Table IV. Maternal KIR2DS1 significantly increases birth weight when the fetus has more HLA-C2 epitopes than the mother: categorical analysis
SubjectsMaternal KIR2DS1 GenotypeMedian Birth Weight (6–89th Centile) (%)High Birth Weight (>89th Centile) (%)Effect of KIR2DS1 on Birth Weight
OR95% CIp Value
Less C2 in fetus than mother (n = 280)Positiven = 76 (35.3)n = 25 (38.5)1.250.702.260.45
Negativen = 139 (64.7)n = 40 (61.5)
Equal C2 in fetus and mother (n = 725)Positiven = 215 (39.6)n = 75 (41.2)1.100.781.550.59
Negativen = 328 (60.4)n = 107 (58.8)
More C2 in fetus than mother (n = 304)Positiven = 95 (40.8)n = 47 (66.2)2.931.665.180.0002
Negativen = 138 (59.2)n = 24 (33.8)
  • Presence versus absence of KIR2DS1 was tested for effect on birth weight as a categorical variable by logistic regression. United Kingdom and Norway cohorts were combined and then analyzed in groups defined by combinations of maternal and fetal HLA-C type (Table III). Cohort and sex of the baby were included as covariates.

  • CI, confidence interval; n, number of pregnancies.