Question | Answer |
Physiologic process by which a fetus is expelled from the uterus | Labor |
Defined as an increase in myometrial contractility resulting in effacement and dilation of the uterine cervix | Labor |
What are the two major functions of contractions during labor | To dilate the cervix, to push the fetus through the birth canal |
What are the three mechanical variables during delivery known as the three P’s | the powers, the passenger, and the passage |
One of the three P’s it is the force generated by uterine musculature | Powers |
What does an external tocodynamometer measure | Number of contractions in an average 10 minute window, intensity, and duration of contractions |
What is the most precise method of measuring contractions | Intrauterine pressure monitoring via internal pressure transducers (IUPC) |
What is classically considered to be adequate labor | 3-5 contractions in 10 minutes, however there is no consensus for criteria |
Macrosomia is considered to be an infant over __ | 4,500 g |
What is the lie of the fetus | The longitudinal axis of the fetus to the uterus |
What are the different presentations of the fetus | vertex, breech, shoulder, compound |
What does the station of the fetus mean | A measurement of descent through the birth canal |
How often are breech presentations found in term pregnancies | 3-4% |
External cephalic version is routinely done after __ weeks | 36 |
What landmarks designate 0 station for the fetus | Ischial spines |
Cardinal movements of labor: passage of widest diameter of presenting part to below the plane of the pelvis | Engagement |
Cardinal movements of labor: downward passage of presenting part through the pelvis | Descent |
Cardinal movements of labor: passive flexion of fetal head as it descends due to resistance related to body pelvis | Flexion |
Cardinal movements of labor: rotation of presenting part (usually from transverse to anterior-posterior) | Internal rotation |
Cardinal movements of labor: brings base of occiput in contact with the inferior margin of the pubic symphysis, head is delivered by extension | Extension |
Cardinal movements of labor: rotation to the correct anatomic position in relation to the fetal torso | External rotation (restitution) |
Cardinal movements of labor: delivery of body of fetus | Expulsion |
What are the Cardinal movements of labor | Engagement, descent, flexion, internal rotation, extension, external rotation (restitution), expulsion |
What is the first stage of labor | Onset of labor to full dilation |
What is the second stage of labor | Interval between full dilation (10cm) and delivery |
What is the third stage of labor | Time from delivery to expulsion of placenta |
What are the risks of parenteral pain management in labor (fentanyl PCA) | Maternal risk for aspiration and respiratory depression, fetal risk for respiratory depression (common need for Narcan at delivery) |
An epidural may slow down labor, however it does not increase the risk of __ | C-section |
__ is characterized by the slow, abnormal progression of labor | Dystocia of labor |
What is the leading indication of primary c-section | Dystocia of labor |
What is the rate of c-section in the US | 1 in every 10 births |
60% of all c-sections in the US are attributable to the diagnosis of __ | Dystocia of labor |
What terms should we never use when talking about dystocia of labor | Failure to progress, or CPD (cephalopelvic disproportion) |
What are acceptable terms to use when referring to dystocia of labor | Labor slower than normal (protraction disorder), complete cessation of progress (arrest disorder) |
What are the risk factors for prolonged labor | Older, medical (DM, HTN, obesity), macrosomia, prolonge rupture of membranes and or chorioamnionitis, short maternal stature, high station at complete dilation, occiput posterior position, pelvic abnormalities |
What are the intervention options for arrest of descend | Forceps, vacuum, c-section |
What is AROM | Artificial rupture of membranes |
What are the contraindications of labor induction | Prior classical c-section, active genital herpes, placenta or vasa previa, umbilical cord prolapse, transverse lie |
What is the best tool to predict the likelihood of successful labor induction (resulting in vaginal delivery) | Bishop score |
A bishop score of __ or greater is favorable for induction of labor | 6 |
What are cervical ripening agents | Prostaglandins such as misoprostol |
List the methods of labor induction | Cervical ripening agents (misoprostol), membrane stripping, oxytocin, mechanical dilation, amniotomy (artificial rupture of membranes) |
What is the mechanism by which membrane stripping works to induce labor | Increases prostaglandin release |
Delivery that requires additional maneuvers following failure of gently downward traction on the fetal head to effect delivery of the shoulders | Shoulder dystocia |
What is the rate of shoulder dystocia | .06-1.4% of deliveries |
What are the risk factors for shoulder dystocia | Maternal obesity, diabetes, hx of macrosomic infant, current macrosomia, hx of shoulder dystocia |
Warning signs of shoulder dystocia | Prolonged 2nd stage, recoil of head on perineum (turtle sign), lack of spontaneous restitution |
Fetal complications of shoulder dystocia | Brachial plexus injury, clavicle/humerus fx, asphyxia |
Treatment for shoulder dystocia | McRoberts maneuver, episiotomy, suprapubic pressure, Rubin’s screw, Wood’s screw, delivery of posterior shoulder (humerus fx), Zavanelli |
What is McRoberts maneuver | Dorsiflexion of hips against the abdomen to ease birth of fetus with shoulder dystocia. |
What is the most common cause of postterm pregnancy | Error in dating |
With postterm pregnancy what are the risks to the fetus | Stillbirth, meconium aspiration, intrauterine infection, uteroplacental insufficiency |
With postterm pregnancy what are the risks to the mother | Increased labor dystocia, perineal injury related to macrosomia, and c-section rate |
What are the leading causes of preterm deliveries | Preterm labor (PTL) and preterm premature rupture of membranes (PPROM) |
Preterm delivery is before __ weeks | 37 |
Major determinant of infant mortality in developed countries | Preterm delivery |
Preterm delivery is particularly acute among what group | African Americans |
Leading cause of developmental disability in children | Preterm delivery |
What are the key risk factors for preterm delivery | Smoking, African American, maternal age (young and old), social factors (poverty, poor housing, crime) |
The fetal fibronectin test has a high __ value in predicting delivery within the next 14 days | Negative predictive |
What is the best tool we have right now to determine patients not at risk for imminent delivery | Fetal fibronectin and cervical length |
What is the purpose for prolonging pregnancy when the patient goes into preterm labor | To allow administration of steroids for fetal lung maturity and maternal transport to a facility with a NICU |
What doesn’t work in preventing preterm labor | Bedrest, hydration, pelvic rest, antibiotics |
What are the tocolytic agents used in the management of pre term labor | Beta-mimetic (terbutaline), magnesium sulfate, calcium channel blockers (Procardia), prostaglandin synthetase inhibitors (indomethacin) |
What should be given to women at risk for preterm delivery between 24-34 weeks to reduce the risk of respiratory distress syndrome, mortality, and intraventricular hemorrhage | Antenatal steroids (betamethasone, dexamethasone) |
What are the risk factors for PPROM | Intraamniotic infection, prior hx, lower SES/teens, smokers, hx of STD, hx of cervical cerclage, uterine overdistention |
What do you do if the mother goes in to labor any time after 34 weeks | Proceed with delivery, GBS prophylaxis |
What do you do if the mother goes in to labor between 24/23 -31 weeks | Expectant management, GBS prophylaxis, steroids recommended, tocolysis, antibiotics |
What do you do if the mother goes in to labor before 24/23 weeks | Patient counseling about poor outcome, expectant management, no steroids, no GBS prophylaxis or antibiotics |