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Urinary Tract Infection in Pregnancy

ICD 10 definition of urinary tract infections – infections affecting structures participating in the secretion and elimination of urine : the kidneys , ureters , urinary bladder and urethra.

Hw common ? UTI’s are common in pregnancy – they are the most common bacterial infection in pregnancy It may be asymptomatic UTI in pregnancy has been associated with
○ prelabour rupture of membranes
○ preterm labor and delivery
○ clinical and subclinical chorioamnionitis
○ postpartum fever in mother and neonatal infection Pyelonephritis can be life threatening
○ ↑ risk of perinatal and neonatal morbidity
○ preterm delivery and low birth weight

Cause –Pregnant ♀ are at ↑ ed risk of UTIs Beginning in week 6-7 and peaks during weeks 22-24 Physiological alterations in the urinary tract
○ dilatation of the ureters and renal pelvis
○ decreased ureteral peristalsis
○ bladder tone decreases –> increased urinary capacity
○ ↑ urinary statsis and uretrovesical reflux
○ blood volume expansion ↑ GFR and urinary output
○ glycosuria Other factors which may contribute include
○ anatomical changes for eg bladder displacement
 mechanical obstruction of ureters
○ hyperestrogenism
○ gestational bacterial virulence factors

As per site of infection –Urethra ( urethritis ) Bladder ( cystitis ) Kidney ( pyelonephritis ) Blood stream ( urosepsis )

OR

Upper or Lower urinary tract where the kidneys are the threshold between the two levels

Pathogen –E Coli is the commonest cause ~ 80 %
 – other pathogens include

 Klebsiella pneumoniae Proteus mirabilis Enterobacter species Staphylococcus saprophyticus Group B beta-hemolytic streptococcus & genital mycoplasm Ureaplasma urealyticum ( rarely causes UTI , but of significance particularly in pregnancy due to association with chorioamnionitis )

Terminology –Asymptomatic bacteriuria 
○ positive culture without declared symptoms
○ culture from a single MSU specimen yeilds the same bacterial strain in any trimester in quantitative counts of > 100,000 colony forming units / ml Acute cystitis
○ involves only the lower urinary tract
○ inflammation of the bladder due to bacterial or non-bacterial causes
○ signs and symptoms include hematuria , dysuria , suprapubic discomfort , frequency , urgency and nocturia Pyelonephritis
○ most common UTr complication in pregnant ♀
○ fever , flank pain and tenderness and sig bacteriuria
○ other symptoms may include nausea , vomiting , frequency , urgency and dysuria

History-Fetal well-being Current symptoms ( urinary and systemic ) Previous h/o UTI –> recurrent episodes more common if previous history
Co-existing vaginal discharge 
( r/o STI – may have similar symptoms ) Medical history Predisposing factors ( see next box ) Frequency of sexual intercourse New sexual partner Spermicide use Low socioeconomic status

Risk factorsClosely associated with socioeconomic status- UTI occurs 
in up to 20 % of pregnancies in disadvantaged groups 
( Vasquez 2003 ) Diabetes mellitus Recurrent UTI Anatomical abnormalities of the urinary tract Higher parity Sickle cell disease Age less than 15 yrs at first UTI

Examination Check
○ temp
○ pulse
○ blood pressure
○ respiratory rate
○ oxygen saturation Abdominal examination Try and distinguish between upper and lower UTI – patients with pyelonephritis are
○ sicker
○ may be febrile ( > 38° ) , tachycardic and have renal angle as well as suprapubic tenderness Auscultate fetal heart rate
○ can be done from 12th week Procalcitonin has been shown to be better at predicting acute pyelonephritis than WBC/ CRP

Asymptomatic Bacteriuria Asymptomatic bacteriuria increases the risk of pyelonephritis in pregnant women- untreated 20-40 % of pregnant women may develop pyelonephritis later in pregnanct Treatment of asymptomatic bacteriuria in pregnancy is indicated and considered an accepted and recommended strategy CKS NHS suggests ○ screen for asymptomatic bacteriuria on the 1st ante-natal visit by sending urine for culture ○ if asymptomatic bacteriuria is found –> send a 2nd urine sample for culture If the 2nd urine culture confirms asymptomatic bacteriuria
○ treat with 7 days with a sensitive antibiotic
○ options when sensitivities are known
 Amoxicillin 250 mg tds * 7 days
 Nitrofurantoin 50 mg qds or 100 mg bd MR * 7 days
 Trimethoprim 200 mg bd for 7 days ( see caution about folate )
 Cefalexin 500 mg bd or 250 mg 6 hrly for 7 days Send urine for culture at every antenatal visit until delivery If group B streptococcus is isolated- inform antenatal services




testing –Send urine for culture and sensitivity –> all pregnant women with a suspected UTI
○ before starting treatment
○ seven days after treatment 
( test of cure )
 Dipstick
○ Nitrite accurately predicts UTI
○ Highly specific but not highly sensitive
○ Leukocyte esterase – is produced by neutrophils and may happen in pyuria
○ Chlamydia and ureaplasma urolyticum may be associated with pyuria and negative urine cultures
 Negative nitrite and leucocyte esterase can be used to r/o UTI in pregnancy

Choice of antibiotics –Prescribe antibiotics to all women with a suspected
 UTI during pregnancy- also check local guidance
 Nitrofurantoin 50 mg qds or 100 mg ( MR ) bd for 7 days
○ avoid in term and breastfeeding ( risk neonatal haemolysis )
It has been used extensively and is considered safe in pregnancy
Not appropriate for treating pyelonephritis
 Trimethoprim 200 mg bd for 7 days ( off label use )- good evidence to support use in pregnancy is lacking – used commonly
○ give folic acid 5 mg daily – first trimester
○ avoid use if folate deficient or taking a folate antagonist
○ avoid in first trimester ( teratogenic )
○ Breast feeding- safe in short term
 Cefalexin 500 mg bd or 250 mg 6 hrly for 7 days
○ safe in all stages of pregnancy and breast feeding
 Amoxicillin 500 mg tds for 7 days
○ safe in all stages of pregnancy and breast feeding
○ increasing resistance
 Co-amoxiclav 625 mg tds
 Fosfomycin 3g single dose ( BNF says use only if potential benefit outweighs risk )

Advice / admit –Suspected pyelonephritis –> admit Specialist advice
○ symptoms that fail to respond to appropriate antibiotic Rx guided by urine culture
○ recurrent UTIs 


Follow-up-Follow up results in case resistant pathogens are found Repeat urine culture seven days after finishing antibiotic treatment If group B streptococcus is isolated- inform antenatal services If no bacterial growth- consider an alternative cause of symptoms

Why important –UTI in pregnancy is associated with adverse outcomes
 for the mother and the baby Association with pre-eclampsia Chrioamnionitis -GBS bacteriuria strong association Pre-term delivery ↑ ed risk UTI and neonatal GBS disease Maternal UTI and neonatal UTI – some evidence to show association

LINKS AND RESOURCES

INFORMATION FOR PATIENTS

Health Navigator New Zealand PIL UTI in pregnancyhttps://www.healthnavigator.org.nz/health-a-z/u/uti-in-pregnancy/

Baby centre UK https://www.babycentre.co.uk/a536353/urinary-tract-infections-in-pregnancy

American Pregnancy Association https://americanpregnancy.org/pregnancy-complications/urinary-tract-infections-during-pregnancy/

RESOURCES FOR CLINICIANS

Antibiotic and dosage guide from Goucestershire Hospitals NHS Trust https://www.gloshospitals.nhs.uk/gps/antimicrobial-resources/adult-antibiotic-treatment-guidelines-site-infection/urinary-tract-infection-pregnancy/

Management of UTIs in pregnancy in Primary Care from Oxfordshire Commissioning Group https://www.oxfordshireccg.nhs.uk/professional-resources/documents/clinical-guidelines/gynaecology/UTIs-in-pregnancy-january-15.pdf

An article from CDC on choice of antibiotics Ailes EC, Summers AD, Tran EL, et al. Antibiotics Dispensed to Privately Insured Pregnant Women with Urinary Tract Infections — United States, 2014. MMWR Morb Mortal Wkly Rep 2018;67:18–22. DOI: http://dx.doi.org/10.15585/mmwr.mm6701a4external icon.

Western Australia North Metropolitan Health Service Women and Newborn Health service Infections: Urinary Tract infection in pregnant women guideline https://www.kemh.health.wa.gov.au/~/media/Files/Hospitals/WNHS/For%20health%20professionals/Clinical%20guidelines/OG/WNHS.OG.InfectionsObstetricGynaeAntibioticTreatmentUrinaryTractInfection.pdf

World Health Organisation on asymptomatic bacteriuria in pregnancy https://extranet.who.int/rhl/topics/preconception-pregnancy-childbirth-and-postpartum-care/antenatal-care/who-recommendation-antibiotics-asymptomatic-bacteriuria

References A likely urinary tract infection in a pregnant woman BMJ 2017 ;357:j1777 Urinary tract infections in adults NICE guidance QS90 June 2015 Urinary tract infections ( lower ) – women CKS NHS Management of suspected bacterial urinary infection in adults SIGN 88 July 2012 Treatments for symptomatic urinary tract infections during pregnancy Cochrane Database of Systemic Reviews Juan C Vazquez , Edgardo Abalos January 2011 Urinary-tract infections BNF May 2017 Renal Disease in Pregnancy Patient UK Guideline on urological infections European Association of Urology- EAU March 2013 Primary Care Antimicrobial Guidelines All Wales Medicines Strategy Group September 2015 Urinary Tract Infections During Pregnancy Am Fam Physician. 2000 feb 1;61 (3) :713-720 Mandell , Douglas and Bennett’s Principles and Practice of Infectious Diseases Updated Edition January 2015 Urinary Tract Infections in Pregnancy Medscape Emilie Katherine Johnson et al Jul 2016 Health Protection Agency : uncomplicated urinary tract infections audit in primary care BPAC NZ Managing urinary tract infections in pregnancy Oxford Maternal and Perinatal Health Institute – Urinary Tract Infections in Pregnancy accessed via https://www.gfmer.ch/omphi/maternal-infections/pdf/UTI-in-pregnancy.pdf

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