The effect on fetal growth of protozoan and helminthic infection during pregnancy.

This is a prospective study of 14,914 pregnant women conducted in Guatemala City, Guatemala. Stool samples were obtained from the studied patients before the first prenatal visit (mean gestational age 21.6 +/- 8.4 weeks) for the diagnosis of parasitic infections during pregnancy. Forty-four percent had at least one parasite detected, and 24% were infected with helminths. Ascaris lumbricoides was the most prevalent (14.5%). Infected mothers were less educated, had less adequate water and sanitary conditions, and had lower nutritional status. The incidence of intrauterine growth retardation (IUGR) increased with the number of parasitic species detected (up to two or more species, P less than .01). High levels of infection (greater than or equal to + +) were associated with an increased risk of IUGR for protozoa and helminths, except for Strongyloides stercoralis and Hymenolepis nana. Chronically malnourished women of short stature had significantly higher IUGR rates when infected with one or two or more species (P less than .01). Up to 10% of the IUGR rates may be attributed to parasitic infections among the malnourished women.