Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have often heard that right and left ovaries alternate in releasing ovum.

Is it always true? What controls this rhythm? Is it simply because the other ovary is unresponsive to LH or FSH? If so, why?

share|improve this question
I am not sure if this alternation occurs. Can you post the reference ? – WYSIWYG Oct 13 '13 at 16:07
up vote 3 down vote accepted

Nope, not true. It's a pretty common myth; that paper cites a reference from 1932 in primates claiming to show that the ovaries alternate. A few papers before this, in particular this one from 1991 showed that ovulation was not alternating, but this was the first to do so in actually fertile woman. In particular,

Alternate ovulation occurred in 61 of the 119 succeeding ovulations (51.3%, not significant) which means that there was no consistent tendency to alternation.

Alternation only occurred half the time. Neither did they find a difference between side preference; right-side ovulation occurred in just over 50% of the cases, not significantly different.

FSH, follicle-stimulating hormone, and LH, luteinizing hormone, stimulate each ovary equally, but one ovary will get slightly ahead. Ovulation (and indeed pregnancy at times) is a positive-feedback loop, meaning the response will be exponential; if one ovary is even just slightly ahead it will rapidly dominate the other. The less-developed one quickly senses the other is ahead of the game and ceases to respond.

share|improve this answer
Can you provide details of the positive feedback loop and the sensing the "lost race" by the less developed ovary as mentioned in your answer? – Satwik Pasani Nov 15 '13 at 14:56

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.