Age-related nomograms for antral follicle count and anti-Mullerian hormone for subfertile Chinese women in Singapore

Antral follicle count (AFC) and anti-Mullerian hormone (AMH) are known as the most reliable markers of a woman's ovarian reserve and are related to age. There is currently no specific local age-related centile charts for AFC and AMH. Therefore, we aim to examine the relationship between AFC and AMH with age and construct age-related nomograms among a subfertile Asian population. This is a study involving Chinese women who had their AFC and AMH measured as part of their subfertility screening from December 2010 until November 2014 in KK Women's and Children's Hospital, Singapore. Ordinary least squares regression analysis was used to estimate the relationship of AFC and AMH with age, while age-related AFC and AMH nomograms for the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentiles were produced using the lambda-mu-sigma method. A total of 1,009 women, aged 26 to 44 year-old, were included. On average, the AFC and AMH decreased respectively by 0.79 follicle (95% confidence interval -0.93, -0.64) and 0.38 ng/mL (95% confidence interval -0.43, -0.32) per year of age. The age-related nomograms of AFC showed an approximately linear pattern, inversely correlated with age, regardless of the percentile. For AMH, the pattern is linear for the 75th percentile and below but shows a slightly accelerating decline for the 90th and 97th percentile. Overall, there were large inter-individual variations in AFC and AMH up to about 40 year-old. The declines of AFC and AMH over age are mostly linear among subfertile Chinese women in Singapore. The age-related AFC and AMH nomograms could be used as a reference chart by fertility practitioners. However, future validation with longitudinal data is required.