Natural negative controls illustrating reproductive and metabolic influences on HRV patterns are that (1) LH pulsatility is disrupted in obese and diabetic women80,81, and (2) mid cycle and luteal fluctuations in HRV are absent in polycystic ovarian syndrome (PCOS), a leading cause of female infertility58,59. Here, PLOD1 is linked to polycystic ovary syndrome.