Haplogroup-associated differences in neonatal death and incidence of low birth weight at elevation: a preliminary assessment.

Abstract

We sought to assess reproductive fitness differences between mitochondrial deoxyribonucleic acid haplogroups at high altitude. This study considers differences in outcomes of conception, birth weight, and neonatal mortality rates for 62 women classified according to haplogroups (B or non-B). The number of low-weight births (<2500 g) for the non-B group was significant (P =.019). Mothers in the non-B group reported more spontaneous abortions (P =.171) and stillbirths (P =.301). The difference in conceptions per woman between groups was significant (P =.036). However, no difference in infants alive at 1 month of age was evident. Neonatal death was significant (P =.017). The odds of an unsuccessful outcome among mothers in the B group was compared with mothers in the non-B group and was significant (P =.029). The chance of an adverse outcome, that is, fetal or infant death before 1 month, for mothers in the B group was between 11.1% and 88.7% lower than for mothers in the non-B group. The neonatal mortality rate for the non-B group was significantly elevated relative to the B group. The molecular basis for these observations is not clear.