Reading for Ob, Chinese Presentation, Ob Lecture

Labor consists of a series of rhythmic, involuntary or medically induced contractions of the uterus that event in effacement (thinning and shortening) and dilation of the uterine cervix. The Globe Health Organization (WHO) defines normal birth as follows:

• The birth is spontaneous in onset and depression take a chance at the start of labor and remains and so throughout labor and delivery.

• The infant is born spontaneously in the vertex position between 37 and 42 weeks of pregnancy.

The stimulus for labor is unknown, but digitally manipulating or mechanically stretching the cervix during examination enhances uterine contractile action, virtually likely by stimulating release of oxytocin by the posterior pituitary gland.

Normal labor usually begins within 2 weeks (before or afterward) the estimated commitment engagement. In a first pregnancy, labor usually lasts 12 to 18 hours on average; subsequent labors are often shorter, averaging 6 to 8 hours.

Rupture of the chorioamniotic membranes or bloody show is diagnostic for onset of labor.

Encarmine show (a pocket-size amount of blood with mucous discharge from the cervix) may precede onset of labor by as much as 72 hours. Bloody show tin can exist differentiated from aberrant 3rd-trimester vaginal bleeding Vaginal Bleeding During Late Pregnancy Bleeding during late pregnancy (≥ xx weeks gestation, but earlier birth) occurs in 3 to four% of pregnancies. Some disorders tin can cause substantial blood loss, occasionally enough to crusade hemorrhagic... read more considering the amount is small, bloody evidence is typically mixed with mucus, and the pain due to abruptio placentae Abruptio Placentae Abruptio placentae is premature separation of a normally implanted placenta from the uterus, usually after 20 weeks gestation. It can be an obstetric emergency. Manifestations may include vaginal... read more (premature separation) is absent. In most significant women, previous routine ultrasonography has been done and ruled out placenta previa Placenta Previa Placenta previa is implantation of the placenta over or near the internal os of the cervix. Typically, painless vaginal bleeding with brilliant red blood occurs afterwards twenty weeks gestation. Diagnosis... read more than . However, if ultrasonography has not ruled out placenta previa and vaginal bleeding occurs, placenta previa is assumed to be present until information technology is ruled out. In such cases, digital vaginal examination is contraindicated, and ultrasonography is done equally soon as possible to determine the location of the placenta and rule out abruptio placentae.

Labor begins with irregular uterine contractions of varying intensity; they apparently soften (ripen) the neck, which begins to efface and amplify. As labor progresses, contractions increase in duration, intensity, and frequency.

At that place are 3 stages of labor.

The 1st phase—from onset of labor to total dilation of the neck (about 10 cm)—has 2 phases, latent and active.

During the latent phase, irregular contractions become progressively coordinated, discomfort is minimal, and the cervix effaces and dilates to four cm. The latent phase is difficult to time precisely, and duration varies, averaging viii hours in nulliparas and 5 hours in multiparas; duration is considered aberrant if it lasts > twenty hours in nulliparas or > 12 hours in multiparas.

If the membranes have not spontaneously ruptured, some clinicians apply amniotomy (artificial rupture of membranes) routinely during the active phase. Equally a consequence, labor may progress more rapidly, and meconium-stained amniotic fluid may be detected earlier. Amniotomy during this stage may be necessary for specific indications, such as facilitating internal fetal monitoring to confirm fetal well-being. Amniotomy should exist avoided in women with HIV infection or hepatitis B or C, so that the fetus is non exposed to these organisms.

The 2nd stage is the time from full cervical dilation to delivery of the fetus. On average, it lasts 2 hours in nulliparas (median 50 minutes) and 1 hour in multiparas (median 20 minutes). Information technology may final another hour or more if conduction (epidural) analgesia or intense opioid sedation is used. For spontaneous delivery, women must supplement uterine contractions by expulsively bearing down. In the 2d stage, women should be attended constantly, and fetal heart sounds should exist checked continuously or after every contraction. Contractions may be monitored past palpation or electronically.

The 3rd phase of labor begins after delivery of the infant and ends with commitment of the placenta. This stage commonly lasts only a few minutes but may last upwards to thirty minutes.

• one. Lawrence A, Lewis 50, Hofmeyr GJ, Styles C: Maternal positions and mobility during first phase labour. Cochrane Database Syst Rev (viii):CD003934, 2013. doi: 10.1002/14651858.CD003934.pub3

• 2. Aasheim V, et al: Perineal techniques during the second stage of labour for reducing perineal trauma. Cochrane Database Syst Rev 6:CD006672, 2017. doi: ten.1002/14651858.CD006672.pub3

• iii. Gupta JK, Sood A, Hofmeyr GJ, et al: Position in the second stage of labour for women without epidural amazement. Cochrane Database Syst Rev 5:CD002006, 2017. doi: 10.1002/14651858.CD002006.pub4

• 4. Lemos A, Amorim MM, Dornelas de Andrade A, et al: Pushing/begetting down methods for the second phase of labour. Cochrane Database Syst Rev. 3:CD009124, 2017. doi: 10.1002/14651858.CD009124.pub3

Further confirmation is not needed if during examination, fluid is seen leaking from the neck. Confirmation of more subtle cases may require testing. For example, the pH of vaginal fluid may exist tested with Nitrazine paper, which turns deep bluish at a pH > 6.v (pH of amniotic fluid: vii.0 to seven.6); false-positive results can occur if vaginal fluid contains blood or semen or if sure infections are present. A sample of the secretions from the posterior vaginal fornix or neck may be obtained, placed on a slide, air dried, and viewed microscopically for ferning. Ferning (crystallization of sodium chloride in a palm leaf pattern in amniotic fluid) usually confirms rupture of membranes.

If rupture is still unconfirmed, ultrasonography showing oligohydramnios (scarce amniotic fluid) provides further prove suggesting rupture. Rarely, amniocentesis with instillation of dye is done to ostend rupture; dye detected in the vagina or on a tampon confirms rupture.

When a woman's membranes rupture, she should contact her doctor immediately. About fourscore to ninety% of women with PROM at term ( ≥ 37 weeks) and almost 50% of women with preterm PROM (< 37 weeks) go into labor spontaneously within 24 hours; > 90% of women with PROM get into labor within 2 weeks. The earlier the membranes rupture before 37 weeks, the longer the delay between rupture and labor onset. If membranes rupture at term merely labor does not start inside several hours, labor is typically induced to lower risk of maternal and fetal infection.

Most women prefer hospital commitment, and almost health care practitioners recommend it because unexpected maternal and fetal complications may occur during labor and delivery or postpartum, fifty-fifty in women without risk factors. About 30% of hospital deliveries involve an obstetric complication Introduction to Abnormalities and Complications of Labor and Commitment Abnormalities and complications of labor and delivery should be diagnosed and managed as early as possible. Near of the following complications are evident earlier onset of labor: Multifetal... read more (eg, laceration, postpartum hemorrhage Postpartum Hemorrhage Postpartum hemorrhage is blood loss of > k mL or blood loss accompanied by symptoms or signs of hypovolemia within 24 hours of birth. Diagnosis is clinical. Handling depends on etiology... read more than ). Other complications include abruptio placentae Abruptio Placentae Abruptio placentae is premature separation of a normally implanted placenta from the uterus, usually later on 20 weeks gestation. It tin can be an obstetric emergency. Manifestations may include vaginal... read more , abnormal fetal heart charge per unit design, shoulder dystocia Fetal Dystocia Fetal dystocia is abnormal fetal size or position resulting in difficult commitment. Diagnosis is by test, ultrasonography, or response to augmentation of labor. Treatment is with physical... read more , need for emergency cesarean delivery Cesarean Commitment Cesarean delivery is surgical delivery by incision into the uterus. Up to 30% of deliveries in the Usa are cesarean. The charge per unit of cesarean delivery fluctuates. It has recently increased, partly... read more , and neonatal depression or abnormality.

Nonetheless, many women want a more homelike environment for delivery; in response, some hospitals provide birthing facilities with fewer formalities and rigid regulations but with emergency equipment and personnel available. Birthing centers may exist freestanding or located in hospitals; care at either site is similar or identical. In some hospitals, certified nurse-midwives provide much of the care for low-risk pregnancies. Midwives work with a physician, who is continuously available for consultation and operative deliveries (eg, by forceps, vacuum extractor, or cesarean). All birthing options should be discussed.

For many women, presence of the their partner or some other support person during labor is helpful and should be encouraged. Moral support, encouragement, and expressions of amore decrease anxiety and brand labor less frightening and unpleasant. Childbirth education classes can set up parents for a normal or complicated labor and commitment. Sharing the stresses of labor and the sight and audio of their own child tends to create potent bonds between the parents and between parents and child.

The parents should be fully informed of whatever complications.

Typically, pregnant women are brash to get to the hospital if they believe their membranes accept ruptured or if they are experiencing contractions lasting at least 30 seconds and occurring regularly at intervals of about six minutes or less. Within an hour after presentation at a hospital, whether a woman is in labor can usually be adamant based on the following:

• Occurrence of regular and sustained painful uterine contractions

• Bloody evidence

• Membrane rupture

• Complete cervical effacement

If these criteria are not met, false labor may be tentatively diagnosed, and the pregnant woman is typically observed for a time and, if labor does not brainstorm inside several hours, is sent home.

When pregnant women are admitted, their blood pressure level, heart and respiratory rates, temperature, and weight are recorded, and presence or absenteeism of edema is noted. A urine specimen is collected for poly peptide and glucose analysis, and blood is drawn for a complete blood count (CBC), blood typing, and antibody screening. If routine laboratory tests were not washed during prenatal visits, they should be washed; these tests include screening for HIV, hepatitis B, syphilis, and group B streptococcal infection.

A helpful mnemonic device for evaluation is the 3 Ps:

• Powers (contraction strength, frequency, and elapsing)

• Passage (pelvic measurements)

• Passenger (eg, fetal size, position, centre rate pattern)

Leopold maneuver

(A) The uterine fundus is palpated to determine which fetal function occupies the fundus. (B) Each side of the maternal belly is palpated to make up one's mind which side is fetal spine and which is the extremities. (C) The area above the symphysis pubis is palpated to locate the fetal presenting part and thus determine how far the fetus has descended and whether the fetus is engaged. (D) One mitt applies force per unit area on the fundus while the index finger and thumb of the other hand palpate the presenting function to confirm presentation and engagement.

If labor is active and the pregnancy is at term, a clinician examines the vagina with 2 fingers of a gloved hand to evaluate progress of labor. If bleeding (particularly if heavy) is present, the examination is delayed until placental location is confirmed past ultrasonography. If haemorrhage results from placenta previa, vaginal test can initiate severe hemorrhage.

If labor is not active but membranes are ruptured, a speculum examination is washed initially to certificate cervical dilation and effacement and to estimate station (location of the presenting office); all the same, digital examinations are delayed until the active stage of labor or issues (eg, decreased fetal eye sounds) occur. If the membranes have ruptured, any fetal meconium (producing greenish-brown discoloration) should be noted because it may be a sign of fetal stress. If labor is preterm (< 37 weeks) or has not begun, only a sterile speculum test should exist washed, and a culture should exist taken for gonococci, chlamydiae, and grouping B streptococci.

Cervical dilation is recorded in centimeters as the bore of a circle; ten cm is considered complete.

Effacement is estimated in percentages, from zero to 100%. Because effacement involves cervical shortening as well every bit thinning, it may exist recorded in centimeters using the normal, uneffaced average cervical length of 3.5 to 4.0 cm as a guide.

Station is expressed in centimeters above or below the level of the maternal ischial spines. Level with the ischial spines corresponds to 0 station; levels above (+) or beneath (−) the spines are recorded in cm increments. Fetal lie, position, and presentation are noted.

• Lie describes the relationship of the long axis of the fetus to that of the female parent (longitudinal, oblique, transverse).

• Position describes the relationship of the presenting part to the maternal pelvis (eg, occiput left inductive [OLA] for cephalic, sacrum right posterior [SRP] for breech).

• Presentation describes the part of the fetus at the cervical opening (eg, breech, vertex, shoulder).

Women are admitted to the labor suite for frequent observation until delivery. If labor is active, they should receive niggling or nada past rima oris to prevent possible vomiting and aspiration during delivery or in example emergency commitment with full general anesthesia is necessary.

Shaving or clipping of vulvar and pubic hair is not indicated, and it increases the risk of wound infections.

An IV infusion of Ringer'southward lactate may be started, preferably using a large-bore indwelling catheter inserted into a vein in the hand or forearm. During a normal labor of 6 to 10 hours, women should be given 500 to yard mL of this solution. The infusion prevents dehydration during labor and subsequent hemoconcentration and maintains an adequate circulating claret volume. The catheter also provides immediate admission for drugs or blood if needed. Fluid preloading is valuable if epidural or spinal anesthesia is planned. If instrumental or cesarean delivery seems unlikely, women may potable clear liquids.

Analgesics may be given during labor equally needed, but just the minimum amount required for maternal comfort should be given considering analgesics cantankerous the placenta and may depress the neonate'southward animate. Neonatal toxicity tin occur considering after the umbilical cord is cut, the neonate, whose metabolic and excretory processes are young, clears the transferred drug much more than slowly by liver metabolism or by urinary excretion. Preparation for and education virtually childbirth lessen anxiety.

If epidural injection is inadequate or if 4 administration is preferred, fentanyl (100 mcg) or morphine sulfate (up to 10 mg) given IV every 60 to 90 minutes is commonly used. These opioids provide adept analgesia with merely a small total dose. If neonatal toxicity results, respiration is supported, and naloxone 0.01 mg/kg tin can be given IM, IV, subcutaneously, or endotracheally to the neonate as a specific antagonist. Naloxone may be repeated in one to 2 minutes as needed based on the neonate'south response. Clinicians should check the neonate ane to 2 hours after the initial dosing with naloxone considering the effects of the earlier dose abate.

If fentanyl or morphine provides insufficient analgesia, an additional dose of the opioid or some other analgesic method should exist used rather than the so-called synergistic drugs (eg, promethazine), which have no antitoxin. (These drugs are actually additive, non synergistic.) Synergistic drugs are all the same sometimes used because they lessen nausea due to the opioid; doses should be small.

• 1. Practise Guidelines for Obstetric Anesthesia: An Updated Report past the American Society of Anesthesiologists Chore Force on Obstetric Anesthesia and the Society for Obstetric Anesthesia and Perinatology*. Anesthesiology 124:270–300, 2016. doi: 10.1097/ALN.0000000000000935

• Category I: Normal

• Category Two: Indeterminate

• Category Three: Abnormal

A normal blueprint strongly predicts normal fetal acid-base status at the fourth dimension of observation. This design has all of the post-obit characteristics:

• HR 110 to 160 beats/infinitesimal at baseline

• Moderate Hour variability (by half dozen to 25 beats) at baseline and with movement or contractions

• No belatedly or variable decelerations during contractions

Early decelerations and age-appropriate accelerations may exist present or absent in a normal pattern.

An indeterminate design is any design non clearly categorized equally normal or abnormal. Many patterns qualify as indeterminate. Whether the fetus is acidotic cannot exist determined from the pattern. Indeterminate patterns require shut fetal monitoring so that any deterioration can be recognized as presently as possible.

An aberrant blueprint usually indicates fetal metabolic acidosis at the time of observation. This pattern is characterized by one of the following:

• Absent baseline Hr variability plus recurrent belatedly decelerations

• Absent baseline HR variability plus recurrent variable decelerations

• Absent baseline HR variability plus bradycardia (Hour < 110 beats/minute without variability or < 100 beats/infinitesimal)

• Sinusoidal pattern (fixed variability of near v to 40 beats/minute at about iii to 5 cycles/minute, resembling a sine moving ridge)

Aberrant patterns require prompt actions to correct them (eg, supplemental oxygen, repositioning, treatment of maternal hypotension, discontinuation of oxytocin) or training for an expedited delivery.

Patterns reflect fetal status at a particular point in time; patterns tin and do change.

Monitoring can be transmission and intermittent, using a fetoscope for auscultation of fetal Hr. However, in the US, electronic fetal HR monitoring (external or internal) has become standard of treat high-risk pregnancies, and many clinicians use it for all pregnancies. The value of routine use of electronic monitoring in low-adventure deliveries is often debated. Electronic fetal monitoring has not been shown to reduce overall mortality rates in big clinical trials and has been shown to increment rate of cesarean delivery, probably because many credible abnormalities are false positives. Thus, the rate of cesarean commitment is higher among women monitored electronically than among those monitored by auscultation.

Fetal pulse oximetry has been studied as a way to confirm abnormal or equivocal results of electronic monitoring; status of fetal oxygenation may help determine whether cesarean delivery is needed.

Fetal ST-segment and T-wave analysis in labor (STAN) tin can exist used to check the fetal ECG for ST-segment acme or low; either finding presumably indicates fetal hypoxemia and has a loftier sensitivity and specificity for fetal acidosis. For STAN, an electrode must be attached to the fetal scalp; so changes in the T wave and ST segment of the fetal ECG are automatically identified and analyzed.

If transmission auscultation of fetal Hour is used, it must be washed throughout labor according to specific guidelines, and one-on-one nursing intendance is needed.

• For low-risk pregnancies with normal labor, fetal HR must be checked afterward each contraction or at least every 30 minutes during the 1st stage of labor and every fifteen minutes during the 2nd stage.

• For high-adventure pregnancies, fetal Hr must be checked every 15 minutes during the 1st phase and every 3 to five minutes during the 2nd phase.

Listening for at least 1 to 2 minutes first at a wrinkle'southward peak is recommended to cheque for late deceleration. Periodic auscultation has a lower fake-positive charge per unit for abnormalities and incidence of intervention than continuous electronic monitoring, and it provides opportunities for more personal contact with women during labor. However, following the standard guidelines for auscultation is often difficult and may not exist toll-constructive. Also, unless done accurately, auscultation may not notice abnormalities.

Electronic fetal HR monitoring may be

• External: Devices are applied to the maternal abdomen to record fetal heart sounds and uterine contractions.

• Internal: Amniotic membranes must be ruptured. Then, leads are inserted through the neck; an electrode is attached to the fetal scalp to monitor Hour, and a catheter is placed in the uterine cavity to measure intrauterine pressure.

Usually, external and internal monitoring are similarly reliable. External devices are used for women in normal labor; internal methods are used when external monitoring does non supply plenty data about fetal well-existence or uterine contraction intensity (eg, if the external device is not functioning correctly).

A nonstress test records fetal heart charge per unit and uterine contractions using external electronic monitors and correlates the HR with fetal movements (reported past the mother); it is called nonstress because no stressors are applied to the fetus during the exam, although sounds (eg, bong, acoustic stimulator) may exist used to wake the fetus. Hr is expected to increase when the fetus is moving and at other intervals. The nonstress examination is typically washed for 20 minutes (occasionally for xl minutes). Results are considered reactive (reassuring) if there are 2 accelerations of xv beats/minute over 20 minutes. Absence of accelerations is considered nonreactive (nonreassuring). Presence of tardily decelerations suggests hypoxemia, potential for fetal acidosis, and the need for intervention.

A biophysical profile is unremarkably done later a nonreassuring nonstress exam. The biophysical profile adds ultrasonographic assessment of amniotic fluid volume and sometimes assessment of fetal movement, tone, breathing, and HR, to the nonstress test. A nonstress test and biophysical profile are oftentimes used to monitor complicated or high-risk pregnancies Overview of High-Risk Pregnancy In a loftier-risk (at-risk) pregnancy, the mother, fetus, or neonate is at increased chance of morbidity or mortality before, during, or afterwards delivery. In 2017, overall maternal mortality rate in... read more (eg, complicated past maternal diabetes or hypertension or past stillbirth or fetal growth restriction in a previous pregnancy).

Wrinkle stress testing (oxytocin challenge test) is now rarely done. In this test, fetal movements and HR are monitored (typically externally) during contractions induced by oxytocin. When done, contraction stress testing must be washed in a hospital.

If a problem (eg, fetal HR decelerations, lack of normal Hr variability) is detected during labor, intrauterine fetal resuscitation is tried; women may be given oxygen by a tight nonrebreather face up mask or rapid IV fluid infusion or may be positioned laterally. If fetal center pattern does non improve in a reasonable period and delivery is not imminent, urgent delivery past cesarean is needed.

• ane. Macones GA, Hankins GD, Spong CY, et al: The 2008 National Institute of Child Health and Human Evolution workshop report on electronic fetal monitoring: Update on definitions, interpretation, and inquiry guidelines. J Obstet Gynecol Neonatal Nurs 37 (5):510–515, 2008. doi: x.1111/j.1552-6909.2008.00284.x

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