Zhu Jinliang, Wang Zhongwei, Chen Lixue, Liu Ping
Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China.
National Clinical Research Center for Obstetrics and Gynecology, Peking University Third Hospital, Beijing 100191, China.
Hum Reprod. 2020 Jul 1;35(7):1553-1561. doi: 10.1093/humrep/deaa120.
Is the vanishing of a co-twin after or before the ultrasonic registration of cardiac activity at approximately 6-8 weeks of gestation associated with adverse perinatal outcomes?
The timing of the demise of a co-twin after the registration of cardiac activity is an independent risk factor for adverse perinatal outcomes.
A significant body of evidence has confirmed that vanishing twin (VT) pregnancies are associated with higher levels of risk for preterm birth (PTB), low birthweight (LBW), small-for-gestational age (SGA) and perinatal mortality, compared with singleton pregnancy. However, the impact of co-twin vanishing, before or after the presence, of cardiac activity, on perinatal outcomes has yet to be extensively investigated.
STUDY DESIGN, SIZE, DURATION: We retrospectively reviewed the medical records of 38 876 singletons delivered from ART cycles between 2006 and 2018, at the Peking University Third Hospital.
PARTICIPANTS/MATERIALS, SETTING, METHODS: In total, 35 188 singletons were delivered from the singleton pregnancy group, 2256 singletons from the VT pregnancy group after that cardiac activity was noted, and 1432 singletons were delivered from the VT pregnancy group before cardiac activity could be registered. Using the Poisson model, the adjusted risk ratio (aRR) was used to estimate the incidence of PTB, LBW, SGA and perinatal mortality, in the pregnancies of two types of VT compared with singleton pregnancies after correction for potential confounding factors.
The vanishing of a co-twin after the registration of cardiac activity was associated with an increased risk of perinatal mortality when compared with the group of singleton pregnancies (0.5% vs 0.2%; P = 0.006); this association still existed after adjustment for potential confounders (aRR 2.19, 95% CI 1.12-4.30; P = 0.023). Furthermore, it was significantly associated with a higher risk of PTB (all cycles aRR 2.00, 95% CI 1.77-2.24; P < 0.001; fresh transfer aRR 2.06, 95% CI 1.78-2.38; P < 0.001; frozen transfer aRR 1.87, 95% CI 1.52-2.28; P < 0.001), LBW (all cycles aRR 2.47, 95% CI 2.12-2.88; P < 0.001; fresh transfer aRR 2.50, 95% CI 2.07-3.02; P < 0.001; frozen transfer aRR 2.39; 95% CI 1.83-3.12; P < 0.001) and SGA (all cycles aRR 1.56, 95% CI 1.35-1.80; P < 0.001; fresh transfer aRR 1.53, 95% CI 1.29-1.81; P < 0.001; frozen transfer aRR 1.62, 95% CI 1.24-2.11; P < 0.001). However, prior to the presence of cardiac activity, the vanishing of a co-twin was not associated with a higher risk of perinatal mortality (all cycles aRR 0.71, 95% CI 0.17-2.92; P = 0.636; fresh cycles aRR 0.51, 95% CI 0.07-3.70; P = 0.502; frozen cycles aRR 1.29, 95% CI 0.17-9.66; P = 0.803), PTB (all cycles aRR 1.11, 95% CI 0.91-1.34; P = 0.301; fresh cycles aRR 1.10, 95% CI 0.87-1.39; P = 0.447; frozen cycles aRR 1.13, 95% CI 0.81-1.58; P = 0.467), LBW (all cycles aRR 1.19, 95% CI 0.91-1.55; P = 0.207; fresh cycles aRR 1.08, 95% CI 0.77-1.51; P = 0.668; frozen cycles aRR 1.45, 95% CI 0.93-2.25; P = 0.100) and SGA (all cycles aRR 1.09, 95% CI 0.89-1.35; P = 0.405; fresh cycles aRR 0.97, 95% CI 0.75-1.26; P = 0.839). Pregnancies involving the two types of VT were significantly different in terms of PTB (all cycles aRR 1.80, 95% CI 1.45-2.24; P < 0.001; fresh cycles aRR 1.88, 95% CI 1.44-2.45; P < 0.001; frozen cycles aRR 1.65, 95% CI 1.13-2.40; P = 0.009), LBW (all cycles aRR 2.08, 95% CI 1.55-2.79; P < 0.001; fresh cycles aRR 2.32, 95% CI 1.61-3.36; P < 0.001; frozen cycles aRR 1.65, 95% CI 1.01-2.70; P = 0.046) and SGA (all cycles aRR 1.70, 95% CI 1.36-2.11; P < 0.001; fresh cycles aRR 1.87, 95% CI 1.42-2.45; P < 0.001).
LIMITATIONS, REASONS FOR CAUTION: The present data are not able to differentiate between co-twin demise occurring in the first or second trimester. Because the second trimester ultrasound scan is not an integral aspect of IVF assessment, this information was not available in the database.
Adverse perinatal outcomes in ART babies can be avoided by replacing one embryo at a time. It is possible to apply selective single embryo transfer strategy for all while maintaining acceptable success rates.
STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the National Natural Science Foundation of China for Young Scholars (Reference number: 31801251). No competing interests to declare.
not applicable.
双胎之一在妊娠约6 - 8周心脏活动超声记录之后或之前消失，是否与不良围产期结局相关？
双胎之一在心脏活动记录之后消失是不良围产期结局的独立危险因素。
大量证据证实，与单胎妊娠相比，消失双胎（VT）妊娠与早产（PTB）、低出生体重（LBW）、小于胎龄儿（SGA）和围产期死亡率的风险更高相关。然而，双胎之一在心脏活动出现之前或之后消失对围产期结局的影响尚未得到广泛研究。
研究设计、规模、持续时间：我们回顾性分析了2006年至2018年在北京大学第三医院接受辅助生殖技术（ART）周期分娩的38876名单胎婴儿的病历。
参与者/材料、环境、方法：单胎妊娠组共分娩35188名单胎婴儿，心脏活动记录后VT妊娠组分娩2256名单胎婴儿，心脏活动记录前VT妊娠组分娩1432名单胎婴儿。采用泊松模型，校正潜在混杂因素后，用调整风险比（aRR）估计两种类型VT妊娠与单胎妊娠相比PTB、LBW、SGA和围产期死亡率的发生率。
与单胎妊娠组相比，心脏活动记录后双胎之一消失与围产期死亡率增加相关（0.5%对0.2%；P = 0.006）；校正潜在混杂因素后该关联仍然存在（aRR 2.19，95%可信区间1.12 - 4.30；P = 0.023）。此外，它与PTB（所有周期aRR 2.00，95%可信区间1.77 - 2.24；P < 0.001；新鲜胚胎移植aRR 2.06，95%可信区间1.78 - 2.38；P < 0.001；冷冻胚胎移植aRR 1.87，95%可信区间1.52 - 2.28；P < 0.001）、LBW（所有周期aRR 2.47，95%可信区间2.12 - 2.88；P < 0.001；新鲜胚胎移植aRR 2.50，95%可信区间2.07 - 3.02；P < 0.001；冷冻胚胎移植aRR 2.39；95%可信区间1.83 - 3.12；P < 0.001）和SGA（所有周期aRR 1.56，95%可信区间1.35 - 1.80；P < 0.001；新鲜胚胎移植aRR 1.53，95%可信区间1.29 - 1.81；P < 0.001；冷冻胚胎移植aRR 1.62，95%可信区间1.24 - 2.11；P < 0.001）的较高风险显著相关。然而，在心脏活动出现之前，双胎之一消失与围产期死亡率较高风险无关（所有周期aRR 0.71，95%可信区间0.17 - 2.92；P = 0.636；新鲜周期aRR 0.51，95%可信区间0.07 - 3.70；P = 0.502；冷冻周期aRR 1.29，95%可信区间0.17 - 9.66；P = 0.803）、PTB（所有周期aRR 1.11，95%可信区间0.91 - 1.34；P = 0.301；新鲜周期aRR 1.10，95%可信区间0.87 - 1.39；P = 0.447；冷冻周期aRR 1.13，95%可信区间0.81 - 1.58；P = 0.467）、LBW（所有周期aRR 1.19，95%可信区间0.91 - 1.55；P = 0.207；新鲜周期aRR 1.08，95%可信区间0.77 - 1.51；P = 0.668；冷冻周期aRR 1.45，95%可信区间0.93 - 2.25；P = 0.100）和SGA（所有周期aRR 1.09，95%可信区间0.89 - 1.35；P = 0.405；新鲜周期aRR 0.97，95%可信区间0.75 - 1.26；P = 0.839）。涉及两种类型VT的妊娠在PTB（所有周期aRR 1.80）方面有显著差异，95%可信区间1.45 - 2.24；P < 0.001；新鲜周期aRR 1.88，95%可信区间1.44 - 2.
