Clinical features of a fatal shoulder dystocia: The hypovolemic shock hypothesis

Contributing factors of birth asphyxia in Thailand: a case-control study

BACKGROUND

Birth asphyxia is of significant concern because it impacts newborn health from low to severe levels. In Thailand, birth asphyxia remains a leading cause of delayed developmental health in children under 5 years old. The study aimed to determine the maternal, fetal and health service factors contributing to birth asphyxia.

METHODS

A case-control design was conducted on a sample of 4256 intrapartum chart records. The samples were selected based on their Apgar scores in the first minute of life. A low Apgar score (≤ 7) was chosen for the case group (852) and a high Apgar score (> 7) for the control group (3408). In addition, a systematic random technique was performed to select 23 hospitals, including university, advanced and secondary, in eight health administration areas in Thailand for evaluating the intrapartum care service. Data analysis was conducted using SPSS statistical software.

RESULTS

The odds of birth asphyxia increases in the university and advanced hospitals but the university hospitals had the highest quality of care. The advanced and secondary hospitals had average nurse work-hours per week of more than 40 h. Multivariable logistic regression analysis found that intrapartum care services and maternal-fetal factors contributed to birth asphyxia. The odd of birth asphyxia increases significantly in late-preterm, late-term pregnancies, low-birth weight, and macrosomia. Furthermore, maternal comorbidity, non-reassuring, and obstetric emergency conditions significantly increase the odd of birth asphyxia. In addition, an excellent quality of intrapartum care, a combined nursing model, low nurse work-hours, and obstetrician-conducted delivery significantly reduced birth asphyxia.

CONCLUSION

Birth asphyxia problems may be resolved in the health service management offered by reducing the nurse work-hours. Excellent quality of care required the primary nursing care model combined with a team nursing care model. However, careful evaluation and monitoring are needed in cases of comorbidity, late-preterm, late-term pregnancies, low-birth weight, and macrosomia. Furthermore, increasing the obstetrician availability in obstetric emergencies and non-reassuring fetal status is important.

Cardiac Asystole at Birth Re-Visited: Effects of Acute Hypovolemic Shock

Births involving shoulder dystocia or tight nuchal cords can deteriorate rapidly. The fetus may have had a reassuring tracing just before birth yet may be born without any heartbeat (asystole). Since the publication of our first article on cardiac asystole with two cases, five similar cases have been published. We suggest that these infants shift blood to the placenta due to the tight squeeze of the birth canal during the second stage which compresses the cord. The squeeze transfers blood to the placenta via the firm-walled arteries but prevents blood returning to the infant via the soft-walled umbilical vein. These infants may then be born severely hypovolemic resulting in asystole secondary to the loss of blood. Immediate cord clamping (ICC) prevents the newborn's access to this blood after birth. Even if the infant is resuscitated, loss of this large amount of blood volume may initiate an inflammatory response that can enhance neuropathologic processes including seizures, hypoxic-ischemic encephalopathy (HIE), and death. We present the role of the autonomic nervous system in the development of asystole and suggest an alternative algorithm to address the need to provide these infants intact cord resuscitation. Leaving the cord intact (allowing for return of the umbilical cord circulation) for several minutes after birth may allow most of the sequestered blood to return to the infant. Umbilical cord milking may return enough of the blood volume to restart the heart but there are likely reparative functions that are carried out by the placenta during the continued neonatal-placental circulation allowed by an intact cord.

Cord Management of the Term Newborn

Keeping the umbilical cord intact after delivery facilitates transition from fetal to neonatal circulation and allows a placental transfusion of a considerable amount of blood. A delay of at least 3 minutes improves neurodevelopmental outcomes in term infants. Although regarded as common sense and practiced by many midwives, implementation of delayed cord clamping into practice has been unduly slow, partly because of beliefs regarding theoretic risks of jaundice and lack of understanding regarding the long-term benefits. This article provides arguments for delaying cord clamping for a minimum of 3 minutes.

Shoulder dystocia, umbilical cord blood gases and neonatal encephalopathy

The interpretation of umbilical cord gases may not be straightforward following shoulder dystocia. We reviewed Perinatal and Maternal Mortality Review Committee data from New Zealand infants with moderate and severe neonatal encephalopathy (NE) for 2010-2017 inclusive. If one or more of: pH of ≤7.1; base excess of ≤-12 mmol/L; or lactate of ≥6 mmol/L were present it was considered an abnormal result. One-third (12/36) of infants born following shoulder dystocia had documented umbilical cord gases within the normal range. It is important for clinicians to be aware of this possibility when assessing newborn infants with NE.

Intrapartum Asphyxiated Newborns Without Fetal Heart Rate and Cord Blood Gases Abnormalities: Two Case Reports of Shoulder Dystocia to Reflect Upon

Our report covers two cases of severe hypoxic-ischemic encephalopathy in newborns whose birth was complicated by shoulder dystocia. In both cases, there were inconsistencies observed among cardiotocographic traces, baby's clinical conditions at birth, and umbilical cord blood gases. Namely, normal cardiotocographic monitoring and cord pH > 7, in spite of the fact that the newborns were severely depressed at birth and their blood gases evaluated within 1 h from birth showed a severe metabolic acidosis. Moreover, one of the two newborns displayed moderately low hemoglobin levels. Metabolic and infectious causes were ruled out. Both newborns developed severe hypoxic-ischemic encephalopathy and received therapeutic hypothermia for 72 h. Both survived, one with a severe dystonic cerebral palsy whereas the other developed only a mild developmental delay in language. Cardiac asystole theory could explain these two cases, reinforcing the need for specific resuscitation guidelines for infants experiencing a birth complicated by shoulder dystocia.

Italian Recommendations for Placental Transfusion Strategies

At delivery, if the cord is not clamped, blood continues to pass from the placenta to the newborn during the first minutes of life, allowing the transfer of 25-35 ml/kg of placental blood to the newborn, depending on gestational age, the timing of cord clamping, the position of the infant at birth, the onset of respiration, and administration of uterotonics to the mother. However, deriving benefits from delayed cord clamping (DCC) are not merely related to placental-to-fetal blood transfusion; establishing spontaneous ventilation before cutting the cord improves venous return to the right heart and pulmonary blood flow, protecting the newborn from the transient low cardiac output, and systemic arterial pressure fluctuations. Recent meta-analyses showed that delayed cord clamping reduces mortality and red blood cell transfusions in preterm newborns and increases iron stores in term newborns. Various authors suggested umbilical cord milking (UCM) as a safe alternative when delayed cord clamping is not feasible. Many scientific societies recommend waiting 30-60 s before clamping the cord for both term and preterm newborns not requiring resuscitation. To improve the uptake of placental transfusion strategies, in 2016 an Italian Task Force for the Management of Umbilical Cord Clamping drafted national recommendations for the management of cord clamping in term and preterm deliveries. The task force performed a detailed review of the literature using the GRADE methodological approach. The document analyzed all clinical scenarios that operators could deal with in the delivery room, including cord blood gas analysis during delayed cord clamping and time to cord clamping in the case of umbilical cord blood banking. The panel intended to promote a more physiological and individualized approach to cord clamping, specifically for the most preterm newborn. A feasible option to implement delayed cord clamping in very preterm deliveries is to move the neonatologist to the mother's bedside to assess the newborn's clinical condition at birth. This option could safely guarantee the first steps of stabilization before clamping the cord and allow DCC in the first 30 s of life, without delaying resuscitation. Contra-indications to placental transfusion strategies are clinical situations that may endanger mother 's health and those that may delay immediate newborn's resuscitation when required.