Anovulatory cycle Anovulatory cycle The anovulatory cycle is a menstrual cycle characterized by varying degrees of menstrual intervals and the absence of ovulation and a luteal phase. In the absence of ovulation, there will be infertility. While the normal menstrual cycle in the human typically lasts 4 weeks (28 days, range 24–35 days) and consists of a follicular phase, ovulation, and a luteal phase, followed by either menstruation or pregnancy, the anovulatory cycle has cycle lengths of varying degrees. In many circumstances, menstrual intervals are prolonged exceeding 35 days leading to oligomenorrhea (cycle >35 – 180 days interval), or even longer, amenorrhea.
Menstrual synchrony synchrony throughout an inter-birth interval, Power et al. argued that once we take account of birth seasonality – enhancing the effects of menstrual synchrony by clumping fertile cycles within a relatively brief time-window – it emerges that reproductive synchrony can be effective as a female strategy to undermine primate-style sexual monopolization by dominant males. The controversy remains unresolved. Adopting a compromise position, one school of Darwinian thought argues that the human female may once have had adaptive reasons for evolving a 29.5-day menstrual cycle – implying some theoretical potential for synchrony to a lunar clock – but did so in