Rat embryo culture to detect nutritional deficiency in women with poor reproductive histories.

The cause of habitual early pregnancy loss is not known for most affected couples. It has been proposed that a deficiency of amino acids or other nutrients may contribute to early embryo loss, and an assay based on culture of rat embryos in human serum has been proposed to evaluate women with poor reproductive histories. We tested this assay in women with unexplained infertility (n = 27), habitual abortion (n = 15), and normal midtrimester pregnancies (n = 10) by examining the ability of subject's serum to support the normal development of rat embryos in culture with and without supplemental vitamins and amino acids. Nonpregnant women with nutrient deficiencies identified in this manner were given oral supplements or placebo and were retested. A similar proportion of women in each group had serum that was unable to support the normal development of rat embryos without supplemental vitamins and amino acids. When oral supplements were used, most sera were able to support normal embryo growth. There were no seroconversions on placebo. In spite of the apparent success in producing seroconversions on oral supplementation, only two women conceived, one on the placebo treatment and one on nutritional supplements. Because serum nutrient deficiencies identified by rat embryo culture could not distinguish normal pregnant women from women with unexplained infertility or habitual abortion, and because of the low pregnancy rates, we could not confirm the utility of this assay for the general population of women with habitual abortion.(ABSTRACT TRUNCATED AT 250 WORDS)