Hemoglobin Differences in Uncomplicated Monochorionic Twins in Relation to Birth Order and Mode of Delivery

Maternal and fetal outcomes after planned cesarean or vaginal delivery in twin pregnancy: a comparison between 2 third level birth centers

BACKGROUND

Twin pregnancy is associated with higher risks of adverse perinatal outcomes for both the mother and the babies. Among the many challenges in the follow-up of twin pregnancies, the mode of delivery is the last but not the least decision to be made, with the main influencing factors being amnionicity and fetal presentation. The aim of the study was to compare perinatal outcomes in two European centers using different protocols for twin birth in case of non-cephalic second twin; the Italian patients being delivered mainly by cesarean section with those in Belgium being routinely offered the choice of vaginal delivery (VD).

METHODS

This was a dual center international retrospective observational study. The population included 843 women with a twin pregnancy ≥ 32 weeks (dichorionic or monochorionic diamniotic pregnancies) and a known pregnancy outcome. The population was stratified according to chorionicity. Demographic and pregnancy data were reported per pregnancy, whereas neonatal outcomes were reported per fetus. We used multiple logistic regression models to adjust for possible confounding variables and to compute the adjusted odds ratio (adjOR) for each maternal or neonatal outcome.

RESULTS

The observed rate of cesarean delivery was significantly higher in the Italian cohort: 85% for dichorionic pregnancies and 94.4% for the monochorionic vs 45.2% and 54.4% respectively in the Belgian center (p-value < 0.001). We found that Belgian cohort showed significantly higher rates of NICU admission, respiratory distress at birth and Apgar score of < 7 after 5 min. Despite these differences, the composite severe adverse outcome was similar between the two groups.

CONCLUSION

In this study, neither the presentation of the second twin nor the chorionicity affected maternal and severe neonatal outcomes, regardless of the mode of delivery in two tertiary care centers, but VD was associated to a poorer short-term neonatal outcome.

Hemoglobin differences in twins are related to the time of cord clamping, not intertwin transfusion - a prospective cohort study

Background

Delayed cord clamping increases placental transfusion. In vaginal deliveries higher hemoglobin concentrations are found in the second-born twin. We hypothesized it is unrelated to intertwin transfusion but to the time of cord clamping. Methods: It was a prospective cohort study of 202 women delivering twins > 32 weeks of gestation. Monoamniotic pregnancy, antenatal intertwin transfusions, fetal demise or major abnormalities were excluded from the study. The time of cord clamping depended on the obstetrician’s decision. Hemoglobin, hematocrit, and reticulocyte count were measured at birth and during the second day of life.

Results

At birth, hemoglobin and hematocrit levels were significantly higher in the first-born twins delivered with delayed than with early cord clamping. Higher hemoglobin and hematocrit levels were observed during the second day of life in all twins delivered with delayed cord clamping. The lowest levels were observed in twins delivered with early cord clamping. Infants delivered with delayed cord clamping were at a lower risk of respiratory disorders and NICU hospitalization.

Conclusion

The observed differences in Hgb concentrations between the infants in a twin pregnancy are related to cord clamping time.

Neonatal management and outcome in complicated monochorionic twins: What have we learned in the past decade and what should you know?

Monochorionic (MC) twin pregnancies are at increased risk of neonatal morbidity and mortality due to the shared placenta with vascular connections that can give rise to various complications, including twin-twin transfusion syndrome, twin anemia polycythemia sequence (TAPS), selective fetal growth restriction, and other hematological imbalances at birth. Each complication presents its own challenges and considerations in the neonatal period. Measurement of hemoglobin levels and reticulocyte count is required to establish a correct diagnosis. Placenta dye injection is needed to properly distinguish between the various conditions. Risk factors for adverse outcome in MC twins include prematurity, severe cerebral injury, and the type of MC pregnancy complication. We, therefore, recommend cerebral ultrasound examinations in all complicated MC twins at birth to rule out a severe brain injury. Lastly, we strongly encourage screening for hearing loss using automated auditory brainstem response in all spontaneous TAPS donors to prevent permanent speech development delay.

Large Hemoglobin Differences at Birth in Monochorionic Twins with a Placental Chorangioma and Delayed Cord Clamping

We report a case of a monochorionic diamniotic twin with an uncomplicated pregnancy, but with an unexpected large intertwin hemoglobin (Hb) difference at birth. Twin 1 was delivered vaginally and had an uneventful neonatal course. The umbilical cord of Twin 1 was clamped approximately 5 min after birth. After the birth of Twin 1, Twin 2 developed severe bradycardia and showed limited cardiac output on ultrasound, for which an emergency cesarean section was performed. A full blood count revealed an Hb of 20.1 g/dL for Twin 1 and 10.2 g/dL for Twin 2 (intertwin difference 9.9 g/dL). Reticulocyte counts were similar, 40‰ and 38‰, respectively. Placental examination revealed 10 vascular anastomoses, including one arterio-arterial anastomosis with a diameter of 1.4 mm. Additionally, a large chorangioma was present on the placental surface of Twin 2. There was no color difference on the maternal side of the placenta. Based on the reticulocyte count ratio and the placental characteristics, twin anemia polycythemia sequence was ruled out as the cause of the large intertwin Hb difference. In this report, we discuss the various potential causes that could explain the large intertwin Hb difference including the role of delayed cord clamping in Twin 1, and the role of a large chorangioma, which may have attracted blood from the fetal circulation of Twin 2.

Impact of Deferred Cord Clamping on Mortality and Severe Neurologic Injury in Twins Born at <30 Weeks of Gestation

OBJECTIVE

To determine whether deferred cord clamping (DCC) compared with early cord clamping (ECC) was associated with reduction in death and/or severe neurologic injury among twins born at <30 weeks of gestation.

STUDY DESIGN

We performed a retrospective cohort study including all liveborn twins of <30 weeks admitted to a tertiary-level neonatal intensive care unit (NICU) in Canada between 2015 and 2018 using the Canadian Neonatal/Preterm Birth Network database. We compared DCC ≥30 seconds vs ECC <30 seconds. Our primary outcome was a composite of death and/or severe neurologic injury (severe intraventricular hemorrhage grade III/IV and/or periventricular leukomalacia). Secondary outcomes included neonatal morbidity and health care utilization outcomes. We calculated aORs and β coefficients for categorical and continuous variables, along with 95% CI. Models were fitted with generalized estimated equations accounting for twin correlation.

RESULTS

We included 1597 twins (DCC, 624 [39.1%]; ECC, 973 [60.9%]). Death/severe neurologic injury occurred in 17.8% (n = 111) of twins who received DCC and in 21.7% (n = 211) of those who received ECC. The rate of death/severe neurologic injury did not differ significantly between the DCC and ECC groups (aOR 1.07; 95% CI, 0.78-1.47). DCC was associated with reduced blood transfusions (adjusted β coefficient, -0.49; 95% CI, -0.86 to -0.12) and NICU length of stay (adjusted β coefficient, -4.17; 95% CI, -8.15 to -0.19).

CONCLUSIONS

The primary composite outcome of death and/or severe neurologic injury did not differ between twins born at <30 weeks of gestation who received DCC and those who received ECC, but DCC was associated with some benefits.

Perinatal outcome after planned vaginal delivery in monochorionic compared with dichorionic twin pregnancy

OBJECTIVE

To assess, according to chorionicity, the perinatal outcome of twin pregnancy in which vaginal delivery is planned.

METHODS

JUMODA (JUmeaux MODe d'Accouchement) was a national prospective population-based cohort study of twin pregnancies, delivered in 176 maternity units in France, from February 2014 to March 2015. In this planned secondary analysis, we assessed, according to chorionicity, the perinatal outcome of twin pregnancies, in which vaginal delivery was planned, that delivered at or after 32 weeks of gestation with the first twin in cephalic presentation. In order to select a population with well-recognized indications for planned vaginal delivery, we applied the same exclusion criteria as those in the Twin Birth Study, an international randomized trial. Monochorionic twin pregnancies with twin-to-twin transfusion syndrome or twin anemia-polycythemia sequence were defined as complicated and were excluded. The primary outcome was a composite of intrapartum mortality and neonatal morbidity and mortality. Multivariable logistic regression models were used to control for potential confounders. Subgroup analyses were conducted according to birth order (first or second twin) and gestational age at delivery (< 37 or ≥ 37 weeks of gestation).

RESULTS

Among 3873 twin pregnancies, in which vaginal delivery was planned, that delivered at ≥ 32 weeks' gestation with the first twin in cephalic presentation, meeting the inclusion criteria of the Twin Birth Study, 729 (18.8%) were uncomplicated monochorionic twin pregnancies and 3144 (81.2%) were dichorionic twin pregnancies. The rate of composite intrapartum mortality and neonatal morbidity and mortality did not differ between uncomplicated monochorionic (27/1458 (1.9%)) and dichorionic (107/6288 (1.7%)) twin pregnancies when adjusting for conception by assisted reproductive technologies (adjusted relative risk, 1.07 (95% CI, 0.66-1.75)). No significant difference in the primary outcome was found between the groups on subgroup analyses according to birth order and gestational age at delivery.

CONCLUSION

When vaginal delivery is planned, and delivery occurs at ≥ 32 weeks of gestation with the first twin in cephalic presentation, uncomplicated monochorionic twin pregnancy is not associated with a higher rate of composite intrapartum mortality and neonatal morbidity and mortality compared with dichorionic twin pregnancy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Haemodynamic effects of umbilical cord milking in premature sheep during the neonatal transition

OBJECTIVE

Umbilical cord milking (UCM) at birth may benefit preterm infants, but the physiological effects of UCM are unknown. We compared the physiological effects of two UCM strategies with immediate umbilical cord clamping (UCC) and physiological-based cord clamping (PBCC) in preterm lambs.

METHODS

At 126 days' gestational age, fetal lambs were exteriorised, intubated and instrumented to measure umbilical, pulmonary and cerebral blood flows and arterial pressures. Lambs received either (1) UCM without placental refill (UCMwoPR); (2) UCM with placental refill (UCMwPR); (3) PBCC, whereby ventilation commenced prior to UCC; or (4) immediate UCC. UCM involved eight milks along a 10 cm length of cord, followed by UCC.

RESULTS

A net volume of blood was transferred into the lamb during UCMwPR (8.8 mL/kg, IQR 8-10, P=0.01) but not during UCMwoPR (0 mL/kg, IQR -2.8 to 1.7) or PBCC (1.1 mL/kg, IQR -1.3 to 4.3). UCM had no effect on pulmonary blood flow, but caused large fluctuations in mean carotid artery pressures (MBP) and blood flows (CABF). In UCMwoPR and UCMwPR lambs, MBP increased by 12%±1% and 8%±1% and CABF increased by 32%±2% and 15%±2%, respectively, with each milk. Cerebral oxygenation decreased the least in PBCC lambs (17%, IQR 13-26) compared with UCMwoPR (26%, IQR 23-25, P=0.03), UCMwPR (35%, IQR 27-44, P=0.02) and immediate UCC (34%, IQR 28-41, P=0.02) lambs.

CONCLUSIONS

UCMwoPR failed to provide placental transfusion, and UCM strategies caused considerable haemodynamic disturbance. UCM does not provide the same physiological benefits of PBCC. Further review of UCM is warranted before adoption into routine clinical practice.

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.

Haemoglobin discordances in twins: due to differences in timing of cord clamping?

OBJECTIVE

Our objective was to study the differences in haemoglobin (Hb) at birth in dichorionic (DC) versus monochorionic (MC) twins in relation to birth order and mode of delivery.

METHODS

All consecutive DC twin pregnancies and uncomplicated MC twin pregnancies with two live-born twins delivered at our centre were included in this retrospective cohort study. Hb levels at birth and on day 2 were evaluated in association with birth order and mode of delivery. The occurrence of polycythaemia (venous haematocrit >65%) was also recorded.

RESULTS

A total of 300 DC and 290 MC twin pairs were included. In DC and MC twins delivered vaginally, second-born twins had a higher Hb level at birth compared with their co-twin (mean Hb level 16.7 vs 15.9 g/dL (p<0.01) in DC twins and 17.8 vs 16.1 g/dL (p<0.01) in MC twins). In twins delivered through caesarean section, no intertwin differences in Hb levels were detected. Polycythaemia occurred significantly more often in second-born twins compared with first-born twins delivered vaginally: 10 (5%) vs 2 (1%) (p=0.02) in DC twins and 20 (12%) vs 2 (1%) (p<0.01) in MC twins.

CONCLUSIONS

Second-born DC and MC twins delivered vaginally have higher Hb levels at birth compared with first-born twins. Intertwin Hb differences in MC twins may partly be related to blood transfusion through the vascular anastomoses. Since DC twins do not have anastomoses, other factors may lead to Hb differences, including differences in timing of umbilical cord clamping.

Hematological disorders at birth in complicated monochorionic twins

INTRODUCTION

Monochorionic twins are at risk of severe complications including twin-twin transfusion syndrome (TTTS), twin anemia-polycythemia sequence (TAPS) and acute peripartum TTTS. The pathophysiology is based on inter-twin blood transfusion through placental vascular anastomoses. Areas covered: This review focuses on the incidence, management and outcome of neonatal hematological complications at birth in TTTS, TAPS and acute peripartum TTTS. Expert commentary: Hematological disorders are often present at birth in monochorionic twins and include acute or chronic anemia, polycythemia and thrombocytopenia. Routine measurement of complete blood counts in all complicated monochorionic twins is strongly recommended. Increased awareness on these disorders and correct diagnostic tests will lead to prompt and adequate management at birth.