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 .
Effect of pregnancy planning and fertility treatment on cognitive outcomes in children at ages 3 and 5: longitudinal cohort study
Objective To investigate how pregnancy planning , time to conception , and infertility treatment influence cognitive development at ages 3 and 5 . Design Prospect i ve population based cohort study . Setting Millennium Cohort Study in the United Kingdom . Participants 18 818 children recruited at 9 months and followed up at 3 and 5 years . 11 790 singletons with available data on pregnancy , cognitive outcomes , and confounders were included in analyses at age 3 and 12 136 at age 5 . Exposure measures Mothers reported whether the pregnancy was planned , and their feelings when first pregnant ; those in whom the pregnancy was planned provided time to conception , and details of any assisted reproductive technologies . The population was divided into “ unplanned ” ( unplanned and unhappy ) , “ mistimed ” ( unplanned but happy ) , “ planned ” ( planned , time to conception < 12 months ) , “ subfertile ” ( planned , time to conception ≥12 months ) , “ induced ovulation ” ( received clomiphene citrate ) , and “ assisted reproduction ” ( in vitro fertilisation or intracytoplasmic sperm injection ) . The “ planned ” group was the comparison group in all analyses . Outcome measures Three components of the British Ability Scales ( BAS II ) . Naming vocabulary assessed verbal ability at age 3 ; this test was repeated at age 5 with the picture similarities and pattern construction subscales , which measure non-verbal and spatial abilities . Results In unadjusted analyses , the scores on all scales in children from unplanned pregnancies were significantly lower than in those from planned pregnancies — for example , the difference in mean verbal ability score at age 3 was −4.8 ( 95 % confidence interval −6.0 to −3.7 ; P<0.05 ) , equivalent to an average delay of four months . After adjustment for sociodemographic factors these differences were attenuated : −0.3 ( −1.3 to 0.7 ) , equivalent to no delay . Children born after assisted reproduction performed consistently better in verbal ability tests ( 3.8 ( −0.2 to 7.9 ) at age 3 and 3.5 ( 0.2 to 6.8 ) at age 5 ) , which suggests that on average these children are three to four months ahead ; this difference did not completely disappear with adjustment for confounders . Children born after infertility treatment had lower mean scores in non-verbal tests ( −1.2 ( −4.1 to 1.6 ) after assisted reproduction and −1.5 ( −3.5 to 0.4 ) after induced ovulation ) and in spatial ability tests ( −2.7 ( −6.9 to 1.6 ) after assisted reproduction ) , though the differences were not significant . Conclusions Pregnancy planning , subfertility , or assisted reproduction do not adversely affect children ’s cognitive development at age 3 or 5 . The differences observed in the unadjusted analyses are almost entirely explained by marked inequalities in socioeconomic circumstances between the groups
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 .