Postpartum infection

• The postpartum (puerperal) period runs for 6 weeks after birth^[2]. Any infection in this window is a postpartum infection. The uterus, the surgical wound, the urinary tract, the breast and the blood vessels are the usual sites. ^[8]
• Fever is the commonest early warning. Significant postpartum fever is an oral temperature of 38.5 °C or higher in the first 24 hours, or 38 °C for at least 4 consecutive hours after that^[7].
• The commonest single cause of a persistent fever after delivery is endometritis, an infection of the uterine lining, which occurs in 1 to 3% of vaginal births and 5 to 10 times more often after caesarean section^[7][8].
• Suspected sepsis in a recently pregnant person is an emergency. A high-risk person needs a broad-spectrum antimicrobial without delay, within 1 hour of identification, plus cultures, blood tests and fluids^[2].
• Most infections respond well to antibiotics chosen by site, and the mother is usually encouraged to continue breastfeeding^[5].

By the end of this page you should be able to:

1. Define postpartum infection, name its main sites, and state where the commonest causes start.
2. Explain the risk factors for each major postpartum infection from the route of delivery and the intrapartum events.
3. Work through a stepwise investigation of a fever after birth and interpret the key tests (full blood count, CRP, culture, lactate).
4. Choose an empirical antibiotic regimen with dose, route and duration for endometritis, wound infection, urinary infection, mastitis and septic pelvic thrombophlebitis, and know when to escalate.
5. Recognise septic pelvic thrombophlebitis, retained products and drug fever in the woman who is not improving.
6. Describe prevention, including caesarean prophylaxis, and tailor care for breastfeeding women, obesity and women with recent obstetric intervention.

Classification by site is the most useful way to think about fever after birth: endometritis, wound and perineal infection, urinary tract infection, mastitis and breast abscess, and septic pelvic thrombophlebitis. Classification by timing also helps: early infection appears within the first 24 to 48 hours (group A streptococcal infection, staphylococcal toxic shock, clostridial infection and some wound infections), while late infection appears after 48 hours and can present up to the weeks after childbirth (including chlamydial endometritis and some abscesses) ^[7]. Classification by severity runs from localised infection to systemic sepsis. ^[5]

Related conditions need separating too. Chorioamnionitis is an intrauterine infection before or during birth, not a postpartum infection; the same organism spectrum is often involved, but the intrapartum onset changes management^[6]. Sheehan syndrome (postpartum pituitary necrosis) follows severe haemorrhage and causes feverless collapse and hypopituitarism, not infection. Uterine inversion and uterine rupture are obstetric emergencies that can present with pain and bleeding rather than infection.

Infection affects 5 to 7% of postpartum women, with higher rates after caesarean section, and is probably undercounted because many infections are diagnosed only after discharge^[7]. Sepsis during and following pregnancy remains an important cause of maternal death globally, accounting for 11% of all maternal deaths^[1].

• Endometritis occurs in 1 to 3% of vaginal births and 5 to 10 times more often after caesarean section, that is, roughly 1.5 to 5% of planned or emergency caesareans in recent studies^[7][8].
• Surgical site (wound) infection after caesarean section occurs in 3 to 5% of women in the era of routine prophylaxis, though older series put the figure as high as 15%^[7]. It can be recognised in up to 84% of cases only after discharge, so post-discharge surveillance matters^[7].
• Breast infection is the most common postpartum infection in some series, accounting for about 12% of all postpartum infections, most in the first 4 weeks after discharge; reported rates of mastitis range from 2 to 33% of lactating women^[7]. Breast abscess follows in about 3% of lactating women in one Australian cohort^[7].
• Urinary tract infection: bacteriuria is found in 8 to 12% of postpartum women using midstream urine but only 3.2% by suprapubic aspiration, and only a quarter of these women have symptoms^[7].
• Septic pelvic thrombophlebitis occurs in 1 in 500 to 1 in 800 caesarean sections and 1 in 9000 vaginal deliveries^[7].

Risk factors group by site, and several commonly overlap (caesarean section, prolonged rupture of membranes, multiple vaginal examinations, manual removal of the placenta):

• Endometritis: prolonged rupture of membranes (more than 18 hours), chorioamnionitis, prolonged labour or operative time, colonisation with group A or group B streptococcus, bacterial vaginosis, multiple vaginal examinations, internal monitoring, retained products of conception, caesarean section, especially after labour^[7][8].
• Wound infection: diabetes, obesity, smoking, prolonged systemic steroids, pre-existing infection such as chorioamnionitis or bacterial vaginosis, long operation, foreign material (sutures), manual removal of placenta, anaemia^[7].
• Mastitis: milk stasis, incomplete emptying, malposition at the breast, nipple trauma or cracked nipples, skipped feeds, oversupply; staphylococcal reservoir in the infant or the mother's nose^[5][7].
• Urinary infection: caesarean or operative delivery, urinary catheterisation, epidural anaesthesia, high maternal body mass index; pyelonephritis can follow if infection ascends^[7].
• Septic pelvic thrombophlebitis: caesarean section and, in particular, chorioamnionitis (relative risk 2.74) ^[7].

Women at high risk of sepsis are those in the first the weeks after childbirth with diabetes (including gestational diabetes) or other comorbidity, impaired immunity, invasive procedures such as caesarean section, forceps delivery or removal of retained products, prolonged rupture of membranes, contact with group A streptococcal infection, or continued bleeding or offensive discharge^[2].

Postpartum infection is polymicrobial in origin. Organisms that line the lower genital tract and the skin ascend into the uterus or contaminate the wound. Aerobic gram-positive cocci (group A and group B streptococci, enterococci, staphylococci), anaerobic gram-positive cocci (peptococci, peptostreptococci) and aerobic and anaerobic gram-negative bacilli (Escherichia coli, Klebsiella, Proteus, Bacteroides and Prevotella species) are the usual pathogens in endometritis^[7]. Staphylococcus aureus, followed by coagulase-negative staphylococci and more rarely E. coli or streptococci, causes most mastitis and is the dominant organism in skin and soft tissue infection of the breast^[5][7]. Community urinary infection is caused mainly by E. coli.

There is no single modifiable trait that prevents infection entirely. Prevention instead works on the routes of acquisition: antibiotics before caesarean incision^[4][7], aseptic technique during delivery and epidural procedures^[7], sterile skin preparation, good perineal hygiene and management of diabetes, anaemia and obesity in pregnancy.

Most postpartum infection follows ascent: vaginal and cervical flora move into the relatively avascular decidua and myometrium during labour, especially once membranes have ruptured or the cervix has been repeatedly examined. Endometritis begins as an infection of the decidua and often involves the myometrium and parametrial tissues. From there infection can spread by direct extension (abscess, peritonitis), by lymphatics, or by thrombosis of the small pelvic veins, producing septic pelvic thrombophlebitis. A wound infection is a local surgical site infection that can spread from the fascia into the pelvis and abdomen. Urinary infection ascends from the urethra and bladder; in a recently catheterised postpartum woman the distinction between cystitis and pyelonephritis can be clinical. Mastitis begins with milk stasis and entry of skin organisms, usually Staphylococcus aureus, through a cracked nipple; unresolved stasis and infection collect into an abscess. Group A streptococcal infection (and, rarely, staphylococcal toxic shock and clostridial infection) is notable because it can be dramatically rapid, with micro-abscesses in the myometrium and shock, and requires early, aggressive treatment and possible surgery^[7].

Endometritis typically develops in the first week (15% are delayed to 1 to 6 weeks) ^[6] and is diagnosed clinically: fever in a woman with a tender, enlarged or subinvoluting uterus, together with foul-smelling lochia and leukocytosis, after another source of fever has been excluded^[6]. Fever is often the first sign; uterine tenderness, bleeding and foul lochia follow, and the illness can progress to systemic inflammatory response and sepsis if untreated^[7].

Definitions in use include: postpartum fever over 38 °C with uterine tenderness, foul-smelling lochia and leukocytosis over 12,000 per microlitre after excluding another site of infection, developing within the first 5 days after delivery, or a single temperature over 38.3 °C, or two temperatures over 38 °C on separate occasions with the same associated clinical findings^[6]. Positive sepsis screen or systemic illness upgrades the evaluation to full sepsis care.

Wound infection presents with pain at the incision, often before fever, with erythema, swelling, discharge or fluctuance. Deeper infection may show as fever with a tense, painful incision, haemato-serous or purulent drainage, opening of the wound or (on imaging) collections of fluid or gas in the pelvis^[7]. Episiotomy infection presents with increasing pain, oedema, discharge and sometimes systemic upset; erythema and tenderness over the wound are typical, and disproportionate pain or systemic illness raises concern for a deep or necrotising infection, which needs surgical exploration^[7].

Typical features are dysuria, frequency, urgency and suprapubic pain; pyelonephritis adds loin pain with fever, rigors, nausea and tenderness over the renal angle. Asymptomatic bacteriuria is common and its significance is uncertain; treatment should follow clinical assessment including risk factors and cultures^[7].

Mastitis is acute cellulitis or inflammation of the breast, most often in the first few weeks of breastfeeding. The clinical definition is a tender, hot, swollen, wedge-shaped area of breast with fever, chills, flu-like aching and systemic illness^[5]. Milk stasis gives diffuse bilateral congestion; infective mastitis is usually unilateral and segmental. An abscess is suggested by localized fluctuance, persistent pain in one spot and systemic symptoms despite antibiotics^[7].

SPT is infection spreading through the pelvic venous plexuses, which can involve the ovarian veins and extend into the inferior vena cava. It typically presents with persistent fever, pelvic pain and leukocytosis despite 3 to 5 days of adequate antibiotics for endometritis^[7]. Thrombi can often be shown by CT or MRI; in several series thrombi were seen in about 20% of women febrile for more than 5 days despite appropriate therapy^[7].

Late-onset endometritis beyond 7 days should raise suspicion for Chlamydia trachomatis^[7]. Influenza (including postpartum) and other non-obstetric sources (pneumonia, pyelonephritis, appendicitis, breast inflammation) must be considered. Drug fever, dehydration, and pulmonary atelectasis are occasional explanations. Fever within 24 hours may also be physiological after epidural, or caused by prostaglandins and neuraxial analgesia, although infection should be excluded before ascribing fever to these.

The investigation follows the principle of find the source and treat before culture results when the patient is sick. For suspected sepsis in a recently pregnant person, the minimum set includes blood cultures, full blood count, C-reactive protein, urea and electrolytes, creatinine, liver function tests, clotting screen and a blood gas including lactate; imaging as needed^[2].

• Treat sepsis first: if a high-risk criterion is met, give a broad-spectrum antimicrobial without delay, within 1 hour of identification, plus blood cultures, blood tests, fluids and senior review, and discuss with a consultant^[2].
• Start source control at the same time: drainage of abscess or haematoma, wound opening, uterine evacuation for infected retained products, or (rarely) surgery for severe group A streptococcal or clostridial disease^[1][7].
• Choose antibiotics by likely site and organism, then narrow once culture and sensitivity results are available^[2][7].
• Continue intravenous treatment until the woman has been afebrile for 24 hours, with improving pain and (in endometritis) normalising leukocyte count; there is no evidence that oral antibiotics after successful intravenous therapy improve outcomes for uncomplicated endometritis^[7][8].
• Most patients respond to parenteral antibiotics for endometritis within 48 hours and are afebrile by 96 hours; treat 3 to 5 days and review daily^[7].
• Encourage continuing breastfeeding (or expression) during mastitis, because emptying helps recovery; reassure that dicloxacillin, cephalexin and clindamycin used for mastitis are compatible with breastfeeding^[5].
• For a penicillin allergy, avoid cross-reactivity assumptions: this page marks penicillin-allergic options; for severe allergy an infection specialist or microbiologist should choose safe agents and doses^[1].
• Review antimicrobial choices against the local antibiogram: the regimens below are empirical starting points and should be refined with microbiology advice, particularly where resistant organisms are common^[1][7].

Empirical therapy: clindamycin 900 mg IV every 8 hours plus gentamicin 5 mg/kg IV every 24 hours (alternatively gentamicin 1.5 mg/kg IV every 8 hours)^[7][8]. Add ampicillin 2 g IV every 6 hours if enterococcus is suspected or isolated, or if there is no improvement after 48 hours: neither clindamycin nor clindamycin-gentamicin covers enterococcus reliably^[6][7]. For suspected group B streptococcus or in women known to be GBS-positive, add ampicillin or (if clindamycin-resistant) vancomycin instead of clindamycin^[6]. If there is a severe penicillin allergy, one acceptable combination is clindamycin 900 mg IV every 8 hours plus gentamicin 5 mg/kg IV every 24 hours plus vancomycin 1.5 g IV every 12 hours, with microbiology advice^[6]; patients with renal dysfunction should have an infection specialist consulted^[6].

For very mild disease identified after discharge, oral outpatient regimens can be considered: doxycycline 100 mg twice daily plus metronidazole 500 mg twice daily, or levofloxacin 500 mg daily plus metronidazole 500 mg three times daily, or amoxicillin-clavulanate 850 mg by mouth twice daily, with careful follow-up^[7]>. Late endometritis is often milder and amenable to outpatient oral treatment, for example doxycycline or erythromycin plus metronidazole, with testing for Chlamydia^[7]. There is no proven benefit from continuing treatment with oral antibiotics after successful intravenous therapy for uncomplicated endometritis^[7][8].

The Cochrane review confirmed that intravenous clindamycin plus gentamicin is more effective than other regimens or combinations for treating endometritis after birth, and that drugs with good activity against penicillin-resistant organisms perform better^[8].

Failure to improve: reassess after 48 to 72 hours. Causes include wound infection (up to half of such patients), enterococcal superinfection, poorly dosed gentamicin (check levels), resistant organisms, a pelvic abscess, septic pelvic thrombophlebitis, or non-infectious fever such as drug fever. Add ampicillin, broaden appropriately, image the pelvis and escalate^[6][7].

• Localised surgical site infection: cefazolin (1 to 2 g every 8 hours) or vancomycin (1 g every 12 hours) iv, directed at gram-positive organisms; plus or minus metronidazole or amoxicillin-clavulanate depending on anaerobic exposure, with drainage of pus and opening of the wound as needed^[7].
• Systemic or pelvic infection: intravenous broad-spectrum antibiotics as for endometritis, namely gentamicin 5 mg/kg daily plus clindamycin 900 mg every 8 hours plus or minus ampicillin (2 g then 1 g every 4 to 6 hours); alternatively ampicillin plus gentamicin plus metronidazole 500 mg every 8 hours, or levofloxacin plus metronidazole, with source control; parenteral therapy until 24 to 48 hours afebrile, with pain improving and leukocyte count normalising^[6][7]. ^[1]
• Oral switch for stable patients: cephalexin 500 mg four times daily plus or minus metronidazole 400 mg three times daily, or clindamycin 450 mg three times daily, or amoxicillin-clavulanate; for MRSA add co-trimoxazole 960 mg twice daily, with care in breastfeeding women with G6PD deficiency or jaundiced infants^[3].
• Episiotomy infection: oral antibiotics with coverage of streptococci, staphylococci, enteric and anaerobic organisms; for third or fourth degree tear prophylaxis (typically 3 days of treatment) follow NICE/RCOG local guidance; keep the wound clean; surgical exploration if necrotising infection is suspected^[3][7].

Antibiotic therapy for 3 to 5 days with adequate coverage (intravenous ampicillin 2 g then 1 g every 4 hours, gentamicin 5 mg/kg every 24 hours and clindamycin 900 mg every 8 hours) is the foundation^[7]. The addition of heparin is controversial: historical responders were those whose fever resolved within 48 hours of heparin, but the only randomised trial showed no benefit, and a systematic review concluded that heparin has no proven benefit beyond adequate antimicrobial therapy^[7]. Anticoagulation is nevertheless commonly added in many units because of the associated thrombosis; local protocol should guide the decision, and the woman should be imaged. Add anticoagulation in any case if there is concurrent thrombosis on imaging or another indication.

• First-line empirical therapy is a penicillinase-resistant penicillin such as dicloxacillin 500 mg by mouth four times daily^[5].
• Alternatives are cephalexin 500 mg four times daily or clindamycin 300 mg four times daily if the woman is penicillin-allergic^[5].
• For suspected MRSA (household contact, no response, or known carrier), choose an anti-MRSA agent such as clindamycin or vancomycin early; ask about MRSA history before starting^[5][7].
• A 10 to 14 day course is recommended to reduce the risk of recurrence from under-treated mastitis^[5].
• Continue breastfeeding or regular expression, use emptying and anti-inflammatory measures, review at 24 to 48 hours; if there is no response, consider MRSA or abscess.
• An abscess requires drainage (ultrasound-guided aspiration or incision) plus antibiotics; co-amoxiclav or flucloxacillin/cloxacillin are usual choices depending on local resistance.
• Clinical evidence for antibiotics in mastitis is sparse and comes from two small Cochrane trials; a Cochrane review found that antibiotic therapy plus breast emptying produced faster resolution than emptying alone (relative risk 1.89) but larger trials are needed^[7].

• Acute uncomplicated cystitis: nitrofurantoin 100 mg by mouth twice daily for 5 days, or trimethoprim-sulfamethoxazole 160/800 mg one double-strength tablet twice daily for 3 days, with pyelonephritis covered longer (7 days for a fluoroquinolone, 14 days for trimethoprim-sulfamethoxazole, 3 days for nitrofurantoin in some protocols); ciprofloxacin 500 mg twice daily for 3 days is a second-line option. Oral beta-lactams are a last line only. Nitrofurantoin and trimethoprim-sulfamethoxazole are considered safe in breastfeeding in the absence of glucose-6-phosphate dehydrogenase deficiency^[7].
• Acute pyelonephritis: oral fluoroquinolone for 7 days or trimethoprim-sulfamethoxazole (one double-strength tablet) twice daily for 14 days, with an initial intravenous dose of ceftriaxone or an aminoglycoside for severe infection or unknown resistance^[7]. In the context of sepsis, also follow the pegnant sepsis pathway (NICE) and RCOG guidance on pyelonephritis (cefotaxime plus gentamicin; if penicillin-allergic, gentamicin plus ciprofloxacin; for extended-spectrum beta-lactamase, gentamicin plus meropenem) ^[1].

• Sepsis and septic shock, with adult respiratory distress syndrome, renal failure, liver injury, disseminated intravascular coagulation and death^[1][2].
• Abscess (pelvic or breast) requiring drainage; wound breakdown needing secondary closure.
• Necrotising fasciitis and myositis, particularly from group A streptococcus, with rapid progression to toxic shock^[7].
• Peritonitis from spreading infection.
• Septic pelvic thrombophlebitis and, rarely, propagation with pulmonary embolism.
• Infertility or future pregnancy complications from tubal damage after severe or untreated pelvic infection.
• Breast abscess, recurring mastitis, scarring and possible interruption of breastfeeding with inadequate treatment.
• Clostridium and toxic shock syndromes with high mortality and hemoconcentration (Clostridium sordellii) or intravascular haemolysis (Clostridium perfringens)^[6].

With prompt recognition and source-directed antibiotics, most women recover fully and breastfeeding continues. Cochrane evidence shows intravenous clindamycin plus gentamicin is highly effective for endometritis, and parenteral treatment is associated with clinical improvement in most women within 48 hours^[7][8]. Mortality from postpartum sepsis arises mainly from delayed recognition and failure to escalate. Women who develop septic pelvic thrombophlebitis often remain febrile for days despite antibiotics, but the response can be prompt once adequate therapy, imaging and (selective) anticoagulation are in place. Long-term complications (abscess, subfertility) are concentrated in the group that is not treated early.

• Caesarean delivery: give a single dose of 1 or 2 g of cefazolin 15 to 60 minutes before skin incision, with clindamycin or erythromycin for women with penicillin allergy, and a repeat dose if the operation exceeds 3 hours or blood loss exceeds 1500 mL. Administration before incision, rather than at cord clamping, reduces maternal infectious morbidity without increasing neonatal sepsis^[4][6][7].
• Asepsis: chlorhexidine-alcohol is superior to povidone-iodine for surgical site antisepsis; follow strict protocols because concentrated chlorhexidine is flammable; good skin preparation, sterile gown and gloves, face masks and hand hygiene for regional anaesthesia^[6][7].
• Antepartum and intrapartum: treat infection in pregnancy, screen for group B streptococcus as indicated, avoid unnecessary vaginal examinations, limit membrane rupture times and use antibiotic prophylaxis for invasive procedures^[4][3].
• Postpartum practices: hand hygiene; good perineal hygiene and pad changes, daily showering; keep episiotomy wounds clean; early emptying and prompt care for nipple trauma; early recognition and treatment of breastfeeding problems; management of diabetes, anaemia and obesity.
• Prophylaxis is not indicated for all women after an uncomplicated vaginal birth, for assisted vaginal birth or for episiotomy without tear: this is core to WHO guidance on avoiding unnecessary antibiotics and limiting resistance^[4].
• Prophylaxis is indicated for women with third or fourth degree perineal tears, manual removal of the placenta, and caesarean section, according to WHO^[4].
• Vaccination and contact: encourage influenza vaccination; GA streptococcal contact tracing is needed if two or more postpartum infection episodes occur in six months^[7].
• Screening: no universal laboratory screening for postpartum infection after vaginal birth is recommended from the sources used here; instead, systematic assessment at each postnatal contact (symptoms and signs of infection, wound and breast examination and risk stratification) is the WHO/NICE approach^[3][4].

• Breastfeeding women: most antibiotics used for these infections are compatible with breastfeeding; earlier generations wrongly advised stopping feeds, which increases complications. Encourage continuation or regular expression; nitrofurantoin and trimethoprim-sulfamethoxazole are safe if the mother does not have G6PD deficiency, and fluoroquinolones should not be first line. Guidance from resources such as LactMed should inform prescribing^[3][5][7].
• Women after caesarean section or operative delivery: higher risk, discharge counselling on wound symptoms, infection symptoms and thresholds red flags.
• Women with obesity and diabetes: higher SSI risk; careful glycaemic control; augmented doses of prophylaxis in some units.
• Older adults and immunocompromised women (HIV, steroids, diabetes): may have muted features, atypical organisms, or more severe disease.
• Neonates: if maternal sepsis is confirmed, assess the baby for infection and consider screening and treatment protocols^[3]. Antibiotic choice during treatment should consider neonatal exposure.
• Recent pregnancy up to 6 weeks postpartum keeps a woman in a higher-risk sepsis group even after discharge; six-week postpartum visit should review any symptoms^[2][3].

• A clinical diagnosis is often all that is possible: fever, uterine tenderness and offensive lochia are enough to start broad-spectrum antibiotics without waiting for cultures when sepsis is suspected^[1][7].
• Oral amoxicillin-clavulanate or other broad oral regimens may be used for mild, stable disease when admission is not feasible, with clear safety-net advice.
• Simple infection prevention (hand hygiene, aseptic technique, chlorhexidine skin preparation, prophylaxis before caesarean section) has large effects and is WHO-supported even in low-resource environments^[4].
• Because postpartum mastitis and abscess occur in all settings, early education on breast emptying and prompt antibiotics plus abscess drainage are important; where ultrasound is unavailable, drainage is clinical.
• Where gentamicin monitoring is unavailable, follow locally agreed zero-ordered dosing and avoid nephrotoxic co-therapies; escalate any oliguria.
• Any deteriorating woman needs transfer to a facility able to give intravenous fluids, antibiotics, surgery and, if indicated, critical care.

• Postpartum infection is any infection in the the weeks after childbirth; endometritis is the commonest persistent fever cause and is polymicrobial^[2][7].
• Significant postpartum fever is 38.5 °C in the first 24 hours or 38 °C for at least 4 consecutive hours thereafter^[7].
• Endometritis occurs in 1 to 3% of vaginal births and 5 to 10 times more often after caesarean section; caesarean prophylaxis cuts the risk substantially^[4][7][8].
• In suspected sepsis, give broad-spectrum antibiotics, fluids and senior review within 1 hour^[2].
• First-line empirical therapy for endometritis is clindamycin 900 mg IV every 8 hours plus gentamicin 5 mg/kg IV every 24 hours, with ampicillin 2 g IV every 6 hours for suspected enterococcus or GBS^[6][7].
• Total intravenous duration is usually 24 hours after afebrile with recovery in most by 48 to 96 hours; oral follow-up is not needed for uncomplicated endometritis^[7][8].
• Mastitis is treated with dicloxacillin 500 mg by mouth four times daily (or cephalexin or clindamycin) for 10 to 14 days, plus emptying and (as needed) abscess drainage; most antibiotics are compatible with breastfeeding^[5].
• Septic pelvic thrombophlebitis presents as persistent fever despite 3 to 5 days therapy, thrombi on imaging; the evidence for heparin is conflicting^[7].
• Pregnancy and lactation change antibiotic choice; local antibiograms matter, and local specialist advice should guide escalation^[1][7].

postpartum-haemorrhage; preeclampsia-hellp-and-eclampsia; sepsis; shock; urinary-tract-infection; superficial-surgical-site-infection.