Why do I need to pee when I nurse or pump?

Does this sound familiar?

You sit down to feed a baby and suddenly feel that unmistakeable tingling in your bladder.

Shoot, you think. I forgot to pee first.

Ugh, it’s getting bad.

Should I trust my pelvic floor? Or should I go pee mid-feed?

If I leave the baby, they’ll cry. If I stay here, I’ll pee here.

How do I pee while nursing a baby?

Ugh, I guess now’s the time to learn.

You’re not alone. The science behind the urge to pee while nursing or pumping occurs at a hormonal level, which means it probably happens to most people (though some may not notice). But actually there isn’t a lot of research out there directly on the impact of nursing/pumping on outcomes such as urinary urgency or a need to pee.So I’ve put together for you a list of logical reasons why we would think this happens.

Let’s start off with the hormones.

First, when you nurse or pump, you’re often triggering *a lot* of different hormones, including estrogen. Estrogen is associated with more urinary urgency and frequency, though we don’t actually know yet why that’s so. (a lot of the research on this has focused on people going through menopause rather than lactation.) But it contributes.

Nursing and pumping also triggering progesterone. We know a little more about what this hormone does to your urinary tract; it makes the muscles in your urinary tract lose tone. Progesterone is also why, if you’ve been pregnant, you might have felt more of an urge to pee while pregnant. The same thing may be at play when you’re nursing or pumping.

Your body is also flooded with oxytocin while nursing/pumping. In addition to being the love hormone, oxytocin might also make you feel the urge to pee. The detrusor muscle is a smooth muscle that lines the bladder; it relaxes to allow the bladder to expand (that is, to store more urine). Oxytocin can actually make that detrusor muscle constrict, meaning empty your bladder.

But there could be other factors to this beyond hormones, as well. Maybe pulling a baby toward your abdomen while nursing puts more pressure on a partially full bladder. Maybe you’ve been drinking a lot more water. Maybe you actually needed to pee for a while, but it only became obvious to you while nursing or pumping, because nursing or pumping is a time when you’re likely to be checking in with your body.

Whatever the reason(s), know you’re not alone.

Keep in mind that if you can’t control your bladder when you get that urge to pee, that’s a sign that your pelvic floor needs help. Check out this article for more information, and talk to your medical care provider about what treatment plan might be right for you.

Do you have other ideas for why this phenomenon might occur? Comment below!