You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Endometrial thickness in women with ovulatory dysfunction. This study is designed to evaluate the relationship between endometrial thickness and clinical/biochemical parameters in women with chronic anovulation. One hundred and twenty women with ovulatory dysfunction were prospective included, endometrial thickness and endocrine and metabolic parameters were measured. The interval between the examination day and the day of the most recent menstrual bleeding (the anovulatory interval) for the studied subject was an average of 145 ± 186 days. The endometrial thickness averaged 7.1 ± 3.2 mm. Correlation analyses revealed that the endometrial thickness was positively correlated with body mass index but was not correlated with age, serum androgens, or estradiol (E2) levels. We further classified the subjects into two groups based on endometrial thickness: Group A, endometrial thickness <7 mm and Group B, endometrial thickness ≥7 mm. The anovulatory interval, follicle-stimulating hormone, luteinizing hormone, E2 and androgen levels were not significantly different between Groups A and B. Group B had higher body weight and more risk for metabolic syndrome. We concluded that endometrial thickness in women with ovulatory dysfunction is positively correlated with body weight status but is not correlated with serum androgens or E2 levels.
{"Chemical": ["androgens", "estradiol", "androgen"]}