The same uterus pressure that makes you want to wee can also make your lower back uncomfortable.
As the baby grows, the weight of your womb can pull on the muscles around your back, interrupt your sleep and lead to an even more irritated lower lumbar.
Most pregnant women complain of lower back pain at some point during their pregnancy - particularly late on when the baby is at its heaviest.
Early on, it's also common to experience aching in this region. Your posture and alignment are having to adapt to the new you so it's not unusual to feel discomfort as your body gets used to the changes.