| Objective:1. To explore environmental factors related with unexplained recurrent spontaneous abortion.2. To study the distribution of urinary BPA in both cases and controls, the differences of BPA concentration in different subgroups, and to further estimate relationship between BPA concentration and unexplained recurrent spontaneous abortion.Method:1.We conducted a hospital-based 1:2 matched case-control study in Suzhou City of Jiangsu Province, from October 2008 to December 2010. The case group was recruited from the First Affiliated Hospital of Soochow University, the Second Affiliated Hospital of Soochow University, Maternity and Child Care of Kunshan City. Cases were included whose abortion within one month after excluding chromosomal abnormalities, anatomical reproductive system abnormalities, endocrine disorders, reproductive tract infections and autoimmune diseases. Recurrent spontaneous abortion (RSA), traditionally has been defined as 3 consecutive times or more spontaneous abortions with the same partner before 20 weeks of gestation with birth weight of less than 500 grams. At present, this criterion has been extended to include the 2 consecutive times or more spontaneous abortions. Finally there were 69 eligible in all after diagnosed as unexplained recurrent spontaneous abortion. Each case was matched with two normal controls by±2 yrs in age, same living district and same gestational age. 132 controls were recruited after excluding the women who have borne the children with congenital malformation, stillbirth, low birth weight, premature birth and other adverse pregnancy outcomes. Each participant gave written informed consent before she was scheduled for an interview. A structured questionnaire was administered to collect data on demographic characteristics, menstrual history, pregnancy history, contraceptive history, disease history, treatment history, personal lifestyle, living environment, decoration, occupational and family history, etc.2. The morning specimens urine of 69 cases and 114 controls were collected using specially treated glass apparatus, and detected using high performance liquid chromatographic after fluorescent derivatization. 3.Multiple Conditional logistic regression and multiple classification logistic regression were to estimate the association of the relationship between menstrual history, pregnancy history, contraceptive history, disease history, treatment history, personal lifestyle, living environment, decoration, occupational history, family history and recurrent spontaneous abortion of undentified etiology by OR and 95%CI. SAS 9.13 software was conducted in all the analysis. A two-sided test P-value<0.05 was considered to be statistically significant.Results:1. It was found that the risk of RSA statistically increased (P= 0.0384 for trend test) with the extension time of noise exposure in original residence. Compared with none exposure group, noise exposure in current residence was associated with increased 5-time RSA risk (OR=5.88, 95%CI=1.13-30.50) after adjustment for potential confounding factors. The risk of RSA was shown the elevated tendency (P= 0.0102 for trend test) with the longer time of noise exposure in current residence. Women who exposed more than 60 minutes every day in current residence have an increased risk of RSA(OR=5.36, 95%CI=1.60-17.91). Compared with those who live in the rooms without decoration, women living in the decorated rooms using paint showed an elevated risk of RSA(OR=7.45, 95%CI=1.00-55.50). The subjects who exposed to the painting smell from the new furniture were associated with the increasing risk of RSA when compared with none-exposure group (OR=2.67, 95%CI=1.15-6.20). Passive smoking in pregnancy may be a risk factor of RSA(OR=2.17,95%CI=0.93-5.04,P =0.0728 ).2. Compared with no noise exposure in workplace before pregnancy, the OR of RSA of women exposed in noise was 2.40(95%CI=1.13-5.07). With increasing the intensity and time of noise exposure, the risk of RSA were increasing, there was a significant dose-response relationship between the intensity and time of noise exposure and risk of RSA.3. Compared with husband of none alcohol drinking, alcohol drinking husbands were associated with the increasing risk of RSA of their wives (OR=3.49, 95%CI=1.00-12.22). Husbands exposed to more electromagnetic radiation, toxic chemicals and others harmful factors during work were shown an elevating risk of RSA to their partners (P=0.0332 for trend test).Median values of non-creatinine-adjusted urinary BPA in cases and controls were 0.10μg/ml, 0.04μg/ml, respectively, which were transformed as 76.57μg/gCr and 22.64μg/gCr after being adjusted by creatinine levels. Adjusted BPA level was significantly higher in cases than in controls (Wilcoxon test, Z=3.529, P=0.0004). The risk of RSA was linked with the increased urinary BPA levels (P=0.0003 for trend test). After being adjusted by creatinine, significant differences for BPA level were found among controls, cases having experienced two abortions, and three or more abortions. BPA concentration were 20.87μg/g Cr, 65.40μg/g Cr, 96.75μg/g Cr, respectively (F=7.19, P=0.0010), but no significant differences between groups with two abortions, and three or more abortions.Conclusion:Our study showed that noise exposure in residence or in workplace, living in the rooms decorated with paint on the wall, paint smell from the newly brought furnitures, husband of drinking alcohol and occupational exposure to harmful hazards may be the risk factors of RSA. Exposure to BPA may be associated with RSA risk. |
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