the soil - transmitted helminthiases are ancient diseases that 
 continue to cause misery and disability in poor populations . about 2 billion harbor these 
 infections worldwide , of whom 300 million suffer 
 associated severe morbidity . of the total number infected , an 
 estimated 400 millions are school - age children . in 1999 , world 
 health organization ( who ) estimated that schistosomiasis and 
 soil - transmitted helminthiasis represented more than 40% of the 
 disease burden due to all tropical diseases , excluding malaria 
 . tropical diseases such as malaria , schistosomiasis , intestinal 
 helminths , and filariasis have a dramatic impact on reproductive 
 health . many cases of unexplained pregnancy loss are due to 
 undiagnosed tropical diseases . malnutrition or anemia caused by 
 intestinal worms may be worsened by pregnancy and make the 
 pregnancy difficult . in the developing world , young women , pregnant women , and their 
 infants and children frequently experience a cycle , where 
 undernutrition ( macronutrient and micronutrient ) and repeated 
 infection , including parasitic infections , lead to adverse 
 consequences that can continue from one generation to the next . 
 among parasitic infections , malaria and intestinal helminths coexist widely with micronutrient deficiencies and contribute 
 importantly to anemia and this cycle of retarded growth and 
 development . in somewhat more limited or focal geographic 
 settings , other parasitic diseases ( eg , schistosomiasis , 
 filariasis ) it is undoubtedly 
 much better to enter a pregnancy free of infection and 
 nutritionally replete than the various alternatives . intestinal parasitic infections , especially due to the helminths , 
 increase anemia in pregnant women [ 26 ] . additionally , hookworm infections induce deficiencies of iron , total energy , 
 protein , and possible folate and zinc [ 4 , 7 ] . the results of this are low pregnancy weight gain and intrauterine growth 
 retardation ( iugr ) , followed by low birth weight ( lbw ) , with its 
 associated greater risks of infection and higher perinatal 
 mortality rates ; this has been reported in the majority of 
 studies , although a causal link remains to be completely proven 
 [ 79 ] . for these reasons , in the setting of no large previous studies in 
 venezuela about this problem , a national multicentric study was 
 conducted with the objectives to describe preliminarily the 
 epidemiological importance of intestinal parasitosis in pregnant 
 women and its possible impacts . the study was a transversal analysis of pregnant women attending 
 to prenatal control outpatient health care centers in venezuela . pregnant women from fifteen centers located in semi - urban and 
 rural areas of nine states in the country were studied during the 
 period january 2003july 2004 . all women accepted to be studied 
 and included in this study . women with previous diagnosis of 
 infectious diseases as hiv / aids , hbv infection , syphilis , or 
 toxoplasmosis were not enrolled . evaluation of those women included , as a part of their routine 
 prenatal control , an initial interrogation , physical examination , 
 and laboratory studies : count of blood cells ( cbc ) ( including 
 thick and thin films , stained with giemsa ) , serological screening 
 studies for hiv-1 and -2 ( elisa ) , hbv ( hbsag and igm anti - hbc ) , 
 vdrl , and fta - abs , and toxoplasmosis ( antibody titers by dat ) . for 
 this study , we considered as normal levels of hb in women those 
 between 1216  g / dl , and between 3748% for the hematocrit . isolation of enteric 
 bacterial and viral pathogens was not studied in these samples . different stool examinations were used for efficacy in detecting 
 parasites . these were direct wet - mount , formaldehyde - ether 
 sedimentation method and modified acid - fast staining techniques 
 [ 10 , 11 ] . the who guide for diagnosis of intestinal 
 parasitosis ( 1994 ) was used as an identification reference 
 . all data were collected with a unique structured 
 questionnaire , and then this information was integrated after being sent 
 by electronic mail to a central database . univariated and multivariated analyses were made to determinate 
 risk factors for intestinal parasitosis and related anemia . differences concerning paraclinical parameters were evaluated 
 using the fisher exact test and the chi - squared test . all tests 
 were two - sided with differences considered significant at p < .05 . the mean gestational age at enrollment moment 
 was 28.5  4.0 weeks ( 60% was on the 3rd trimester ) . at clinical evaluations , all 
 serological studies were negative in all women ( hiv , hbv , vdrl , toxoplasmosis ) . the mean hemoglobin levels were 10.3  4.0  g / dl , mean hematocrit was 30.6  1.8% . intestinal parasitosis was seen in 767 women ( 73.9% ) . from this 
 total , 360 ( 46.9 % ) presented infections due to two 
 simultaneous intestinal parasite species , 84 ( 10.9 % ) with 
 three intestinal parasite species , and only 2 women presented 
 infections due to more than three intestinal parasite species ( 0.3 
 % ) . in this studied group of women , ten different species of 
 intestinal parasites were found , 2 nonpathogenic protozoans , 3 
 pathogenic protozoans , and 5 helminths species 
 ( table 1 ) . ascaris lumbricoides was the most 
 common parasite and helminth identified in this study ( 57.0 % ) 
 followed by trichuris trichiura ( 36.0 % ) . from those 
 women with dual infection ( 360 ) , univariated and multivariated analyses made to assess risk factors 
 for intestinal parasitosis and related anemia only found 
 significance for the presence of intestinal parasitosis as a risk 
 to have anemia during pregnancy , relative risk ( rr ) was 2.56 
 ( 95%ci 2.133.08 ) ( table 2 ) . when this was 
 adjusted for helminth infection , rr = 1.56 ( 95%ci 1.431.69 ) , 
 and for protozoan infection , rr = 1.49 ( 95%ci 1.381.61 ) . 
 additionally relative risk was adjusted for helminth species ; for 
 a. lumbricoides , rr = 2.01 ( 95%ci 1.832.20 ) ; 
 trichiura , rr = 1.18 ( 95%ci 1.081.30 ) ; 
 necator americanus , rr = 1.23 ( 95%ci 1.071.41 ) . 
 finally , relative risk was also adjusted for dual helminth 
 infections and those due to a lumbricoides and t 
 trichiura , rr = 1.99 ( 95%ci 1.832.15 ) and rr = 1.60 ( 95%ci 1.511.70 ) , respectively ( table 2 ) . finally when compared , levels of hemoglobin , hematocrit , and 
 eosinophils count were significantly different between those 
 women with intestinal parasitic infections ( table 3 ) . 
 with the eosinophilia , we found significance for its presence as 
 marker to be diagnosed as to have intestinal parasitosis during 
 pregnancy ( 27.6% in infected women , 7% in noninfected women ) , 
 rr was 1.33 ( 95%ci 1.261.42 ; yates   = 48.07 , 
 p < .0001 ) . the burden of disease imposed on helminth - infected 
 girls and women in childbearing age , especially when pregnant , may 
 very well define the single most important contribution of 
 intestinal parasitic infections to the calculation of their global 
 disease burden . pregnancy requires extra nutrients , especially 
 iron , and produces a  physiological anemia  due to hemodilution 
 [ 13 , 14 ] . the anemia results in both decreased appetite and lowered aerobic and physical work capacity , even without the added 
 weight gain to transport  and this is in girls and women who , in 
 the tropics , must often carry their youngest child and the 
 household water supply long distances and also manage to till 
 their fields daily without mechanized equipment . the total amount 
 of work a woman can do in a day definitely decreases when she is 
 anemic , whatever the cause is , and pregnancy plus helminth 
 infections produce a double burden for women in some rural farming 
 communities . women may even acquire helminth infections 
 in the process of growing the family 's food and thus increase 
 their degree of anemia in pregnancy , as for example , in vietnam , 
 where insufficiently composted human feces may be used as 
 fertilizer on vegetable crops . in this study , where more than a thousand young asymptomatic pregnant 
 women were evaluated , we observed a high prevalence of intestinal 
 parasitosis ( more than 70% ) , higher than those previously reported for pregnant    women in congo ( 9% ) , nigeria 
 ( 12.5% ) , mexico ( 38.2% ) , brazil ( sao paulo state , 45.1% ; rio de janeiro state , 69.2% ) 
 [ 17 , 18 ] , and indonesia ( 69.7% ) . although current 
 evaluated women were transversally analyzed and more than 65% 
 had anemia , those with anemia corresponded mainly to infected 
 women ( more than 80% of those with anemia ) . almost the half of 
 infected women presented mixed infections , due to two different 
 parasite species which represented a significant risk to have 
 anemia , almost twice than those women who did not . but the most 
 important risk factor to be found with anemia in pregnancy at this 
 series was to be simply presented an intestinal parasitic 
 infection at pregnancy ( rr = 2.56 ) , independently if this was due 
 helminths or protozoans . species adjusted analysis showed that for 
 this study the most important parasite representing a risk to be 
 found with anemia at pregnancy was a lumbricoides ( rr = 2.01 ) ; the risk of anemia has been frequently reported for n americanus , ancylostoma duodenale , t 
 trichiura , strongyloides stercoralis and 
 enterobius vermicularis [ 7 , 19 , 20 ] , but rarely for a lumbricoides , which may cause intestinal obstruction , liver abscess , local irritation , and damage with 
 malabsorption as main cellular related events associated with the 
 infection [ 21 , 22 ] ; a lumbricoides plays an important role in precipitating protein - energy malnutrition in 
 undernourished children , this infectious disease is a 
 form of malnutrition . those women infected presented not 
 just a higher frequency of anemia but also significant lower 
 levels of hemoglobin and hematocrit and , obviously , higher levels 
 of eosinophilia . this last , at least in this series , evidenced to 
 be a diagnostic marker for intestinal parasitosis , and with it , 
 this type of infection in pregnant women at endemic zones could be 
 suspected , even if a stool screening is negative ( which should be 
 repeated at least 3 consecutive times ) . intestinal parasites 
 ( especially helminths ) can be tissue dwelling or intestinal but 
 all induce a dramatic expansion of the th2 lymphocyte subset 
 [ 24 , 25 ] . it remains unclear whether these th2-derived 
 responses , including ige , eosinophilia , and mastocytosis are 
 important in the protective immune response to the parasite , or 
 are responsible for immune - mediated pathology , or both , 
 but at least is a paraclinical marker of infection . given these results , the importance and potential 
 impacts of intestinal parasitosis at pregnancy , such as the 
 anemia , are quietly obvious . independently to etiology , 
 parasitoses are associated with conditions for development of 
 anemia at pregnancy . this indicates the need for 
 periodical stool examinations during pregnancy as part of routine 
 laboratory test in the prenatal control of women . considering 
 this , systematic screening and treatment of anemia and associated 
 factors such as intestinal helminthiasis and protozoasis is needed 
 for the pregnant women population , as has been established in 
 other countries , to significantly improve the health of 
 mothers and children , because it is undoubtedly much better to 
 enter a pregnancy free of infection and nutritionally replete than 
 the various alternatives . existing intervention strategies for 
 micronutrient support and for the control of common 
 parasitic infections before or during pregnancy , 
 particularly   intestinal parasitosis , should be followed . however , further research to identify barriers and priority 
 approaches to achieving this goal remain very important in 
 resource - poor settings , where targeted public health efforts are 
 required . as has been stated in other studies , it is necessary to modify 
 some preventive measures of information and education and to give 
 specific treatment before the pregnancy in order to increase some 
 of the pregnant women 's health indicators . the newborn of mothers 
 with intestinal parasitosis have a greater probability of being 
 born with less weight than what is expected , although we 
 did not evaluate this issue on the current study . these results enhanced the need for wide implementation of 
 intermittent iron and folic acid supplementation as a valid 
 strategy when used as a preventive intervention in prenatal care 
 settings . but that antihelminthic therapy could be given 
 to infected women before conception as public health strategy to 
 improve iron status may be also considered . additionally once 
 diagnosed , if the woman is on the second or third gestation 
 trimester , it could be treated . in the current study , all women in 
 this condition were treated with mebendazol 500  mg after first 
 trimester , as has been recommend by some authors who consider a 
 possible national strategy for prevention and control is to give a 
 single dose of this drug during the second or third gestation 
 trimesters . the current study reflects the need of routine coproparasitological 
 study among pregnant women in rural and endemic zones for 
 intestinal parasites . additional research on pregnant 
 intestinal parasitic infection impact on newborn health is 
 on - going . parasite positivity in stool specimens examined from 
 pregnant women studied . relative risk for anemia at pregnancy according to the presence of 
 intestinal parasitosis . comparisons between levels of hematological laboratory variables in 
 those women with or without intestinal parasitosis ( mean  sd ) .
introduction . intestinal parasitic infections , especially 
 due to helminths , increase anemia in pregnant women . 
 the results 
 of this are low pregnancy weight gain and iugr , followed by lbw , 
 with its associated greater risks of infection and higher 
 perinatal mortality rates . for these reasons , in the setting of no 
 large previous studies in venezuela about this problem , a national 
 multicentric study was conducted 
 . methods . 
 pregnant women 
 from nine states were studied , a prenatal evaluation with a 
 coproparasitological study . 
 univariated and multivariated analyses 
 were made to determine risk factors for intestinal parasitosis 
 and related anemia . results . during 19 months , 
 1038 
 pregnant women were included and evaluated . 
 intestinal parasitosis 
 was evidenced in 73.9% : a lumbricoides 57.0% , 
 t trichiura 36.0% , g lamblia 14.1% , 
 e hystolitica 12.0% , n americanus 8.1% , 
 e vermicularis 6.3% , s stercoralis 3.3% . 
 relative risk for anemia in 
 those women with intestinal parasitosis was 2.56 ( p < .01 ) . 
 discussion . 
 intestinal parasitoses could be associated 
 with conditions for development of anemia at pregnancy . 
 these 
 features reflect the need of routine coproparasitological study 
 among pregnant women in rural and endemic zones for intestinal 
 parasites . 
 further therapeutic and prophylactic protocols are 
 needed . 
 additional research on pregnant intestinal parasitic 
 infection impact on newborn health is also considered .