Some 30 % of all pregnant women carry the bacteria in their vagina or digestive system. In the case of a urinary tract infection, bacteria have entered the bladder or ureter, causing symptoms such as a burning sensation, frequent urination, lower abdominal pain and, occasionally, pain when you urinate. Fever is another symptom. The infection is treated with antibiotics. This infection can occasionally trigger early contractions. In the US, we do universal screening. Most women will be screened at week 36. Always contact your midwife or birth center if you have regular and/or painful contractions before week 37+0.