Monochorionic twin pregnancies

Craniopagus parasiticus: successful separation of a 28-week preterm newborn from parasite sibling twin bearing lethal congenital anomalies associated to Cantrell's pentad and sirenomelia-case-based review of the literature

PURPOSE

This paper reviews the plausible etiological mechanisms, clinical features, preoperative analysis, and documented modern-day craniopagus parasiticus surgical separation attempts as well as an historical review of the few cases documented in the literature.

METHODS

We describe the successful separation of a 28-week preterm newborn from its parasite sibling twin bearing lethal congenital anomalies associated to Cantrell's pentad and sirenomelia. Description of the case, plausible explanations on the mechanisms of conjointment along with the associated congenital abnormalities of the deceased twin are examined along with an historical revision of craniopagus parasiticus and their separation attempts with special attention to the previously undocumented attempt of the Dominican CP separation surgery by Lazareff et al. RESULTS: The use of the deceased twin cranial vault tissues (skin, bone, and duramater) as an autologous implant due to the identical genetical profile served to remodel and close the skull of the surviving twin with good esthetic results and no tissue rejection. To our knowledge, this is the youngest preterm set of craniopagus parasiticus separated in an emergency fashion with good functional and esthetic outcome.

CONCLUSIONS

Craniopagus parasiticus is an infrequent subvariant of this rare form of twin conjointment which may require urgent separation due to the associated malformations of the parasitic twin; therefore, the fact that both siblings are genetically identical may prove as an advantage to use duramater, bone, and soft tissues from the parasitic twin as ideal grafts for covering the resultant defect after the separation has been performed.

Maternal vascular endothelial growth factor receptor and interleukin levels in pregnant women with twin-twin transfusion syndrome

Twin-twin transfusion syndrome (TTTS) is an unusual and serious condition that occurs in twin pregnancies when identical twins share a placenta but develop discordant amniotic fluid volumes. TTTS is associated with an increased risk of fetal death and birth defects if untreated. This study investigated the soluble levels of biomarkers including growth factors and interleukins in pregnant women with and without TTTS during pregnancy. We quantified plasma levels of VEGF-R1, VEGF-R2, IL-1β, IL-6 and IL-8 in twin pregnant women with (n=53) and without TTTS (n=72) and in women with single pregnancy (n=30) by ELISA and analyzed the association of maternal circulating biomarker levels with TTTS. Our results showed that maternal VEGF-R1 levels were significantly higher in twins compared to single pregnancy (P<0.05) and were decreased in the second trimester compared to the first trimester (P = 0.065, 0.019 and 0.072 for twins with and without TTTS and single pregnancy, respectively). VEGF-R2 levels had a trend to be lower in twins compared to single pregnancy. In addition, soluble VEGF-R1 and VEGF-R2 levels were significantly decreased while IL-6 levels were increased after surgical treatment with laser in twin pregnant women with TTTS (P = 0.016, 0.041 and 0.04, respectively). These results suggest that IL-6, VEGF-R1 and VEGF-R2 are involved in vascular regulation and stabilization in twin pregnancies and may contribute to the pathogenesis of TTTS and thus play a prognostic role in the surgical treatment of TTTS.

Risk factors for failure in the newborn hearing screen test in very preterm twins

BACKGROUND

We aimed to identify prenatal and postnatal risk factors associated with abnormal newborn hearing screen (NHS) results and subsequently confirmed sensorineural hearing loss (SNHL) in preterm twin neonates.

METHODS

Electronic medical records of 159 twin neonates who were born alive after ≤32 weeks were retrospectively reviewed for hearing loss in both ears. Histopathologic examination of the placenta was performed and clinical data, including method of conception and factors specific to twins, were retrieved from a computerized perinatal database. The main outcome measure was failure to pass the NHS test. The generalized estimation equations model was used for twins.

RESULTS

Thirty-two neonates (20.1%) had a "refer" result, and, on the confirmation test, permanent SNHL was identified in 4.4% (7/159) of all neonates. Neonates who had a "refer" result on the NHS test were more likely to be of lower birth weight, more likely to have been conceived with the use of in vitro fertilization (IVF), and more likely to have higher rates of intraventricular hemorrhage (IVH) and bronchopulmonary dysplasia. However, monochorionic placentation, death of the co-twin, or being born first was not associated with a "refer" result on the NHS test. Multivariable logistic regression revealed that conception after IVF and the presence of IVH were the only variables to be statistically significantly associated with "refer" on the NHS test. No parameters studied were found to be significantly different between the SNHL and no SNHL groups, probably because of the relatively small number of cases of SNHL.

CONCLUSION

In preterm twin newborns, IVF and the presence of IVH were independently associated with an increased risk of abnormal NHS results, whereas the factors specific to twins were not associated with abnormal NHS results.

Minimally Invasive Fetal Surgery

Fetal surgery corrects severe congenital anomalies in utero to prevent their severe consequences on fetal development. The significant risk of open fetal operations to the pregnant mother has driven innovation toward minimally invasive procedures that decrease the risks inherent to hysterotomy. In this article, we discuss the basic principles of minimally invasive fetal surgery, the general history of its development, specific conditions and procedures used to treat them, and the future of the field.

Intrauterine fetal death in triplet gestation caused by feto-fetal transfusion syndrome - a case report

Feto-fetal transfusion syndrome (FFTS) severely affects monochorionic (MC) multiple pregnancies and affects 1 in 1600 pregnancies overall. The number of increasing disputed obstetrics cases in China is related to unavailability of prompt diagnosis of FFTS. We present here a woman with a MC triplet pregnancy with intrauterine fetal death at 33 weeks of gestation due to FFTS. Subsequent pathological anatomy showed that the MC placenta contained vascular anastomoses, including arterio-arterial anastomosis and arterio-venous anastomosis. These anastomoses led to unidirectional blood flow with the absence of adequate compensatory counter-transfusion and bi-directional flow. When encountering such challenging conditions, medical practitioners should discreetly compare the fetuses' characteristics with features of placental blood vessels and consult morphological and pathological findings. Furthermore, they should perform ultrasound examinations, particularly focussing on fetal size differences and the maximum vertical pocket in the diagnosis of FFTS, especially in MC multiple pregnancies with abdominal symptoms.

Selective reduction in complicated monochorionic twins: prediction of obstetric outcome and comparison of techniques

OBJECTIVES

To compare the outcomes of radiofrequency ablation (RFA) and bipolar cord coagulation (BPC) methods for selective feticide in complicated monochorionic (MC) twin gestations and to determine risk factors for adverse pregnancy outcome.

METHODS

This was a retrospective cohort study of all patients with complicated MC twin pregnancy who underwent selective reduction in a single tertiary care center between 2000 and 2014. We compared the two methods with respect to various demographic, obstetric and perinatal outcome variables.

RESULTS

Fifty-three selective terminations in complicated MC twin gestations were performed, 36 by RFA and 17 by BPC. Each technique resulted in a similar overall survival rate of the remaining twin (88.9% vs 76.5%, P = 0.25). Likewise, the mean procedure-to-delivery interval, the rate of spontaneous preterm delivery < 37, < 34, < 32 and < 28 weeks and the rate of preterm prelabor rupture of the membranes did not differ between the groups. However, among patients in the BPC group, there was a trend towards earlier gestational age at delivery (31.3 vs 35.0 weeks, P = 0.09) compared with in the RFA group. There was selective reduction by RFA due to selective intrauterine growth restriction (sIUGR) in 19 cases, 17 (89.5%) of which survived perinatally, with delivery at a median gestational age of 37 weeks. There were no significant differences in perinatal outcome, irrespective of whether the procedure was performed pre- or post-viability. All post-viability reductions, most of which were by RFA, resulted in perinatal survival.

CONCLUSIONS

Perinatal outcome of complicated MC twin gestations undergoing selective feticide seems to be similar regardless of whether termination is by BPC or RFA. Nevertheless, RFA appears to be particularly useful in MC twins complicated by sIUGR and in cases requiring selective reduction beyond the age of viability.

Predictive value of cardiovascular parameters in twin-to-twin transfusion syndrome

OBJECTIVE

To evaluate the prognostic value of the Children's Hospital Of Philadelphia (CHOP) cardiovascular score and the modified myocardial performance index (MPI), in determining the risk of recipient fetal loss in twin-to-twin transfusion syndrome (TTTS).

METHODS

This cohort study was based on data collected prospectively from 105 pregnancies complicated by TTTS (Quintero stages I-IV) and treated with laser photocoagulation between May 2008 and February 2013. Fetuses underwent detailed anatomical and Doppler ultrasonography with cardiac assessment as part of routine care. CHOP score and right MPI were calculated and cut-offs selected using receiver-operating characteristics curve analysis. These were compared according to loss of recipient fetus, using univariate and multivariate logistic regression. The correlation between CHOP score, MPI and Quintero stage was determined and we investigated differences in MPI before and after laser coagulation in a cohort of 90 recipient fetuses.

RESULTS

Rates of recipient fetal loss were significantly higher when the CHOP score was ≥ 3 (39.5% vs 12.9%, P = 0.002) and when MPI z-score was > 1.645 (34.5% vs 10.6%, P = 0.004). After adjustment for Quintero stage, the risk of recipient fetal loss remained significantly higher when the CHOP score was ≥ 3 (odds ratio, 3.09; 95% CI, 1.035-9.21). There was a positive correlation between CHOP score, MPI and Quintero stage. MPI was significantly lower after compared with before laser coagulation.

CONCLUSION

CHOP score and MPI are predictors of recipient fetal loss in TTTS and may be used to supplement Quintero's classification.

Outcomes of non-vertex second twins, following vertex vaginal delivery of first twin: a secondary analysis of the WHO Global Survey on maternal and perinatal health

BACKGROUND

Mode of delivery remains a topic of debate in vertex/non-vertex twin pregnancies. We used the WHO Global Survey dataset to determine the risk of adverse maternal/perinatal outcomes associated with presentation of the second twin, following vaginal delivery of a vertex first twin.

METHODS

We analysed a derived dataset of twin pregnancies ≥ 32 weeks gestation where the first twin was vertex and delivered vaginally. Maternal, delivery and neonatal characteristics and adverse outcomes were reported by presentation of the second twin. Logistic regression models (adjusted for maternal and perinatal confounders, mode of delivery and region) were developed to determine odds of adverse outcomes associated with presentation.

RESULTS

1,424 twin pregnancies were included, 25.9% of these had a non-vertex second twin and Caesarean was more common in non-vertex presentations (6.2% vs 0.9%, p < 0.001). While the odds of Apgar < 7 at 5 minutes were higher in non-vertex presenting second twins (16.0% vs 11.4%, AOR 1.42 95% CI 1.01-2.00), the odds of maternal ICU admission (4.6% vs 1.7%, AOR 1.30, 95% CI 0.88-1.94), blood transfusion (6.0% vs 3.4%, AOR 1.23, 95% CI 0.67-2.25), stillbirth (7.6% vs 4.7%, AOR 1.15, 95% CI 0.72-1.73), early neonatal death (3.8% vs 2.1%, AOR 1.68, 95% CI 0.96-2.94), and NICU admission (26.6% vs 23.2%, AOR 0.93, 95% CI 0.62-1.39) were not.

CONCLUSION

After a vaginal delivery of a vertex first twin, non-vertex presentation of the second twin is associated with increased odds of Apgar <7 at 5 minutes, but not of other maternal/perinatal outcomes. Presentation of the second twin is not as important a consideration in planning twin vaginal birth as previously considered.

Birth defects associated with perturbations in preimplantation, gastrulation, and axis extension: from conjoined twinning to caudal dysgenesis

Congenital malformations represent approximately 3 in 100 live births within the human population. Understanding their pathogenesis and ultimately formulating effective treatments are underpinned by knowledge of the events and factors that regulate normal embryonic development. Studies in model organisms, primarily in the mouse, the most prominent genetically tractable mammalian model, have equipped us with a rudimentary understanding of mammalian development from early lineage commitment to morphogenetic processes. In this way, information provided by studies in the mouse can, in some cases, be used to draw parallels with other mammals, including human. Here, we provide an overview of our current understanding of the general sequence of developmental events from early cell cleavages to gastrulation and axis extension occurring in human embryos. We will also review some of the rare birth defects occurring at these stages, in particular those resulting in conjoined twinning or caudal dysgenesis.

Discordance of first-trimester crown-rump length is a predictor of adverse outcomes in structurally normal euploid dichorionic twins

OBJECTIVE

The purpose of this study was to determine the association between discordant crown-rump length (CRL) measurements in structurally normal euploid dichorionic twins and adverse pregnancy outcomes.

METHODS

This retrospective cohort study included women with dichorionic twins who underwent chorionic villus sampling and delivered in our facility from January 2000 to September 2007. Only pregnancies with viable twin fetuses and normal karyotypes were included. The association between CRL discordance, defined as a CRL discrepancy of 9% or greater, and adverse pregnancy outcomes was evaluated.

RESULTS

Seventy-eight women met inclusion criteria and included 24 discordant twins (group 1) and 54 concordant twins (group 2). Maternal ages were similar: mean ± SD, 38.2 ± 3.1 years in group 1 versus 39.2 ± 3.9 years in group 2 (P = not significant). The median gestational ages at delivery were 35.6 ± 3.1 weeks in group 1 and 37.3 ± 2.0 weeks in group 2 (P < .01). At least 1 major complication occurred in 19 women (79%) in group 1 and 25 (46%) in group 2 (P = .01). Group 1 had significantly more major complications overall (P = .0008). Preterm premature rupture of membranes occurred in 10 women (42%) in group 1 and 6 (11%) in group 2 (P = .005). Delivery before 37 weeks' gestation occurred in 19 of 24 women (79%) in group 1 and 24 of 54 (44%) in group 2 (P = .006). There was a significant difference for younger gestational age at delivery in the discordant group (P < .01).

CONCLUSIONS

Our data suggest that there is an increased risk of adverse pregnancy outcomes in chromosomally normal dichorionic twins with first-trimester discordant CRL measurements. These results may be clinically useful for counseling, management, and antenatal surveillance.

Monochorionic diamniotic triplet pregnancy with prenatal diagnosis of cord entanglement

BACKGROUND

Monozygotic monochorionic triplet pregnancies in which triplets share an amniotic cavity (di- or monoamniotic) are very rare. In addition to the other risks of high-order multiple pregnancy, such triplets are at risk for cord entanglement and therefore cord accident and intrauterine demise.

CASE

A 32-year-old primigravid woman was found on ultrasound at 25 to 26 weeks' gestation to have a monochorionic diamniotic triplet pregnancy, a short dilated cervix, one fetus with biometry < 10th centile, and cord entanglement. The woman was hospitalized, ultrasound assessment was performed three times per week, and elective Caesarean section was performed at 30 weeks. The triplets subsequently did well.

CONCLUSION

Monochorionic diamniotic triplet pregnancy with cord entanglement can be successfully managed by admission, close inpatient monitoring, and elective delivery.

Selective reduction in complicated monochorionic pregnancies: radiofrequency ablation vs. bipolar cord coagulation

OBJECTIVE

To compare radiofrequency ablation (RFA) and bipolar cord coagulation (BPC) methods for selective fetal reduction in the treatment of complicated monochorionic (MC) multifetal gestations.

METHODS

This was a retrospective review of patients who underwent selective reduction by RFA and BPC. Computer-generated random sampling was performed to match patients who had undergone BPC with patients who had undergone RFA, in a 2 : 1 ratio, controlling for gestational age and indication. The primary outcome was fetal survival.

RESULTS

Twenty patients in the RFA group were matched with 40 patients in the BPC group. Fewer additional intra-operative procedures were performed in the RFA group compared with the BPC group: amnioinfusion, 10% vs. 75%, respectively (P < 0.01); and amnioreduction, 5% vs. 40%, respectively (P = 0.004). The overall survival rates were 87.5% in the RFA group and 88% in the BPC group (P = 0.94). Median gestational age at delivery was 36 (range, 26-41) weeks in the RFA group and 39 (range, 19-40) weeks in the BPC group (P = 0.59). Preterm delivery (at < 28, < 32 or < 37 weeks), weeks gained after the procedure and birth weight at delivery were also similar. Although the preterm premature rupture of membranes (PPROM) rate was higher in the BPC group (22.5%) compared with the RFA group (5%), the difference was not statistically significant (P = 0.09).

CONCLUSIONS

Overall fetal survival rate following selective reduction in complicated MC pregnancies is similar whether reduction is performed by RFA or BPC. Fewer additional intraoperative procedures are required for RFA than for BPC. The possibility that RFA is associated with a lower rate of postoperative PPROM than is BPC will have to be confirmed in larger series.

Initial fetal cardiovascular profile score predicts recipient twin outcome in twin-twin transfusion syndrome

BACKGROUND

The aim of this study was to assess the relationship between cardiomyopathy and recipient twin (RT) outcome in twin-twin transfusion syndrome (TTTS).

METHODS

Fetal echocardiography and outcomes data in 62 consecutive pregnancies with TTTS were reviewed. The primary outcome was neonatal RT survival. The severity of RT cardiomyopathy at presentation was assessed by the cardiovascular profile score (CVPS). RT outcomes and odds of survival were compared between groups stratified by CVPS.

RESULTS

Overall neonatal survival for all fetuses was 61% (76 of 124). RT survival was 58% (36 of 62). Grouped by CVPS, RT survival was greater (50%) for those with CVPS > or = 9 and even higher (74%) for CVPS of 10. Among the components of the CVPS, atrioventricular valve regurgitation was associated with negative RT outcome. Other factors at presentation were not predictive of RT outcome.

CONCLUSIONS

A normal CVPS in the RT in TTTS is predictive of improved survival compared with an abnormal CVPS, even in RTs with minor deductions. Standard clinical staging did not predict outcome. Cardiac assessment by CVPS may improve clinical decision making and the timing of fetal interventions.

Nuchal translucency thickness in monochorionic multiple pregnancies: value in predicting pregnancy outcome

OBJECTIVES

The purpose of this study was to investigate the value of first-trimester nuchal translucency (NT) thickness in predicting the pregnancy outcome in monochorionic multiple pregnancies.

METHODS

Thirty monochorionic multiple pregnancies were evaluated for NT thickness at a median gestational age of 12 weeks (range, 11-14 weeks). Information on pregnancy outcome was obtained from all cases. A poor pregnancy outcome was defined as fetal death or miscarriage before 24 weeks, development of twin-twin transfusion syndrome (TTTS), or preterm delivery before 32 weeks.

RESULTS

The NT thickness was above the 95th percentile for gestational age in at least 1 fetus in 5 (17%) pregnancies, and a poor pregnancy outcome was recorded in 14 (47%) pregnancies. The overall sensitivity was 36% (5/14); specificity, 100% (16/16); positive predictive value, 100% (5/5); and negative predictive value, 64% (16/25). In pregnancies with increased compared with normal NT thickness, no significant correlation was found with the subsequent development of TTTS (1/5 [20%] versus 5/25 [20%]) and miscarriage or fetal death before 24 weeks (1/5 [20%] versus 3/25 [12%]). However, among the 20 pregnancies not complicated by TTTS or loss before 24 weeks, there was a significantly increased rate of delivery before 32 weeks in the former group (3/4 [75%] versus 1/16 [6.3%]; P = .01).

CONCLUSIONS

In monochorionic multiple pregnancies, an increased NT thickness measurement had a high specificity and positive predictive value for adverse perinatal outcomes. However, the sensitivity and negative predictive value were low, with a normal NT thickness measurement poorly predicting development of complications; therefore, close sonographic follow-up should be carried out in all cases, irrespective of NT thickness.

[Twin pregnancies in southern Reunion Island: a three-year cross-sectional study of risk factors and complications]

OBJECTIVES

To describe characteristics of multiples pregnancies in southern Reunion Island.

MATERIAL AND METHODS

A three-year [corrected] cross-sectional observational study aimed at describing risk factors, events and [corrcected] complications and associated with twin pregnancies from 22 weeks gestation onward, within a tertiary care hospital centre, the Groupe Hospitalier Sud-Réunion.

RESULTS

The study included 241 multiple pregnancies out of 15 837 pregnant women. The regional incidence of multiple pregnancies was 1.5%. Indicators of eligible twin pregnancies (n=234) were mother age up or equal to 35 years (63% of women, OR 8.4; CI95% 6.3-11.1), infertility treatments (15%): ovarian stimulations (OR: 50.2; CI95% 24.7-102) and in vitro-fertilisations (OR: 44.3; CI95% 22.6-86.3). A low maternal corpulence before pregnancy (BMI<20) and celibacy were negatively associated with twin pregnancies. Prenatal cares for twin pregnancies were globally adequate. The need for hospitalisation was 50% (30% of whom for preterm delivery threats). Twin pregnancies increased risks for pre eclampsia (OR: 3.0; CI95% 1.6-5.7) and gestational diabetes (OR: 1.9; CI95% 1.2-2.8). Caesareans and instrumental delivery rates were 50% and 12% (vs 16% and 7%), respectively. Twin infants were preterm for 62% and very preterm for 18%. Last, they were more likely to die than singletons (perinatal mortality: 78 per thousand for monochorionic twins, 57 per thousand for bichorionic twins vs 17 per thousand, p<0.0001, respectively).

CONCLUSION

In Reunion Island, the incidence of multiple pregnancies is similar to that seen in Europe, but seems less due to assisted reproduction techniques. In return, they are associated with higher morbidity and mortality rates.