***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: To study the relation of maternal periconceptional vitamin use  to the risk of  a congenital urinary tract anomaly ( CUTA )  , we conducted a case-control study using the Washington State Birth Defect Registry . We identified CUTA cases with no known chromosomal abnormality in seven counties in western Washington State occurring between January 1 , 1990 , and December 31 , 1991 . We r and omly selected a sample , as controls , of all infants delivered in five large hospitals in King County who did not have a birth defect and who were born in the same year as the cases . About 55 % of all infants in King County and a smaller proportion of infants in the other six counties are delivered in these five hospitals . We interviewed mothers of 118 cases and 369 controls to obtain information about their vitamin use during the pregnancy and during the year before the conception . After adjustment for maternal race , family income , county of maternal residence , and birth year , we found that women who used multivitamins during the first trimester had only 15 % the risk of bearing a child with a CUTA compared with women who did not take vitamins [ odds ratio ( OR ) = 0.15 ; 95 % confidence interval ( CI ) = 0.05–0.43 ] . The reduction was smaller for use restricted to the second or third trimesters ( OR = 0.31 ; 95 % CI = 0.09–1.02 ) . Among women who used vitamins during the first trimester , vitamin use before conception was not associated with any further reduction in the risk , nor did there appear to be an association with the amount or br and of vitamin used . Restricting the analysis to residents of King County did not change the results . Our results indicate that prenatal multivitamin use , particularly during the first trimester , may reduce the risk of a CUTA . Because all of the preparations taken by study participants contained many vitamins as well as folic acid , it was not possible to identify which one ( or several ) chemical(s ) may have been responsible for the reduced risk of a CUTA OBJECTIVE --To study the effect of periconceptional multivitamin supplementation on neural tube defects and other congenital abnormality entities . DESIGN --R and omised controlled trial of supplementation with multivitamins and trace elements . SETTING --Hungarian family planning programme . SUBJECTS--4156 pregnancies with known outcome and 3713 infants evaluated in the eighth month of life . INTERVENTIONS --A single tablet of a multivitamin including 0.8 mg of folic acid or trace elements supplement daily for at least one month before conception and at least two months after conception . MAIN OUTCOME MEASURES --Number of major and mild congenital abnormalities . RESULTS --The rate of all major congenital abnormalities was significantly lower in the group given vitamins than in the group given trace elements and this difference can not be explained totally by the significant reduction of neural tube defects . The rate of major congenital abnormalities other than neural tube defects and genetic syndromes was 9.0/1000 in pregnancies with known outcome in the vitamin group and 16.6/1000 in the trace element group ; relative risk 1.85 ( 95 % confidence interval 1.02 to 3.38 ) ; difference , 7.6/1000 . The rate of all major congenital abnormalities other than neural tube defects and genetic syndromes diagnosed up to the eighth month of life was 14.7/1000 informative pregnancies in the vitamin group and 28.3/1000 in the trace element group ; relative risk 1.95 ( 1.23 to 3.09 ) ; difference , 13.6/1000 . The rate of some congenital abnormalities was lower in the vitamin group than in the trace element group but the differences for each group of abnormalities were not significant . CONCLUSIONS --Periconceptional multivitamin supplementation can reduce not only the rate of neural tube defects but also the rate of other major non-genetic syndromatic congenital abnormalities . Further studies are needed to differentiate the chance effect and vitamin dependent effect The objective in the Hungarian r and omised double-blind controlled trial was to study the preventive effect of periconceptional multivitamin supplementation on  neural tube-defects and other congenital abnormalities .  There were 2,471 and 2,391 informative offspring ( prenatally diagnosed and terminated malformed fetuses , stillborn fetuses , and liveborn infants ) in the multivitamin and placebo-like trace element groups , respectively . A single tablet either of a multivitamin containing 0.8 mg of folic acid or trace element supplement was given daily for at least one month before conception and at least until the date of the second missed menstrual period . The total rate of major congenital abnormalities was 20.6/1,000 in the multivitamin and 40.6/1,000 in the trace element group . After the exclusion of six cases of neural-tube defects in the trace element group the difference was very highly significant [ P = 0.0003 ; relative risk of 0.54 ( 95 % CI 0.39 , 0.76 ) ] . Multivitamin supplementation appeared to result in a significant reduction in the rate of urinary tract abnormalities , mainly obstructive defects , and in the rate of sporadic cardiovascular malformations , mainly ventricular septal defects . This report is regarded as a hypothesis-generating study encouraging others to see if the result can be repeated OBJECTIVE The preventive efficacy of the periconceptional use of multivitamins is well established for neural tube defects , much less so for other birth defects . We conducted a population -based , case-control study to assess the effects of multivitamin use on the risk for conotruncal defects , a group of severe heart defects that includes transposition of the great arteries , tetralogy of Fallot , and truncus arteriosus . METHODS From the population -based Atlanta Birth Defects Case-Control Study , we identified 158 case infants with conotruncal defects and 3026 unaffected , r and omly chosen control infants , born from 1968 through 1980 to mothers residing in metropolitan Atlanta .  Periconceptional multivitamin use was defined as reported regular use from 3 months before conception through the third month of pregnancy . We present the results of the crude analysis , because the multivariate model yielded essentially identical results . RESULTS Mothers who reported periconceptional multivitamin use had a 43 % lower risk of having infants with conotruncal defects ( odds ratio [ OR ] , 0.57 ; 95 % confidence interval [ CI ] , 0.33 to 1.00 ) than did mothers who reported no use . The estimated relative risk was lowest for isolated conotruncal defects ( OR , 0.41 ; 95 % CI , 0.20 to 0.84 ) compared with those associated with noncardiac defects ( OR , 0.91 ; 95 % CI , 0.33 to 2.52 ) or a recognized syndrome ( OR , 1.82 ; 95 % CI , 0.31 to 10.67 ) . Among anatomic subgroups of defects , transposition of the great arteries showed the greatest reduction in risk ( OR , 0.36 ; 95 % CI , 0.15 to 0.89 ) . CONCLUSIONS Periconceptional multivitamin use is associated with a reduced risk for conotruncal defects . These findings could have major implication s for the prevention of these birth defects We investigated whether a woman 's periconceptional use of a multivitamin containing folic acid was associated with a reduced risk for delivering offspring with a conotruncal heart defect or a limb deficiency .  Data were derived from a population -based case-control study of fetuses and liveborn infants with conotruncal or limb defects among a 1987 - 88 cohort of births in California .  Telephone interviews were conducted with mothers of 207 ( 87.0 % of eligible ) conotruncal cases , 178 ( 82.0 % ) limb defect cases , and of 481 ( 76.2 % ) r and omly selected liveborn nonmalformed control infants . Reduced risks were observed for maternal use of multivitamins containing folic acid from one month before until two months after conception . Odds ratios and 95 % confidence intervals for any compared to no multivitamin use were 0.70 ( 0.46 - 1.1 ) for conotruncal defects and 0.64 ( 0.41 - 1.0 ) for limb defects . Controlling for maternal race/ethnicity , age , education , gravidity , alcohol use , and cigarette use result ed in a further reduction to the odds ratio for conotruncal defects , 0.53 ( 0.34 - 0.85 ) , but not for limb defects . Among non-vitamin using women , consumption of cereal containing folic acid was also associated with reduced risk for both defects . Women who take multivitamins have 30 - 35 % lower risk of delivering offspring with either conotruncal or limb defects . This association may not be attributable to folic acid specifically , but may be a consequence of other multivitamin components , or some unknown behaviors that highly correlate with regular use of a multivitamin . However , should the association prove causal , it offers an important opportunity for preventing thous and s of serious birth defects We studied the association between multivitamin use during the periconceptional period and the occurrence of  neural tube defects using data from the Atlanta Birth Defects Case-Control Study . There were 347 babies with neural tube defects who were live born or stillborn to residents of metropolitan Atlanta from 1968 through 1980 . The 2829 control-babies born without birth defects were r and omly selected through birth certificates .  Periconceptional multivitamin use was defined as reported use for each of the three months before conception through the first three months of pregnancy . Mothers who reported not using multivitamins any time during the six-month period were defined as nonusers . Fourteen percent of mothers reported periconceptional multivitamin use and 40 % reported nonuse .  Multivitamin users were different from nonusers in a number of demographic , health-related , and life-style characteristics . We found an overall apparent protective effect of periconceptional  multivitamin use on the occurrence of neural tube defects , with a crude estimated relative risk of 0.40 ( 95 % confidence interval , 0.25 to 0.63 ) . At this time , it is not possible to determine whether this apparently lower risk is the direct result of multivitamin use or the result of other characteristics of women who use multivitamins 
    Output:
    
BENEFITS , HARMS , AND COSTS The benefit is reduced lethal and severe morbidity birth defects and the harm is minimal .