Longer distance between umbilical cord insertions is associated with spontaneous twin anemia polycythemia sequence

Thick artery-artery anastomoses delay the onset of selective fetal growth restriction in monochorionic diamniotic twins: a 7-year single-center cohort study

Objective

This study aimed to investigate differences in placental characteristics between early- and late-onset selective fetal growth restriction (sFGR) in monochorionic diamniotic twins.

Methods

A total of 253 patients with sFGR between April 2013 and April 2020 were retrospectively analyzed. Placental characteristics of early- and late-onset sFGR were compared.

Results

The gestational age at diagnosis and delivery in the early-onset group was significantly less than that in the late-onset group [22.0 (16.9-23.9) and 28.4 (24.0, 36.3) weeks, P < 0.001; 33.1 ± 2.2 and 33.7 ± 2.5 weeks, P = 0.025]. The birth weight of normal growth and growth-restricted fetuses in the early-onset group was less than the late-onset group [1,990 ± 422 and 2,162 ± 525 g, P = 0.044; 1,320 ± 409 and 1,595 ± 519 g, P = 0.001]. The birthweight discordance ratio in the early-onset group was greater than the late-onset group (0.34 ± 0.12 and 0.29 ± 0.13, P = 0.001). The early-onset group had a significantly lower prevalence of sFGR type I than the late-onset group (37.5 and 62.0%, P = 0.018). The early-onset group had a significantly higher prevalence of sFGR type III than the late-onset group (30.4 and 12.7%, P = 0.048). The early-onset group had a lower prevalence of thick artery-artery anastomoses than the late-onset group (37.5 and 62.0%, P = 0.006). The placental territory discordance ratio in the early-onset group was higher than in the late-onset group [0.60 (0.01, 0.80) and 0.50 (0.01, 0.88), P = 0.018].

Conclusion

Unequal placental territory is the cause for most of the late-onset sFGR. Thick artery-artery anastomoses may delay the onset time of these cases of sFGR.

Effect of fetoscopic laser surgery on the placental characteristics and birth-weight discordance of twins with twin-to-twin transfusion syndrome

Objective

This study explored the effect of fetoscopic laser surgery on the placental structure and birth-weight discordance of twin-to-twin transfusion syndrome (TTTS).

Methods

A retrospective cohort study was conducted in TTTS patients who were admitted to the Peking University Third Hospital between April 2014 and April 2020. The patients were divided into two groups: laser group and control group. Placentas with twin survival were injected, and pregnancy outcomes and placental characteristics of the two groups were compared. The correlation between the birth-weight discordance and placental characteristics in each group was analyzed.

Results

The gestational age at first diagnosis in the laser group was significantly smaller than that in the control group (21.6 ± 2.8 weeks vs. 27.7 ± 3.0 weeks, p < 0.001). The proportion of patients with TTTS stage-I in the laser group was significantly lower than the control group (9.4 vs. 64.0%, p < 0.001). The gestational age at delivery in the laser group was significantly larger than that in the control group (33.6 ± 2.1 weeks vs. 31.4 ± 2.5 weeks, p = 0.001). In the laser group, the birth-weight discordance ratio was positively correlated with the placental territory discordance ratio (Spearman coefficient = 0.556; p = 0.001).

Conclusion

The birth-weight discordance is positively correlated with placental territory discordance in TTTS patients after FLS.

Comparison of pregnancy outcomes and placental characteristics for monochorionic diamniotic twins with and without proximate umbilical cord insertion

INTRODUCTION

This study was developed to evaluate the relative placental characteristics and pregnancy outcomes associated with monochorionic diamniotic (MCDA) twins with and without proximate umbilical cord insertion (PCI).

METHODS

All MCDA twins delivered with complete placentas for whom placental characteristics were assessed via dye injection between April 1, 2013 and April 1, 2021 were included in the present cohort study. Cases were separated into PCI and non-PCI groups, and pregnancy outcomes and placental characteristics were then compared between these groups.

RESULTS

Birthweight discordance rates were significantly lower in the PCI group relative to the non-PCI group (7.3 ± 7.5% vs 29.9 ± 16.8%, P＜0.001), while relative to the non-PCI group, rates of artery-artery (AA), vein-vein (VV), thick AA, and thick VV anastomoses were significantly higher in the PCI group (95.5% vs 67.0%, P = 0.008, 59.1% vs 16.4, P＜0.001,90.5% vs 34.9%, P＜0.001, 54.5% vs 10.5%, P＜0.001). Significantly more anastomoses were observed in the PCI group (7 (3,11) vs 6 (3,15), P = 0.015), and they were significantly larger on average than those in the non-PCI group 12.8 (6.7,21.3) mm vs 11.9 (3.4, 24.6) mm, P = 0.009). Significantly lower placental territory discordance and UCI ratios were evident in the PCI group relative to the non-PCI group (23.5 (15.0,51.0) % vs 60.0 (2.0,80.0) %, P＜0.001, 13.3 ± 5.8% vs 56.1 ± 18.0%, P < 0.001). Marginal cord insertion rates were lower in the PCI group relative to the non-PCI group (13.6% vs 77.5%, P < 0.001).

DISCUSSION

The placental structure of MCDA twins with PCI is distinct from that of twins without PCI, and these results suggest PCI may be indicative of the more even distribution of placental territory between MCDA fetuses.

Placental characteristics of selective intrauterine growth restriction with changing patterns in umbilical artery Doppler flow in monochorionic diamniotic twins

OBJECTIVES

To compare the placental features between selective intrauterine growth restriction (sIUGR) patients, with dynamic classification (DC) and stable classifications (SC).

METHODS

A cohort study was conducted from 1st April 2013 to 1st April 2020, we recruited sIUGR patients who had delivered at our center and examined placental characteristics with dye injection. The primary outcome was placental characteristics.

RESULTS

The prevalence of large artery-artery anastomosis (AAA) was significantly higher in sIUGR with DC than sIUGR with SC (88.2 vs. 46.6%, p=0.001). The total diameter of AAA was significantly larger in sIUGR with DC than sIUGR with SC [2.9 (1.4, 7.0) vs. 2.4 (0.3, 7.1) mm, p=0.032]. The total number of artery-vein anastomosis was significantly smaller in sIUGR with DC than sIUGR with SC [3 (1, 12) vs. 5 (1, 15), p=0.023]. The incidence of neonatal asphyxias of growth-restricted fetuses were higher in sIUGR with DC than sIUGR with SC (23.5 vs. 5.9%, p=0.033).

CONCLUSIONS

Large AAA is probably associated to sIUGR with dynamic classification.

Comparison of pregnancy outcomes and placental characteristics between selective fetal growth restriction with and without thick arterio-arterial anastomosis in monochorionic diamniotic twins

Background

Unequal placental territory in monochorionic diamniotic twins is a primary cause of selective fetal growth restriction (sFGR), and vascular anastomoses play important role in determining sFGR prognosis. This study investigated differences in placental characteristics and pregnancy outcomes in cases of sFGR with and without thick arterio-arterial anastomosis (AAA).

Methods

A total of 253 patients diagnosed with sFGR between April 2013 and April 2020 were retrospectively analyzed. An AAA greater than 2 mm in diameter was defined as a thick AAA. We compared placental characteristics and pregnancy outcomes between cases of sFGR with and without thick AAA.

Results

Prevalence of AAA, thick arterio-venous anastomosis (AVA), veno-venous anastomosis (VVA), and thick VVA were significantly higher in the thick AAA group relative to the non-thick AAA group (100.0 vs. 78.5%, P < 0.001; 44.3 vs. 15.4%, P < 0.001; 27.1 vs. 10.8%, P = 0.017, and 24.3 vs. 6.2%, P = 0.004, respectively). The total numbers of AVA and total anastomoses were significantly higher in thick AAA group relative to the non-thick AAA group (5 [1, 14] vs. 3 [1, 15, P = 0.016; and 6 [1, 15] vs. 5 [1, 16], P = 0.022, respectively). The total diameter of AAA, AVA, VVA, and all anastomoses in the thick AAA group was larger than in the non-thick AAA group (3.4 [2.0,7.1] vs. 1.4 [0.0, 3.3], P < 0.001; 6.3 [0.3, 12.0] vs. 2.5 [0.3, 17.8], P < 0.001; 4.2±1.8 vs. 1.9±1.2, P =0.004; and 10.7 [3.2,22.4] vs. 4.4 [0.5, 19.3], P < 0.001, respectively). Growth-restricted fetuses in the thick AAA group exhibited significantly increased birthweight relative to those in thenon-thick AAA group (1570 (530, 2460)g vs. 1230 (610, 2480)g, p = 0.002).

Conclusions

In the placentas associated with sFGR, thick AAA can co-occur with thick AVA and VVA, and placental angiogenesis may differ significantly based upon whether or not thick AAA is present. The birth weights of growth-restricted fetuses in cases of sFGR with thick AAA are larger than in cases without thick AAA.

The relationship between placental characteristics and birthweight discordance in different types of selective intrauterine growth restriction in monochorionic diamniotic twins: A single-center 7 year cohort study

OBJECTIVE

To clarify the relationships between placental characteristics and birthweight discordance in three types of selective intrauterine growth restriction (sIUGR) in monochorionic diamniotic twins.

METHODS

A retrospective cohort study was conducted between april 2013 and april 2020. Associations between placental characteristics and birthweight discordance were evaluated through multiple linear regression analyses with two models for each sIUGR type. Model A was adjusted for gestational age, Model B additionally adjusted for the impact of placental characteristics interacted.

RESULTS

In cases of type I sIUGR, birthweight discordance ratio was positively associated with placental territory discordance ratio [(β = 0.181,95%CI(0.072,0.290), p < 0.05), (β = 0.239,95%CI(0.125, 0.353), p < 0.05)] under both Model A and Model B. In-type II sIUGR [(β = -0.012,95%CI(-0.020, -0.004), p < 0.05) (β = -0.010,95%CI (-0.018, -0.002), p < 0.05)] and type III sIUGR [(β = -0.011,95%CI (-0.021, -0.001), p < 0.05), (β = -0.012,95%CI(-0.022, -0.003), p < 0.05)], birthweight discordance ratio was negatively associated with the total diameter of all the anastomoses as calculated with both Model A and Model B.

CONCLUSION

Birthweight discordance is primarily related to placental territory discordance in type I sIUGR, whereas vascular anastomoses play important roles for growth-restricted fetal compensation in type II and III sIUGR.