The short answer is no. Read on…
Conventional medical practice says that one of the most if not the most important hormones is AMH which indicates woman’s egg reserve. If this is low, the chances of her getting pregnant will be low. This may be the case with IVF technology where stimulating drugs are injected to retrieved eggs cycle by cycle. A high AMH implies a high egg reserve, which in turn implies more eggs can be retrieved. This increases the chances of more good quality eggs to be retrieved, which then means an IVF cycle is more likely to be successful. However, does the same reasoning applies to a context different from ART (Assisted Reproductive Technology) i.e. natural pregnancy?
Does AMH level relate to probability of natural pregnancy?
Hagen et al. addressed this very question in a recent issue of the journal Fertility and Sterility (Low concentration of circulating anti-mullerian hormone is not predictive of reduced fecundability in young healthy women: a prospective cohort study 2012; 98:1602-8). They followed a total of 186 young Danish couples that intended to discontinue contraception to become pregnant until they conceived or for six menstrual cycles. They calculated the fecundability ratio (FR) (i.e., the monthly probability of conceiving) and time to pregnancy (TTP) was measured as the number of cycles from stopping birth control to pregnancy. They measured AMH levels and anticipated that those with low AMH levels would have a low FR and take longer to conceive. AMH levels were measured and were divided into 3 groups low (quintile 1), medium (quintile 2 -4) and high (quintile 5). The results are interesting.
59% of couples conceived during the study period. There was no difference in the FR in women with low or medium AMH levels (FR 0.81; 95% CI 0.44 – 1.40). In contrast women with high AMH levels had reduced FR (FR 0.62; 95% CI 0.39 – 0.99). High AMH levels are often seen in women with polycystic ovary syndrome (PCOS) and have irregular cycles. This decrease in FR was significant even when women with irregular menses were excluded from the analysis.
In IVF-related literature, a low AMH level is useful as a marker of follicle quantity than egg quality. This study demonstrates that in the context of natural conception in young women, where only one egg is involved, low AMH level also does not reflect egg quality.
Women with high AMH levels and regular cycles had lower chance of conception. These women may be similar to the group often termed ovulatory PCOS. They have other hormonal imbalances (elevated circulating levels of testosterone) that may be responsible for the lower FR.
They conclude that low AMH levels in young healthy women do not seem to be a predictor of reduced fecundability. This is consistent with high egg quality in these young women, despite a reduced ovarian reserve. Conversely, women with high AMH levels had a 40% reduction in the FR, and this persisted even after exclusion of women with irregular cycles.
In another study by Isabelle Streuli et al. published in 2014 in Reproductive BioMedicine 28, Issue 2, Pages 216–224, the researchers determined whether anti-Müllerian hormone (AMH) concentration influences the time necessary to conceive a live-born child – effective time to pregnancy (eTTP) – in a population of women who conceived naturally. This is an observational study of 87 women with a planned spontaneous pregnancy resulting in a live birth. eTTP was assessed retrospectively by a questionnaire and AMH was measured in a frozen serum sample from first trimester of pregnancy. eTTP was correlated with age (r = −0.24, P = 0.02), but not with AMH (r = −0.10) or body mass index (r = 0.05). With logistic regressions, the only variable that affected the probability of pregnancy within 3 or 6 months was age, irrespective of whether an AMH concentration limit of 1.0 ng/ml or 2.0 ng/ml was chosen. In conclusion, this study suggests that there is no relationship between AMH concentration and eTTP and therefore speaks against determining AMH in women who are not infertile for the purpose of predicting their chances of pregnancy. The findings are concordant with previous reports describing AMH as a quantitative but not a qualitative marker of ovarian reserve and therefore does not reflect a woman’s ability to become pregnant.
So does low AMH mean lower chances of natural pregnancy?
Current research findgings suggest no.