Can Periods Rule Out Pregnancy? Aunt Vadge Explains

Hi Aunt Vadge,

If I had sex on the 27th, 28th, 29th, 1st, 2nd and 5th (October/November) where he came in me every time, but I started my period on the 2nd and ended on the 5th, what are the chances of me being pregnant?

I’m on the pill, but I’ve forgotten to take it for two of the nights.

Thanks,
Worried
_____

Hello Worried,

It’s understandable to be concerned about the chances of pregnancy when there have been missed pills. The effectiveness of the birth control pill largely depends on taking it consistently and as directed¹.

If you’ve missed two pills in a cycle, particularly if they were on consecutive days or during the first or third week of your pill pack, the risk of pregnancy can increase.

Here’s what you should consider:

When in your cycle did you miss the pills? Missing pills during the first week can be riskier because it follows the pill-free or placebo week, during which your hormone levels are already low, potentially allowing for ovulation to occur if you don’t start the new pack on time.
Having unprotected sex on the days leading up to and just after missing your pills does present a risk for pregnancy, because sperm can live inside the female reproductive system for up to five days, and the effectiveness of the pill may be compromised by missed doses.
Having your period after sex may initially seem reassuring, but it is important to understand that bleeding while on the pill is not the same as a natural menstrual period; it’s a withdrawal bleed that occurs due to the drop in hormone levels during the placebo week. Therefore, this bleeding doesn’t necessarily guarantee that you’re not pregnant.

Given your situation, here’s what I suggest you do:

Take a pregnancy test if it has been more than two weeks since the last instance of unprotected sex. This will give you the most accurate result.
Review the instructions for missed pills in the information that came with your contraceptive pack. Different pills have different guidance on what to do if you’ve missed one or more pills.
Use backup contraception, like condoms, until you have taken seven active pills in a row to safeguard against pregnancy.
If you frequently forget to take your pill, consider setting an alarm as a reminder, or discuss alternative contraceptive options with your doctor that don’t require daily action, like an IUD or implant.

Remember that if you make any mistake with your pills, the sooner you address it, the better. Don’t hesitate to speak with a healthcare provider if you’re unsure about what steps to take or if you have any other questions about your birth control.

Take care,
Aunt Vadge

References

1.
Creinin MD, Jensen JT, Chen MJ, Black A, Costescu D, Foidart JM. Combined Oral Contraceptive Adherence and Pregnancy Rates. Obstetrics & Gynecology. Published online April 5, 2023:989-994. doi:10.1097/aog.0000000000005155