[evanderman (OP)]

The ovarian cycle is controlled by the hypothalmic pulsing of GnRH and subequent release of FSH/LH.  The effects of these pituitary hormones on the ovaries is well established.  Given the release of these hormones into the general circulation and subsequent exposure to both ovaries, what is the cause for ovulation to switch, or at least potentially switch, between ovaries from month to month?  Do both ovaries undergo an ovarian cycle each month?

Evan

[chris]

This is a really interesting point and something I've wondered about in the past too. One thing to consider along the same lines is that although one egg is eventually released by the ovary (usually) around day 14, over the preceeding days many follicles are matured - at least 40 or so - but these eventually involute and one lucky winner is selected to fully mature and reach ovulation state.

I don't think the mechanism by which this is achieved is known, but a similar process may be at work to establish alternating ovulation.

The requirement for so many follicles to be matured is to supply adequate oestrogen output to drive endometrial proliferation, in preparation to accept an embryo.

Obviously the process does go wrong occasionally - roughly once in every 70 pregnancies - multiple births are testimony to that !

Does anyone know how ovulation is generally restricted to one egg ?

Chris