The main purpose of the present study was to evaluate the effects of factors associated with spontaneous pre-term births so that the high risk woman could be identified before or at early stages of pregnancy. For this purpose, we have compared the measurements of 21 anthropometric traits and mean fluctuating asymmetry over 8 bilateral anthropometric traits, as well as age, occupation, education, previous obstetric history, complications during pregnancy, medicines received during and after pregnancy and some others in women who delivered babies of short (26-36 wk, n = 113 ind.) and normal gestational age (n = 103). Diseases and mean fluctuating asymmetry of eight morphological traits in the newborn infants themselves were also studied.
Both univariate and multivariate analyses were carried out and these were in agreement, showing a highly significant increase in the morbidity rate (especially of respiratory diseases) among pre-term infants and in complications during pregnancy in their mothers. Among other variables associated with the current pre-term birth were previous spontaneous pre-term births, suggesting their special risk value. The estimate of the sib correlation in gestational age on the liability scale was about 0.63. Spearman and Pearson correlations in gestational age for siblings were 0.34 and 0.31, respectively.