Abstract：
OBJECTIVE: Longitudinal hematological changes throughout twin pregnancies have not been reported. This study aimed to reveal longitudinal changes in hematological indices in twin pregnancies.
METHODS: We conducted a retrospective chart review of hematological changes in uncomplicated twin pregnancies delivered at ≥37 weeks of gestation between 2010 and 2013 and randomly selected uncomplicated singletons during the same period. A complete blood count and hemogram were performed as blood examinations in the first trimester (9-13 weeks), late second trimester (22-27 weeks), mid-third trimester (33-35 weeks, only in twin pregnancies), and late third trimester (36-38 weeks). We evaluated inter-trimester differences in hematological indices and compared the values between twin and singleton pregnancies in each trimester.
RESULTS: The final analysis group included 60 twin pregnancies and 63 singleton pregnancies. The white blood cell (WBC) count in twin pregnancies decreased throughout the pregnancy after the first trimester and became significantly lower than that in singletons in the late third trimester. The WBC count showed only a slight decrease in the third trimester in singleton pregnancies, whereas it showed a marked decrease throughout the pregnancy in twin pregnancies. The marked decrease in the total WBC count in twin pregnancies is mainly due to a decrease in neutrophils. The red blood cell count and hemoglobin and hematocrit values in twin pregnancies showed more marked decreases in the second trimester than in singletons. No decrease was observed after the second trimester of pregnancy. The platelet count decreased in the third trimester of twin pregnancies.
CONCLUSIONS: We clarified the longitudinal hematological changes in twin pregnancies that showed augmentation of or differed from those of singleton pregnancies. It should be specifically mentioned that the WBC count markedly decreased through pregnancy after the first trimester, which is a characteristic change in twin pregnancies.
METHODS: We conducted a retrospective chart review of hematological changes in uncomplicated twin pregnancies delivered at ≥37 weeks of gestation between 2010 and 2013 and randomly selected uncomplicated singletons during the same period. A complete blood count and hemogram were performed as blood examinations in the first trimester (9-13 weeks), late second trimester (22-27 weeks), mid-third trimester (33-35 weeks, only in twin pregnancies), and late third trimester (36-38 weeks). We evaluated inter-trimester differences in hematological indices and compared the values between twin and singleton pregnancies in each trimester.
RESULTS: The final analysis group included 60 twin pregnancies and 63 singleton pregnancies. The white blood cell (WBC) count in twin pregnancies decreased throughout the pregnancy after the first trimester and became significantly lower than that in singletons in the late third trimester. The WBC count showed only a slight decrease in the third trimester in singleton pregnancies, whereas it showed a marked decrease throughout the pregnancy in twin pregnancies. The marked decrease in the total WBC count in twin pregnancies is mainly due to a decrease in neutrophils. The red blood cell count and hemoglobin and hematocrit values in twin pregnancies showed more marked decreases in the second trimester than in singletons. No decrease was observed after the second trimester of pregnancy. The platelet count decreased in the third trimester of twin pregnancies.
CONCLUSIONS: We clarified the longitudinal hematological changes in twin pregnancies that showed augmentation of or differed from those of singleton pregnancies. It should be specifically mentioned that the WBC count markedly decreased through pregnancy after the first trimester, which is a characteristic change in twin pregnancies.
摘要：
目的：整个双胎妊娠的纵向血液学变化尚未报道。这项研究旨在揭示双胎妊娠中血液学指标的纵向变化。
方法：我们对2010年至2013年妊娠≥37周时分娩的无并发症双胎妊娠和同期随机选择的无并发症单胎的血液学变化进行了回顾性分析。在妊娠早期（9-13周）进行完整的血细胞计数和血象检查，妊娠中期晚期（22-27周），妊娠中期（33-35周，仅在双胞胎怀孕中），和晚期妊娠（36-38周）。我们评估了孕期血液学指标的差异，并比较了每个孕期的双胎和单胎妊娠之间的值。
结果：最终分析组包括60例双胎妊娠和63例单胎妊娠。在妊娠早期，双胎妊娠的白细胞（WBC）计数在整个妊娠期间下降，并且在妊娠晚期明显低于单胎。白细胞计数显示在单胎妊娠的妊娠晚期仅略有下降，而在整个双胎妊娠中，它显示出明显的下降。双胎妊娠中白细胞总数的显著减少主要是由于中性粒细胞的减少。双胞胎妊娠中的红细胞计数，血红蛋白和血细胞比容值在孕中期比单胎中下降更明显。妊娠中期后没有观察到下降。双胎妊娠晚期血小板计数下降。
结论：我们阐明了双胎妊娠的纵向血液学变化，其表现为单胎妊娠的增加或不同于单胎妊娠。应该特别提到的是，在妊娠早期后，WBC计数显着下降，这是双胎妊娠的典型变化.
方法：我们对2010年至2013年妊娠≥37周时分娩的无并发症双胎妊娠和同期随机选择的无并发症单胎的血液学变化进行了回顾性分析。在妊娠早期（9-13周）进行完整的血细胞计数和血象检查，妊娠中期晚期（22-27周），妊娠中期（33-35周，仅在双胞胎怀孕中），和晚期妊娠（36-38周）。我们评估了孕期血液学指标的差异，并比较了每个孕期的双胎和单胎妊娠之间的值。
结果：最终分析组包括60例双胎妊娠和63例单胎妊娠。在妊娠早期，双胎妊娠的白细胞（WBC）计数在整个妊娠期间下降，并且在妊娠晚期明显低于单胎。白细胞计数显示在单胎妊娠的妊娠晚期仅略有下降，而在整个双胎妊娠中，它显示出明显的下降。双胎妊娠中白细胞总数的显著减少主要是由于中性粒细胞的减少。双胞胎妊娠中的红细胞计数，血红蛋白和血细胞比容值在孕中期比单胎中下降更明显。妊娠中期后没有观察到下降。双胎妊娠晚期血小板计数下降。
结论：我们阐明了双胎妊娠的纵向血液学变化，其表现为单胎妊娠的增加或不同于单胎妊娠。应该特别提到的是，在妊娠早期后，WBC计数显着下降，这是双胎妊娠的典型变化.
