Pyelonephritis in pregnancy


Urinary tract infections (UTIs) are common during pregnancy. Acute cystitis, pyelonephritis and asymptomatic bacteriuria (positive urine culture in an asymptomatic woman). Approximately 1-4 % of pregnant women experience acute cystitis and the incidence of asymptomatic bacteriuria during pregnancy ranges from 2-10%.

Pregnant women with acute pyelonephritis need special attention, as this kind of infection may not only have an adverse effect on the mother with anaemia, renal and respiratory insufficiency but also on the unborn child with more frequent preterm labour and birth.  

Many factors may contribute to the development of pyelonephritis during pregnancy. One important factor is ureteral dilatation, thought to occur due to hormonal effects and mechanical compression from the growing uterus. Ureteral dilation can cause bacteria to spread from the bladder to the kidneys, increasing the risk of pyelonephritis.

A diagnosis of acute pyelonephritis should be considered if a patient presents with systemic symptoms such as fever (> 38°C), flank pain and nausea or vomiting. Symptoms of lower UTI such as frequency and dysuria may or may not be present. Pyelonephritis in pregnancy can have serious consequences such as maternal sepsis, pre-term labour and premature delivery and requires prompt and aggressive treatment. Hospital admission and intravenous antibiotics are usually required. Intravenous antibiotics are usually continued until the patient has been afebrile for 48 hours. Oral antibiotics are then used for 10-14 days.