I have light bleeding about 4-5 days after the unprotected sex. What could it be?

Question

Hello doctor,

I was not supposed to start my period for about two more weeks but, for the past three or four days I have been having a very light bleeding (sometimes dark red and sometimes light red) that seems to be a period. I had unprotected sex on the 19th but, I am on birth control. It is not like my normal period and not as light as I would think spotting would be. It started about four to five days after the unprotected sex. Is there any explanation for this or is it just the birth control messing with my system?

Answer 1

Hi,

Welcome to icliniq.com.

This is what is typically called breakthrough bleeding (BTB). This is seen in cases of usage of birth control pills with high estrogen content of 30 micrograms of estradiol.

The event is not related to unprotected sex as you had intercourse in your safe period, as you said you have two more weeks for periods. So, this bleeding started at the time of ovulation when estrogen is in excess and progesterone is limited.

The thickened proliferative endometrium (uterine lining) starts breaking and causes spotting till the progesterone part of the pills become active and secretory phase ensues.

My advice would be to be placed on low dose oral contraceptive pills for birth control rather than high dose pills. Then this breakthrough bleeding which is a common side effect of high dose pills can be avoided.

If there is persistent bleeding, consult a gynecologist.