Obstetric Complications Flashcards
When is preterm birth?
- Birth after 20 weeks gestation and before 36 6/7 weeks
How is diagnosis of preterm birth done?
- Uterine contractions accompanied with cervical change or cervical dilation of 2 cm and/or 80% effaced
What causes preterm labor?
- Spontaneous
- Multiple gestations
- Preterm premature rupture of membranes (PPROM)
- Pregnancy associated hypertension
- Cervical incompetence or uterine anomalies
- Antepartum hemorrhage
- IUGR
What are some socioeconomic factors that cause PTL?
- African American’s twice as likely as Caucasians
- Decrease access to prenatal care
- High stress levels
- Poor nutrition
- Questionable genetic differences
What are some medical and obstetrical factors that cause PTL?
- Previous history of PTL
- History of second trimester abortion
- Repeated spontaneous first trimester abortions
- Bleeding in the first trimester
- UTI/genital tract infections
- Multiple gestation
- Uterine anomalies
- Polyhydramnios
- Incompetent cervix
What are some infections that may cause PTL?
- Bacterial vaginosis
What is done to help reduce PTL due to bacterial vaginosis?
- Treatment for group B strep, gonorrhea, and chlamydia
How does the length of the cervix affect PTL?
- Relative risk of PTL increases as cervical length decreases
- Checked via ultrasound
What is a screening tool used to check cervical length?
- Fetal fibronectin (FFN)
- Released from the basement of the fetal membranes
- Released in response to disruption of the membranes as with uterine activity, cervical shortening, or infection
When does the placental-vascular pathway begin?
- At time of implantation
What is seen at the level of the placental-decidual-myometrial interface?
- Immunologic component
- Vascular component
- Low resistance connection of spiral arteries
What could alteration to any of the components see at the level of the placental-decidual-myometrial interface do?
- May result in poor fetal growth which is a risk factor for PTL as well as growth restriction and preeclampsia
What is the stress-strain pathway?
- Mental and physical stress are thought to induce a stress response that increases the release of cortisol and catecholamines
What does cortisol do?
- Released from adrenals
- Stimulates early placental corticotropin-releasing hormone (CRH) gene expression and increased CRH levels are known to assist in labor at term
How do catecholamines affect PTL?
- Affect blood flow and can cause uterine contractions
What is the uterine stretch pathway?
- Uterine stretches as a result of increasing volume
- If the uterus gets to a “full term” size, then contractions may begin
What must be present for the diagnosis of PTL?
- Uterine contractions
- Cervical change or cervical dilation of 2 cm or greater AND/OR 80% effacement
What are the symptoms of PTL?
- Menstrual like cramping
- Low/dull backache
- Pelvic pressure
- Increase in discharge/blood discharge
- Uterine contractions
What is done to look for PTL?
- Initial assessment done with cervical exam to assess dilation, effacement and fetal presenting part
- Evaluate for any underlying correctable problems such as infections
- External monitoring for uterine activity and fetal heart rate
- Reevaluate the cervix and during that hour oral or IV hydrate
- Cultures are taken
What is done once a diagnosis has been made?
- CBC
- UA
- Urine culture
- Obtain an ultrasound
What is the management of PTL?
- If diagnosed 2 cm and/or 80% effaced or made cervical change then begin tocolysis (if gestational age is less than 34 weeks and no contraindication)
What does magnesium sulfate do?
- Acts on the cellular level and competes with calcium for entry into the cell at the time of depolarization
- May have a role in neuroprotection or prevention of cerebral palsy
How much magnesium sulfate is given?
- 6g load IV and then 3g/hour maintenance
- Therapeutic range is 5.5-7 mg/dL
- Continue until both doses of steroids are given
- Titrate down if uterine activity decreases
What are some maternal side effects of magnesium sulfate?
- Feeling of warmth and flushing
- Nausea and vomiting
- Respiratory depression
- Cardiac conduction defects and arrest at high serum levels
What are some neonate side effect of magnesium sulfate?
- Loss of muscle tone
- Drowsiness
- Lower Apgar scores
What is nifedipine?
- An oral agent effective in suppressing preterm labor
- Minimal maternal and neonatal side effects
What does nifedipine do?
- Inhibits slow, inward current of calcium during the second phase of the action potential
What side effects are seen with nifedipine?
- Headache
- Cutaneous flushing
- Hypotension
- Tachycardia
What do prostaglandin synthetase inhibitors do?
- Inhibit prostaglandin production that induce myometrial contractions
What is the most common prostaglandin synthetase inhibitor?
- Indomethacin which can be given orally
- Can result in oligohydramnios
- Can cause the premature closure of fetal ductus arteriosus and result in primary hypertension and heart failure
What are infants that are exposed to indomethacin at a higher rate of?
- Necrotizing enterocolitis
- Intracranial hemorrhage
What is the biggest risk with PTL?
- Fetal lung maturation
What is used for fetal lung maturation?
- Glucocorticoids which reduces mortality and incidence of RDS and intraventricular hemorrhage
When are glucocorticoids given?
- Given between 24 and 34 weeks gestation
How are glucocorticoids given?
- Either two doses of 12mg betamethasone given 24 hours apart or 4 doses of dexamethasone given every 12 hours
How long do the effects of glucocorticoids last?
- 7 days
What is the lower limit of viability?
- 22?-24 weeks or 500 grams
What should be done for a preterm infant?
- Continuous fetal monitoring and act quickly on abnormal patterns as premature infants have less reserves
What is the delivery method if there is vertex presentation?
- Vaginal is preferred
- Some recommend c section due to low birth weight
What is the delivery method if there is breech presentation?
- Increased risk of cord prolapse or compression as well as head entrapment with vaginal delivery therefore most will c-section
What are some prevention methods of PTL?
- IM progesterone
- Vaginal progesterone (used in women with short cervix)
- Pessary-Arabian pessary (used in women with short cervix)
What are some risk factors for PPROM?
- History of preterm premature rupture of membranes
- Vaginal/cervical infections
- Second and third trimester bleeding
- Incompetent/short cervix
- Low BMI
- Lower socioeconomic status
- Smoking and illicit drug use
- Nutritional deficiencies
How is the diagnosis of PROM made?
- Based on history
- Loss of fluid
- Confirmation of amniotic fluid in vagina
- Confirmed with a sterile speculum
Why do you not check the cervix of a presumed ruptured preterm patient?
- Increases the risk of infection especially during the prolonged latency before delivery
What are the three tests to confirm PROM?
- Pooling
- Nitrazine paper (turns blue)
- Ferning
- May also use ultrasound to evaluate amniotic fluid volume to aid in diagnosis
What are some causes of false positives in nitrazine results?
- Urine
- Semen
- Cervical mucous
- Blood
- Vaginitis
What are some causes of false negatives in nitrazine results?
- Remote PROM with no remaining fluid
- Minimal leakage
What are some maternal risks with management of PPROM?
- Endomyometritis
- Sepsis
- Failed induction due to unfavorable cervix
What does management of PPROM depend on?
- Gestational age at time of rupture (if less than 24 weeks, may lead to pulmonary hypoplasia)
- Amniotic fluid index (any value less than 5 cm is considered or no 2 cm deepest vertical pocket = oligohydramnios)
- Fetal status
- Maternal status
What is the goal of conservative management of PPROM?
- Continue pregnancy until lung profile is mature
- Usually will deliver around 34 weeks due to benefits of delivering outweighing the risks
What is monitored for and how is it diagnosed?
- Monitor for signs of chorioamnionitis
- Diagnosed by maternal temperature greater than 100.,4
- Fetal or maternal tachycardia
- Tender uterus
- Foul smelling amniotic fluid/purulent discharge
What antibiotic use is recommended in management of PPROM?
- 48 hour course of IV ampicillin and erythromycin/azithromycin followed by 5 days of amoxil and erythromycin
What tocolytic use is recommended in management of PPROM?
- No recommendation can be made for or against
- Can be used if no evidence of chorioamnionitis
- Use mainly to get steroids on board
What steroid use is recommended in management of PPROM?
- Use up to 34 weeks of gestation to reduce the risk of RDS
What is the outpatient management in PPROM?
- No real place for outpatient management
- May manage in cases of extreme prematurity until reaches viability
What is intrauterine growth restriction?
- When the birth weight of a newborn is below 10% for a given gestational age
What are growth restricted fetuses at risk for?
- Meconium aspiration
- Hypoxia
- Stillbirth
- Polycythemia
- Hypoglycemia
- Cognitive delay
- Adult onset conditions like HTN, DM, CAD, stroke
What are some causes of IUGR?
- Poor nutritional intake/low maternal body weight
- Cigarette smoking
- Drug abuse
- Alcoholism
- Cyanotic heart disease
- Pulmonary insufficiency
- Antiphospholipid syndrome
- Collagen vascular disease/autoimmune disorders
- Teratogen exposure
What are some placental causes of IUGR?
- Insufficient substrate transfer through placenta as well as defective trophoblast invasion
- Conditions that may result in placental insufficiency like HTN, renal disease, placenta or cord abnormalities, preexisting diabetes
What are some fetal causes of IUGR?
- Infectious diseases (listeria, TORCH)
- Congenital anomalies/genetic disorders
- Multiple gestations
- Chromosomal abnormalities
How is IUGR diagnosed?
- Physical exam –> fundal height
- Ultrasound –> biometry
- Direct studies –> amniocentesis or percutaneous umbilical blood sampling
- Doppler studies
How is IUGR managed pre-pregnancy?
- Optimizing disease processes
- I.E. blood sugar control in diabetes, control of HTN
How is IUGR managed in antepartum?
- Decrease any modifying factors –> improve nutrition, stop smoking
- Goal is to deliver before fetal compromise but after fetal lung maturity
What is monitored in antepartum?
- Non-stress test twice weekly
- Biophysical profile
- Doppler studies of umbilical artery
What is post term pregnancy?
- Pregnancy that continues past 42 weeks
What is seen in post term pregnancy?
- Perinatal mortality is 2-3x higher
- Postmaturity syndrome
What is postmaturity syndrome?
- Related to aging and infarction of the placenta
- Loss of subcutaneous fat, long fingernails, dry and peeling skin and abundant hair
What are some etiologies of postterm pregnancy?
- Usure due dates
- Fetal adrenal hypoplasia
- Anencephalic fetuses
- Placental sulfatase deficiency
- Extra-uterine pregnancy
What is the management of a postterm pregnancy?
- In 41st week: begin antenatal testing to include twice weekly NST and biophysical profile
- In 42nd week: induction of labor
- Induction of labor at 41 weeks is preferred
What is intrauterine fetal demise?
- Fetal death after 20 weeks gestation but before onset of labor
What are some causes of IUFD?
- Most are unknown (50%)
How is IUFD diagnosed?
- Suspect if patient complains of absence of fetal movements or if unable to Doppler fetal heart tones
- Confirm by ultrasound with lack of fetal activity and absence of fetal cardiac activity
What is the follow up on an IUFD?
- TORCH titers
- Parvovirus studies
- Listeria cultures
- Anticardiolipin antibodies
- Hereditary thrombophilias
- Fetal chromosome studies
- Fetal autopsy
