I had the same thing happen last night. It was a sudden sharp pain in my lower right abdomen that lasted for a few seconds then went away but it went on like that for about an hour. I'm 20w5d. After a lil research I figure its round ligament pain.
I would check it out but also I had the same thing on and off for a few days. Your body is changing and stretching so it's more than likely just that. I called my midwife and she said that to me but also said if it becomes continuous then go to the hospital or contact her again. its beem fine though and has eased off.
I've been going though the exact same thing for about a week and a half now. I went to the hospital on Christmas and the doctor said it was a combination of round ligament pain and colon backup. I then went to my normal doctor yesterday and she said she thinks it's a pulled muscle. The baby is fine, but there is nothing I really can do besides take Tylenol and use a heating pad. Definitely call your doctor, but I wouldn't worry too much
Ive not had this but just wanted to say if drinking water, resting, bathing or massaging doesnt help within a few minutes then call your midwife and get it checked out today. Im also 19 wks and just about ready to run to a&e should i feel anything strange. Dont delay, get it checked out.