I get this on and off- not as strong as period pains though, and I'd say the feeling is a bit duller overall, with the occasional sharp 'fanny dagger'. My midwife said its probably my uterus stretching/ round ligament issues. I sometimes wonder if it's the baby hitting a nerve, as it feels a little like nerve pain. Also worth mentioning that some women get period pains at around the time they would have normally have had their period (the body works in mysterious ways). Regardless though, it would do no harm to call your midwife if you're at all worried.
CityMole thank you, reasurring, describes what it is really well. That's interesting about the period time. Couple of wks time I've got until next appt, I will mention it then if not before on phone, Cheers!