GC-MS/MS Links Prenatal Phthalates to Fetal Growth

Researchers examining whether exposure to plasticiser chemicals during the first three months of pregnancy affects how a baby grows in the womb, and whether stress experienced by the mother during this same period plays any role in that relationship, quantified urinary concentrations of nine phthalate (PAE) using gas chromatography-tandem mass spectrometry (GC-MS/MS). A paper based on their work was published in the International Journal of Hygiene and Environmental Health.¹

Why Might Plasticiser Chemicals and Maternal Stress Be a Concern During Pregnancy?

Phthalates are a group of chemicals commonly found in the environment that can interfere with the body's hormonal system. They have been detected in amniotic fluid, umbilical cord blood, and newborn urine, meaning they are able to pass through the placenta and reach the developing baby.^2-4Research suggests that exposure to these chemicals during pregnancy can have a harmful effect on how the baby grows and develops. ^5-8At the same time, pregnancy is often a period of heightened stress for many women, whether from work pressures, social situations, or other personal challenges. Research has shown that high levels of stress during pregnancy can also have a negative impact on how a baby grows and develops.^9,10

Does Exposure to Plasticiser Chemicals During the First Trimester Affect Fetal Growth, and Does Maternal Stress Play a Role in this Relationship?

The study followed 704 pregnant women during their first trimester. Baby growth was tracked using ultrasound scans, measuring various dimensions including head size, belly size, leg bone length, estimated weight, and placental thickness. Levels of nine plasticiser-related chemicals were measured in urine samples, and mothers self-reported their stress levels. Several statistical methods were used to look at how individual chemicals and chemical mixtures related to baby growth. The findings showed that higher levels of certain plasticiser chemicals were linked to smaller measurements in specific areas of fetal growth — including head size, belly size, leg bone length, and placental thickness. When looking at the combined effect of multiple chemicals together, higher overall exposure was associated with reduced leg bone length. Maternal stress was also linked to a thinner placenta, and the more stressors a mother reported, the more pronounced this effect was. Stress also appeared to influence how certain plasticiser chemicals affected baby growth, suggesting that the two factors can interact with one another.¹

“First-trimester PAEs exposure was associated with impaired fetal growth,” wrote the authors of the paper,¹ “and these associations were potentially amplified by gestational stress.”

The researchers believe that their study has several strengths worth highlighting. It followed participants forward in time rather than looking back, which is a more reliable way to study cause and effect. Detailed medical records and questionnaire data were collected in a thorough and timely manner, reducing the risk of inaccurate information. Unlike many similar studies that only looked at birth measurements, this one also used regular ultrasound scans during pregnancy, giving a clearer picture of how babies were growing in the womb.¹

That said, the study has some limitations. Chemical exposure was only measured once during early pregnancy, which may not fully capture how levels changed over time, though the chemicals in question tend to be stable indoors over long periods, so a single reading can still be informative. Because smoking and alcohol use were uncommon among participants, these factors could not be fully accounted for in the analysis, meaning some other influences on the results cannot be entirely ruled out. Finally, since stress levels were self-reported by participants, there is a chance that some answers may not have been fully accurate.¹

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References

1. Wu, N.; Hu, Z.; Xiao, X. et al. Association of Phthalate Exposure During Early Pregnancy with Fetal Growth and the Effect Modification by Gestational Stress. Int J Hyg Environ Health 2026, 275, 114826. DOI: 10.1016/j.ijheh.2026.114826
2. 2.Golestanzadeh, M.; Goodarzi-Khoigani, M.; Shahrbanoo Daniali, S. et al. Association Between Phthalate Metabolites in Human Amniotic Fluid and Offspring Birth Size: A Sub-Study of the PERSIAN Birth Cohort. Environ Sci Pollut Res Int. 2022, 29 (51), 76970-76982. DOI: 10.1007/s11356-022-20839-1
3. 3.Hwa, H. L.; Peng, F. S.; Ting, T. T. et al. Monitoring Phthalates in Maternal and Cord Blood: Implications for Prenatal Exposure and Birth Outcomes. Environ Toxicol Chem. 2022, 41 (3), 715-725. DOI: 10.1002/etc.5280
4. 4.Li, X.; Liu, L.; Wang, H. et al. Phthalate Exposure and Cumulative Risk in a Chinese Newborn Population. Environ Sci Pollut Res Int. 2019, 26 (8), 7763-7771. DOI: 10.1007/s11356-019-04216-z
5. 5.Li, J.; Qian, X.; Zhou, Y. et al. Trimester-Specific and Sex-Specific Effects of Prenatal Exposure to Di(2-ethylhexyl) Phthalate on Fetal Growth, Birth Size, and Early-Childhood Growth: A Longitudinal Prospective Cohort Study. Sci Total Environ. 2021, 777, 146146. DOI: 10.1016/j.scitotenv.2021.146146
6. 6.Uldbjerg, C. S.; Lim, Y. H.; Krause, M. et al. Sex-Specific Associations Between Maternal Exposure to Parabens, Phenols and Phthalates During Pregnancy and Birth Size Outcomes in Offspring. Sci Total Environ. 2022, 836, 155565. DOI: 10.1016/j.scitotenv.2022.155565
7. 7.Guo, J.; Wu, M.; Gao, X. et al. Meconium Exposure to Phthalates, Sex and Thyroid Hormones, Birth Size and Pregnancy Outcomes in 251 Mother-Infant Pairs from Shanghai. Int J Environ Res Public Health 2020, 17 (21), 7711. DOI: 10.3390/ijerph17217711
8. 8.Goodrich, J. M.; Ingle, M. E.; Domino, S. E. et al. First Trimester Maternal Exposures to Endocrine Disrupting Chemicals and Metals and Fetal Size in the Michigan Mother-Infant Pairs study. J Dev Orig Health Dis. 2019, 10 (4), 447-458. DOI: 10.1017/S204017441800106X
9. Goin, D. E.; Izano, M. A.; Eick, S. M. Maternal Experience of Multiple Hardships and Fetal Growth: Extending Environmental Mixtures Methodology to Social Exposures. Epidemiology 2021, 32 (1), 18-26. DOI: 10.1097/EDE.0000000000001272
10. Sable, M. R.; Wilkinson, D. S. Impact of Perceived Stress, Major Life Events and Pregnancy Attitudes on Low Birth Weight. Fam Plann Perspect. 2000, 32 (6), 288-94.