Background
The incidence rate of missed abortion is increasing year by year, but the etiology has not been fully elucidated. Adverse pregnancy history and exposure to polycyclic aromatic hydrocarbons (PAHs) may increase the risk of missed abortion.
Objective
To investigate the interaction between adverse pregnancy history and PAHs exposure on missed abortion in early pregnancy, and to provide evidence for the etiologic research of missed abortion.
Methods
A total of 114 pregnant women diagnosed with missed abortion in the Department of Obstetrics of the First Hospital of Shanxi Medical University from March to December 2019 were selected as the case group, and 139 pregnant women who visited the same hospital for voluntary induced abortion in the same period as the control group, to collect basic information and medical information of abortion, stillbirth, intrauterine growth retardation, and other adverse pregnancy history. Abortion villus tissues were collected to detect PAH-DNA adducts levels, stratified by pregnancy and adverse pregnancy history and grouped by quartile method: Q1 (< 404.61 ng·L−1), Q2 (404.61−453.75 ng·L−1), Q3 (453.76−506.72 ng·L−1), and Q4 (≥506.73 ng·L−1). SPSS 25.0 statistical software was used for χ2 test and multiple logistic regression, and additive and multiplicative models were used to investigate the interaction between adverse pregnancy history and PAH-DNA adducts level on missed abortion. The PAH-DNA adducts were grouped by tertiles and quartiles, and P33, P50, P67 andP75 were used as data cut points for sensitivity analysis.
Results
The proportion of adverse pregnancy history in the case group (32.46%) was higher than that in the control group (12.23%) (P < 0.001). Among 160 subjects with≥2 pregnancies, the proportion of adverse pregnancy history in the case group (57.81%) was higher than that in the control group (17.71%) ( P < 0.001). The results of χ2 test stratified by pregnancy for different PAH-DNA adducts levels between the two groups showed that the PAH-DNA adducts level was associated with missed abortion in subjects with≥2 pregnancies (χ2=10.14, P=0.017). Being further stratified by adverse pregnancy history, the PAH-DNA adducts level in subjects with no adverse pregnancy history was associated with missed abortion (χ2=9.70, P=0.021). The results of logistic regression analysis showed that adverse pregnancy history (OR=5.88, 95%CI: 2.79−12.39) and PAH-DNA adducts (OR=3.01, 95%CI: 1.22−7.40) increased the risk of missed abortion, but no interaction between them was found. The relative excess risk of interaction (RERI), the attributable percentage of interaction (AP), and the synergy index (SI) and its 95%CI were 0.60 (95%CI: −0.58−1.77), 0.74 (95%CI: −0.83−2.30), and 0.20 (95%CI: 0.01−5.43), respectively.
Conclusions
Adverse pregnancy history and PAH-DNA adducts in pregnant women may increase the risk of missed abortion. The effect of the interaction between them on the occurrence of missed abortion is not supported by the current study.
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