The Associations Between Maternal Exposure To Organophosphate Pesticide During Early Pregnancy And Fetal Development.

Objectives:To investigate the associations between the urinary levels of organophosphate pesticide(OP)metabolites in early pregnant women and spontaneous abortion or embryonic chromosomal aberration.To explore the effects of maternal exposure to OPs during early pregnancy on fetal development.The aim of this study is to provide a scientific basis for preventing the effects of OPs on fetal development and birth defects.Part One:The associations between maternal exposure to organophosphate pesticides during early pregnancy and spontaneous abortion Methods:A population-based 1:2 matched case-control study was used to recruit 227patients with clinically diagnosed spontaneous abortion in early pregnancy from a local comprehensive hospital.A total of 454 early pregnant women who took a prenatal examination in the hospital during the same period were selected as controls with age(±2 years)for the matching conditions.Assessment of exposure to OPs was based on self-reported pesticide use and analysis of urinary OP metabolites.And other potential factors associated with spontaneous abortion were also investigated.Serum homocysteine and urinary nonspecific OP metabolites dialkylphosphate(DAP)in pregnant women were detected using high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)?including:dimethyl phosphate(DMP),diethyl phosphate(DEP),dimethyl thiophosphate(DMTP).dimethyl dithiophosphate(DMDTP),and diethyl dithiophosphate(DEDTP).The urinary concentration of creatinine was detected by alkaline picric acid method(the Jaffe method).The urinary concentrations of OP metabolites were adjusted based on creatinine levels.And the creatinine-adjusted OP metabolite concentrations were log-transformed for statistical analysis.SPSS was used for data analysis,and the associations between the urinary levels of OP metabolites in pregnant women and spontaneous abortion were analyzed by conditional logistic regression models.Results:The mean age of pregnant women was 30.65 ± 4.59 years in the case group and 30.44± 4.49 years in the control group.There was no significant difference in the mean age of pregnant women between the two groups,P=0.573.The majority of urine samples from the pregnant women(98.7%in case group and 99.1%in control group)contained one or more OP metabolites.The results of univariate analysis showed that the detection frequencies of DMP.DEP,DMTP,DMDTP and DEDTP in the urine of pregnant women in the case group were 97.4%,62.6%,70.5%,14.5%and 76.2%,respectively.And the detection frequencies of these metabolites in the control group were 97.8%,67.8%,46.7%.13.5%and 60.7%,respectively.The detection frequencies of urinary DMTP and DEDTP in the case group was higher than that in the control group(P<0.05).The median levels of DMP,DEP,DMTP,DMDTP,DEDTP and total DAP in the urine of the case group were 0.54,0.08,0.93,0.03,0.90 and 3.24(ng/mg),respectively.And the median concentrations of these 5 metabolites and total DAP in the control group were 0.71,0.07,0.72,0.04,0.66,and 2.76(ng/mg),respectively.The average level of DMTP,DEDTP and total DAP in the case group was higher than that in the control group,but the average concentration of DMP was lower than that in the control group(P<0.05).In addition,the pregnant women and/or their husband in the case group were more frequently exposed to other environmental factors than those in the control group,such as repellent,pesticide,paint,noise,radiation,plasticizer,and polycyclic aromatic hydrocarbons(PAHs).And the rate of multiple pregnancies,induced abortion and adverse pregnancy history was higher in the case group than that in the control group.However,the proportion of pregnant women taking folic acid,multiple nutrients,and calcium in the case group was lower than that in the control group.The average level of serum homocysteine in the case group was higher than that in the control group.The differences between the two groups were statistically significant(P<0.05).The results of conditional logistic regression analysis showed that the detection of DMTP in women's urine increased the risk of spontaneous abortion(OR=2.62.95%CI 1.40?4.91),after adjusting for potential factors.Increased urinary level of DMTP or decreased urinary level of DMP were associated with spontaneous abortion.Exposure to high concentrations of DMTP(above 75%percentile)significantly increased the risk of spontaneous abortion(OR=2.72.95%CI 1.31?5.66).However,exposure to high levels of DMP(above 75%percentile)reduced the risk of spontaneous abortion(OR=0.46.95%CI 0.23?0.93).Part Two:The associations between maternal exposure to organophosphate pesticides during early pregnancy and chromosomal aberrations in embryosMethods:A population-based 1:4 matched case-control study was used to collect 160 cases of spontaneous abortion tissues during early pregnancy.Karyotype BACs-on-Beads(BoBs)technology combined with fluorescence in situ hybridization(FISH)technology were used to analyze the karyotype of aborted embryos.The women with embryonic chromosome aberrations(100 cases)were identified as the case group.Of these,women were excluded because of the embryo chromosomal aberration was caused by a balanced translocation of the parent chromosomes(n=1),lost to follow-up(no parental peripheral blood was collected for verification,n=9),or without urine samples(n=2).The final sample included in the analysis were 88 women.A total of 352 early pregnant women who took a prenatal examination in the hospital during the same period were selected as controls with age(± 2 years)for the matching conditions.Conditional logistic regression models were used to analyze the associations between the urinary levels of OP metabolites in early pregnant women and the chromosomal aberrations in embryos.Results:The mean age of pregnant women was 31.30±4.94 years in the case group and 31.13 ± 4.52 years in the control group.There was no significant difference in the mean age of pregnant women between the two groups.P=0.519.The results of univariate analysis showed that the detection frequencies of urinary DMTP and DEDTP in the case group was significantly higher than that in the control group,and the average level of DMTP?DEDTP and total DAP in the case group was significantly higher than that in the control group,P<0.05.In addition,the pregnant women and/or their husband in the case group were more frequently exposed to repellent and pesticide than those in the control group.And the rate of multiple pregnancies and adverse pregnancy history was higher in the case group than that in the control group.However,the proportion of pregnant women taking folic acid in the case group was lower than that in the control group.The average level of serum homocysteine in the case group was significantly higher than that in the control group(P<0.05).The results of conditional logistic regression analysis showed that the detection of DMTP in women's urine increased the risk of chromosomal aberrations in embryos(OR=4.07,95%CI 1.53?10.83),after adjusting for potential factors.Urinary levels of DMTP were positively associated with the risk of embryo chromosomal aberrations(OR = 6.91,95%CI 1.19?39.96).Part Three:Effects of maternal exposure to organophosphorus pesticide during early pregnancy on fetal birth outcomesMethods:A birth cohort study was established to recruit early pregnant woman who took a prenatal examination.All recruited subjects were followed up to the end of this pregnancy.The birth outcomes of the fetuses(including birth weight,birth length,gestational age,or stillbirth/fetal death),and the pregnancy-related disease of the pregnant women were obtained from medical records.Congenital malformations or chromosomal aberrations were diagnosed by professionals in the hospital.Multiple linear regressions were used to analyze the correlations between the levels of OP metabolites in the urine of pregnant women and the fetal birth outcome.And multiple logistic regression models were used to analyze the effects of OPs exposure during early pregnancy on adverse birth outcomes(including premature birth,low birth weight and small for gestational age).Results:A total of 447 fetal birth outcomes were followed up,including 433 live births,4 stillbirths/fetal deaths,2 spontaneous abortions,4 congenital malformations,and 4 chromosomal aberrations.The average birth weight of live births was 3162.24±424.67 grams,the average birth length was 50.00±1.95 cm,and the average gestational age was 38.87 ± 1.49 weeks.Among them,6.5%(n=28)were premature birth,3.9%(n= 1 7)were low birth weight,and 7.6%(n=33)were small for gestational age.Analysis of factors related to OP exposure showed that women who used pesticides or often ate watermelon had a higher level of some OP metabolites.The urinary levels of OP metabolites were relatively higher in women who were multiparous or had a history of adverse pregnancy.Pregnant women who cooked meals every day,washed fruits and vegetables with soda/hot water,or often ate apples had a lower level of some OP metabolite in their urine.P<0.05.Analysis of factors related to fetal birth outcomes showed that the urinary levels of DMTP or DEP were lower in pregnant women with preterm delivery,LBW or SGA.The maternal levels of homocysteine in blood were positively associated with the fetal gestational age at birth.The results of multiple linear regression analyses showed that the urinary DMTP levels in pregnant women was positively correlated with the fetal birth weight(adjusted ?=184.3,95%CI 28.2?340.4).The results of multiple logistic regression analyses showed that the risk of LBW increased as the urinary level of DEDTP increased,the adjusted ORs were 4.7(95%CI 1.3?17.3).However,the risk of LBW and premature birth decreased as the urinary level of DMTP increased,the adjusted ORs were 0.02(95%CI 0.001?0.2)and 0.06(95%CI 0.01?0.5),respectively.In addition,the risks of adverse birth outcomes were higner in women who were older or multiparous,and in women with adverse pregnancy history,premature rupture of membranes,or hypertensive disorders during pregnancy,and in women who exposed to PAHs,mosquito repellent,paint,and noise before and after pregnancy.Conclusions:Pregnant women in this study were ubiquitously exposed to low levels of OPs.Maternal exposure to OPs during early pregnancy may increase the risk of fetal chromosomal aberrations and spontaneous abortion.Maternal exposures to different types of OPs may have different effects on fetal development.Exposure to some high toxic OPs,such as phorate,terbufos,which can be converted into DEDTP,increased the risk of fetal intrauterine growth restriction.In addition,early pregnancy BMI,supplementation of multiple nutrients,and serum homocysteine levels were positively correlated with fetal birth weight,birth length,or gestational age.Maternal age,multiparous,adverse pregnancy history,pregnancy-related diseases,and exposure to environmental factors(such as repellents,PAHs,paint,noise)were negatively associated with fetal birth weight,birth length,and/or gestational age.