This site is 100% ad supported. Please add an exception to adblock for this site.

OB Test 2


undefined, object
copy deck
What 5 factors influcence labor?
the passage, the fetus, the relationship between the passage and the fetus, the physiologic forces of labor, and the psychosocial considerations
Name and describe the 4 types of pelvic types.
*Gynecoid- inlet rounded with all inlet diameters adequate.

*Android- inlet heart shaped with short posterior sagittal diameter, midpelvis diameter reduced, and outlet capacity reduced.

*Anthropoid- inlet oval in shape, with long anterposterior diameter, midpelvis diameters adequate, outlet adequate.

*Platypelloid- inlet oval in shape, with transverse diameters, midpelvic diameters reduced, outlet capacity inadequate.
What pelvic type is favorable for vaginal birth?
What is molding?
cranial bones overlap under pressure of the powers of labor and the demands of the unyielding pelvis.
What are sutures?
*membranous spaces between the cranial bones. * cranial sutures allow for molding of the fetal head and help the clinician to identify the position of the fetal head during vaginal examination.
What are fontanelles?
*intersections of sutures

*the anterior and posterior fontanelles are clinically useful in identifying the positon of the fetal head in the pelvis and in assessing the sataus of the newborn after birth. The anterior fontanelle is diamond shaped and measures about 2x3 cm. It permits growth of the brain by remaining unossified for as long as 18 months. The posterior fontanelle is much smaller and closes within 8-12 weeks after birth. It is shaped like a small triangle and marks the meeting point of the sagittal suture and the lambdoidal suture.
What are the major landmarks of the fetal skull?
* Mentum: chin * Sinciput- anterior area known as the brow * Bregma-large diamond-shaped anterior fontanelle * Vertex- area between the anterior and posterior fontanelles * Posterior fontanelle- intersection between posterior cranial sutures * Occiput- area of the fetal skull occupied by the occipital bone, beneath the posterior fontanelle.
What is fetal attitude?
the relation of the fetal parts to one another. The normal attitude of the fetus is one of moderate flexion of the head, flexion of the arms onto the chest, and flexion of the legs onto the abdomen.
What is fetal lie?
the relationship of the cephalocaudal (spinal column) axis of the fetus to the cephalocaudal axis of the woman. The fetus may assume either a longitudinal or a transverse lie.
What is fetal presentation?
is determined by fetal lie and by the body part of the fetus that enters the pelvic passage first.
What is malpresentations?
breech or shoulder presentations are assoicated with difficulties during labor, and labor does not proceed as expected.
Cephalic Presentation
*Vertex Presentation- vertex is the most common type of preentation. The fetal head is completely flexed onto the chest, and the smallest diameter of the fetal head preents to the maternal pelvis. The occiput is the presenting part.

*Military Presentation- the fetal head is neither flexed nor extended. The occipitofrontal diameter presents to the maternal pelvis; the top of the head is the presenting part.

*Brow Presentation- the fetal head is partially extended. The occipitomental diameter, the largest anterorposterior diameter is presented to the maternal pelvis; the sinciput is the presenting part.

*Face Presentation- the fetal head is hyperextended. The submentobregmatic diameter presents to the maternal pelvis, the face is the presenting part.
Breech Presentation
(the sacrum is the landmark to be noted)
*Complete breech- the fetal knees and hips are both flexed, the thighs are on the abd, and the calves are on the posterior aspect of the thighs. The buttocks and feet of the fetus present to the maternal pelvis.

*Frank Breech- the fetal hips are flexed, and the knees are extended. The buttocks of the fetus presents to the maternal pelvis.

*Footling Breech- the fetal hips and legs are extended, and the feet are the presenting part.
Shoulder presentation
Also called a transverse lie. The scapula is the landmark to be noted.
What is engagement?
when the largest diameter of hte presenting part reaches or passes through the pelvic inlet.
What does engagement confirm?
it confirms the adequacy of the pelvic inlet, it does not indicate whether the midpelvis and outlet are also adequate.
What is synclitism?
occurs when the sagittal suture is midway between the symphysis pubis and the sacral promontory. Upon vaginal examination, the suture feels midline between these two maternal landmarks
What is asynclitism?
when the sagittal suture is directed toward either the symphysis pubis or the sacral promontory. Upon vaginal exam, the suture feels somewhat turned to one side within the pelvis making it asymmetrical.
Why is it important to identify asynclitism?
it can lenghten the time of decent or interfere with the decent process.
What is station?
the relationship of the presenting part to an imaginary line drawn between the ischial spines of the maternal pelvis.
What is the imporants of the ischial spines?
the ischial spines mark the narrowest diameter through which the fetus must pass. As a landmark, the ischial spines have been designated a zero station. If the presenting part is higher than the spines, a negitive number is assigned, noting centimeters above 0. Positve numbers indicate that the presenting part has passed the ischial spines. Station -5 is at the pelvic inlet and station +4 is at the outlet.
What is fetal position?
the relationship between a designated landmark on the presenting fetal part and the front, sides, or back of the maternal pelvis.
What are the landmarks for vertex, face, breech, and shoulder presentations?
*Face- mentum
*Breech- sacrum
*Shoulder-acromion process on scapula
How does the nurse determine position?
the nurse notes what quadrant of the maternal pelvis the appropriate landmark is directed toward: left anterior, right anterior, left posterior, right posterior.
What is the most common fetal positon?
occiput anterior
Abbreviations for fetal position.
*The side of the maternal pelvis-Right (R), Left (L)
*The fetal presenting part-Occiput (O), Mentum (M), Sacrum (S), Acromion process (A)
*Position of the landmark- Anterior (A), Posterior (P), Transverse (T)

*The term dorasl (D) is used when denoting the fetal position in a transverse lie, it refers to the fetal back.
What is the primary force of labor?
Uterine ctx are rhythmic but intermittent. Between ctx there is a resting period to allow uterine muscles to rest and provides respite for the laboring woman, also to restore uteroplanental circulation.
What are the phases of contractions?
increment-the building up of the contraction (the longest phase), acme- the peak of the contraction, decrement- the letting up of the contraction.
What does frequency refer to?
the time between the beginning of one contraction and the beginning of the next.
What is duration?
it is measured from the beginning of one ctx to its completion.
What does intensity refer to?
refers to the strength of the contraction during acme.
What is the normal uterine pressures when using an intrauterine catheter?
normal resting in the uterus (between contractions) averages 10-12 mmHG. During acme the intensity ranges from 25-40 mmH in early labor, 50-70 mmHg in active labor, and 70-90 mmHg during transition, and 70-100 mmHg while pusing in the second stage.
What is the secondary force in labor?
After the cervix is completely dilated, the maternal abd muscles contract as the woman pushes. This bearing down aids in the expulsion of the fetus and placenta.
What is efacement?
the drawing up of the internal os and the cervical cananl inot the uterine side walls.
What cervical change takes place during efacement?
the cervix changes progressively from a long, thick structure to a structure that is tissue paper thin.

In primigravidas efacement usually precedes dilation.
What is dilatation?
the uterus elongates with each contraction, decreasing the horisontal diameter. The elongation causes a straightening of the fetal body, pressing the upper portion against the fundus and thrusting the presenting part down toward the lower uterine segment and the cervix. The pressure exerted by the fetus is called the fetal axis pressure.
What causes cervical dilatation?
the longitudinal muscle fibers are pulled upward over the presenting part. This action and the hydrostatic pressure of the fetal membranes cause cervical dilatation.

When the cervix is completely dilated and retracted up into the lower uterine segment, it can no longer be palpated.
What causes fetal alignment with the bony pelvis?
round ligaments pulls the fundus forward, aligning the fetus with the bony pelvis
What are the musculature changes in the plevic floor during ctx?
the levator ani muscle and fascia of the pelvic floor draw the rectum and vagina upward and forward with each cxt, along the curve of the pelvic floor. As the fetal head decends to the pelvic floor, the pressure of the presenting part causes the perineal structure, which was once 5 cm in thickness, to thin to <1 cm. The anus everts, exposing the interior rectal wall as the fetal head decends forward.
What are the premonitory signs of labor?
lightening, Braxton Hicks ctx, cervical changes, bloody show, ROM, sudden burst of energy, wt loss of 1-3 lbs, diarrhea, indigestion, or N&V.
What is lighetning?
the effects that occur when the fetus begins to settle intot he pelvic inlet (engagement).
What may result for the downward pressure of hte presenting part ?
Leg cramps or pains due to pressure on the nerves that course through the obtruator foramen in the pelvis, increased pelvic pressure, increased venous stasis, leading to edema in the lower extremities, increased vaginal secretions resulting from congestion of the vaginal mucous membranes.
What are Braxton Hicks ctx?
irregular, intermittent ctx that have been occuring througthout pregnancy. The pain seems to be focused in the abd and groin but amy feel like "drawing" sensations experienced in dysmenorrhea.
What type of cervical changes are considered premonitory signs of labor?
sofening of the cervix is called ripening. As term approaches, collagen fibers in the cervix are broken down by the action of enzymes increasing the amounts of hyaluronic acid. The water content of the cervix also increases.
What is bloody show?
pink, tinged secretions. It is considered a sign that labor will begin within 24 to 48 hours.
Issues surrounding ROM
If membranes rupture and labor does not begin within 12-24 hrs spontaneously labor may be induced to decrease the risk of infection.

When the membranes rupture, the amniotic fluid may be expelled in large amounts. If engagement has not occured, there is a danger of the umnilical cord washing out with the fluid (prolapsed cord).
Differences between true and false labor
The contractions of true labor produce progressive dilatation and effacement of the cervix.
Amniotic fluid
Normal- pale, straw-colored with small white particles. At 20 wks volume ranges from 700-1000mls.

Abnormal- volume less than 400 ml is oligohydramnios, volumes more than 2000 ml is hydramnios, meconium staining, chroioamnionitis (infection), foul smelling, hemorrhage
What is an amniotomy?
artificial rupture of memebranes (AROM)
What is crowning?
when the fetal head is encircled by the external opening of the vagina (introitus).
What are the cardinal movements of labor?
engagement, decent, flexion, internal rotation,extention, restitution, external rotation, and expulsion.
What is decent?
Decent occurs because of 3 forces (1) pressure of the amniotic fluid, (2) direct pressure of the uterine fundus on the breech, (3) contraction of the abd muscles, and (4) extension and straightening of the fetal body. The head enters the inlet in the occiput transverse or oblique position because the pelvic inlet is widest from side to side. The sagittal suture is an equal distance from the maternal symphysis pubis and sacral promontory.
What is flexion?
flexion occurs as the fetal head descends and meets resistance from the soft tissues of the pelvis, the muscles of hte pelvic floor, and the cervix. As a result of the resistance, the fetal chin flexes downward onto the chest.
What is internal rotation?
The fetal head must rotate to fit the diameter of the pelvic cavity. As the occiput of the fetal head meets resistance from the levator ani muscles and their fascia, the occiput rotates- usually from L to R- and the sagittal suture aligns in the anteroposterior pelvic diameter.
What is extension?
the resistance of hte pelvic floor and the mechanical movement of the vulva opening anteriorly and forward assist with estension of the fetal head as it passes usder the symphysis pubis. With this position change, the occiput, then the brow and face, emerge from the vagina.
What is restitution?
The shoulders of the fetus enter the pelvis inlet obliquely and remain oblique when the head rotates to the anteroposterior diameter through internal rotation. Because of this rotation, the neck becomes twisted. Once the head is born and is free of pelvic resistance, the neck untwists, turning the head to one side (restitution, and aligns with the postion of the back in the birth canal
What is external rotation?
As the shoulders rotate to the anteroposterior postition in the pelvis, the head turns to one side.
What is explusion?
After the external rotation, and through the pushing efforts of the woman, the anterior shoulder meets the undersurface of the symphysis pubis and slips under it. As lateral flexion of the shoulder and head occurs, the anterior shoulder is born before the posterior shoulder. The body follows quickly.
What are the signs of placental separation?
Usually appears about 5 minutes after the birth. These signs are (1) a globular-shaped uterus, (2) a rise of the fundus in the abd, (3) a sudden gush or trickle of blood, and (4) further protrusion of the umbilical cord out of the vagina.
When is a placenta considered to be retained?
if 30 minutes have elapsed from completeion of the second stage of labor.
"shiny Schultze"
the placenta is delivered with the fetal "shiny" side presenting
"dirty Duncan"
the placenta rolls up and presents sideways with the maternal surface delivering first.
What is the fourth stage of labor?
occurs 1-4 hours after birth. Blood loss ranges from 250-500 ml. This results in a moderate drop in both systolic and diastolic blood pressure, increased pulse pressure, and moderate tachycardia. The uterus is midline of the abd.
Cardiovascular changes in labor
During labor there is a significant increase in cardiac output. With each contraction, 300-500 mL of blood volume is forced back into the maternal circulation, which results in an increase in cardiac output as much as 31%. Maternal positon also affects cariac output. BP rises as a result of increased cardiac output. In the first stage, systolic pressure increases by 35 mmHg and diastolic increases by about 25 mmHg. There may be further increases during pushing.
Respiratory changes in labor
O2 demand and consumption increase at the onset of ctx. With anxiety, comes hyperventilation, with hyperventilation there is a fall in PaCO2, and respiratory alkalosis results. By the end of the first stage, most women have developed mild metabolic acidosis compenstated by respiratory alkalosis. As they push PaCO2 levels may rise along with blood lactate levels and mild respitatory acidosis occurs. By the time the baby is born there is a metabolic acidosis uncompensated for by repsiratory alkalosis. Acid-base levels return to pregnant levels by 24 hours after birth, and to normal within a few weeks.
Renal system changes in labor
The pressure from presenting parts my impair blood and lymph drainage fromt he base of the bladder, leading to edema.
Immune system and other blood values during labor
the WBC increases to 25,000-30,000 during labor and early postpartum. The change is mostly due to increased neutrophils resulting form a physiologic repsonse to stress. The increased WBC count makes it difficult to identify infection. Maternal blood glucose levels decrease b/c glucose is used as an energy source during uterine ctx. The decreased BG levels lead to a decrease in insulin requirements.
Causes of pain during labor
Pain during the first stage of labor arises from (1) dilatation of the cervix, which is the primary source of pain; (2) stretching of the lower uterine segments; (3) pressure on adjacent structures; (4) hypoxia of the uterine muscle cells during ctx.

During the second stage of labor pain is due to (1) hypoxia of hte contracting uterine muscle cells; (2) distention of the vagina and perineum; (3) pressure on adjacent structures.

Pain during the third stage results from uterine ctx and cervical dilatation as the placenta is expelled.

Deck Info