Lots of things can affect how much vaginal discharge we have. The list may be too long to even go into!
Normal vaginal discharge is a sign of health of the vagina, and whether we have sex or use tampons, or get a bit dehydrated, it really shouldn't change. Odorous or itchy discharge are symptoms of vaginitis, yeast infections, BV, or after too much sex, but may be difficult to distinguish from abnormal vaginal discharge.
For most of us normal vaginal discharge consists of 1 to 4 mL fluid (per 24 hours), but this is a pretty hard judgement call to know how much you really had. Normal discharge can appear on your underwear and look white or transparent, feel smooth, thick or thin, and has some sort of smell, but can be odorless. The cause of vaginal fluid, also termed discharge ,is formed by a variety of sources including mucus from the cervix, vaginal secretions in combination with sloughing of vaginal surface cells, it is filled with organisms called the normal vaginal flora, and vaginal transudate which is literally fluid that just leaks out the walls between the surface cells naturally. We don't have to be aroused to have vaginal discharge.
Ovulation and other hormones, including pregnancy, will affect whether you notice your vaginal discharge (“physiological leukorrhea”), such as at midmenstrual cycle close to the time of ovulation and can be changed by any oral contraceptive pills.
Diet can affect the vaginal discharge content, the bacteria, the smell and the quantity. In addition to diet, sexual activity, medication, and stress can also affect the volume and character of normal vaginal discharge.
Women often will have a change in their vaginal discharge when they are on birth control pills. Clear vaginal discharge, if you are on or off birth control pills. may mean ovulation, or an estrogen effect on the cervical mucus. Oddly you really should not be ovulating on the birth control pills. You can detect ovulation by performing OPK tests, but also by the stretch test of your mucus. Ovulatory mucus will be able to stick to your fingers and not pull away as you separate your thumb and forefinger, much like egg white. A physician can test your cervical mucus midcycle to see if you are showing that ovulatory effect, by looking at a smear mid cycle to see if it is showing ferns when dried and on a slide under a microscope.
Although the studies on how a birth control pill works all talk abut changing the mucus of the cervix (such that it is a block to sperm), the recent studies looking at ovulation rates do not use this simple home mucus measurement as clinical evidence of ovarian suppression, but we definitely could.
Definitely check in with your gyno if you notice a change in discharge. You could have a check up that determines if your regular clear discharge is ovulation or if your discharge is actually a vaginal infection or cervical infection. If you are regularly ovulating on contraceptive pills that is not normal.
And if you have a new partner, getting that double check for an STD is a good idea. If you are ovulating on the birth control pill then you may need to be evaluated to see if this is the right birth control pill for you. Pills fail in several women out of a 100 each year, and inadequate ovulation suppression can be a reason for the failure!