Is there a difference in cognitive development between preschool singletons and twins born after intracytoplasmic sperm injection or in vitro fertilization？

Objective： To explore whether there exist differences in cognitive development between singletons and twins born after in vitro fertilization （IVF） or intracytoplasmic sperm injection （ICSI）. Methods： A total of 566 children were recruited for the study, including 388 children （singletons, n=175; twins, n=213） born after IVF and 178 children （singletons, n=87; twins, n=91 ） born after ICSI. The cognitive development was assessed using the Chinese-Wechsler Intelligence Scale for Children （C-WISC）. Results： For all pre-term offspring, all the intelligence quotient （IQ） items between singletons and twins showed no significant differences no matter if they were born after IVF or ICSI. There was a significant difference in the cognitive development of IVF-conceived full-term singletons and twins. The twins born after IVF obtained significantly lower scores than the singletons in verbal IQ （containing information, picture ＆ vocabulary, arithmetic, picture completion, comprehension, and language）, performance IQ （containing maze, visual analysis, object assembly, and performance）, and full scale IQ （P〈0.05）. The cognitive development of full-term sin- gletons and twins born after ICSI did not show any significant differences. There was no significant difference between the parents of the singletons and twins in their characteristics where data were collected, including the age of the mothers, the current employment status, the educational backgrounds, and areas of residence. There were also no consistent differences in the duration of pregnancy, sex composition of the children, age, and height between sin- gletons and twins at the time of our study although there existed significant differences between the two groups in the sex composition of the full-term children born after ICSI （P〈0.05）. Conclusions： Compared to the full-term singletons born after IVF, the full-term twins have lower cognitive development. The cognitive development of full-term singletons and twins born after ICSI did not show any significant differences. For all pre-term offspring, singletons and twins born after IVF or ICSI, the results of the cognitive development showed no significant differences.

研究目的:调查体外受精(IVF)和单精子胞浆内注射(ICSI)孕育的学龄前单双胎子代在认知发展上是否存在显著性差异。创新要点:在严格匹配人口学资料的基础上区分早产儿和足月儿后,比较了两种辅助生育技术单双胎子代的认知发展水平。在排除早产和技术的影响后,双胎子代的智商仍显著低于单胎子代,为继续在临床推进单胚胎移植提供了新的证据。研究方法:共566名学龄前辅助生育技术子代学龄前儿童纳入本研究,分为4组:IVF-足月、IVF-早产、ICSI-足月和ICSI-早产,相同组内的单双胎子代的人口学数据严格匹配(见表1、3、5、7)后,采用中文版的韦氏儿童智力测验评估单双胎子代的智商水平(见表2、4、6、8)。重要结论:IVF足月双胎子代的认知发展水平显著低于足月单胎子代,而ICSI足月单双胎子代的认知发展水平无显著差异。对于早产子代来说,无论是孕育于IVF或ICSI,单胎和双胎的认知发展均无明显差异。