SUMMARY ANSWER The available high- quality evidence indicates that specific treatments may give rise to different effects on cognitive development , with certain treatments , including ICSI , associated with cognitive impairment .
STUDY QUESTION Does  fertility treatment  influence cognitive ability in school aged children , and does the impact vary with the type of treatment ?
WHAT IS KNOWN ALREADY Previous review s of the literature concerning cognitive outcomes among children conceived with medical assistance have concluded that study findings are generally ' reassuring ' , but limited attention has been paid to the quality of this research .
In addition , no review has separately assessed the range of treatment modalities available , which vary in invasiveness , and thus , potentially , in their effects on developmental outcomes .
A prospective longitudinal study of the physical, psychomotor, and intellectual development of singleton children up to 5 years who were conceived by intracytoplasmic sperm injection compared with children conceived spontaneously and by in vitro fertilization.
OBJECTIVE To assess the somatic , psychomotor , and intellectual development of children conceived through intracytoplasmic single sperm injection ( ICSI )  over the whole preschool period . DESIGN Prospect i ve , controlled , cohort study . SETTING Fertility clinic in Brussels , Belgium . PATIENT(S ) Sixty-six ICSI-conceived children prospect ively compared with 52 IVF-conceived and 59 spontaneously conceived children . All children were full-term singletons . INTERVENTION(S ) Home visits by a trained psychologist . St and ardized interviews . Assessment s using the revised Brunet-Lézine scale and the revised Wechsler preschool and primary scale of intelligence . MAIN OUTCOME MEASURE(S ) Physical growth and general health . Formal developmental and intellectual assessment s. RESULT ( S ) Children conceived by ICSI were healthy : no significant differences appeared in the incidence of combined congenital malformations ( 11.3 % ) , health problems ( 44.1 % ) , surgical interventions ( 18.6 % ) , and hospitalizations ( 6.8 % ) , nor for the developmental assessment s ( mean developmental quotient at 9 months : 93.9 ; at 18 months : 102.0 ) . For the intellectual assessment s , the between-group differences disappeared when adjusted for levels of parental education ( mean intelligence quotient at 3 years : 97.0 ; at 5 years : 103.3 ) . CONCLUSION ( S ) This pilot study shows that throughout the preschool period , ICSI-conceived children have psychomotor and intellectual development similar to that of IVF-conceived and spontaneously conceived children . These conclusions need to be confirmed by multicenter studies
SUMMARY ANSWER The available high- quality evidence indicates that specific treatments may give rise to different effects on cognitive development , with certain treatments , including ICSI , associated with cognitive impairment .
STUDY QUESTION Does  fertility treatment  influence cognitive ability in school aged children , and does the impact vary with the type of treatment ?
WHAT IS KNOWN ALREADY Previous review s of the literature concerning cognitive outcomes among children conceived with medical assistance have concluded that study findings are generally ' reassuring ' , but limited attention has been paid to the quality of this research .
In addition , no review has separately assessed the range of treatment modalities available , which vary in invasiveness , and thus , potentially , in their effects on developmental outcomes .