Over one-quarter of miscarriages may be preventable, according to the results of a study published in BJOG: An International Journal of Obstetrics and Gynaecology.
A nationwide study used data from 91,427 pregnancies included in the Danish National Birth Cohort, between 1996 and 2002, to identify the modifiable risk factors for miscarriage and to estimate the preventable proportion of miscarriages which could be attributed to these factors.
Miscarriage in Denmark is defined as a fetal death and/or expulsion before 22 completed weeks of gestation. Of the 91,427 pregnancies examined in this study, 3,177 resulted in miscarriage. Information on lifestyle was collected by computer-assisted telephone interviews.
The study examines nine potentially modifiable risk factors for miscarriage using the Cox regression model to provide the estimations. The risk factors include; amount of exercise, alcohol consumption, smoking, coffee consumption, work schedule, lifting of more than 20 kilograms daily, maternal age at conception, pre-pregnancy weight status and previously diagnosed genital diseases.
The results show that the potentially modifiable risk factors associated with increased miscarriage risk include; age of 30 years or more at conception, underweight or obese prepregnancy, alcohol consumption during pregnancy, lifting of more than 20 kilograms daily and night work during the antenatal period.
The study estimates that 25.2% of the miscarriages might be prevented by reduction of all the associated risk factors to low levels, and modification of risk factors acting before and during pregnancy could lead to prevention of 14.7% and 12.5% of the miscarriages respectively.
The survey concludes that maternal age at conception and alcohol consumption during pregnancy were the most important risk factors. It estimated that 11.4% of miscarriages may be prevented if maternal age at conception is between 25 and 29 years, and 9% of miscarriages could be prevented if no alcohol was consumed during pregnancy.
