Jie Sheng

Prenatal phthalate exposure and placental size and shape at birth: A birth cohort study

Objective There is concern over the potential placental effects of prenatal phthalate exposure, and the potential adverse effects of prenatal phthalate exposure require further study; however, few data are available in humans. We investigated the associations between phthalate exposure in each trimester and both placental size and shape at birth. Methods We measured the urinary concentrations of phthalate metabolites among 2725 pregnant women in the Ma’anshan Birth Cohort. Before collecting urine samples from each of the three trimesters, the pregnant women were interviewed via questionnaires. Placental information was obtained from hospital records. We estimated the sex‐specific associations between urinary phthalate concentrations in each trimester and both placental size and shape at birth using adjusted multiple regression. A linear mixed model was used for the repeated measures analysis with subject‐specific random intercepts and slopes for gestational age at sample collection to test the effect of phthalate levels on placental size and shape and to estimate the effect sizes. Results Overall, placental breadth increased by 0.148 cm (95% CI: 0.078, 0.218) with each 1 ln‐concentration increase in MBP in the first trimester. The difference between placental length and breadth (length–breadth) decreased by 0.086 cm (95% CI: −0.159, −0.012) and 0.149 cm (95% CI: −0.221, −0.076) with each 1 ln‐concentration increase in MMP and MBP, respectively, in the first trimester. In the second trimester, placental thickness increased by 0.017 cm (95% CI: 0.006, 0.027), 0.020 cm (95% CI: 0.004, 0.036), 0.028 cm (95% CI: 0.007, 0.048), and 0.035 cm (95% CI: 0.018, 0.053) with each 1 ln‐concentration increase in MMP, MBP, MEOHP, and MEHHP, respectively. In the third trimester, placental thickness increased by 0.037 cm (95% CI: 0.019, 0.056) and 0.019 cm (95% CI: 0, 0.037) with each 1 ln‐concentration increase in MBP and MEHP, respectively. Multiple linear regression for each offspring sex indicated that prenatal phthalate exposure increased placental thickness in both the first and second trimesters in males, whereas the corresponding relationship was close to null in females. Linear mixed models (LMMs) yielded similar results. Conclusion Our results suggest the presence of associations between prenatal phthalate exposure and placental size and shape. Exposure to certain phthalates may cause the placenta to become thicker and more circular. Associations appeared stronger for the subsample representing male offspring than those for the subsample representing female offspring. Given the few studies on this topic, additional research is warranted. HighlightsThis study was a prospective cohort study with a large sample size.We evaluated the associations between throughout pregnancy phthalate exposure and placental size and shape.We assessed the urinary concentrations of seven phthalate metabolites among 2725 pregnant women.Prenatal phthalate exposure appeared to effect boys placental growth.

Effects of Prenatal Phthalate Exposure on Thyroid Hormone Concentrations Beginning at The Embryonic Stage

Limited studies have consistently shown an association of phthalates exposure with thyroid hormones (THs) in pregnant women. However, it remains unknown on which specific phthalates can affect THs and whether any effects could differ by gestational age. In the present study, we investigated associations between serum concentrations of phthalate monoesters [monoethyl phthalate (MEP), mono-(n + iso)-butyl phthalate (MBP) and mono(2-ethylhexyl) phthalate (MEHP)] and THs [thyroid-stimulating hormone (TSH), total thyroxine (TT4) and free thyroxine (FT4)] in Chinese pregnant women. 1,397 women were recruited from the China-Anhui Birth Cohort. Maternal serum samples were collected and used to measure phthalate metabolites and THs. Covariate-adjusted linear regression analyses showed that natural log (Ln)-transferred concentrations of MBP and LnMEHP were negatively associated with TT4 (β = −0.277 and –0.461, respectively; p < 0.001). Stratification analyses by gestational weeks showed significant associations of LnMBP and LnMEHP with TT4 in gestational weeks 5 to 8, 9 to 12, and 13 to 20. Our findings suggest an association of serum phthalates with lower TT4. The influence of MBP and MEHP on TT4 concentrations throughout the early pregnancy may begin from the embryonic stage (gestational weeks 5 to 8).

Urinary concentrations of phthalate metabolites in early pregnancy associated with clinical pregnancy loss in Chinese women

Limited evidence revealed conflicting results on relationship between phthalate exposure and clinical pregnancy loss (gestational weeks >6). A prospective cohort study in Chinese pregnant women (n = 3220) was conducted to investigate the association between urinary phthalate metabolites and clinical pregnancy loss (gestational weeks 6 to 27; n = 109). Morning urine samples during gestational weeks 5 to 14 (mean 10.42) were collected to measure monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono (2-ethylhexyl) phthalate (MEHP), mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP). The concentrations of low- and high-molecular weight phthalate metabolites (ΣLMWP <250 Da and ΣHMWP >250 Da) were calculated. Adjusted logistic regression models showed increased risks of clinical pregnancy loss in women with higher creatinine- normalized concentrations of MEP, MBP, MEOHP, MEHHP, ΣLMWP and ΣHMWP. Stratified analysis by gestational weeks (10 weeks) of miscarriage indicated positive associations of MEP, MEOHP, MEHHP and ΣHMWP with embryonic loss (during gestational weeks 6 to 10). The only association of foetal loss (during gestational weeks 11 to 27) was observed with MEHHP. Our findings suggested that Chinese women who were exposed to phthalates during early pregnancy had an increased risk of clinical pregnancy loss, especially embryonic loss.

Association between serum arsenic levels and gestational diabetes mellitus: A population-based birth cohort study

Gestational diabetes mellitus (GDM) is a common obstetric complication with adverse effects on both mothers and their children. Previous studies revealed the link between Arsenic (As) exposure and incidence of diabetes mellitus (DM), but the data on the association between maternal As exposure and GDM is scarce. We examined this association among a population-based birth cohort. As concentrations were determined at multiple time points during pregnancy by ICP-MS. The association between As levels and GDM prevalence was examined using logistic regression model after adjustment for confounders. A total of 419 (12.85%) women were diagnosed with GDM. The incidences of GDM gradually increased with increasing quartiles of As levels with significant trend. As levels were associated with the GDM (95%CI: 1.29-2.43) at only the 4th quartile in the first trimester. After adjustment for maternal age, prepregnancy body mass index (BMI), monthly income, gestational age and parity, the association remains significant (95%CI: 1.22-2.38). Stratified analyses showed the associations were largely limited to normal maternal age (95%CI: 1.19-3.04) and normal weight women (95%CI: 1.18-2.66). Our study showed an association between As and GDM in a birth cohort and explored first trimester may be the critical period for As associated GDM. This association was universal in the general pregnant population of normal age and of normal weight.

Thyroid autoantibodies in pregnancy are associated with hypertensive disorders of pregnancy: Ma'anshan Birth Cohort Study

Hypertensive disorders of pregnancy (HDP) have been associated with adverse health outcomes for both mothers and children. Previous studies examining associations of maternal thyroid autoantibodies with HDP indicate conflicting results. The objective of this study was to examine associations of maternal thyroid autoantibody positivity in the first and the second trimesters with the risk of HDP.

The impact of isolated maternal hypothyroxinaemia on the incidence of large‐for‐gestational‐age infants: the Ma'anshan Birth Cohort study

The purpose of this study was to investigate whether isolated maternal hypothyroxinaemia (IMH) is associated with risks of small/large‐for‐gestational‐age (SGA/LGA) infants.

Impact of maternal thyroid autoantibodies positivity on the risk of early term birth: Ma’anshan Birth Cohort Study

PurposeWe aim to investigate associations of maternal serum anti-thyroperoxidase autoantibody (TPOAb) with duration of gestation. We aim to investigate whether maternal TPOAb positivity is associated with the risk of premature or early term birth.MethodsThis was a prospective birth cohort study performed in an iodine sufficient area of China. Serum samples were collected from 2931 women at both the first and second trimesters of pregnancy. Thyrotropin (TSH), free thyroxine (FT4), and TPOAb levels were measured. Data on gestational age at birth was obtained from delivery records.ResultsThe prevalence of early term birth was 23.8%, while the prevalence of premature birth was 4.2%. The prevalence of TPOAb positivity was 12.1% in the first trimester and was 7.2% in the second trimester. Gestational age at birth was inversely associated with lgTPOAb both in the first trimester (β, −0.283, 95% CI −0.408, −0.158; P < 0.001) and in the second trimester (β, −0.174, 95% CI −0.319, −0.030; P = 0.018), after adjustment for potential confounding factors. There was a positive association of TPOAb positivity with the risk of early term birth both in the first (OR = 1.691, 95% CI 1.302, 2.197) and second trimesters (OR = 1.644, 95% CI 1.193, 2.264), after adjustment for potential confounding factors. TPOAb positivity in the second trimester was associated with a 1.863-fold higher risk of premature birth (OR = 1.863, 95% CI 1.009, 3.441), after adjustment for potential confounding factors.ConclusionsOur results show that TPOAb is associated with shorter duration of gestation and with higher risk of premature and early term birth.