Part 2 Flashcards
time frame of childbirth considered premature
20-37 weeks
1 cause of neonatal morbidity and mortality
prematurity
cervical changes without uterine contractions are typically d/t
cervical insufficiency
cervical insufficiency definition
painless shortening or dilation of the cervix that occurs in the second or early 3rd trimester and results in preterm birth
cervical insufficiency is related to _____% of second trimester miscarriages
25%
cervical insufficiency is associated with what possible pathologies?
uterine anomalies DES exposure Cervical procedures (ie: conization)
what is cervical cerclage?
treatment for cervical insufficiency in which stitches are used to close the cervix during pregnancy in order to help prevent pregnancy loss or premature birth
When is cerclage done, removed, and who can’t get it?
- done around weeks 14-16
- removed around weeks 36-38
- ineligible if the mother has cervicitis, dilation > 4 cm, or if the membranes have already ruptured
what are braxton hicks contractions?
contractions that occur without causing cervical changes
painless contractions that are felt as tightening or pressure and
last 10-20 minutes
aka false labor
usually get better with walking/activity
how many contractions are needed in order for cervical change to occur
> 4/hour
what are contractions felt as?
abdominal tightening, low back pain, or pelvic pressure
in order to be termed “preterm labor” what must be present?
contractions that are causing cervical effacement or dilation
what is the cause of preterm labor?
no idea
what are some risk factors for preterm labor?
- Smoking
- Cocaine
- Uterine malformation
- Cervical incompetence
- Infection (STI, Group B Strep, UTI/Pyelo)
- Low pre-pregnancy weight of mother
what are some complications of preterm labor for the mother and fetus?
- Hypertension
- Diabetes
- Infection
- PROM
- Abruptio placentae
delivery of a baby
at a hospital with a NICU
cervical changes associated with preterm labor
- Dilation of > 2 cm at presentation
- Dilation of > 1 cm at serial exams
- Effacement > 80% (2 cm)
what are some late symptoms of preterm labor?
- Bloody mucus vaginal discharge (“bloody show”)
- Contractions, pressure, cramps, and low back pain
what cervical length (found on US) increases the risk of preterm labor?
cervical length of 2 cm at 24 weeks
what is significant about Fetal Fibronectin found in cervical/vaginal secretions?
if present, the risk raises for delivery of the fetus within 2 weeks
If cervical length is less than 4 cm and Fetal Fibronectin is absent =
50% chance of delivery before 34 weeks
If cervical length is 4 cm and Fetal Fibronectin is absent =
11% chance of delivery before 34 weeks
3 reasons to get amniocentesis for diagnosis of preterm labor
obtain lung maturity if estimated gestation date is uncertain
if you suspect chorioamnionitis
if the fetus is > 34 weeks gestation
how is preterm labor managed?
Decisions are made based on estimated gestation date, estimated weight of the fetus, and existence of contraindications to suppressing preterm labor
antibiotics given for Group B Strep
Penicillin or Ampicillin
Cefazolin, clindamycin, erythromycin or vanco if PCN-Allergy
when do you stop antibiotics for Group B Strep?
if the re-test in 5 weeks is negative
what do you give to help the fetus develop it’s lungs?
steroids
what are tocolytics?
drugs that stop contractions
what is the goal of using tocolytics in regards to preterm labor?
- short term goal is to continue the pregnancy for 48 hours after steroid use to ensure lung maturity and viability
- long term goal is to continue the pregnancy past 34-36 weeks when fetal morbidity and mortality decrease
who is considered for the use of tocolytics in preterm labor?
mother’s with cervical dilation less than 5
what is considered “successful” tocolytic use?
when contractions fall to less than 4 to 6 per hr
tocolytic: magnesium sulfate -side effects -signs of toxicity -treatment of toxicity -begin use when
-Side effects:
nausea, fatigue, muscle weakness
-Signs of Magnesium toxicity:
decreased reflexes, respiratory depression, cardiac collapse
-Treat toxicity with calcium gluconate
-Begin when preterm birth is expected within 2-24 hours, gestational age confirmed between 24-32 weeks, and when any contraindications to Magnesium have been ruled out
tocolytic: CCBs (Nifedipine) -how does it work? -side effects
- inhibit calcium uptake into uterine muscle cells (via voltage-dependent channels) which reduces uterine contractility and relaxes uterine muscles
- SEs: hypotension, tachycardia
tocolytic: beta-mimetic adrenergic agents -action -side effects -used only to -drug used and how
- Direct action on beta 2 receptors to relax uterus
- Severe side effects - dose related cardiovascular effects (pulmonary edema, adult RDS, elevated SBP, reduced DBP, tachycardia)
- Used only to stabilize and triage until other tx determined
- Terbutaline: Not FDA approved; Use subcutaneous boluses only in an inpatient setting for max of 48-72 hrs
tocolytic: prostaglandin synthase inhibitors -drug name -MOA -fetal side effects -requires you to check for -limited use for who
- Indomethacin
- Inhibits prostaglandin synthesis (prostaglandin is a mediator of uterine muscle contractility)
- Serious fetal effects: Oligohydramnios, Premature closure of ductus arteriosus (PDA), Intracranial hemorrhage
- Requires US every 48-72 hrs to check for oligohydramnios
- Limited to
when is a cesarian used in preterm labor?
For borderline cases (23-24 wks and 500-600g wt) - regard the parents’ wishes
how is preterm labor prevented?
- Avoid risk factors
- Administer Progestin if mother has a prior history of preterm labor _ Weekly IM injections of 17-alpha hydroxyprogesterone caproate from 16-36 weeks decreases risk of recurrence by 30% _ Vaginal suppositories may reduce the risk of short cervix
what is a cesarian?
-Delivery of fetus, placenta, and membranes through an abdominal and uterine incision -Indicated in cases where vaginal delivery is either not feasible or would impose undue risks to the mother or baby
risk of cesarian
-Thromboembolus -Excessive bleeding -Infection -Fetal tachypnea -Fetal hemorrhage and hypoxia w/placenta transected
why are cesarian rates increasing?
-Lower rates of vaginal births after C-section (VBAC) (1/3 of caesarians) -Lower operative vaginal delivery rates (vacuum, forceps, or suction) in regards to dystocia or failure to progress and fetal distress -Fewer vaginal breech deliveries -basically we’re getting wimpy, and when complications arise we find it easier just to cut the woman open
what are the 3 P’s that must be adequate in order for a vaginal delivery to occur?
power passenger pelvis
what is labor dystocia?
labor progresses and then either stops completely (arrests) or becomes prolonged (protracted)
the fetal head is too large to pass through the pelvis when (3 disproportions)
-Inlet disproportion - in the primigravida - patient begins labor with the fetal head unengaged -Midpelvic disproportion - if the anteroposterior diameter is short, the ischial spines are prominent, or the sacrospinous ligament is short -Outlet disproportion - usually requires a trial of forceps or vacuum before a safe vaginal delivery is determined to be impossible
other reasons for cesarian
-fetal heart rate abnormalities (decelerations are bad) -transverse lie or breech presentation -Placenta previa -Preeclampsia/eclampsia -Placental abruption -Multiple gestations -Fetal abnormalities -Cervical cancer -Active genital herpes infection
success of a vaginal birth after cesarian (VBAC) depends on -dystocia -mal-presentation -uterine rupture
how many they’ve had before and why they needed them -Dystocia - lower rate of successful VBAC -Mal-presentation - higher rate of VBAC success -Uterine rupture rate (weakened wall) after low transverse incision is low, but can lead to death of fetus and morbidity/mortality of the mother
best candidates for VBAC
-1 prior low-transverse caesarean section -Those who present in labor -Those with nonrecurring conditions (eg: no breech, abnormal fetal heart rate patterns, or placenta previa in prior pregnancy) -Those with a prior vaginal delivery
who cannot get a VBAC
-Prior classical (vertical) uterine incision -Prior myomectomy
cesarian incision
-A low transverse (Pfannenstiel) uterine incision is usually made in an effort to decrease blood loss, ease repair, and decrease the risk of rupture vs vertical incision (also better for cosmetic purposes)
complications of cesarian
-postpartum hemorrhage -endometritis (prophylactic ABX often used to avoid this) -wound infection -incision healing
what is an episiotomy
laceration used to help ease of a vaginal delivery
what does an episiotomy increase the risk of?
postpartum incontinence
why are episiotomies recommended?
- If extensive vaginal tearing appears likely -Infant is in an abnormal position -Infant is large (fetal macrosomia) -Infant needs to be delivered quickly
what are the 2 episiotomy incision options and their pros/cons?
-Midline or median: done vertically; is the easiest to repair but has a higher risk of extending into the anal area -Mediolateral: done at an angle; offers the best protection from an extended tear affecting the anal area, but is often more painful and may be more difficult to repair
what can be done to decrease the need for an episiotomy?
-Perineal massage, either antepartum or during the second stage of labor, can decrease muscular resistance and reduce the likelihood of laceration -Use of warm compresses on the perineum during pushing can reduce third-degree and fourth-degree lacerations
first degree laceration
Injury to perineal skin only
second degree laceration
Injury to perineum involving muscles but not the anal sphincter
third degree laceration
Injury to perineum involving the anal sphincter complex
IIIa degree laceration
Less than 50% of external sphincter torn
IIIb degree laceration
More than 50% of external sphincter torn
IIIc degree laceration
Both external sphincter and internal anal sphincter torn
fourth degree laceration
Injury to the perineum involving the anal sphincter complex (external and internal sphincters) and anal epithelium
natural labor pain management (3)
-Lamaze -Hypnosis -Relaxation/meditation
things to think about when administering pharmacological pain relief to the mother during labor…
-All analgesics cross the placenta -Systemic medications produce higher maternal and fetal blood levels than regionally administered drugs -Many drugs have central nervous system depressant effects -While they may have the desired effect on the mother, they also may exert a mild to severe depressant effect on the fetus or newborn
what class of drugs are commonly used in the first stage of labor because they produce both a state of analgesia and mood elevation?
narcotics
narcotic: Codeine
60mg IM
narcotic: Meperidine
50-100mg IM (or 25-50mg IV titration)
narcotic: Fentanyl
PO or Epidural
narcotic: Sufentanil
-Derivative of Fentanyl with increased potency and lipophilicity -Widely used for intrathecal and epidural analgesia during labor
narcotic: Remifentanil
-Newer ultra-short-acting synthetic opioid with rapid onset (~1 min) -Rapidly metabolized by nonspecific blood and tissue (not renally or hepatically - so it does no accumulate in the fetus)
narcotic: Butorphanol (Stadol)
-1-2 mg IV or IM every 3-4 hours -Onset of analgesia is within a few minutes -Less respiratory depression compared with an equivalent dose of Morphine
narcotic: Nalbuphine (Nubain)
-Mixed agonist.antagonist opioid similar to Butorphanol but potency is equivalent to that of Morphine (mg:mg)
narcotic: Propofol
-Ideal agent for induction of general anesthesia at a dose of 2 mg/kg -It also can be used in 10- to 20-mg increments during surgery under regional block to treat nausea and vomiting.
narcotic: Etomidate
-Rapid onset of anesthesia with minimal cardiorespiratory effects makes it ideal for those who are hemodynamically unstable -Induction dose of 0.2-0.3 mg/kg -Undergoes a rapid hydrolysis that leads to quick recovery
narcotic: Ketamine
-Stimulates the cardiovascular system to maintain heart rate, blood pressure, and cardiac output -Useful in the setting of major blood loss, when rapid induction of general anesthesia is required. However, it has significant hallucinogenic effects that limit its utility in obstetrics -Maternal cardiovascular status and uterine blood flow are well maintained. Effective low doses of 0.25-0.5 mg/kg but without loss of consciousness or protective reflexes -The margin of safety is narrow, so it should be used only by physicians able to easily secure and protect the airway if loss of consciousness occurs -For caesarean delivery, general anesthetic induction can be produced with 1-2 mg/kg IV
most commonly use inhalation anesthetics (3)
sevoflurane desflurane isoflurane