Birth weight before and after a spontaneous abortion.

A survey of pregnancies occurring in 3502 women doctors provided an opportunity to examine the relationship between early fetal loss and birth weight. This was found to be complex. The most important observations were that the mean birth weight of babies preceding a spontaneous fetal loss was lower than that of livebirths preceding another livebirth, and that in the subgroup of women with repeated early losses, mean birth weight fell with increasing pregnancy order. In contrast, mean birth weight of the first livebirth following a single spontaneous abortion was higher, though not significantly, than that of livebirths in the first pregnancy.