeks.
True or false - twins typically weigh less than singletons of the same gestational age.
True - but their weights usually remain within the normal range
True or false - prematurity is a major cause of morbidity and mortality among twin gestations.
True
What is one intervention that may help reduce the risk of having preterm and low-birth weight babies in a multiple gestation?
Adequate weight gain in the first 20-24 weeks of pregnancy.
What is twin-twin transfusion syndrome and in what type of twins is it most common?
The result of an intrauterine blood transfusion from one twin to the other; monochorionic, diamniotic twins
How do the twins present in twin-twin transfusion syndrome?
Donor twin: smaller and anemic
Recipient twin: larger and plethoric
List 2 clues to the presence of twin-twin transfusion syndrome.
- Large weight discordance (not necessary for diagnosis)
2. Polyhydramnios around the larger recipient twin and oligohydramnios are the smaller donor twin.
What is superfecundation?
Fertilization of two different ova at two separate acts of intercourse in the same cycle
___ increases the risk of morbidity and mortality and increases with higher orders of multiple gestations.
Preterm delivery (50+% of twins, 90+% of triplet, almost all quadruplet)
What are the associated risks of premature birth?
- Respiratory distress syndrome
- Intracranial hemorrhage
- Cerebral palsy
- Blindness
- Low birth weight
The optimal mode of delivery for twins in which the first twin is in the breech presentation is by ___.
Cesarean delivery (ECV in twins is contraindicated for the presenting twin)
In pregnancies with size greater than dates and an elevated maternal serum AFP, what is the next best step in management?
U/S
Conjoined twins can be diagnosed using standard U/S as early as when?
The end of the first trimester
What are thoracopagus twins?
Conjoined twins joined face to face at the chest
What is the most common abnormal karyotype encountered in spontaneous abortions, accounting for ~40-50% of cases?
Autosomal trisomy
Triploidy - 15%, Tetraploidy - 5%, Monosomy X - 15-25%
What is the most common chromosomal aneuploidy noted in spontaneous abortions?
Trisomy 16
The risk of developing microcephaly and severe intellectual disability is greatest between ___ weeks gestation.
8-15
The Committee on Biological Effects reported that no risk of intellectual disability has been documented with doses even exceeding 50 rad at less than ___ weeks and or greater than ___ weeks gestation.
8; 25
___ is the most common inherited thrombophilic disorder, affecting ~5% of Caucasian women in the United States.
5
What happens in FVL mutation?
Point mutation alters factor V, making it resistant to inactivation by protein C, leading to a thrombophilic effect
The FVL mutation is associated with obstetric complications, including what 4 things?
Stillbirth, preeclampsia, placental abruption, and IUGR
How might a fetus with Trisomy 18 be detected?
Likely to have congenital anomalies on prenatal U/S
More than ___% of cases of Trisomy 21 and 18 may be detected with the ___ screen.
90; quad
A congenital parvovirus infection associated with fetal demise would likely cause ___ in the fetus, which would be identified on U/S.
Hydrops
Uncontrolled ___ during ___ is associated with a high rate of birth defects.
Diabetes; organogenesis
What are the most common sites affected by uncontrolled diabetes during organogenesis?
The spine and the heart (although all birth defects are increased)
What happens when fetuses in utero are exposed to high levels of glucose transplacentally?
Increased growth and polyuria leading to an increase in the amniotic fluid volume
While some viral infections are also associated with placentomegaly and polyhydramnios, the fetus will have ___ growth depending on the timing of the infection.
Normal or decreased
Severe HTN and active anti-phopspholipid antibody syndrome are often associated with ___ and ___.
Oligohydramnios; IUGR
The risk of ___ is increased if hypothyroidism goes untreated.
Miscarriage
The most likely cause of painless cervical dilation that leads to pelvic pressure, bulging membranes, and fetal loss is ___.
Cervical incompetence or insufficiency (look for a history of cone biopsy)
True or false - although uncontrolled diabetes can lead to fetal malformations and early miscarriage, it is not typically a cause of fetal loss in the second trimester.
True
What risks are associated with advanced maternal age?
Stillbirth, preeclampsia, gestational diabetes, IUGR
What test should be done on all women with vaginal bleeding during pregnancy (unless documented earlier in the pregnancy)/
Maternal blood type
In the setting of vaginal bleeding during pregnancy and a patient with Rh-negative blood type, what is indicated?
RhoGAM
List the risks associated with gestational diabetes.
- Fetal death
- Fetal macrosomia (IUGR can also occur)
- Polyhydramnios
- Congenital malformations (CV, neural tube defects, caudal regression syndrome)
- Preterm birth
- Hypertensive complications
Stages of grief?
Denial, Anger, Bargaining, Depression, Acceptance
In the setting of intrauterine fetal demise, what can help the parents through the bereavement process?
- Allowing the parents to decide when to deliver
- Keeping the patient adequately anesthetized during L&D
- Letting the parents hold the baby for as long as they desire
- Allowing the parents to decide whether to have care on the maternity floor
- Offering an autopsy to determine the cause of death
- Having someone take pictures and keeping mementos for the parents
What indicates an early viable pregnancy?
Presence of a yolk sac, appropriate levels of hCG and progesterone
What are U/S criteria for a missed abortion?
Crown rump length of >7 mm with no cardiac activity
If a patient has an arrest of dilation in the active phase of labor, what is a reasonable next step?
Start oxytocin to increase the frequency and strength of contractions
If a patient has an arrest of dilation in the active phase of labor, is given oxytocin, and still does not have cervical chance once she is having more frequent contractions on oxytocin, what would be a reasonable next step?
Place an IUPC to assess the strength of the contractions
In a patient whose cervix is unfavorable, how should the process of induction be started?
Misoprostol administration prior to oxytocin induction; Foley bulb or AROM cannot be achieved in a patient with a closed cervix
What 9 things are associated with breech presentation?
- Prematurity
- Multiple gestation
- Genetic disorders
- Polyhydramnios
- Hydrocephaly
- Anencephaly
- Placenta previa
- Uterine anomalies
- Uterine fibroids
Define prolonged latent phase.
> 20 hours for nulliparas
>14 hours for multiparas
Prolonged latent phase may be treated with ___ or ___.
Rest; augmentation of labor
Why is AROM not recommended in the latent phase of labor?
It places the patient at increased risk of infection
List the 6 risk factors associated with an increased incidence of shoulder dystocia.
- Fetal macrosomia
- Maternal obesity
- DM
- Post-term pregnancy
- Prior delivery complicated by a shoulder dystocia
- Prolonged second stage of labor
Define secondary arrest of dilation.
No further cervical change in the active phase for more than 4 hours
What is often recommended in the setting of secondary arrest of dilation?
Amniotomy
When is continued monitoring of labor appropriate?
If clinical evaluation indicates that the fetus is not macrosomic or there is no obvious fetopelvic disproportion; if either were indicated, C-section would be indicated
If a patient is remote from delivery with a category III FHR tracing, what is indicated?
C-section
Cord prolapse occurs in less than 1% of pregnancies and is associated with ___, in particular ___.
Abnormal fetal presentation; backup transverse lie
Cord prolapse is more common in women who have ___, ___, or a ___. There is no association with maternal age or parity.
ROM, polyhydramnios, premature or small fetus
What is the next best step in a patient presenting with shoulder dystocia + retraction of the fetal head?
McRoberts maneuver - hyperflexing the mother’s legs to her abdomen, which widens the pelvis and flattens the lumbar spine
What interventions are contraindicated with shoulder dystocia?
Fundal pressure and operative vaginal delivery
What is a significant risk factor for placental abruption?
Polyhydramnios with rapid decompression of the intrauterine cavity
Typically, normal labor progresses about ___/hr in the active phase of labor.
1cm (multiparous women can progress 1-2cm/hr)
What is placenta accreta?
Occurs when the placenta grows into the myometrium
List risk factors for placenta accreta.
- Hx of prior C-section -> scar tissue formation, which can prevent proper implantation of the placenta
- Low anterior placenta
What is vasa previa?
Rare condition where the umbilical cord inserts into the membranes and the exposed vessels are over the cervix
What are common signs of a placental abruption?
Abdominal pain, bleeding, uterine hypertonus, fetal distress
What are risk factors for placental abruption?
Smoking, cocaine use, chronic hypertension, abdominal trauma, prolonged PROM, multiparity, history of prior abruption
How is placental abruption treated?
Emergent C-section with appropriate resuscitation, including IV fluids and blood products as needed
What is placenta previa?
Abnormal location of the placenta
Maternal risks of placental abruption?
Excessive blood loss, DIC, possible hysterectomy
Fetal risks of placental abruption?
Neurological injury from anoxia or death
When is a double set-up examination indicated?
Only in the setting of marginal (anterior) previa with vertex presentation
Smoking increases the risk of several serious complications of pregnancy, including what 5 things?
Placental abruption, placenta previa, fetal growth restriction, preeclampsia, infection
What is bloody show?
During pregnancy, the cervix is extremely vascular and with dilation, a small amount of bleeding may occur; it is not of clinical significance and often occurs with normal labor
What are the components of cryoprecipitate?
Fibrinogen, von Willebrand’s, Factor 8 and 13, and fibronectin
In most cases, preterm labor is ___.
Idiopathic
What are some possible causes of preterm labor?
Most are idiopathic; dehydration and uterine distortion (from fibroids or structural malformations) can be associated with preterm labor. In some cases, it is due to iatrogenic causes (induction).
When is ampicillin indicated in the setting of preterm labor?
In patients whose GBS status is unknown; continue until culture result is negative or labor stops
What is the use of nifedipine in preterm labor?
Tocolytic agent used to do delay the progression of labor to allow for the benefit of betamethasone to hasten pulmonary maturation
When should terbutaline be used as a tocolytic?
Never - the FDA has indicated that it should not be used secondary to its side effects and lack of efficacy
In the setting of an intra-amniotic infection, what should be done?
Delivery; in the case of reassuring heart tones, there are no contraindications for labor induction.
Which tocolytics are contraindicated in patients with DM?
Terbutaline and ritodrine (FDA says no terbutaline anyway)
When is mag sulfate contraindicated?
Myasthenia gravis
When is indomethcain contraindicated?
After 32 weeks due to risk of premature ductus arteriosus closure
High levels of magneisum sulfate may cause ___ at 12-15 mg/dL or ___ at >15 mg/dL. What happens prior to this?
Respiratory depression; cardiac depression; diminished or absent deep tendon reflexes (areflexia)
Treatment with betamethasone from 24-34 weeks has been shown to increase ___ and reduce the incidence and severity of ___.
Pulmonary maturity; RDS
Treatment with betamethasone from 24-34 weeks is also associated with decreased ___ and ___ in the newborn.
Intracerebral hemorrhage; necrotizing enterocolitis
What is fibronectin?
Extracellular matrix protein thought to act as an adhesive between the fetal membranes and underlying decidua
The presence of fibronectin in the cervical mucus between 22 and 34 weeks is thought to indicate what?
A disruption or injury to the maternal-fetal interface
Fetal fibronectin is FDA-approved for use in women with symptoms of preterm labor from ___ to ___ weeks, and during routine screening of asymptomatic patients from ___ to ___ weeks.
24-35; 22-30
What makes fetal fibronectin a strong test?
It has a negative predictive value of 99.2% in symptomatic women (aka, 99/100 patients with a single negative test result will not deliver in the next 14 days). The PPV is 16.7.
MOA of mag sulfate?
Competes with calcium for entry into cells
MOA of indomethacin?
Non-specific COX inhibitor which blocks prostaglandin production
MOA of ritodrine?
Impairs intracellular cAMP concentration to facilitate myometrial relaxation
MOA of nifedipine?
CCB that interferes with calcium ion transfer through the myometrial cell membrane, thus decreasing the intracellular free calcium concentration and inducing relaxation
MOA of atosiban?
Oxytocin receptor antagonist that blocks the intracytoplasmic calcium release associated with contractions and downregulates prostaglandin synthesis
Preterm birth occurs in ___% of pregnancies and has several modifiable or preventable risk factors, including what?
10; smoking (most important risk behavior), alcohol use
Not associated with prior spontaneous abortion
True or false - there is a likelihood of recurrent preterm birth in a woman with a sister having recurrent preterm birth.
False - there is a likelihood of recurrent preterm birth in a woman with a prior history of preterm birth, but not with a sister having a recurrent preterm birth
