Neonatal Outcomes of Low-Risk, Late-Preterm Twins Compared With Late-Preterm Singletons

Risk of intrapartum cesarean delivery in twin pregnancies: A retrospective cohort study

OBJECTIVE

To compare the risk of intrapartum cesarean delivery (CD) between patients with twin and singleton pregnancies undergoing a trial of labor and identify risk factors for intrapartum CD in twin pregnancies.

METHODS

The present study was a retrospective cohort study of patients with a twin or singleton pregnancy who underwent a trial of labor at ≥340/7 weeks in a single center (2015-2022). The primary outcome was the rate of intrapartum CD. In twin pregnancies, this outcome was limited to CD of both twins. The association of plurality with intrapartum CD was estimated using multivariable Poisson regression.

RESULTS

A total of 20 754 patients met the study criteria, 669 of whom had a twin pregnancy. Patients with twins had a greater risk of intrapartum CD (of both twins) than those with singleton pregnancies (22.1% vs 15.9%, respectively; aRR 1.38 [95% CI: 1.15-1.66]), primarily due to a greater risk of failure to progress. In addition, 4.1% of the twin pregnancies had a CD for the second twin, resulting in an overall CD rate in twin pregnancies of 26.2%. Variables associated with intrapartum CD in twin pregnancies included nulliparity (aOR 3.50, 95% CI: 2.34-5.25), birthweight discordance >20% (aOR 2.47, 95% CI: 1.27-4.78), and labor induction (aOR 1.64, 95% CI: 1.07-2.53). The rate of intrapartum CD was highest when all three risk factors were present (67% [95% CI: 41%-87%]).

CONCLUSION

Twin pregnancies are associated with a greater risk of intrapartum CD than singleton pregnancies. Information on the individualized risk of intrapartum CD may be valuable when counseling patients with twins regarding mode of delivery.

Outcomes of dichorionic twin pregnancies with fused versus separate placentas

PURPOSE

In a certain proportion of dichorionic twin pregnancies, the two placentas are fused. The clinical significance of this finding remains unclear. Our objective was to compare outcomes of dichorionic twin pregnancies with fused versus separate placentas as determined on first-trimester ultrasound.

METHODS

Retrospective study of patients with dichorionic twins followed at a tertiary center between 2014 and 2022. The co-primary outcomes were fetal growth restriction and preeclampsia. Associations between fused placentas and the study outcomes were estimated using multivariable Poisson regression and were reported as adjusted relative risk (aRR) with a 95%-confidence interval (CI).

RESULTS

Of the 328 eligible patients, 175 (53.4%) and 153 (46.6%) had fused and separate placentas, respectively. Compared with pregnancies with separate placentas, patients with fused placentas had a lower risk of preeclampsia [aRR 0.48 (95%-CI 0.24-0.97)] but a higher risk of fetal growth restriction [aRR 1.23 (95%-CI 1.02-1.48)] and admission to the neonatal intensive care unit [aRR 1.31 (95%-CI 1.01-1.71)]. In addition, pregnancies with fused placentas were more likely to have a total placental weight below the 10th percentile than those with separate placentas [aRR 1.93 (95%-CI 1.16-3.21)].

DISCUSSION

Dichorionic twin pregnancies with fused placentas have a lower risk of preeclampsia but are more likely to be complicated by fetal growth restriction, observations that may be attributed to the lower total placentas mass in pregnancies with fused compared with separate placentas. Fused placentas can be used as a potential biomarker for the prediction of pregnancy complications in dichorionic twin pregnancies.

National and international guidelines on the management of twin pregnancies: a comparative review

Twin gestations are associated with increased risk of pregnancy complications. However, high-quality evidence regarding the management of twin pregnancies is limited, often resulting in inconsistencies in the recommendations of various national and international professional societies. In addition, some recommendations related to the management of twin gestations are often missing from the clinical guidelines dedicated to twin pregnancies and are instead included in the practice guidelines on specific pregnancy complications (eg, preterm birth) of the same professional society. This can make it challenging for care providers to easily identify and compare recommendations for the management of twin pregnancies. This study aimed to identify, summarize, and compare the recommendations of selected professional societies from high-income countries on the management of twin pregnancies, highlighting areas of both consensus and controversy. We reviewed clinical practice guidelines of selected major professional societies that were either specific to twin pregnancies or were focused on pregnancy complications or aspects of antenatal care that may be relevant for twin pregnancies. We decided a priori to include clinical guidelines from 7 high-income countries (United States, Canada, United Kingdom, France, Germany, and Australia and New Zealand grouped together) and from 2 international societies (International Society of Ultrasound in Obstetrics and Gynecology and the International Federation of Gynecology and Obstetrics). We identified recommendations regarding the following care areas: first-trimester care, antenatal surveillance, preterm birth and other pregnancy complications (preeclampsia, fetal growth restriction, and gestational diabetes mellitus), and timing and mode of delivery. We identified 28 guidelines published by 11 professional societies from the 7 countries and 2 international societies. Thirteen of these guidelines focus on twin pregnancies, whereas the other 16 focus on specific pregnancy complications predominantly in singletons but also include some recommendations for twin pregnancies. Most of the guidelines are recent, with 15 of the 29 guidelines published over the past 3 years. We identified considerable disagreement among guidelines, primarily in 4 key areas: screening and prevention of preterm birth, using aspirin to prevent preeclampsia, defining fetal growth restriction, and the timing of delivery. In addition, there is limited guidance on several important areas, including the implications of the "vanishing twin" phenomenon, technical aspects and risks of invasive procedures, nutrition and weight gain, physical and sexual activity, the optimal growth chart to be used in twin pregnancies, the diagnosis and management of gestational diabetes mellitus, and intrapartum care.This consolidation of key recommendations across several clinical practice guidelines can assist healthcare providers in accessing and comparing recommendations on the management of twin pregnancies and identifies high-priority areas for future research based on either continued disagreement among societies or limited current evidence to guide care.

Late preterm antenatal corticosteroids in singleton and twin gestations: a retrospective cohort study

BACKGROUND

In 2016, the American College of Obstetricians and Gynecologists recommended antenatal corticosteroids in the late preterm period for women at risk for preterm delivery. Limited real-world evidence exists on neonatal outcomes, particularly for twin gestations, following the guideline change. The study objective is to determine the association of antenatal corticosteroids in late preterm singleton and twin pregnancies with respiratory complications and hypoglycemia in a real-world clinical setting.

METHODS

This is a retrospective cohort study comprising late preterm deliveries (4,341 mother-child pairs) within the Mount Sinai Health System, 2012-2018. The exposure of interest is antenatal corticosteroid administration of betamethasone during pregnancy between 34 0/7 and 36 6/7 weeks. Our primary outcomes are neonatal respiratory complications and hypoglycemia. Multivariable logistic regression was used to estimate the association between antenatal corticosteroid exposure and these two outcomes. We stratified the study population by singleton gestations and twins to minimize the potential confounding from different obstetric management between the two groups.

RESULTS

Among a total of 4,341 mother-child pairs (3,309 singleton and 1,032 twin mother-child pairs), 745 mothers received betamethasone, of which 40.94% (305/745) received the full course. Relative to no treatment, a full course of betamethasone was associated with reduced odds of respiratory complications (OR = 0.53, 95% CI:[0.31-0.85], p < 0.01) and increased odds of hypoglycemia (OR = 1.86, 95%CI:[1.34-2.56], p < 0.01) in singletons; however, the association with respiratory complications was not significant in twins (OR = 0.42, 95% CI:[0.11-1.23], p = 0.16), but was associated with increased odds of hypoglycemia (OR = 2.18, 95% CI:[1.12-4.10], p = 0.02). A partial course of betamethasone (relative to no treatment) was not significantly associated with any of the outcomes, other than respiratory complications in twins (OR = 0.34, 95% CI:[0.12-0.82], p = 0.02).

CONCLUSIONS

Exposure to antenatal corticosteroids in singletons and twins is associated with increased odds of hypoglycemia. Among singletons, exposure to the full dosage (i.e. two doses) was associated with decreased odds of respiratory complications but this was only the case for partial dose among twins. Twin gestations were not studied by the Antenatal Late Preterm Steroids trial. Therefore, our study findings will contribute to the paucity of evidence on the benefit of antenatal corticosteroids in this group. Health systems should systematically monitor guideline implementations to improve patient outcomes.

Chorionicity, birth weight discordance and neonatal morbidity in uncomplicated twin pregnancies delivered from 36 weeks

OBJECTIVES

To investigate the association between chorionicity, birth weight discordance and neonatal morbidity in uncomplicated twin pregnancies progressing to at least 36 weeks of gestation.

STUDY DESIGN

This was a retrospective single centre cohort study of all twin pregnancies referred to our twin clinic between 2011 and 2018. Outcome details were obtained from the computerized maternity and neonatal records. The primary outcome was incidence of composite neonatal morbidity according to chorionicity. We also determined the incidence of composite neonatal morbidity in pregnancies with birth weight discordance. Logistic regression was used to identify and adjust for potential confounders.

RESULTS

Three hundred and eighty-five twin pregnancies (286 dichorionic, 99 monochorionic) were included. Gestational age at birth was significantly lower in pregnancies complicated by neonatal morbidity (p = 0.013) compared with those which were not. On multivariable logistic regression analysis, gestational age at birth (p = 0.031) and birth weight discordance (p = 0.004), but not chorionicity (p = 0.626) were independently associated with neonatal morbidity.

CONCLUSION(S)

In uncomplicated twin pregnancies chorionicity is not associated with neonatal morbidity. Gestational age at birth is the major determinant of neonatal outcome while the clinical impact of weight discordance seems marginally significant.

Evaluation of the effectiveness of antenatal corticoid in preterm twin and single pregnancies: a multicenter cohort study

BACKGROUND

The effects of antenatal corticosteroids (ANSs) on twins are not well established.

OBJECTIVE

To determine the impact of ANS use according to the number of fetuses.

METHODS

Retrospective cohort study of newborns between 23 and 33 weeks of gestational age, birth weight from 400 to 1499 g, without malformations, delivered at 20 public university hospitals from 2010 to 2014.Exposed group: Received ANS (any time, any dose) and no exposed group: no received ANS. Analysis of birth conditions and clinical outcomes. Association of variables, relative risks, and 95% confidence intervals estimated from the adjustment of log-binomial regression models.

RESULTS

About 7165 premature infants were analyzed: 5167 singleton, 937 twins, and 104 triplets. Characteristics of gestations with one, two, or three fetuses not receiving ANS were similar. Reduced hemodynamic instability in single and twins gestations in the first 72 h were observed (Adj R² Twins = 0.78; 95% CI = 0.69-0.86) (Adj R² Singles = 0.79; 95% CI = 0.62-0.99). Reduced peri-intraventricular hemorrhage (Adj R² Twins = 0.54; 95% CI = 0.36-0.78) (Adj R² singles = 0.54; 95% CI = 0.36-0.78); and early sepsis reduction on single and triplex gestations (Adj R² triplex = 0.51; 95% CI = 0.27-0.94) (Adj single R² = 0.51; 95% CI = 0.27-0.94) were observed.

CONCLUSIONS

This study demonstrates ANS produces an important protective factor for severe intraventricular hemorrhage and hemodynamic instability in single and multiple pregnancies. ANS had a protective effect on death and birth conditions improvement just in single gestations. Regarding respiratory aspects was not observed the protective effect in the single or multiple gestations.

Late preterm births: neonatal mortality and morbidity in twins vs. singletons

OBJECTIVE

To examine the outcomes of twins and singletons in the late preterm period.

MATERIALS AND METHODS

This is a retrospective cohort study of data obtained for 165,894 births in California who delivered between 34 + 0 and 36 + 6 weeks. The primary outcome was neonatal and infant mortality. The secondary outcomes included the following neonatal morbidities: respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), seizure, and sepsis. Univariate analysis was performed using chi-square test and multivariable logistic regression was used to adjust for potential confounders.

RESULTS

There were 143,891 singleton and 22,003 twin gestations included in the study. There was no difference in the primary outcome, neonatal and infant mortality between twins and singletons delivered at 34 and 36 weeks. After controlling for multiple potential confounders, significant differences in secondary outcomes of neonatal morbidity were identified. At 34 weeks, twins had significantly higher rates of IVH (aOR 2.47 (95%CI 1.08-5.64)), NEC (aOR 2.46 (95%CI 1.42-4.29)), RDS (aOR 1.60 (95%CI 1.45-1.77)), and sepsis (aOR 1.19 (95%CI 1.05-1.34)) compared to singletons. By 36 weeks, only an increased risk of RDS persisted among twins.

CONCLUSIONS

While there was no difference in mortality among twins and singletons in the late preterm period, twins may have significantly increased neonatal morbidity compared to singletons delivered between 34 + 0 and 36 + 6 weeks.

Prospective risk of stillbirth and neonatal complications for monochorionic diamniotic and dichorionic diamniotic twins after 24 weeks of gestation

INTRODUCTION

Our study compared the prospective risks of intrauterine fetal death (IUFD), neonatal death (NND), perinatal death (PND), and neonatal morbidities in monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin pregnancies.

METHODS

This retrospective cohort study included twin pregnancies who had antenatal care and delivery in a public hospital from 2011 to 2018. Exclusion criteria included monoamnionicity, one/both twin miscarriage, twin-twin transfusion syndrome, or lethal congenital abnormalities. All twins were managed in multiple pregnancy clinic with standardized protocols. Gestational age-specific IUFD, NND, PND, and neonatal morbidity rates were compared according to chorionicity.

RESULTS

Three hundred seventy-eight MCDA and 1282 DCDA twins were included. MCDA twins had higher risks of PND (1.9% vs. 0.7% in DCDA twins, p = 0.05), composite neonatal morbidity (p = 0.01), preterm delivery (p < 0.01), and low birth weight (p < 0.01). The prospective risk of IUFD was 0.6% and 0.4% for MCDA and DCDA twins, respectively after 34 weeks' gestation. No NND occurred among deliveries after 30 weeks. The risk of neonatal morbidity of MCDA twins fell from 22.7% at 34 weeks to 2.7% at 37 weeks (p < 0.01). For DCDA twins, the risk of morbidity fell insignificantly from 36 to 38 weeks (4.0% vs. 3.4%, p = 0.60). Logistic regression analysis suggested that the increased risk of perinatal morbidities was related to the higher rate of preterm delivery in MCDA twins rather than chorionicity.

CONCLUSION

With close fetal monitoring, the risk of late IUFD in twin pregnancies without major complications is low. Perinatal morbidity can be minimized by avoiding late preterm deliveries in twin pregnancies.

Does antenatal steroids treatment in twin pregnancies prior to late preterm birth reduce neonatal morbidity? Evidence from a retrospective cohort study

PURPOSE

To evaluate whether antenatal corticosteroids (ACS) administration during the late-preterm (LPT) period in twin pregnancies is associated with decreased rate of neonatal morbidity.

METHODS

A retrospective cohort study including a total of 290 women with twin pregnancies resulting in live births of 580 neonates who delivered during LPT period between 2016 and 2018 at a tertiary medical center. Patients were allocated into two groups according to ACS exposure. Obstetric and neonatal outcomes were compared between the groups. Primary outcome was neonatal composite respiratory morbidity, defined as the occurrence of at least one of the followings: RDS, TTN, O2 requirement, CPAP use or mechanical ventilation.

RESULTS

Patients exposed to ACS were older and more commonly complicated by gestational diabetes compared to the non-exposed group. Moreover, women exposed to ACS delivered earlier (35.6 vs. 36.3 weeks, P < 0.001) and more frequently by cesarean section (76.4% vs. 54.1%, P = 0.002) compared to the non-exposed group. The rate of composite respiratory morbidity did not differ between the groups. Nevertheless, neonates exposed to ACS had higher rates of neonatal intensive care unit (NICU) admission and hypoglycemia compared to neonates without prior ACS exposure (27.8% vs. 11.7%, P = 0.001; 49.3% vs. 27.1%, P < 0.001, respectively). Multivariable logistic regression revealed that gestational age at delivery was the sole independent risk factor for NICU admission, whereas late-preterm ACS exposure was the only risk factor for hypoglycemia.

CONCLUSION

LPT-ACS administration in twin pregnancies complicated by LPT birth in our study did not reduce neonatal respiratory morbidity but was associated with higher rates of hypoglycaemia.

No. 364-Antenatal Corticosteroid Therapy for Improving Neonatal Outcomes

OBJECTIVE

To assess the benefits and risks of antenatal corticosteroid therapy for women at risk of preterm birth or undergoing pre-labour Caesarean section at term and to make recommendations for improving neonatal and long-term outcomes.

OPTIONS

To administer or withhold antenatal corticosteroid therapy for women at high risk of preterm birth or women undergoing pre-labour Caesarean section at term.

OUTCOMES

Perinatal morbidity, including respiratory distress syndrome, intraventricular hemorrhage, bronchopulmonary dysplasia, infection, hypoglycemia, somatic and brain growth, and neurodevelopment; perinatal mortality; and maternal morbidity, including infection and adrenal suppression.

INTENDED USERS

Maternity care providers including midwives, family physicians, and obstetricians.

TARGET POPULATION

Pregnant women.

EVIDENCE

Medline, PubMed, Embase, and the Cochrane Library were searched from inception to September 2017. Medical Subject Heading (MeSH) terms and key words related to pregnancy, prematurity, corticosteroids, and perinatal and neonatal mortality and morbidity were used. Statements from professional organizations including that of the National Institutes of Health, the American College of Obstetricians and Gynecologists, the Society for Maternal Fetal Medicine, the Royal College of Obstetricians and Gynaecologists, and the Canadian Pediatric Society were reviewed for additional references. Randomized controlled trials conducted in pregnant women evaluating antenatal corticosteroid therapy and previous systematic reviews on the topic were eligible. Evidence from systematic reviews of non-experimental (cohort) studies was also eligible.

VALIDATION METHODS

This Committee Opinion has been reviewed and approved by the Maternal-Fetal Medicine Committee of the SOGC and approved by SOGC Council.

BENEFITS, HARMS, AND/OR COSTS

A course of antenatal corticosteroid therapy administered within 7 days of delivery significantly reduces perinatal morbidity/mortality associated with preterm birth between 24 + 0 and 34 + 6 weeks gestation. When antenatal corticosteroid therapy is given more than 7 days prior to delivery or after 34 + 6 weeks gestation, the adverse effects may outweigh the benefits. Evidence on long-term effects is scarce, and potential neurodevelopment harms are unquantified in cases of late preterm, term, and repeated exposure to antenatal corticosteroid therapy.

GUIDELINE UPDATE

Evidence will be reviewed 5 years after publication to evaluate the need for a complete or partial update of the guideline. If important evidence is published prior to the 5-year time point, an update will be issued to reflect new knowledge and recommendations.

SPONSORS

The guideline was developed with resources provided by the Society of Obstetricians and Gynaecologists of Canada with support from the Canadian Institutes of Health Research (APR-126338).

SUMMARY STATEMENTS

RECOMMENDATIONS: Gestational Age Considerations Agents, Dosage, Regimen, and Target Timing Subpopulations and Special Consideration.

Respiratory morbidity in late preterm twin infants

PURPOSE

Antenatal corticosteroids have been shown to decrease neonatal respiratory morbidity in singleton pregnancies when given during the late-preterm period (34^0/7-36^6/7 weeks). Whether these findings also apply to late-preterm twins, who account for approximately one-third of infants born at 34^0/7-35^6/7 weeks, is currently unclear. The answer to this question depends, in part, on whether the risk of respiratory morbidity among late-preterm twin infants is similar to that observed in late-preterm singletons. We aimed to assess the rate of respiratory morbidity among late-preterm twin infants using a secondary analysis of prospectively collected data from a large international multicenter trial, and to compare that rate with previous studies that used the same definition of respiratory morbidity.

STUDY DESIGN

This was a secondary analysis of the twin birth study. In the current study, we limited the analysis to women who gave birth during the late preterm period. The primary outcomes were the same primary composite respiratory morbidity variables that were used in the randomized controlled trial of Gyamfi-Bannerman et al., on the administration of betamethasone during the late preterm period in singletons (ALPS trial). The risk of respiratory morbidity among late preterm twins was stratified by gestational week at birth.

RESULTS

A total of 1163 women who gave birth to 2324 late preterm twin infants met the inclusion criteria. The rates of respiratory morbidity and severe respiratory morbidity were 16.5% and 8.9%, respectively. The risk of respiratory morbidity was highly dependent on gestational week at birth, being more than fourfold for infants born at 34^0/7-34^6/7 weeks (aOR 4.30, 95%-CI 3.01-6.14) and more than twofold for infants born at 35^0/7-35^6/7 weeks (aOR 2.12, 95%-CI 1.51-2.98) compared with infants born at 36^0/7-36^6/7 weeks. The rate of respiratory morbidity and the theoretical number of women needed to be treated with betamethasone to prevent a single case of respiratory morbidity in the current study were similar to those reported in the APLS trial (16.5% vs. 14.4%, p = 0.103, and NNT 31 vs. 34, respectively).

CONCLUSIONS

The risk-benefit ratio of betamethasone with regard to neonatal respiratory morbidity in women with twins at risk of late-preterm birth is expected to be similar to that observed in singletons.

The place of antenatal corticosteroids in late preterm and early term births

Infants born in the late preterm period and via non-labour caesarean section in the early term period are at increased risk of respiratory morbidity when compared to their term-born counterparts. The morbidity in these infants is less frequent and severe than in early preterm infants. Antenatal corticosteroids reduce respiratory morbidity in these populations; however, the magnitude of the reduction appears to be small and predominantly in the self-limiting condition of transient tachypnoea of the neonate. The smaller benefit, along with possible harmful effects of corticosteroids, raises a question about the role of antenatal corticosteroids in this population. Special obstetric populations such as twin pregnancies and pregnancies complicated by diabetes and growth restriction are at increased risk of prematurity and more vulnerable to its complications. Nevertheless, there is limited evidence regarding the benefits of corticosteroids in these populations and potential concern regarding adverse effects. We recommend an individualised approach when administering corticosteroids at later gestations. In these specific obstetric populations, we do not currently recommend administering corticosteroids in the late preterm/early term periods until more evidence is available.

N° 364 - La Corticothérapie Prénatale Pour Améliorer Les Issues Néonatales

OBJECTIF

Évaluer les avantages et les risques de la corticothérapie prénatale chez les femmes qui présentent un risque d'accouchement prématuré ou qui subissent une césarienne à terme avant début de travail, et formuler des recommandations visant l'amélioration des issues néonatales et des issues à long terme.

OPTIONS

Administrer ou ne pas administrer une corticothérapie prénatale aux femmes qui présentent un risque élevé d'accouchement prématuré ou qui subissent une césarienne avant travail à terme. RéSULTATS: Morbidité périnatale, notamment le syndrome de détresse respiratoire, l'hémorragie intraventriculaire, la dysplasie bronchopulmonaire, l'infection, l'hypoglycémie, ainsi que les troubles de la croissance somatique et cérébrale et du neurodéveloppement; mortalité périnatale; et morbidité maternelle, notamment l'infection et la suppression surrénalienne.

UTILISATEURS CIBLES

Fournisseurs de soins de maternité, notamment les sages-femmes, les médecins de famille et les obstétriciens.

POPULATION CIBLE

Femmes enceintes. ÉVIDENCE: Nous avons interrogé les bases de données Medline, PubMed et Embase ainsi que la Bibliothèque Cochrane, de leur création au mois de septembre 2017. Nous nous sommes servis de Medical Subjet Headings (MeSH) et de mots clés en lien avec la grossesse, la prématurité, les corticostéroïdes ainsi que la mortalité et la morbidité périnatales et néonatales. Nous avons également consulté les déclarations d'organismes professionnels tels que les National Institutes of Health, l'American College of Obstetricians and Gynecologists, la Society for Maternal-Fetal Medicine, le Royal College of Obstetricians and Gynaecologists et la Société canadienne de pédiatrie pour obtenir des références additionnelles. Les essais cliniques randomisés évaluant la corticothérapie prénatale menés sur des femmes enceintes et les revues systématiques antérieures sur le sujet étaient admissibles, tout comme les données venant de revues systématiques d'études non expérimentales (études de cohorte).

VALEURS

La présente opinion de comité a été révisée et approuvée par le Comité de médecine fœto-maternelle de la SOGC, et approuvée par le Conseil de la SOGC. AVANTAGES, INCONVéNIENTS ET COûTS: L'administration d'une corticothérapie prénatale dans les sept jours précédant l'accouchement réduit significativement la morbidité et la mortalité périnatales associées à la naissance prématurée survenant entre 24+0 et 34+6 semaines de grossesse. Si la corticothérapie prénatale est administrée plus de sept jours avant l'accouchement ou après 34+6 semaines de grossesse, les effets indésirables peuvent surpasser les avantages. Les données probantes sur l'impact à long terme de la corticothérapie prénatale sont rares. Par ailleurs, les effets neurodéveloppementaux néfastes potentiels de l'exposition répétée à la corticothérapie prénatale ou de l'administration de corticostéroïdes en période préterme tardive ou à terme n'ont pas été quantifiés. MIS-à-JOUR à LA DIRECTIVE: Une revue des données probantes sera menée cinq ans après la publication de la présente directive clinique afin d'évaluer si une mise à jour complète ou partielle s'impose. Si de nouvelles données probantes importantes sont publiées avant la fin de ces cinq ans, une mise à jour tenant compte des nouvelles connaissances et recommandations sera publiée.

COMMANDITAIRES

La présente directive clinique a été élaborée à l'aide de ressources fournies par la Société des obstétriciens et gynécologues du Canada et avec l'appui des Instituts de recherche en santé du Canada (APR-126338). MOTS CLéS: Corticothérapie prénatale, maturation fœtale, prématurité, période préterme tardive, césarienne avant travail DÉCLARATION SOMMAIRES: RECOMMANDATIONS: Considérations relatives à l'âge gestationnel.

Multiple birth rates of Korea and fetal/neonatal/infant mortality in multiple gestation

Objective

This study was conducted to analyze recent trends of multiple birth rates (MBR) and fetal/neonatal/infant mortalities according to the number of gestations in Korea.

Methods

Data from 2009 to 2015 of live births, infant deaths and stillbirths were obtained from the Korean Vital Statistics. Neonatal mortality rate (NMR), infant mortality rate (IMR), and fetal mortality rate (FMR) in singleton, twin and triplet pregnancies were analyzed according to gestational period (GP; ≤ 23, 24–27, 28–31, and 32–36 weeks).

Results

From 2009 to 2015, twin and triplet birth rates increased 34.5% and 154.3%, respectively. In twin births, NMR and FMR have been decreased significantly (from 10.92 to 8.62, p = 0.034 and from 41.00 to 30.55, p< 0.001, respectively), but IMR did not show significant decrease. There was no significant change of NMR, IMR, and FMR, in triplet births. Overall, in singleton, twin, and triplet births, NMR was 1.26 ± 0.09, 10.6 ± 1.12, and 34.32 ± 11.72, respectively, and IMR was 2.38 ± 0.26, 14.52 ± 1.38, and 41.13 ± 12.2, respectively. FMRs were 12 ± 1.73, 35.99 ± 3.55, and 88.85 ± 16.55, respectively, in singleton, twin, and triplet pregnancies. In spite of decreasing trends in overall mortalities, the odds ratios of NMRs and IMRs in 2015 were approximately 9-fold and 6-fold higher, respectively, in twin births, and approximately 37-fold and 20-fold higher, respectively, in triplet births, than those in singleton births. There were no significant differences in odds ratios of NMRs and IMRs at GP 32–36 among single, twin, and triplet births, although the odds ratios of FMR at GP 32–36 in triplet gestation was significantly higher than those in singleton and twin gestation.

Conclusion

Neonatal/infant mortality in multiple births is still significantly high, which is mainly related with preterm birth. Close fetal monitoring is needed to prevent fetal death in triplet pregnancies, after 32 gestational weeks.