title: Prenatal effects of maternal-fetal HLA compatibility.
abstract: Both retrospective studies of idiopathic aborters, as well as prospective studies of normal couples, have shown reduced fertility among couples sharing HLA antigens. However, the effects of maternal-fetal histocompatibility on surviving embryos are largely univestigated. We thus prospectively studied 53 healthy, fertile women whose timed pregnancies were verified within 21 days of conception. Maternal-fetal histocompatibility status was determined for HLA-A,-B, and -DR locus antigens. Fetal growth rates were monitored by ultrasound at 8, 12, and 20 weeks gestation. Neonates were weighed, measured (birthlength, chest circumference, head circumference), and examined within 72 h of delivery (116 major and minor anomalies) in standardized fashion by one of two geneticists. Although no significant differences were found between infants compatible and incompatible at the HLA-A or HLA-B locus, significant differences were observed between HLA-DR compatible and incompatible infants for sex ratios (p less than .003) and minor anomaly rates (p less than .05). Although differences in mean birthweights between HLA-DR compatible and incompatible infants were not significant in this sample, HLA-DR compatible infants were on average 200 grams smaller than HLA-DR incompatible infants. We interpret these findings as evidence for selection against histocompatible fetuses throughout gestation, particularly with respect to HLA-DR compatibility. Potential immunologic and genetic mechanisms are discussed.
mesh_terms: D000328:Adult; D005314:Embryonic and Fetal Development; D005260:Female; D006680:HLA Antigens / Q000032:analysis* / Q000235:genetics; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens / Q000032:analysis / Q000235:genetics; D006648:Histocompatibility; D006801:Humans; D007231:Infant, Newborn / Q000276:immunology*; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011446:Prospective Studies; D012737:Sex Factors
chemical_list: D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens; D006684:HLA-DR Antigens