Conditions at conception in women with recurrent miscarriage

In order to evaluate the role of conditions at conception in the risk of miscarriage, we sent 234 women with at least two consecutive miscarriages after conceptions from the same partner a short questionnaire asking for the birth dates of their mothers and their live or stillborn siblings and the occurrence of any maternal miscarriages. Complete information was provided by 186 respondents. Using matched logistic regression, we investigated whether these women were born more often than their siblings (total n = 578) to young (< or = 19 years) or relatively old (> or = 40 years) mothers or shortly after a preceding pregnancy (born within 1 year). We also evaluated whether they showed a different month-of-birth distribution. No increased odds ratios were found for young or advanced maternal age, or for short preceding birth intervals. However, relative to their siblings, cases showed a deviant month-of-birth distribution (p = 0.08) with a peak in (late) winter. These results indicate that low and high maternal age and short preceding birth intervals are not determinants of the risk of miscarriage in the daughter. They also suggest that there may be seasonally varying factors that prenatally influence the risk of miscarriage.