Perinatal mortality and morbidity in triplet pregnancy according to chorionicity: systematic review and meta-analysis

Perinatal outcomes and growth discordance of triplet pregnancies based on chorionicity: a retrospective cohort study

BACKGROUND

The worldwide occurrence of triplet pregnancy is estimated to be 0.093%, with a natural incidence of approximately 1 in 8000. This study aims to analyze the neonatal health status and birth weight discordance (BWD) of triplets based on chorionicity from birth until discharge.

METHODS

This was a retrospective study. We reviewed a total of 136 triplet pregnancies at our tertiary hospital between January 1, 2001, and December 31, 2021. Maternal and neonatal outcomes, inter-triplet BWD, neonatal morbidity, and mortality were analyzed.

RESULTS

Among all cases, the rates of intrauterine death, neonatal death, and perinatal death were 10.29, 13.07, and 24.26%, respectively. Thirty-seven of the cases resulted in fetal loss, including 13 with fetal anomalies. The maternal complications and neonatal outcomes of the 99 triplet pregnancies without fetal loss were compared across different chorionicities, including a dichorionic (DC) group (41 cases), trichorionic (TC) group (37 cases), and monochorionic (MC) group (21 cases). Neonatal hypoproteinemia (P < 0.001), hyperbilirubinemia (P < 0.019), and anemia (P < 0.003) exhibited significant differences according to chorionicity, as did the distribution of BWD (P < 0.001). More than half of the cases in the DC and TC groups had a BWD < 15%, while those in the MC group had a BWD < 50% (47.6%). TC pregnancy decreased the risk of neonatal anemia (adjusted odds ratio [AOR] = 0.084) and need for blood transfusion therapy after birth (AOR = 0.119). In contrast, a BWD > 25% increased the risk of neonatal anemia (AOR = 10.135) and need for blood transfusion after birth (AOR = 7.127). TC pregnancy, MCDA or MCTA, and BWD > 25% increased neonatal hypoproteinemia, with AORs of 4.629, 5.123, and 5.343, respectively.

CONCLUSIONS

The BWD differed significantly according to chorionicity. Additionally, TC pregnancies reduced the risk of neonatal anemia and need for blood transfusion, but increased the risk of neonatal hypoproteinemia. In contrast, the BWD between the largest and smallest triplets increased the risk of neonatal anemia and the need for blood transfusion. TC pregnancy, MCDA or MCTA, and BWD > 25% increased the risks of neonatal hypoproteinemia. However, due to the limited number of triplet pregnancies, further exploration of the underlying mechanism is warranted.

The effect of chorionicity on maternal and neonatal outcomes in triplet pregnancies

OBJECTIVE

Triplet gestations are associated with increased maternal, fetal, and neonatal complications particularly early and extreme preterm delivery. Identifying and interrupting the preterm delivery cascade could prevent the fetal, neonatal, and long-term childhood complications. The shared circulation and placental vascular anastomosis are responsible for the occurrence of twin-to-twin transfusion syndrome, selective fetal growth restriction as well as the higher risk of morbidity and mortality observed in mono and dichorionic compared to trichorionic triplet gestations. Thus, the aim of this study was to determine the effect of chorionicity on maternal, fetal, and neonatal outcomes of triplet pregnancies as it has not been fully ascertained.

STUDY DESIGN

A retrospective population-based cohort study of 125 parturient with triplets' pregnancy who delivered at a single tertiary hospital.

RESULTS

98 trichorionic and 27 dichorionic gestations were included. Maternal demographic and obstetric characteristics as well as pregnancy and postpartum complications were similar in the two study groups. The median gestational age at delivery was lower among dichorionic than trichorionic triplet gestations (median 31 vs 33 weeks, p < 0.046). Early (<32 weeks) and extreme preterm delivery (<28 weeks) were more prevalent in the dichorionic than the trichorionic group (early - 56 % vs 34 %, p < 0.038; extreme - 33.3 % vs 8 %, p < 0.002). We found no difference in fetal or newborns' complications and characteristics between the groups. However, the rate of neonatal death was significantly higher in the dichorionic compared to trichorionic triplet gestations (22 % vs 7 %, p < 0.038). A multivariate logistic regression model to determine the variables that contribute to early preterm delivery in triplet gestations showed that women who experienced a past preterm delivery had an independently higher risk for early preterm delivery in the triplet gestation (adj. OR 5.91, 95 % CI 1.16-30.03). Neither maternal age nor chorionicity were found to be independent risk factors for early preterm delivery.

CONCLUSIONS

Dichorionic triplet gestations exhibit a higher rate of early (<32 weeks) and extreme (<28 weeks) preterm delivery and are more prone to neonatal death compared to trichorionic gestations. Past preterm delivery is an independent risk factor for early preterm delivery in a triplet gestation.

Intertwin nuchal translucency difference predicts the chance of co-twin death after fetal reduction in dichorionic triplet pregnancies: a retrospective analysis study

OBJECTIVES

To compare the clinical outcomes of different multifetal pregnancy reduction (MFPR) programs in dichorionic (DC) triplets, and explore the association between early ultrasound characteristics and co-twin death after potassium chloride (KCl) injection into one monochorionic (MC) twin.

METHODS

We retrospectively reviewed the data of DC triplets who underwent MFPR at our center during 2012-2021. Patients were grouped as follows: intracardiac KCl injection into one MC twin (group A), intracardiac KCl injection into both MC twins simultaneously (group B), and reduction of the singleton fetus (group C) and pregnancy outcomes were compared. Logistic regression was used to determine whether ultrasound measurements at 11-13+6 weeks predicted co-twin death and the receiver operator characteristic (ROC) analysis was conducted to assess the predictive performance.

RESULTS

Finally, we enrolled 184 patients. 153 cases were in group A, and 18, 13 cases were in group B and C respectively. Gestational age at the time of MFPR did not differ among the 3 groups (median: [Formula: see text] weeks). The survival rate was 89.6%, 88.9%, and 92.3% in group A, B, and C respectively, which was comparable among groups. Preterm birth was more common in group C (10/12, 83.3%). After KCl injection into one MC twin, co-twin death occurred in 86.3% cases (132/153) within 1 day; however, 3 patients had 2 live births each, with normal postnatal development. Intertwin nuchal translucency (NT) difference/discordance significantly predicted co-twin death within 1 day after MFPR, and the areas under the ROC curve were 0.694 and 0.689, respectively.

CONCLUSIONS

For MFPR in DC triplet pregnancies, reduction of the MC twins results in less preterm birth, and women with KCl injection into either one or both MC twins had similar outcomes. Large intertwin NT difference/discordance was associated with co-twin death within 1 day after KCl injection into one of the MC twins.

Fetoscopic laser surgery for twin-to-twin transfusion syndrome in DCTA triplets compared to MCDA twins: collaborative study and literature review

OBJECTIVE

To compare the outcomes of dichorionic triamniotic (DCTA) triplets with that of monochorionic diamniotic (MCDA) twin gestations undergoing fetoscopic laser surgery (FLS) for treatment of twin-to-twin transfusion syndrome (TTTS).

METHODS

Retrospective cohort study of prospectively collected data of consecutive DCTA triplet and MCDA twin pregnancies with TTTS that underwent FLS at two fetal treatment centers between 2012 and 2020. Preoperative, operative and, postoperative variables were collected. Perinatal outcomes were investigated. Primary outcome was survival to birth and to neonatal period. Secondary outcomes were gestational age (GA) at birth and procedure-to-delivery interval. Literature review was conducted in which PubMed, Web of Science, and Scopus were searched from inception to September, 2020.

RESULTS

Twenty four sets of DCTA triplets were compared to MCDA twins during the study period. There were no significant differences in survival (no survivor, single, or double survivors) to birth and to the neonatal period of the MC twin pairs of the DCTA triplets vs MCDA twins. Median GA at delivery was approximately three weeks earlier in DCTA triplets compared to MCDA twins (28.4 weeks vs 31.4 weeks, p = .035, respectively). Rates of preterm birth (PTB) less than 32 and less than 28 weeks were significantly higher in DCTA triplets compared to twins (<32 weeks: 70.8% vs 51.1%, p = .037, respectively, and <28 weeks: 37.5% vs 20.8%, p = .033, respectively).

CONCLUSION

Perinatal survival including fetal and neonatal are comparable between DCTA triplets and MCDA twins. However, this might have resulted from the small sample size of the DCTA triplets. GA at delivery is earlier in triplets, which could be due to the nature of triplet gestation rather than to the laser procedure itself.

Maternal, Perinatal and Neonatal Outcomes of Triplet Pregnancies According to Chorionicity: A Systematic Review of the Literature and Meta-Analysis

Triplet pregnancies are rare events that affect approximately 93 in 100,000 deliveries in the world, especially due to the increased use of assisted reproductive techniques and older maternal age. Triplet pregnancies are associated with a higher risk of fetal and maternal morbidity and mortality compared to twins and singletons. Chorionicity has been proposed as a major determinant of perinatal and maternal outcomes in triplet pregnancies, although further evidence is needed to clarify the extent and real influence of this factor. Thus, the aim of this study was to conduct a systematic review of the literature and a meta-analysis of the maternal and perinatal outcomes of triplet pregnancies, evaluating how chorionicity may influence these results. A total of 46 studies with 43,653 triplet pregnancies and 128,145 live births were included. Among the main results of our study, we found a broad spectrum of fetal and maternal complications, especially in the group of monochorionic and dichorionic pregnancies. Risk of admission to NICU, respiratory distress, sepsis, necrotizing enterocolitis, perinatal and intrauterine mortality were all found to be higher in non-TCTA pregnancies than in TCTA pregnancies. To date, our meta-analysis includes the largest population sample and number of studies conducted in this field, evaluating a wide variety of outcome measures. The heterogeneity and retrospective design of the studies included in our research represent the main limitations of this review. More evidence is needed to fully assess outcome measures that could not be studied in this review due to scarcity of publications or insufficient sample size.

Three or less? Decision making for or against selective reduction and psychological outcome in forty women with a triplet pregnancy

OBJECTIVES

The aim of the study was to investigate decision making for or against multifetal pregnancy reduction (MFPR) and psychological outcome in women with a triplet pregnancy.

METHODS

We investigated medical and sociodemographic variables and characteristics of the decision process for or against MFPR in forty women with triplet pregnancies who had either undergone MFPR (MFPR-group: N = 10) or had delivered triplets (triplet-group: N = 30). Moreover, emotional experiences of the reduction procedure were assessed. Psychological outcome was measured using the Beck Depression inventory (BDI) and the 36-Item Short Form Health Survey (SF-36).

RESULTS

Women of the MFPR-group had a higher gestational age at delivery (p = 0.001), shorter NICU stay (p = 0.001), higher educational level (p = 0.010), more frequently utilized psychological counseling during the decision process (p = 0.016), rated their gynecologist as more helpful for the decision (p = 0.045), required more time for their decision (p = 0.016), and were more likely to be in paid employment at follow-up (p = 0.041) than women of the triplet-group. MFPR was experienced as stressful (90%) or terrifying (10%). At 3.2 (±2.2) years after delivery, the vast majority of women in both groups were free from clinically relevant depression.

CONCLUSIONS

MFPR, though associated with emotional distress related to the procedure, results in a satisfactory psychological outcome in the majority of women. The decision for or against MFPR may be related to sociodemographic (such as educational) variables, which further supports the concept of framing in medical decision making. Having triplets most probably is associated with multiple (e.g. social or economic) consequences that may remain poorly investigated.

Are neonatal outcomes of triplet pregnancies different from those of singletons according to gestational age?

OBJECTIVES

Multiple pregnancies sustain the high pace of extreme prematurity. Little evidence is available about triplet gestation given the evolution in their management during the last decades. The aim of the study was to compare the neonatal outcomes of triplets with those of matched singletons in a cohort study.

METHODS

An observational retrospective cohort study of triplets and matched singletons born between 2004 and 2017 matched by gestational age was conducted. Additionally, the investigation performed in regard to data from the overall Greek population of interest. The primary outcome was mortality or severe neonatal morbidity based on pregnancy type.

RESULTS

A total of 237 triplets of 24-36 weeks' gestation and 482 matched singletons were included. No differences in the primary outcome between triplets and singletons were found. Rates of severe neonatal morbidities did not differ significantly between triplets and singletons. A threshold of 1000 gr for birthweight and 28 weeks' gestation for gestational age determined survival on triplets [OR: 0.08 (95% CI: 0.02-0.40, p=0.0020) and OR: 0.13 (95% CI: 0.03-0.57, p=0.0020) for gestational age and birthweight respectively]. In Greece stillbirths in triplets was 8 times higher than that of singletons (OR: 8.5, 95% CI: 6.9-10.5). From 3,375 triplets, 94 were stillborn, whereas in singletons, 4,659 out of 1,388,273. In our center 5 times more triplets than the expected average in Greece were delivered with no significant difference in stillbirths' rates.

CONCLUSIONS

No significant differences were identified in mortality or major neonatal morbidities between triplets and matched singletons highlighting the significance of prematurity and birthweight for these outcomes.

Maternal, Fetal, and Neonatal Outcomes of Elective Fetal Reduction Among Multiple Gestation Pregnancies: A Systematic Review

OBJECTIVE

To review the existing literature on fetal and maternal health outcomes following elective pregnancy reduction.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, the Cochrane Database of Systematic Reviews, and the Cochrane Controlled Trials Register.

STUDY SELECTION

Studies involving women pregnant with dichorionic twins, trichorionic triplets, or quadra-chorionic quadruplets who underwent elective fetal reduction of 1 or more fetuses to reduce the risks associated with multiple gestation pregnancies.

DATA EXTRACTION

The main fetal health outcomes measured were gestational age at delivery, preterm birth, miscarriage, birthweight, and small for gestational age at delivery. The main maternal health outcomes measured were gestational diabetes, hypertensive disorders of pregnancy, and cesarean delivery.

DATA SYNTHESIS

Of 7678 studies identified, 24 were included (n = 425 dichorionic twin pregnancies, n = 2753 trichorionic triplet pregnancies, and n = 111 quadra-chorionic quadruplet pregnancies). Fifteen studies (62.5%) did not report maternal health outcomes, while every study reported at least 1 fetal health outcome. Fetal reduction was associated with higher gestational age at birth, lower preterm birth, higher birthweight, and lower rates of small for gestational age infants and intrauterine growth restriction. No consistent pattern was observed for miscarriage and neonatal mortality rates. Following fetal reduction, cesarean delivery rates were lower in most studies. There were no appreciable trends with respect to gestational diabetes or hypertensive disorders of pregnancy.

CONCLUSION

Fetal reduction reliably optimizes gestational age at birth and neonatal birthweight. Miscarriage rates and other adverse procedural outcomes did not increase following transabdominal reduction. Further research on maternal outcomes is needed given a paucity of information in the literature.

Expectant management versus multifetal pregnancy reduction in dichorionic triamniotic (DCTA) triplets: Single centre experience

OBJECTIVES

In trichorionic triplet pregnancies, multifetal pregnancy reduction (MFPR) reduces the risk of preterm birth, neonatal morbidity and mortality without increasing miscarriage. A similar benefit has been suggested in dichorionic triamniotic (DCTA) pregnancy, but multiple methods are currently used. This study investigates if the method of reduction used in DCTA triplet pregnancy influences the evidence of benefit from MFPR.

METHODS

This is a retrospective cohort study of DCTA pregnancies between 2010 and 2019 who attended a single UK fetal medicine tertiary referral center. Cohorts were defined based on MFPR decision and method. The primary outcome was offspring survival until neonatal discharge. The secondary outcomes included miscarriage, preterm birth, livebirth, rates of small for gestational age (SGA) neonates, ans maternal morbidity. To evaluate the differences in neonatal survival until discharge we used Cox proportional regression to calculate hazard rates (HR) and 95% confidence intervals (CI). Differences in secondary outcomes were compared using univariate analysis.

RESULTS

The study reports the outcomes for 83 DCTA pregnancies. MFPR to DCDA twins was chosen in 19 pregnancies (14 radiofrequency ablation, RFA; 5 intrafetal laser, IFL); in 9 pregnancies selective reduction to a singleton was performed by KCl injection. The rate of pregnancies in with ≥ 1 fetus born alive was not different between groups (p = 0.90). However, the number of expected neonates alive at discharge from hospital was highest in the RFA group (89%, HR 0.28, 95% CI 0.21-0.87, p = 0.02). Rates of premature delivery before 32 weeks (p = 0.02), low birth weight (p < 0.001) and birthweight < 10th percentile (p = 0.01) were all elevated in the expectant management group, compared to women who opted for reduction. There was no difference in miscarriage between groups.

CONCLUSIONS

Our study suggests that MFPR by RFA, an established and widely available procedure, is of benefit in promoting neonatal survival until discharge in DCTA triplets.

Effect of monochorionicity on perinatal outcome and growth discordance in triplet pregnancy: collaborative multicenter study in England, 2000-2013

OBJECTIVES

To compare perinatal outcome and growth discordance between trichorionic triamniotic (TCTA) and dichorionic triamniotic (DCTA) or monochorionic triamniotic (MCTA) triplet pregnancies.

METHODS

This was a multicenter cohort study using population-based data on triplet pregnancies from 11 Northern Survey of Twin and Multiple Pregnancy (NorSTAMP) maternity units and the Southwest Thames Region of London Obstetric Research Collaborative (STORK) multiple pregnancy cohort, for 2000-2013. Perinatal outcomes (from ≥ 24 weeks' gestation to 28 days of age), intertriplet fetal growth and birth-weight (BW) discordance and neonatal morbidity were analyzed in TCTA compared with DCTA/MCTA pregnancies.

RESULTS

Monochorionic placentation of a pair or trio in triplet pregnancy (n = 72) was associated with a significantly increased risk of perinatal mortality (risk ratio, 2.7 (95% CI, 1.3-5.5)) compared with that in TCTA pregnancies (n = 68), due mainly to a much higher risk of stillbirth (risk ratio, 5.4 (95% CI, 1.6-18.2)), with 57% of all stillbirth cases resulting from fetofetal transfusion syndrome, while there was no significant difference in neonatal mortality (P = 0.60). The associations with perinatal mortality and stillbirth persisted when considering only pregnancies not affected by a major congenital anomaly. DCTA/MCTA triplets had lower BW and demonstrated greater BW discordance than did TCTA triplets (P = 0.049). Severe BW discordance of > 35% was 2.5-fold higher in DCTA/MCTA compared with TCTA pregnancies (26.1% vs 10.4%), but this difference did not reach statistical significance (P = 0.06), presumably due to low numbers. Triplets in both groups were delivered by Cesarean section in over 95% of cases, at a similar gestational age (median, 33 weeks' gestation). The rate of respiratory (P = 0.28) or infectious (P = 0.08) neonatal morbidity was similar between the groups.

CONCLUSIONS

Despite close antenatal surveillance, monochorionic placentation of a pair or trio in triamniotic triplet pregnancy was associated with a significantly increased stillbirth risk, mainly due to fetofetal transfusion syndrome, and with greater size discordance. In liveborn triplets, there was no adverse effect of monochorionicity on neonatal outcome. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Conjoined twins in a spontaneous monochorionic triplet pregnancy: A case report and literature review

RATIONALE

Conjoined twins are a rare complication of monochorionic pregnancies and an extremely rare condition in spontaneous triplet pregnancies. We report a case of conjoined twins in a spontaneous monochorionic triplet pregnancy. The conjoined twins might have suffered from twin anemia-polycythemia sequence, which was reported to be extremely rare.

PATIENT CONCERNS

A 26-year-old woman conceived spontaneously with an obstetric history of invasive mole 4 years ago.

DIAGNOSES

We initially misdiagnosed her as having monochorionic triamniotic triplets at 10 weeks of gestation. However, we confirmed conjoint twins with the monochorionic diamniotic triplet pregnancy at 12 weeks of gestation and classified them as omphalopagus.

INTERVENTIONS

As the woman decided to continue the pregnancy, regular and careful antenatal care was conducted.

OUTCOMES

Unexpectedly, she had a stillbirth 3 weeks later and had to terminate the pregnancy at 15 weeks of gestation. After abortion, the diagnosis of omphalopagus was confirmed in the induced fetuses. Moreover, the skin colors of the conjoined twins were different: one was plethoric, and the other was pale. Additionally, the parents agreed to examine the chromosome of the fetuses, and the results were normal.

CONCLUSION

Dichorionic triplet and monochorionic triplet pregnancies have a poorer prognosis than trichorionic triplet pregnancies. Surgery is the main therapy for conjoined twins; however, most conjoined twins in triplet pregnancies cannot survive, including omphalopagus twins. The conjoined twins may have suffered from twin anemia-polycythemia sequence, which could probably not be diagnosed intrauterine. Transvaginal probe and 3-dimensional ultrasound may be helpful for clarifying the diagnosis in early pregnancy.

Cardiovascular function during triplet pregnancy

Pregnancy is recognized as a natural physiological stressor to the maternal cardiovascular system. Cardiovascular adaptation is markedly greater in twin pregnancy compared with singleton pregnancy; however, these changes are sparsely documented in triplet pregnancy. The aim of this case series was to compare maternal cardiac function, cardioautonomic regulation, and blood pressure reactivity in healthy singleton, twin, and triplet pregnancies. Resting cardiac structure and function (echocardiography), beat-by-beat blood pressure variability (BPV; photoplethysmography), and heart rate variability (HRV; electrocardiogram) were measured in two triplet, three twin, and three singleton pregnancies (matched for maternal age, prepregnancy body mass index, and gestational age). Hemodynamic responses to a 3-min cold pressor test were also recorded to assess blood pressure reactivity. Due to the small sample size of this case series, statistical comparisons were not made between groups. Compared with singleton and twin pregnancies, individuals pregnant with triplets had greater resting cardiac output but lower cardiac deformation (longitudinal strain, basal circumferential strain, and torsion), sympathetic dominance in cardioautonomic regulation (lower HRV and higher BPV), and elevated blood pressure reactivity in response to the cold pressor test. Taken together, these observations suggest that females with triplet pregnancies may have reduced cardiovascular function, which may contribute to the heightened risk of complications in multifetal pregnancies.NEW & NOTEWORTHY Individuals with healthy triplet pregnancies had greater resting cardiac output but lower left ventricular mechanics when compared with singleton and twin pregnancies matched for gestational age. In addition, triplet pregnancies had greater blood pressure variability and lower overall heart rate variability compared with singleton pregnancies, as well as greater blood pressure reactivity to the cold pressor test. Healthy triplet pregnancies may have reduced cardiovascular function as well as a greater sympathetic contribution to cardiac control.

Triplet pregnancy: What do we tell the prospective parents

Experience managing triplet pregnancies has increased over the past few decades as the incidence has changed related to assisted reproductive practices. Physicians caring for women carrying triplets cannot predict an individual outcome or pregnancy course but must educate patients about the challenges related to these high risk pregnancies. Obstetric providers can describe the wide range of risks associated with triplet gestations, and the general plan for management, but ultimately parents must make decisions with potentially lifelong consequences. Here, we present the diagnostic criteria, common complications, and management options for triplet pregnancies, to help obstetricians counsel patients on the medical and psychosocial consequences of triplet pregnancy, potential complications, and multifetal reduction.

Expectant Management of Monochorionic-Triamniotic Triplets Complicated by Selective In Utero Growth Restriction: Report of 2 Cases

The optimal management of monochorionic-triamniotic (MCTA) triplet pregnancies is not clearly established, and there is no literature to guide management of MCTA complicated with selective intrauterine growth restriction (sIUGR). This gap in knowledge and the concern for higher risk of severe complications have led some medical societies to recommend selective termination of nontrichorionic triplet pregnancies. We sought to report the favourable outcomes of two MCTA complicated by sIUGR expectantly managed at Sainte-Justine Hospital, Montreal, Canada. The first case is of a 42-year-old woman with spontaneous MCTA triplets diagnosed at 18 weeks with type II sIUGR who opted for expectant management. The second patient was a 22-year-old woman with a spontaneous MCTA triplet pregnancy diagnosed at 18 weeks with type III sIUGR. Our experience shows that close serial ultrasounds could potentially allow physicians to foresee fetal deterioration. In our opinion, expectant management should be considered as a management option for MCTA complicated by sIUGR.

Current Resources for Evidence-Based Practice, September 2020

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of “spin” in scientific reporting and its effect on summaries and syntheses of the literature and commentaries on reviews about early versus late amniotomy as part of labor induction protocols and the economic burden associated with maternal morbidity.