Labor & Delivery Flashcards
What are braxton hicks contractions?
also known as false labor, they are contractions not associated with dilation of the cervix
How can braxton hicks contractions be differentiated from true labor?
- they are typically shorter in duration and less intense with discomfort being characterized as over the lower abdomen and groin areas
- they are often resolved with ambulation, hydration, or analgesia
- by contrast, true labor is associated with contractions that are longer in duration, more intense, felt over the fundus with radiation of discomfort to the low back and lower abdomen, and become increasingly intense and frequent with time
What is “lightening”?
changes experienced by the patient which result from the fetal head descending into the pelvis late in pregnancy
- the lower abdomen becomes more prominent
- urinary frequency is exacerbated
- breathing is easier
- the baby feels lighter
What is a “bloody show”?
the passage of blood-tinged mucus late in pregnancy as the cervix begins effacement with concomitant extrusion of mucus from the endocervical glands
What do the terms “lie,” “presentation,” and “position”? mean with regards to labor?
- lie is the relation of the long axis of the fetus to the maternal long axis (longitudinal, transverse, or oblique)
- presentation is the present part (cephalic or breech)
- position is the relation of the fetal presenting part to the right or left side of the maternal pelvis
What is a vertex presentation?
a specific type of cephalic presentation in which the head is sharply flexed onto the fetal chest
What is the purpose of the four leopold maneuvers?
- determining what occupies the fundus, either the head or breech
- determining the location of small parts, either the spine or the limbs
- identifying descent of the presenting part
- identifying the cephalic prominence
Give three reasons to avoid vaginal examination in a women being evaluated for labor?
- premature ROM
- placenta previa
- vaginal bleeding
What is effacement and what terminology is used to describe it?
it is the shortening of the cervical canal from about 2 cm to nearly nothing, expressed as a percent of thinning from a perceived uneffaced state
Why is it significant if on a vaginal exam, a laboring woman has a cervix that is palpable more anteriorly in the vagina?
it suggests the presenting part has descended into the pelvis and means it is more likely than a posterior cervix to undergo change soon
What is pelvic station and how is it communicated?
- it is the level of the presenting part in relation to the ischial spines, which are located halfway between the pelvic inlet and pelvic outlet
- the spines are said to be zero station with each centimeter above being a negative station and each below a positive station (plus or minus 5)
Pelvic station is based on what anatomic landmark?
the ischial spines, located halfway between the pelvic inlet and pelvic outlet
What is the clinical significance of zero station?
when the presenting part of the fetus is at zero station, it suggests that the biparietal diameter of the head, the widest part, has successfully negotiated the pelvic inlet
What anatomic landmarks define the pelvic inlet?
the sacral promontory and symphysis pubis
What are the stages of labor?
- stage 1 latent phase: cervical effacement and early dilation
- stage 1 active phase: more rapid cervical dilation, usually beginning at 6 cm
- stage 2: complete cervical dilation through the delivery of the infant
- stage 3: immediately after delivery of the infant until delivery of the placenta
- stage 4: the immediate postpartum period of about 2 hours after delivery of the placenta during which the patient undergoes physiologic adjustment
List the seven cardinal movements of labor.
- engagement
- flexion
- descent
- internal rotation
- extension
- external rotation
- expulsion
Describe the seven cardinal movements of labor.
- engagement: descent of the biparietal diameter below the pelvic inlet, usually days to weeks prior to labor in nulliparous women
- flexion: the head flexes against the chest to allow the smallest diameter of the head to present to the maternal pelvis
- descent of the presenting part through the birth canal
- internal rotation facilitates presentation of the smallest diameter
- extension to accommodate the upward curve of the birth canal
- external rotation to bring the face forward in relationship to the shoulders
What is the problem with laboring in a supine position?
it leads to compression of the vena cava by the uterus, reducing venous return and thus cardiac output, leading to hypotension
What is the position commonly used in the US for labor?
the dorsal lithotomy position
Why are laboring patients told to avoid oral ingestion of anything except clear fluids?
because if they require anesthesia, aspiration becomes a concern
What sort of fluids would you use to hydrate a laboring patient if oral hydration was insufficient?
- likely half normal saline or D5 half normal saline
- lactated fluids are contraindicated because of the metabolic acid deficit incurred by the lactate
What are lactated ringers contraindicated during labor?
because they incur a metabolic acid deficit
What vertebral levels transmit the pain associated with early and late labor?
- during the first stage, pain from the cervix travels along visceral afferents, which return to T10-T12 and L1
- as the head descends, the lower birth canal and perineum are distended and pain is transmitted along the somatic afferents comprising portions of the pudendal nerves entering at S2-S4
What is an epidural? What is spinal anesthesia?
- epidural: an infusion of local anesthetics or narcotics through a catheter into the epidural space
- spinal: a single injection of anesthetic which affords about two hours of relief
What are two regional forms of anesthesia available during labor?
epidural and spinal anesthesia
How is a pudendal block given?
the ischial spine is located through the vagina and the injection is made just inferomedially to the spine through the sacrospinous ligament
What are the benefits of an epidural over spinal anesthesia?
- it provides a continuous source of anesthesia
- it can be titrated to maintain the patient’s sense of touch and motor ability, facilitating participation in the birthing process
What is the primary complication of spinal anesthesia or epidural?
posdural puncture headache
When do we typically use local blocks during labor?
to provide anesthesia for episiotomies and repair of vaginal and perineal lacerations
When assessing a patient is stage one of labor, what is important to assess?
dilation, effacement, station, position, and the status of the membranes
How do we describe fetal position during labor?
- left/right, presenting part, anterior/posterior/transverse
- so if the babies face is to the left and facing the mom’s posterior then it would be right occiput anterior
What is the median combined time for stage 1 and 2 of labor for nulliparous and multiparous women?
- nulliparous: 5.9 hours
- multiparous: 4.3 hours
If patients get the urge to push during the first stage of labor, what does this indicate, what should you tell them, and why is this the case?
- it indicates the fetal head has likely descended and is applying pressure on the perineum
- tell them to avoid pushing
- if they push against the cervix before it is fully dilated and effaced, it will cause traumatic swelling, adding time to the process of dilation
What risks are associated with artificial rupture of membranes?
- increases the risk of infection
- increases the risk of umbilical cord prolapse if the head has not already engaged
Mothers shouldn’t begin pushing during labor until what point?
second stage
What is caput succedaneum?
edema of the fetal scalp caused by pressure on the fetal head by the cervix, which, like molding, may cause an overestimation of the amount of descent
What two fetal changes may cause an overestimation of fetal descent?
molding and caput succedaneum (edema of the scalp)
What are the indications for episiotomy?
there are no current indications for the procedure
What is the modified Ritgen maneuver?
a method for delivering the head with extension while supporting the perineal tissues
- place one hand over the vertex while the other exerts pressure through the perineum onto the fetal chin
- the chin can be delivered slowly this way, protecting the perineum
Describe how to assist with a delivery after the head begins to crown?
- use the modified Ritgen maneuver, placing one hand over the vertex while the other exerts pressure through the perineum to slowly deliver the chin
- turn the head so it is forward facing in relation to the shoulders
- apply downward pressure with a hand on both sides of the head to deliver the anterior shoulder
- apply upward traction to deliver the posterior shoulder
What indications are there that the placenta has separated from the uterus?
- the uterus becomes globular
- there may be a gush of blood
- there may be a lengthening of the umbilical cord
What is the feared complication of applying too much traction to the placenta before it has separated from the uterus passively?
this may result in inversion of the uterus with profound blood loss and shock
What technique is used to deliver the placenta?
apply gentle downward traction on the umbilical cord while the abdominal hand applies gentle suprapubic counter pressure to secure the uterine fundus and prevent inversion
What medical therapies are available for the treatment of uterine atony?
- oxytocin
- methylergonovine maleate
- prostaglandins such as carboprost or misoprostol
What is the incidence and what are the risk factors for postpartum uterine hemorrhage?
- incidence of 1%
- most commonly occurs in the first hour after delivery of the placenta
- more likely in cases of rapid labor, protracted labor, intrapartum chorioamnionitis, or uterine enlargement secondary to LGA, polyhydramnios, or multiple gestations