Triple trouble: uncovering the risks and benefits of early fetal reduction in trichorionic triplets in a large national Danish cohort study.

BACKGROUND: Triplet pregnancies are high risk for both the mother and the infants. The risks for infants include premature birth, low birthweight, and neonatal complications. Therefore, the management of triplet pregnancies involves close monitoring and may include interventions, such as fetal reduction, to prolong the pregnancy and improve outcomes. However, the evidence of benefits and risks associated with fetal reduction is inconsistent. OBJECTIVE: This study aimed to compare the outcomes of trichorionic triplet pregnancies with and without fetal reduction and with nonreduced dichorionic twin pregnancies and primary singleton pregnancies. STUDY DESIGN: All trichorionic triplet pregnancies in Denmark, including those with fetal reduction, were identified between 2008 and 2018. In Denmark, all couples expecting triplets are informed about and offered fetal reduction. Pregnancies with viable fetuses at the first-trimester ultrasound scan and pregnancies not terminated were included. Adverse pregnancy outcome was defined as a composite of miscarriage before 24 weeks of gestation, stillbirth at 24 weeks of gestation, or intrauterine fetal death of 1 or 2 fetuses. RESULTS: The study cohort was composed of 317 trichorionic triplet pregnancies, of which 70.0% of pregnancies underwent fetal reduction to a twin pregnancy, 2.2% of pregnancies were reduced to singleton pregnancies, and 27.8% of pregnancies were not reduced. Nonreduced triplet pregnancies had high risks of adverse pregnancy outcomes (28.4%), which was significantly lower in triplets reduced to twins (9.0%; difference, 19.4%, 95% confidence interval, 8.5%-30.3%). Severe preterm deliveries were significantly higher in nonreduced triplet pregnancies (27.9%) than triplet pregnancies reduced to twin pregnancies (13.1%; difference, 14.9%, 95% confidence interval, 7.9%-21.9%). However, triplet pregnancies reduced to twin pregnancies had an insignificantly higher risk of miscarriage (6.8%) than nonreduced twin pregnancies (1.1%; difference, 5.6%; 95% confidence interval, 0.9%-10.4%). CONCLUSION: Triplet pregnancies reduced to twin pregnancies had significantly lower risks of adverse pregnancy outcomes, severe preterm deliveries, and low birthweight than nonreduced triplet pregnancies. However, triplet pregnancies reduced to twin pregnancies were potentially associated with a 5.6% increased risk of miscarriage.

Outcome of monochorionic triamniotic triplet pregnancies: Expectant management versus fetal reduction.

OBJECTIVE: To compare the outcomes of monochorionic triamniotic (MCTA) triplets managed expectantly with those reduced to twins. METHOD: This was a retrospective cohort study comparing expectant management (EM) with fetal reduction (FR) to twins in 43 consecutive MCTA triplets with 3 live fetuses at 11-14 weeks between 2012 and 2021. RESULTS: Nineteen patients managed expectantly and 24 triplets reduced to twins were included. The rate of pregnancy with at least one survivor was 84.2% in the EM group and 66.7% in the FR group (P = 0.190). Compared to the EM cases, triplets reduced to twins had a higher median gestational age at delivery (36.0 vs. 33.3 weeks; P < 0.001), a higher mean birth weight (2244.3 ± 488.6 g vs. 1751.1 ± 383.2 g; P < 0.001) and a lower risk of preterm birth before 34 weeks (11.8% vs. 64.7%; P = 0.001). There were no significant differences in the risk of miscarriage, pregnancy complications and composite adverse neonatal outcomes. CONCLUSION: In MCTA triplets, FR to twins could reduce the risk of preterm birth, whereas EM seems to be a reasonable choice when the priority is at least one survivor. However, due to the small sample size of this study, these findings must be interpreted with great caution.

Dichorionic quadruplet pregnancy comprising monozygotic triplets and singleton after intracytoplasmic sperm injection and transfer of two fresh embryos: a case report.

Monozygotic triplet pregnancies are very rare in assisted reproductive technology, and the relationship between monozygotic multiple pregnancies and several assisted reproductive techniques, including blastocyst transfer, remains unclear. Here, the case of a 28-year-old female patient with dichorionic quadruplet pregnancy following intracytoplasmic sperm injection and transfer of two day-3 fresh embryos, without assisted hatching, is reported. At 7 weeks following embryo transfer, the dichorionic quadruplet pregnancy, comprising monozygotic monochorionic triamniotic (MCTA) triplets plus a singleton, was detected by a transabdominal ultrasound scan. After counselling, the patient underwent selective reduction of the MCTA triplet pregnancy at 7 weeks after embryo transfer. The remaining singleton pregnancy was uneventful, resulting in a live birth at 38+ weeks. As the predictors of monozygotic multiple gestations remain poorly characterized, clinicians and patients should give great consideration to the risks associated with monozygotic multiple pregnancies, even if the patient has not undergone blastocyst transfer.

Delayed interval delivery of preterm multiples: experience from a large specialized twin center.

OBJECTIVE: Preterm delivery is a recognized complication of twins and higher order multiple pregnancies. Delayed interval delivery is a rarely used management option for pre- or peri-viable preterm labor in these pregnancies. We describe the management and outcomes of 7 delayed interval deliveries over an 8-year period in a large specialized twin center. STUDY DESIGN: A retrospective cohort study of all delayed interval deliveries of preterm multiples from 2009 to 2016, defined as >24 h between deliveries of twins 1 and 2. RESULTS: During the study period there were 68,845 deliveries with 1377 multiple pregnancies comprising 1331 sets of twins and 46 sets of higher-order multiples. 7 of these were identified as being delayed interval deliveries - 6 twin pregnancies and 1 triplet pregnancy. The mean gestation of delivery of the first infant was 23 + 4 weeks (range 22 + 3 to 30 + 0 weeks) with a mean interval of 10 days (range 1.5-39 days). Outcomes for the first infant delivered were poor, with 5 out of 7 (71%) dying from extreme prematurity. However, out of the remaining twins or triplets, 5/8 (62%) survived. The mean gestation of delivery of the remaining infant (or infants in the triplets) was 25 + 0 weeks (range 23 + 0 to 30 + 2 weeks). Only one mother (16%) developed clinical chorioamnionitis requiring iatrogenic delivery of the remaining infant with subsequent neonatal death due to extreme prematurity. There were no cases of severe maternal morbidity - however, there was one maternal death in the cohort due to an amniotic fluid embolism. The neonatal follow up of the surviving infants to date is mostly normal. CONCLUSION: Delayed interval deliveries can offer hope for survival for the remaining infant(s) with an acceptable risk profile to the mother. Close clinical and laboratory monitoring is essential to reduce the risk of severe maternal morbidity.

Effects of the timing of selective reduction and finishing number of fetuses on the perinatal outcome in triplets: a single-center retrospective study.

OBJECTIVE: This study aimed to evaluate the effect of the timing of selective reduction and finishing the number of fetuses on perinatal outcomes in triplets. METHOD: The study assessed 417 cases of triplets. Perinatal outcomes were compared between selective reduction (SR) performed at 11-14+6 weeks of gestation and SR performed at 15-24+6 weeks of gestation for the same starting and finishing numbers of fetuses. Then, the perinatal outcomes of reduction to singletons and twins were compared for the same range of SR of gestational weeks. RESULTS: The spontaneous abortion rate was 6.5% and 14.9%, respectively, when SR was performed at 11-14+6 weeks of gestation (214 cases) and at 15-24+6 weeks of gestation (94 cases) (p = .019). In total, 74 cases of triplets were reduced to singletons and 214 cases were reduced to twins when SR was performed at 11-14+6 weeks of gestation. Preterm labor rates, low birth weight rates, birth weights, and gestational ages at delivery also showed significant differences (p < .001). In total, 35 cases of triplets were reduced to singletons and 94 cases were reduced to twins when SR was performed at 15-24+6 weeks of gestation. The preterm labor rates, low birth weight rates, birth weights and gestational ages at delivery also significantly differed (p < .05). CONCLUSIONS: When the starting and finishing numbers of fetuses were the same, the timing of SR could affect the spontaneous abortion rates. When the starting number of fetuses was the same, the timing of SR did not affect the neonatal outcome. However, the finishing number of fetuses was the influencing factor.

Risk of preterm birth and neonatal outcomes after cerclage placement in triplet pregnancies.

BACKGROUND: The number of triplet pregnancies in the United States has increased significantly. Perinatal morbidity and mortality are higher in these pregnancies mainly due to higher preterm birth rates. Interventions to decrease the risk of preterm delivery in this population are needed. Evidence regarding cerclage placement in triplets is limited. We performed a population-based, retrospective cohort study to study the risk of preterm birth and neonatal outcomes after cerclage placement in triplet pregnancies. METHODS: All U.S. triplet deliveries from 2006 to 2013 with risk factors for cervical insufficiency were selected, excluding cases with indicated preterm delivery. Cases were categorized according to cerclage placement status. The risk of preterm birth and adverse neonatal outcomes were calculated using propensity score analysis, generalized linear, and logistic regression models. RESULTS: From ∼33 million deliveries, 43,000 were triplets, and 7308 fulfilled eligibility criteria. There was no difference in the gestational age at delivery between the cerclage and noncerclage groups, aOR (95% CI) = 1.0(0.9-1.0). The difference between the risk of preterm delivery at <34 weeks and <32 weeks was not statistically significant. The risk of the composite outcome of neonatal complications was higher in the cerclage compared to the noncerclage group, aOR (95% CI) = 1.5 (1.1-2.2). CONCLUSIONS: Cerclage placement in triplet pregnancies does not appear to decrease preterm birth rates and seems to increase the risk of neonatal complications.

Gestação heterotópica trigemelar (gemelar tubária) espontânea: um relato de caso / Spontaneous triplet heterotopic (tubal twin) pregnancy: a case report

A gestação heterotópica é um fenômeno obstétrico no qual coexistem as gestações tópica e ectópica, achado muito raro em concepções espontâneas. Sua incidência vem aumentando nos últimos anos em razão do aumento de fatores de risco, como histórico de doença inflamatória pélvica, endometriose, cirurgias abdominais e gravidez ectópica. O diagnóstico é desafiador devido à gravidez intrauterina normal, que pode reduzir a atenção à presença da implantação extrauterina concomitante. Quando diagnosticada de forma precoce e associada ao tratamento adequado, tende a um desfecho favorável. Este estudo visa relatar o segundo caso de gestação heterotópica trigemelar espontânea com gestação gemelar tubária e gestação única intrauterina. A paciente do sexo feminino, 34 anos, tercigesta, secundípara, com duas cesarianas prévias, idade gestacional de 9 semanas pela amenorreia, foi admitida com queixa de dor abdominal localizada em fossa ilíaca direita e diagnosticada precocemente com gestação heterotópica por meio de ultrassonografia transvaginal. Foi tratada cirurgicamente com salpingectomia direita após caracterização de rotura tubária e, como resultado, a gravidez tópica seguiu sem intercorrências. Como conclusão, o caso mostra a importância de sempre considerar esse diagnóstico diferencial, mesmo em pacientes com quadro clínico inespecífico, na presença ou não de fatores de risco. A exploração sistemática de toda a pelve na primeira ultrassonografia, até quando houver uma gravidez tópica confirmada, é essencial para o diagnóstico inicial. As modalidades terapêuticas são diversas e dependem principalmente da estabilidade hemodinâmica, idade gestacional, viabilidade da gestação intrauterina e disponibilidade técnica. Independente da estratégia escolhida, objetiva-se o tratamento precoce e a menor manipulação uterina possível para melhor resultado materno-fetal. Palavras-chave: Gravidez Heterotópica. Gravidez Tubária. Gravidez de Trigêmeos.

Functional development of preterm children born from singleton and multiple pregnancies: Preliminary study.

BACKGROUND: In recent years an increasing number of multiple pregnancies have been observed, which is a result of advancements made in reproductive technologies for infertility treatments as well as a tendency for women to delay childbearing until later in life. The risk of preterm birth in the case of a twin pregnancy is five to seven times higher than that of a singleton pregnancy, and in the case of triplet pregnancy, the risk is even 10 times higher. The objective of the study was to assess and compare the functional development of children aged between 2 and 2.5 who were prematurely born from singleton, twin and triplet pregnancies. MATERIAL AND METHODS: The study was carried out in a group of 43 children aged between 2 and 2.5 who were born prematurely (between the 32nd and 36th week of pregnancy) in 2017 and 2018. Group I was made up of 10 children born from singleton pregnancies, group II included 12 children born from six twin pregnancies and group III consisted of 21 children born from seven triplet pregnancies. The evaluation of functional development was conducted using the Munich Functional Developmental Diagnostics. RESULTS: There were no statistically significant differences in functional development between the studied singletons, twins and triplets. In the examined groups of singletons, twins and triplets, the calculated quotient medians for the 50th percentile approximated 1, which means that development was typical and did not differ from the development of the general population. In turn, for the 95th percentile, the median scores usually approximated 0.8, which also indicated that there was no significant delay in development. Had scores been higher than 1, this might have indicated a delay. CONCLUSIONS: On the basis of the study group, no relationship was found between the multiplicity of pregnancies and the functional development of premature babies born between the 32nd and 36th weeks of gestation.

Conjoined twins in dichorionic diamniotic triplet pregnancy: a report of three cases and literature review.

BACKGROUND: Conjoined twins are a rare and serious complication of monochorionic twins. The total incidence is 1.5 per 100,000 births, and about 50% are liveborn. Prenatal screening and diagnosis of conjoined twins is usually performed by ultrasonography. Magnetic resonance imaging can be used to assist in the diagnosis if necessary. Conjoined twins in dichorionic diamniotic triplet pregnancy are extremely rare. CASE PRESENTATION: We reported three cases of dichorionic diamniotic triplet pregnancy with conjoined twins. Due to the poor prognosis of conjoined twins evaluated by multidisciplinary teams, selective termination of conjoined twins was performed in three cases. In case 1, selective reduction of the conjoined twins was performed at 16 gestational weeks, and a healthy female baby weighing 3270 g was delivered at 37 weeks. In case 2, the conjoined twins were selectively terminated at 17 weeks of gestation, and a healthy female baby weighing 2760 g was delivered at 37 weeks and 4 days. In case 3, the conjoined twins were selectively terminated at 15 weeks and 2 days, and a healthy female baby weighing 2450 g was delivered at 33 weeks and 6 days. The babies of all three cases were followed up and are in good health. CONCLUSION(S): Surgical separation is the only treatment for conjoined twins after birth. Early determination of chorionicity and antenatal diagnosis of conjoined twins in triplet gestations are critical for individualized management options and the prognosis of normal triplets. Expecting parents should be extensively counseled by multidisciplinary teams. If there are limitations in successful separation after birth, early selective termination of the conjoined twins by intrathoracic injection of potassium chloride may be a procedure in dichorionic diamniotic triplet pregnancy to improve perinatal outcomes of the normal triplet.

Spontaneous fetal reduction in triplets and prolongation of twin pregnancy for 111 days as an outpatient: a case report.

BACKGROUND: Multiple gestation has been on the rise because of advancement in assisted reproductive technology. Triplet pregnancy is associated with fetal loss and preterm birth as its major complications. Spontaneous triplet pregnancy is rare. In the case of fetal loss, delayed interval delivery has been used to achieve delivery of the retained fetuses. There is no common approach to delayed interval delivery. CASE: A 31-year-old East African lady with spontaneous triplet pregnancy presented to our institution at gestation age of 19 weeks with features of threatened miscarriage. One fetus was miscarried, and delayed interval delivery was done as an outpatient. At gestation age of 35 weeks, she delivered healthy twins by cesarean section. CONCLUSION: Delayed interval delivery improves neonatal outcomes of high-order pregnancy after fetal loss even in a resource-limited setting.

Invasive Group B Streptococcus Disease With Recurrence and in Multiples: Towards a Better Understanding of GBS Late-Onset Sepsis.

Group B Streptococcus (GBS) is a common intestinal colonizer during the neonatal period, but also may cause late-onset sepsis or meningitis in up to 0.5% of otherwise healthy colonized infants after day 3 of life. Transmission routes and risk factors of this late-onset form of invasive GBS disease (iGBS) are not fully understood. Cases of iGBS with recurrence (n=25) and those occurring in parallel in twins/triplets (n=32) from the UK and Ireland (national surveillance study 2014/15) and from Germany and Switzerland (retrospective case collection) were analyzed to unravel shared (in affected multiples) or fixed (in recurrent disease) risk factors for GBS disease. The risk of iGBS among infants from multiple births was high (17%), if one infant had already developed GBS disease. The interval of onset of iGBS between siblings was 4.5 days and in recurrent cases 12.5 days. Disturbances of the individual microbiome, including persistence of infectious foci are suggested e.g. by high usage of perinatal antibiotics in mothers of affected multiples, and by the association of an increased risk of recurrence with a short term of antibiotics [aOR 4.2 (1.3-14.2), P=0.02]. Identical GBS serotypes in both recurrent infections and concurrently infected multiples might indicate a failed microbiome integration of GBS strains that are generally regarded as commensals in healthy infants. The dynamics of recurrent GBS infections or concurrent infections in multiples suggest individual patterns of exposure and fluctuations in host immunity, causing failure of natural niche occupation.

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.

Physical Activity Behaviors and Barriers in Multifetal Pregnancy: What to Expect When You're Expecting More.

The health benefits of prenatal physical activity (PA) are established for singleton pregnancies. In contrast, individuals with multifetal pregnancies (twins, triplets or more) are recommended to restrict or cease PA. The objectives of the current study were to determine behaviors and barriers to PA in multifetal pregnancies. Between 29 May and 24 July 2020, individuals with multifetal pregnancies participated in an online survey. Of the 415 respondents, there were 366 (88%) twin, 45 (11%) triplet and 4 (1%) quadruplet pregnancies. Twenty-seven percent (n = 104/388) of respondents completed no PA at all during pregnancy, 57% (n = 220/388) completed PA below current recommendations, and 16% (n = 64/388) achieved current recommendations (150-min per week of moderate-intensity activity). Most respondents (n = 314/363 [87%]) perceived barriers to PA during multifetal pregnancy. The most prominent were physical symptoms (n = 204/363 [56%]) and concerns about risks to fetal wellbeing (n = 128/363 [35%]). Sixty percent (n = 92/153) felt that these barriers could be overcome but expressed the need for evidence-based information regarding PA in multifetal pregnancy. Individuals with multifetal pregnancies have low engagement with current PA recommendations but remain physically active in some capacity. There are physical and psychosocial barriers to PA in multifetal pregnancy and future research should focus on how these can be removed.

A rare case of monozygotic triplets with Duchenne muscular dystrophy.

Twins with Duchenne muscular dystrophy (DMD) have been widely studied. We report the first rare case of monozygotic triplets with DMD who shared consistent phenotypes, including delayed motor and language milestones, muscle wasting and weakness, joint contracture, and lumbar lordosis. Muscle magnetic resonance imaging and biopsy revealed the similar muscle injury characteristics and dystrophin absence. Short tandem repeat analysis confirmed monozygosity. A de novo mutation (exon 49-52 deletion) was found in the triplets but not in their mother. Treatment included prednisone, idebenone, and rehabilitation management. At the 2-year follow-up, motor function had deteriorated, and muscle fatty infiltration was more extensive and severe. Our case offers a unique opportunity for genetic and therapeutic research. Furthermore, it highlights the critical role of genetic factors in DMD phenotypes and provides a potential choice for treatment observations.

Hyperreactio luteinalis following frozen embryo transfer managed by fetal reduction.

We report a rare case of hyperreactio luteinalis (HL) which developed in association with triplet pregnancy in a 27-year-old woman who underwent assisted reproductive technology treatment for primary infertility. She had undergone frozen embryo transfer 2 months after ovarian retrieval. She presented in the first trimester with abdominal pain and distension associated with ovarian enlargement and did not respond to conservative management. Fetal reduction was done from triplets to twins which resulted in good symptomatic relief for the patient. Fetal reduction may be an effective approach in such situations when conservative strategies fail in HL.

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.

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.