In a study it is observed that the right ovary ovulates more than the left, all are possible explanation for the cause except :- (AIIMS Nov. 2012)
|B||Difference in blood supply to both sides|
|C||Right handedness is more common in population|
|D||Some embryological basis|
Right handedness is more common in population
a. The right ovary is generally dominant.
b. Anatomical asymmetries between the left and right sides are thought to be the reason.
c. The left ovarian vein drains to the left renal vein and the right ovarian vein to the inferior vena cava.
d. The left renal vein is thought to be under higher pressure than the right and therefore drains slower.
e. Because the left ovary drains slower, the corpus luteum takes longer to clear and thereby diminishes the chance that ovulation will occur on that side the following month.
f. No such condition exists on the right side, which is why successive right-side ovulation is more common.
g. Estradiol and testosterone levels are also higher during a right-side cycle; this may also be related to the right ovary’s more efficient plumbing as it flushes lining-plumping hormones into the uterus.
h. All this leads to some fascinating statistics. For instance, right-sided ovulation favors pregnancy more often than left-sided ovulation (64 percent of pregnancies came from women’s right ovaries), according to a study in Japan that tracked nearly 2,700 natural cycles.
i. Interestingly, researchers in another study speculate that right-side ovulation is dominant for most of a women’s reproductive years.
j. Toward perimenopause women are more likely to become left-dominant, presumably because the supply of follicles in the right ovary has diminished.