Shoulder dystocia | |
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Suprapubic pressure being used in a shoulder dystocia | |
Specialty | Obstetrics |
Symptoms | Retraction of the baby's head back into the vagina [1] |
Complications | Baby: Brachial plexus injury, clavicle fracture [2] Mother: Vaginal or perineal tears, postpartum bleeding [3] |
Risk factors | Gestational diabetes, previous history of the condition, operative vaginal delivery, obesity in the mother, an overly large baby, epidural anesthesia [2] |
Diagnostic method | Body fails to deliver within one minute of the head [2] |
Treatment | McRoberts maneuver, suprapubic pressure, Rubin maneuver, episiotomy, all fours, Zavanelli's maneuver followed by cesarean section [3] [2] |
Frequency | ~ 1% of vaginal births [2] |
Shoulder dystocia is when, after vaginal delivery of the head, the baby's anterior shoulder gets caught above the mother's pubic bone. [3] [1] Signs include retraction of the baby's head back into the vagina, known as "turtle sign". [1] Complications for the baby may include brachial plexus injury, or clavicle fracture. [2] [1] Complications for the mother may include vaginal or perineal tears, postpartum bleeding, or uterine rupture. [3] [1]
Risk factors include gestational diabetes, previous history of the condition, operative vaginal delivery, obesity in the mother, an overly large baby, and epidural anesthesia. [2] It is diagnosed when the body fails to deliver within three minutes of delivery of the baby's head. [2] It is a type of obstructed labour. [4]
Shoulder dystocia is an obstetric emergency. [3] Initial efforts to release a shoulder typically include: with a woman on her back pushing the legs outward and upward, pushing on the abdomen above the pubic bone. [3] If these are not effective, efforts to manually rotate the baby's shoulders or placing the woman on all fours may be tried. [3] [2] Shoulder dystocia occurs in approximately 0.4% to 1.4% of vaginal births. [2] Death as a result of shoulder dystocia is very uncommon. [1]
One characteristic of a minority of shoulder dystocia deliveries is the turtle sign, which involves the retraction of the fetal chin against the mother's perineum after the head is delivered. [5] [6] This occurs when the baby's shoulder is obstructed by the maternal pelvis or high in the pelvis.
Possible complications include:
One complication of shoulder dystocia is damage to the upper brachial plexus nerves. These supply the sensory and motor components of the shoulder, arm, and hands. The ventral roots (motor pathway) are most prone to injury.[ citation needed ] The cause of injury to the baby is debated,[ citation needed ] but a probable mechanism is manual stretching of the nerves, which in itself can cause injury.[ citation needed ] Excess tension may physically tear the nerve roots out from the neonatal spinal column, resulting in total dysfunction.[ citation needed ]
About 16% of deliveries where shoulder dystocia occurs have conventional risk factors.[ citation needed ] These include diabetes, [9] fetal macrosomia, and maternal obesity. [10] [11]
Factors which increase the risk/are warning signs:[ citation needed ]
For women with a previous shoulder dystocia, the risk of recurrence is at least 10%. [8]
The steps to treating a shoulder dystocia are outlined by the mnemonic ALARMER: [14]
Typically the procedures are performed in the order listed and the sequence ends whenever a technique is successful. [14] Intentional fracturing of the clavicle, a procedure known as cleidotomy, [15] [16] is another possibility at non-operative vaginal delivery prior to Zavanelli's maneuver, or symphysiotomy, [17] both of which are considered extraordinary treatment measures. Pushing on the fundus is not recommended. [1]
Simulation training of health care providers to prevent delays in delivery when a shoulder dystocia presents is useful. [18]
A number of labor positions and maneuvers are sequentially performed in attempt to facilitate delivery. These include: [14]
More drastic maneuvers include:
Shoulder dystocia occurs in about 0.15% to 4% of term vaginal births. [28]
The brachial plexus is a network of nerves formed by the anterior rami of the lower four cervical nerves and first thoracic nerve. This plexus extends from the spinal cord, through the cervicoaxillary canal in the neck, over the first rib, and into the armpit, it supplies afferent and efferent nerve fibers to the chest, shoulder, arm, forearm, and hand.
A breech birth is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term have a breech baby. Due to their higher than average rate of possible complications for the baby, breech births are generally considered higher risk. Breech births also occur in many other mammals such as dogs and horses, see veterinary obstetrics.
Umbilical cord prolapse is when the umbilical cord comes out of the uterus with or before the presenting part of the baby. The concern with cord prolapse is that pressure on the cord from the baby will compromise blood flow to the baby. It usually occurs during labor but can occur anytime after the rupture of membranes.
Large for gestational age (LGA) is a term used to describe infants that are born with an abnormally high weight, specifically in the 90th percentile or above, compared to other babies of the same developmental age. Macrosomia is a similar term that describes excessive birth weight, but refers to an absolute measurement, regardless of gestational age. Typically the threshold for diagnosing macrosomia is a body weight between 4,000 and 4,500 grams, or more, measured at birth, but there are difficulties reaching a universal agreement of this definition.
Obstructed labour, also known as labour dystocia, is the baby not exiting the pelvis because it is physically blocked during childbirth although the uterus contracts normally. Complications for the baby include not getting enough oxygen which may result in death. It increases the risk of the mother getting an infection, having uterine rupture, or having post-partum bleeding. Long-term complications for the mother include obstetrical fistula. Obstructed labour is said to result in prolonged labour, when the active phase of labour is longer than 12 hours.
Complications of pregnancy are health problems that are related to, or arise during pregnancy. Complications that occur primarily during childbirth are termed obstetric labor complications, and problems that occur primarily after childbirth are termed puerperal disorders. While some complications improve or are fully resolved after pregnancy, some may lead to lasting effects, morbidity, or in the most severe cases, maternal or fetal mortality.
The Zavanelli maneuver is an obstetric maneuver that involves pushing back the delivered fetal head into the birth canal in anticipation of performing a cesarean section in cases of shoulder dystocia.
Obstetrical forceps are a medical instrument used in childbirth. Their use can serve as an alternative to the ventouse method.
A vaginal delivery is the birth of offspring in mammals through the vagina. It is the most common method of childbirth worldwide. It is considered the preferred method of delivery, as it is correlated with lower morbidity and mortality than caesarean sections (C-sections), though it is not clear whether this is causal.
An asynclitic birth or asynclitism are terms used in obstetrics to refer to childbirth in which there is malposition of the head of the fetus in the uterus, relative to the birth canal. Asynclitic presentation is different from a shoulder presentation, in which the shoulder is presenting first. Many babies enter the pelvis in an asynclitic presentation, and most asynclitism corrects spontaneously as part of the normal birthing process.
The McRoberts maneuver is an obstetrical maneuver used to assist in childbirth. It is named after William A. McRoberts, Jr. It is employed in case of shoulder dystocia during childbirth and involves hyperflexing the mother's legs tightly to her abdomen. It is effective due to the increased mobility at the sacroiliac joint during pregnancy, allowing rotation of the pelvis and facilitating the release of the fetal shoulder. If this maneuver does not succeed, an assistant applies pressure on the lower abdomen. Current guidelines strongly recommend against pulling on the infants head, as this could lead to brachial plexus injury. Instead, support while keeping the neck straight is indicated. The technique is effective in about 42% of cases. Note that suprapubic pressure and McRobert's maneuver together will resolve 90% of cases.
Wood's screw maneuver is practiced in obstetrics when dealing with shoulder dystocia – a condition in which the fetal shoulders cannot easily pass through the vagina. In this maneuver the anterior shoulder is pushed towards the baby's chest, and the posterior shoulder is pushed towards the baby's back, making the baby's head somewhat face the mother's rectum.
Anterior shoulder in obstetrics refers to that shoulder of the fetus that faces the pubic symphysis of the mother during delivery. Depending upon the original position of the fetus, either the left or the right shoulder can be the anterior shoulder. It is known as the anterior shoulder as it faces the anterior of the mother. This distinction between the anterior and the posterior shoulder is important as the anterior shoulder is delivered first.
In obstetrics, the presentation of a fetus about to be born specifies which anatomical part of the fetus is leading, that is, is closest to the pelvic inlet of the birth canal. According to the leading part, this is identified as a cephalic, breech, or shoulder presentation. A malpresentation is any presentation other than a vertex presentation.
Posterior shoulder in obstetrics refers to the shoulder of the fetus other than the anterior shoulder. Thus, the posterior shoulder faces the rectum of the mother during delivery. Whether left or the right shoulder becomes the posterior shoulder is dependent upon the original position of the fetus. It is known as the posterior shoulder as it faces the posterior of the mother. This distinction between the anterior and the posterior shoulder is important as the anterior shoulder is delivered first.
A shoulder presentation is a malpresentation at childbirth where the baby is in a transverse lie, thus the leading part is an arm, a shoulder, or the trunk. While a baby can be delivered vaginally when either the head or the feet/buttocks are the leading part, it usually cannot be expected to be delivered successfully with a shoulder presentation unless a cesarean section (C/S) is performed.
An obstetric labor complication is a difficulty or abnormality that arises during the process of labor or delivery.
Rubin's I and II maneuvers, rotational maneuver to deliver the baby in case of shoulder dystocia.
Emergency childbirth is the precipitous birth of an infant in an unexpected setting. In planned childbirth, mothers choose the location and obstetric team ahead of time. Options range from delivering at home, at a hospital, a medical facility or a birthing center. Sometimes, birth can occur on the way to these facilities, without a healthcare team. The rates of unplanned childbirth are low. If the birth is imminent, emergency measures may be needed. Emergency services can be contacted for help in some countries.
Operative vaginal delivery, also known as assisted or instrumental vaginal delivery, is a vaginal delivery that is assisted by the use of forceps or a vacuum extractor.
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