What causes a chemical pregnancy?

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Last updated: June 11, 2025View editorial policy

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From the Guidelines

Chemical pregnancies are primarily caused by chromosomal abnormalities in the embryo, but exposure to certain environmental toxins, such as phthalates and bisphenol A (BPA), can also increase the risk of miscarriage, including chemical pregnancy, by affecting fetal development and placental growth. The causes of chemical pregnancy can be multifactorial, including:

  • Chromosomal abnormalities in the embryo, which are often due to random errors during cell division when the egg and sperm combine 1
  • Hormonal imbalances, particularly low progesterone levels
  • Blood clotting disorders
  • Uterine abnormalities or infections
  • Maternal age, with women over 35 having higher risks due to declining egg quality
  • Certain health conditions, such as uncontrolled diabetes, thyroid disorders, or autoimmune diseases
  • Exposure to environmental toxins, including phthalates and BPA, which can penetrate the placental barrier and affect fetal development 1 Some studies have also suggested that exposure to certain chemicals, such as those used in chemotherapy, can increase the risk of ovarian failure and premature menopause, which can in turn increase the risk of chemical pregnancy 1. However, the most significant and recent evidence suggests that environmental toxins, such as phthalates and BPA, play a crucial role in increasing the risk of chemical pregnancy by affecting fetal development and placental growth 1. It is essential to note that chemical pregnancies often occur very early, usually ending before the fifth week, and are detected only because modern pregnancy tests can identify the pregnancy hormone (hCG) before a missed period. Most women who experience a chemical pregnancy can conceive again successfully, and no specific treatment is typically needed beyond emotional support. If you experience recurrent chemical pregnancies (three or more), consulting with a reproductive endocrinologist is recommended to investigate potential underlying causes.

From the Research

Chemical Pregnancy Causes

The provided studies do not directly address the causes of a chemical pregnancy. However, they do discuss various factors related to polycystic ovary syndrome (PCOS) and other conditions that may contribute to pregnancy complications or infertility.

  • PCOS is a complex metabolic disorder with long-term metabolic and reproductive consequences, characterized by increased androgen levels and insulin resistance 2, 3, 4, 5.
  • The syndrome is associated with various health risks, including glucose intolerance, type 2 diabetes mellitus, hepatic steatosis, metabolic syndrome, hypertension, dyslipidemia, and cardiovascular events 3, 4, 5.
  • Thyroid disorders, such as Hashimoto's thyroiditis, are more common in patients with PCOS, which may contribute to fertility problems 6.
  • Genetic and environmental factors, including diet and lifestyle, may play a role in the development of PCOS and related conditions 4, 5.
  • Insulin resistance, obesity, and metabolic disorders are common in PCOS patients, which may affect ovulation and pregnancy rates 2, 3, 5.

There are no direct research papers provided to assist in answering the question about the causes of a chemical pregnancy. Further research is needed to understand the relationship between PCOS, thyroid disorders, and other factors that may contribute to chemical pregnancy.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Polycystic Ovary Syndrome: A Contemporary Clinical Approach.

Current pharmaceutical design, 2021

Research

Polycystic Ovary Syndrome.

Obstetrics and gynecology, 2018

Research

Polycystic Ovary Syndrome: Common Questions and Answers.

American family physician, 2023

Research

Thyroid disorders in polycystic ovary syndrome.

European review for medical and pharmacological sciences, 2017

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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