INTRODUCTION — This topic will review the postoperative care of women who have undergone cesarean birth and discuss potential sequelae of this procedure. Preoperative and intraoperative issues can be found elsewhere. (See "Cesarean birth: Preoperative planning and patient preparation" and "Cesarean birth: Surgical technique and wound care".)

POSTOPERATIVE CARE — The following sections apply specifically to issues postcesarean birth. General issues related to the postpartum period are discussed extensively elsewhere. (See "Overview of the postpartum period: Normal physiology and routine maternal care".)

The Enhanced Recovery After Surgery (ERAS) Society has published guidelines for perioperative care of patients undergoing cesarean birth, the ERAS Cesarean Delivery Guidelines, which cover the time from decision to operate (starting with the 30 to 60 minutes before skin incision) to hospital discharge [1-3]. The American College of Obstetricians and Gynecologists has published a guideline for enhanced recovery after surgery [4]. Other organizations and many hospitals have also created such guidelines/pathways [5].

Prophylaxis against hemorrhage — We use oxytocin alone for prophylaxis against hemorrhage. Protocols for oxytocin infusion vary by institution and are generally similar to those used for prophylaxis after vaginal birth. (See "Management of the third stage of labor: Prophylactic drug therapy to minimize hemorrhage", section on 'Oxytocin'.)

Skin-to-skin contact — Skin-to-skin contact should begin, ideally, at birth. The mother can watch the birth through transparent drapes, her partner can cut the cord, and the mother can start skin-to-skin contact and breastfeeding during/right after cesarean is done [6,7].

Maternal monitoring — In the immediate postoperative period, vital signs, uterine tone, vaginal and incisional bleeding, and urine output are monitored closely. (See "Overview of the postpartum period: Normal physiology and routine maternal care", section on 'Postpartum findings and changes'.)

Because severe vital sign abnormalities often precede clinical recognition of critical illness, Maternal Early Warning Criteria (MEWC) (table 1) and differential diagnoses for these abnormalities (table 2) have been developed to speed identification and treatment of potentially serious maternal disorders, and thereby reduce maternal morbidity and mortality [8,9]. The criteria do not identify every maternal complication nor are they designed to replace clinical judgment; however, in a prospective observational study of over 1000 deliveries, a similar system (Maternal Early Obstetric Warning System [MEOWS]) had positive and negative predictive values of 54 and 97 percent, respectively, for the identification of maternal morbidity [10]. Tachycardia >120/min and hypotension <90 mmHg are predictive of need for relaparotomy [11].

Laboratory testing — After planned cesarean birth, routine postoperative hemoglobin testing is probably unnecessary in asymptomatic patients who did not have predelivery anemia or develop postpartum hemorrhage as the information does not lead to improved outcomes [12]. No studies have evaluated such testing after cesareans performed during labor, but routine evaluation of postdelivery hemoglobin is also probably unnecessary in uncomplicated, stable patients without excessive bleeding at delivery. Nevertheless, providers often check for anemia as a prudent approach.

Pain management — Multimodal strategies for postoperative pain control after cesarean birth should be employed to promote rapid recovery, enable the patient to care for her newborn, and minimize the need for postoperative opioids. Options for pharmacologic postoperative pain control (eg, neuraxial opioids in patients with neuraxial anesthesia, regular doses of nonsteroidal anti-inflammatory drugs and acetaminophen, consideration of gabapentin and transverse abdominis plane block) are discussed separately (see "Management of acute perioperative pain" and "Anesthesia for cesarean delivery", section on 'Post-cesarean delivery analgesia'). In addition to pharmacotherapy, placing an abdominal binder at the end of surgery or in the recovery room can improve patient comfort and mobility, with no more than minimal risk of adverse effects (eg, impaired the respiratory function) [13,14].

In a prospective study of 621 patients in Brazil who had a planned cesarean birth, the proportion using analgesia for surgery-related pain at 7, 30, 60, and 90 days after discharge was 95.8, 36.0, 15.5, and 17.0 percent, respectively; importantly, none used opioid analgesia after hospital discharge [15]. Severe pain in the early postoperative period, smoking, and presurgical anxiety were risk factors for prolonged postsurgical pain.

Bladder catheter — Removing the catheter as soon as possible (ie, immediately after the skin is closed) minimizes the risk of infection. There is no evidence that routine urine culture or a trial of catheter clamping is useful before removal of the bladder catheter [16,17]. Although a meta-analysis reported that antibiotic administration prior to catheter removal reduced the rate of catheter-associated urinary tract infection [18], there were multiple limitations to these trials. We do not give antibiotic prophylaxis for bladder catheter removal. (See "Catheter-associated urinary tract infection in adults", section on 'Prevention'.)

Resumption of micturition in the four to six hours after removal of the urinary catheter should be verified, and the physician alerted if urinary retention exceeds six hours. (See "Postoperative urinary retention in females".)

Ambulation/diet — Early ambulation (when the effects of anesthesia have abated (in general within four hours of delivery) and oral intake (within six hours of delivery) are encouraged.

Early resumption of ambulation has been associated with faster intestinal recovery and reduction in ileus and venous thrombosis [19]. We suggest that patients ambulate for at least 5 to 10 minutes at least four times per day.

In meta-analyses, early intake of oral fluids or food after cesarean birth was well-tolerated and had no adverse effects on time to bowel action/passing flatus or frequency of nausea, vomiting, paralytic ileus, or analgesic use [20,21]. Early oral intake may enhance the return of bowel function by stimulating the gastrocolic reflex. Chewing gum at least three times per day for at least 15 minutes appears to accelerate postoperative gastrointestinal recovery [22]. (See "Measures to prevent prolonged postoperative ileus".)

Lifting — It is common practice to advise women to avoid lifting anything heavier than the infant. Heavy lifting and lifting from a squat position confer the greatest increases in intraabdominal pressure [23,24]. These activities should probably be minimized in the first one to two weeks of wound healing, although there are no high-quality data regarding the impact of increased intraabdominal pressure on wound healing [25]. Some surgeons suggest that patients avoid lifting >13 pounds (6 kg) from the floor for four to six weeks following abdominal surgery to minimize stress on the healing fascia based on data that unsutured fascial wounds achieve 30 to 50 percent of unwounded tissue strength after four to six weeks [26]; the recovery of sutured wounds may be faster. However, no evidence-based guidelines are available, and waiting one to two months before lifting >13 pounds (6 kg) from the floor can be difficult for mothers with other small children. In fact, some evidence suggests that lifting 20 pounds, climbing stairs, and abdominal crunches generate no more intraabdominal force than rising from a chair [23].

Exercise — Women may slowly increase aerobic training activities, depending on their level of discomfort and postpartum complications. There is little evidence to support specific recommendations for aerobic and strength-training activities, and there is a lack of consensus among surgeons. (See "Exercise during pregnancy and the postpartum period", section on 'After cesarean delivery'.)

In a meta-analysis review, antepartum structured pelvic floor muscle training in early pregnancy appeared to prevent the onset of urinary incontinence in late pregnancy and in the first six months postpartum, but no clear benefit was observed when exercise was begun after delivery [27]. (See "Treatment of urinary incontinence in females", section on 'Pelvic floor muscle (Kegel) exercises'.)

Driving — Women should avoid driving if they are taking opioids or other sedatives or if they have pain with the normal activities required of a driver (eg, turning the body or head, stepping on the brake/accelerator, steering).

Breastfeeding — Breastfeeding can be initiated in the delivery room. The usual drugs/procedures associated with cesarean birth are not a contraindication to breastfeeding. Information about use of drugs during breastfeeding is available in the Lexicomp drug interactions program included with UpToDate and at the LactMed drugs and lactation database. (See "Initiation of breastfeeding".)

Wound care — In a clean surgical wound, epithelialization typically occurs in the 48 hours after surgery. The superficial layer of epithelium creates a barrier to bacteria and other foreign bodies; however, it is very thin, easily traumatized, and gives little tensile strength.

Although data from randomized trials are limited, removal of dressings from clean or clean, contaminated surgical wounds within 48 hours of surgery (ie, the period of epithelization) appears to have no detrimental effect on outcomes, compared with removal after 48 hours [28]. A trial involving 320 patients who underwent scheduled cesarean birth reported no detrimental effects from dressing removal at six versus 24 hours postsurgery [29]. In most patients, we remove the initial dressing 6 to 24 hours after cesarean. Adhesive dressings should be removed slowly, in the direction of hair growth, at an angle of 150° to the skin, thus pulling the tape over itself [30].

There is no conclusive evidence of harm from postoperative showering within 48 hours of surgery in patients with closed surgical wounds [31].

We typically reapproximate the skin with an absorbable subcuticular suture, so removal is unnecessary (see "Cesarean birth: Surgical technique and wound care", section on 'Skin closure'). If staples are used (eg, patient's preference based on prior experience) and the skin incision is transverse, we remove the staples 4 to 6 days postoperatively but consider keeping the staples in up to 10 days postoperatively in women with risk factors for wound complications, such as those with diabetes mellitus or obesity. If the skin incision is vertical, the staples are left in place for at least five to seven days and longer in a patient at high risk of wound complications since there is more tension on the skin edges of a vertical incision. Adhesive strips may be applied after removal of the staples to help keep the wound edges approximated. In patients who scar easily, the scar that results from staples may be more pronounced than one produced by sutures, particularly if the staples are left in place for prolonged periods (>5 to 15 days, depending on the location).

Nausea and vomiting — Patients with a history of postoperative nausea and vomiting or motion sickness may benefit from chewing gum [19] and prophylactic antiemetic therapy. A variety of antiemetics is available (table 3). (See "Postoperative nausea and vomiting", section on 'Antiemetics'.)

Sexual activity — Sexual activity may resume when the patient is ready. In one study of nearly 400 cesarean births in Australia, nearly 50 percent of patients resumed vaginal intercourse by six weeks postpartum [32]. Contraceptive plans should have been discussed during the pregnancy and must be discussed before the woman leaves the hospital. (See "Postpartum contraception: Counseling and methods".)

COMPLICATIONS — The following sections focus on complications after cesarean birth. General issues related to complications in the postpartum period are discussed extensively elsewhere. (See "Overview of the postpartum period: Disorders and complications".)

The major non-anesthesia-related complications related to cesarean birth are surgical site infection (SSI) (figure 1), particularly superficial wound complications; hemorrhage; injury to pelvic organs; and thromboembolic disorders. The risk of severe maternal morbidity is generally higher in women with an unplanned cesarean birth during labor than in those with a scheduled prelabor cesarean birth [33,34]. Cesarean birth in the second stage of labor is generally associated with higher maternal composite morbidity than cesarean birth in the first stage of labor [35].

Data from the United States Nationwide Inpatient Sample showed that 76 in 1000 cesarean births (97 in 1000 primary and 48 in 1000 repeat cesarean births) were associated with at least 1 of 12 complications [36]. However, absolute complication rates vary widely across hospitals [37] and by patient risk factors [38]. Complications related to the placenta accreta spectrum are a particular concern in women undergoing repeat cesarean birth. (See "Placenta accreta spectrum: Clinical features, diagnosis, and potential consequences".)

Fever — An overview of fever in the surgical patient, including clinical manifestations, etiologies, evaluation, and diagnosis, is provided separately and summarized in the table (table 4). (See "Fever in the surgical patient" and "Overview of the postpartum period: Disorders and complications", section on 'Fever/infection/wound complications'.)

In the first 24 to 48 hours after cesarean birth, the most common causes of fever are endometritis, respiratory tract infection or extensive atelectasis, and pyelonephritis, which can be distinguished based on symptoms, physical examination, and basic laboratory tests (urine culture, complete blood count with differential, chest radiography [if respiratory symptoms/findings]). Most patients respond to broad spectrum antibiotic therapy; those who do not respond are most likely to have a resistant organism or surgical site infection. (See 'Wound complications' below.)

Some uncommon causes of persistent or late-onset fever include septic pelvic thrombophlebitis, pelvic abscess, retained productions of conception, and drug fever. (See 'Septic pelvic thrombophlebitis' below and "Drug fever".)

The possibility of breast engorgement or breast infection (mastitis, abscess) should also be considered and can be diagnosed by physical examination. Breast engorgement generally occurs with the onset of lactation whereas infection is a late finding. (See "Common problems of breastfeeding and weaning", section on 'Engorgement' and "Common problems of breastfeeding and weaning", section on 'Breast infections'.)   

Endometritis — In a review of Maternal-Fetal Medicine Units (MFMU) Network prospective studies of cesarean birth (n = 70,000 cesareans), the rate of endometritis was 6 percent for primary cesarean births performed before labor and 11 percent of cesarean births performed during labor [38].

Clinical manifestations, diagnosis, treatment, and prevention of postpartum endometritis are discussed in detail separately. (See "Postpartum endometritis" and "Cesarean birth: Preoperative planning and patient preparation", section on 'Antibiotic prophylaxis'.)

Wound complications — In the same review of MFMU Network prospective studies of cesarean birth mentioned above, wound complications (infection, hematoma, seroma, dehiscence) developed in 1 to 2 percent of primary cesarean births [38]. A meta-analysis of nonrandomized studies found that implementing an evidence-based bundle lowered the rate of SSI (pooled rate 6 percent at baseline versus 2 percent after the intervention, relative risk 0.33, 95% CI 0.25-0.43, number needed to treat = 24) [39]. The bundles varied but included at least three of the following: antibiotic prophylaxis, use of clippers rather than razors, chlorhexidine skin preparation, enhancements to aseptic surgical technique, spontaneous placental removal with gentle traction, patient and staff education initiatives, and skin closure specifications.

Wound infection generally develops four to seven days after the cesarean. Risk factors include obesity, chorioamnionitis, blood transfusion, anticoagulation therapy, alcohol or drug misuse, unscheduled or second-stage cesarean birth, and subcutaneous hematoma [40-42]. Unscheduled cesarean birth is a major risk factor for wound complications, even when evidence-based interventions to reduce postcesarean birth wound complications have been administered [40]. In one study, 28 percent of such patients had a wound complication.

Early wound infections (in the first 24 to 48 hours) are usually due to group A or B beta-hemolytic Streptococcus and are characterized by high fever and cellulitis. Later infections are more likely to be due to Staphylococcus epidermidis or aureus, Escherichia coli, Proteus mirabilis, or cervicovaginal flora [43,44].

Necrotizing fasciitis is a rare but life-threatening complication (0.18 percent of cesarean births in one study [45]). (See "Necrotizing soft tissue infections".)

The basic principles of wound management (role of antibiotics, debridement, topical therapy, dressings, packing, negative pressure, management of disruption) are reviewed in detail separately. (See "Complications of abdominal surgical incisions", section on 'Surgical site infection' and "Basic principles of wound management" and "Overview of the evaluation and management of surgical site infection".)

Hemorrhage — The mean estimated blood loss at cesarean birth is approximately 1000 mL and 18 percent of primary cesarean births have a calculated blood loss >1500 mL; however, estimates of blood loss are not very reliable [46-48]. Routine administration of oxytocin after the newborn is delivered reduces postpartum blood loss and risk of hemorrhage. (See "Anesthesia for cesarean delivery", section on 'Administration of uterotonics'.)

In the same review of MFMU Network prospective studies of cesarean birth mentioned above, 2 to 4 percent of women undergoing a primary cesarean birth received a blood transfusion [38]. Causes of hemorrhage include uterine atony, placenta accreta spectrum, extensive uterine injury, and extension of the incision into the uterine vessels. (See "Overview of postpartum hemorrhage" and "Postpartum hemorrhage: Medical and minimally invasive management" and "Postpartum hemorrhage: Management approaches requiring laparotomy" and "Management of hematomas incurred as a result of obstetric delivery", section on 'Retroperitoneal hematomas'.)

Surgical injury — Adhesions are one of the major risk factors for inadvertent surgical injury. In the same review of MFMU Network prospective studies of cesarean birth mentioned above, a surgical injury (broad ligament hematoma, cystotomy, bowel injury, ureteral injury) occurred in 0.2 to 0.5 percent of women undergoing a primary cesarean birth [38]. In another study of almost 30,000 primary and repeat cesarean births, the overall rate of lower urinary tract injury was 0.27 percent; 3 percent were ureteral and the rest were full- or partial-thickness bladder injuries [49]. The risk of cystotomy is higher for cesareans performed in the second stage than in the first stage and in repeat cesareans [35,50].

Diagnosis, management, and prevention of these injuries are discussed in detail separately. (See "Urinary tract injury in gynecologic surgery: Identification and management" and "Urinary tract injury in gynecologic surgery: Epidemiology and prevention" and "Complications of gynecologic surgery", section on 'Bowel injury'.)

Venous thromboembolism — A study using claims data from 1.7 million pregnancies reported that the frequency of a thrombotic event (ischemic stroke, acute myocardial infarction, venous thromboembolism [VTE]) was 44.8 per 100,000 cesarean births during the first six postpartum weeks [51]. This rate was significantly higher than the rate after vaginal delivery (14.5 per 100,000 deliveries) and 15-fold higher than the rate in postpartum weeks 19 to 24 (3.1 per 100,000 deliveries).

In a meta-analysis of the risks of VTE after cesarean, the overall pooled incidence of deep vein thrombosis and/or pulmonary embolism was 260 per 100,000 cesareans, and the odds of deep vein thrombosis and/or pulmonary embolism following planned and emergency cesarean birth were 2.3 and 3.6, respectively [52]. (See "Cesarean birth: Preoperative planning and patient preparation", section on 'Thromboembolism prophylaxis' and "Deep vein thrombosis and pulmonary embolism in pregnancy: Treatment".)

Maternal mortality — Maternal mortality after cesarean is rare in high income countries (eg, 13 of 100,000 cesareans in the United States [53], 22 of 100,000 cesareans in The Netherlands [54]). A significant proportion of the surgical mortality (and morbidity) of cesarean birth is related to the underlying medical and obstetric factors that necessitate the surgical delivery.

However, in low- and middle-income countries (LMICs), maternal mortality continues to be high. A 2019 systematic review that included nearly 3 million cesarean births in LMICs reported 760 maternal deaths per 100,000 procedures; the highest burden was in sub-Saharan Africa where there were 1090 maternal deaths per 100,000 procedures [55]. One-quarter of all women who died in LMICs had undergone a cesarean. The most common indication for cesarean in women who died was failure to progress, which accounted for one-quarter of the procedures, and the most common cause of death was postpartum hemorrhage, which accounted for one-third of deaths. Interestingly, many cesareans were performed by nonphysicians, but these procedures were associated with a similar rate of maternal death as those performed by physicians (odds ratio 1.3, 95% CI 0.8-2.0). The authors observed high numbers of maternal deaths in countries with very low frequencies of cesarean birth, which suggests that limited access to the procedure is an indicator of limited access to the specialists, blood products, and other basic and critical care resources needed to prevent maternal death when complications arise. They also opined that lack of adequate antenatal care, lack of resources for planned cesarean birth when indicated, and delayed referral of patients with obstructed labor contributed to the high rate of maternal mortality.

Anesthetic complications — Complications of anesthesia are reviewed separately. (See "Anesthesia for cesarean delivery" and "Adverse effects of neuraxial analgesia and anesthesia for obstetrics".)

Ileus and colonic pseudo-obstruction — Adynamic ileus of moderate and severe intensity has been reported in 10 to 20 percent of postcesarean patients [56]. Estimates of the frequency of pathologic or prolonged ileus after cesarean birth are imprecise because ileus is a normal physiologic response to abdominopelvic surgery, definitions of pathologic or prolonged ileus differ, and multiple factors affect the risk of occurrence. Symptoms may include abdominal distention, bloating, and "gassiness"; diffuse, persistent abdominal pain; nausea and/or vomiting; delayed passage of or inability to pass flatus; and inability to tolerate an oral diet. Diagnosis, management, and prevention of postoperative ileus are discussed separately. (See "Postoperative ileus".)

Severe postoperative ileus after cesarean birth may be related to acute colonic pseudo-obstruction (Ogilvie's syndrome), which is characterized by gross dilatation of the cecum and right hemicolon in the absence of an anatomic obstruction. (See "Acute colonic pseudo-obstruction (Ogilvie's syndrome)".)

Septic pelvic thrombophlebitis — Ovarian vein thrombophlebitis (OVT) and deep septic pelvic thrombophlebitis (DSPT) are rare complications of cesarean birth. The two entities share common inflammatory pathogenic mechanisms and often occur together, but may differ in their clinical presentations and diagnostic findings. Patients with OVT usually present with fever and abdominal pain localized to the side of the affected vein within one week after delivery or surgery; thrombosis of the right ovarian vein is visualized radiographically in approximately 20 percent of cases. Patients with DSPT usually present within a few days after delivery or surgery with fever that persists despite antibiotics, in the absence of radiographic evidence of thrombosis. Abdominal or pelvic tenderness is notably absent. (See "Septic pelvic thrombophlebitis".)

Psychological outcome — Cesarean birth has been associated with an increased risk for postpartum depression [57]. Some women express strong feelings of loss, failure, and anger after a cesarean birth [58]. These feelings are likely related, at least in part, to the anxiety associated with medical and obstetric complications necessitating abdominal delivery (especially unplanned abdominal delivery); the stress, pain, and fatigue associated with major surgery; and the baseline psychological status of the parturient. Better psychological outcomes may be realized by realistic preparation for childbirth, maternal involvement in decision making, and attention to the specific needs of the woman who is both postpartum and postoperative [58].

Fetal and neonatal risks — Although cesarean birth is usually performed for the benefit of the fetus, the fetus is also at risk from cesarean birth. Risks include iatrogenic prematurity and birth trauma; the latter occurs in 1 to 3 percent of cesareans and consists mostly of mild lacerations related to emergency delivery [59].

Transient tachypnea of the newborn (TTN) is more common after scheduled cesarean birth, probably because exposure to labor initiates processes that enhance reabsorption of lung fluid. In a review of 29,669 deliveries, the incidence of TTN was approximately threefold higher after planned cesarean than after vaginal delivery (3.1 versus 1.1 percent) [60]. Cesarean birth has also been reported to be a modest risk factor for respiratory distress syndrome (RDS), particularly if the cesarean was performed in a nonlaboring patient [61]. However, this study did not clearly discriminate between TTN and RDS. (See "Transient tachypnea of the newborn".)

In LMICs, perinatal mortality is also a concern. In the systematic review of cesarean birth in LMICs discussed above [55], perinatal mortality in offspring of women who underwent cesarean birth was approximately 85 deaths per 1000 procedures. A high perinatal mortality rate is not surprising given the high rate of maternal mortality in these countries. (See 'Maternal mortality' above.)

LONG-TERM RISKS

Abnormal placentation — Cesarean birth significantly increases the risk of abnormal placentation in future pregnancies, and the risk increases with the number of cesarean births. Given the increased risks of abnormal placentation, experts recommend that women with a prior cesarean birth undergo ultrasound evaluation of the placental site in future pregnancies [62]. (See "Placenta accreta spectrum: Clinical features, diagnosis, and potential consequences".)

●Previa and placenta accreta spectrum – The risk of placenta previa in the general obstetric population, after one cesarean birth, and after ≥3 cesarean births was 4 in 1000, 10 in 1000, and 28 in 1000 deliveries, respectively, in one review [63]. Women with a previa and ≥3 cesarean births were at significantly increased risk of placenta accreta spectrum, compared with women with a previa and no previous cesarean birth (50 to 67 percent versus 3.3 to 4 percent). The risk of placenta accreta spectrum increases with an increasing number of prior cesarean births, even in the absence of placenta previa. (See "Repeat cesarean birth", section on 'Complications relating to abnormal placentation'.)

●Abruption – Placental abruption occurs more often in women with a prior cesarean birth [64-67], but the absolute risk is low, and the association may be due to confounders [68]. (See "Placental abruption: Pathophysiology, clinical features, diagnosis, and consequences".)

Uterine rupture in a subsequent pregnancy — The incidence of uterine rupture is higher in women who undergo a trial of labor after cesarean birth (TOLAC) than in women who undergo planned repeat cesarean delivery (PRCD). The incidence varies depending on the type and location of the prior uterine incision, as well as other factors. (See "Uterine rupture: After previous cesarean birth".)

Scar complications — Rarely, complications develop in the scars resulting from the hysterotomy or abdominal wall incision:

●Cesarean scar defect – A cesarean scar defect is a thinning and indentation of the myometrium at the hysterotomy site that results from inadequate healing of the myometrium at this site. It has been called by various terms, including niche, isthmocele, and uteroperitoneal fistula. These defects are more common with increasing numbers of cesarean births, presumably because preexisting scar tissue negatively influences the healing of a new incision [69].

Potential complications of cesarean scar defects include cesarean scar pregnancy, postmenstrual spotting, pelvic pain, dysmenorrhea, dyspareunia, uterine rupture, and secondary infertility [70-72].

A cesarean scar pregnancy is thought to result from migration of the embryo into the defect. Symptoms and diagnosis are similar to tubal ectopic pregnancy. There are no data on the role of the interval between the previous cesarean birth and hysterotomy scar pregnancy occurrence or the effect of wound closure technique on its occurrence. (See "Cesarean scar pregnancy".)

The overall rate of ectopic pregnancy is not increased after cesarean birth [73].

●Numbness or pain – Branches of the ilioinguinal nerve and the iliohypogastric nerve are severed by transverse abdominal incisions. This often causes persistent numbness in the region around the scar. Less commonly, patients have persistent, radiating pain due to nerve entrapment [74-78]. The diagnostic triad of nerve entrapment after surgery includes: (1) typical burning or lancinating pain near the incision that radiates to the area supplied by the nerve, (2) clear evidence of impaired sensory perception of the nerve, and (3) pain relieved by local infiltration with an anesthetic [76]. Treatment involves surgical repair of the scar with resection of the compromised nerve or nerve block. (See "Nerve injury associated with pelvic surgery".)

●Incisional endometriosis – Incisional endometriosis has been reported in 0.03 to 0.45 percent of patients who have delivered by cesarean [79]. It presents as a tender, palpable mass in the incision [80,81]. The mass increases during menstruation and is associated with cyclic or continuous pain. Differential diagnosis includes incisional hernia. The diagnosis and management of endometriosis at unusual sites are discussed separately. (See "Endometriosis: Pathogenesis, clinical features, and diagnosis", section on 'Anatomic sites'.)

●Incisional hernia – In a study from the Swedish Medical Birth Register, cesarean birth was associated with an increased risk for incisional hernia (OR 2.7, 95% CI 2.5-3.0) [82]. (See "Clinical features, diagnosis, and prevention of incisional hernias".)

Adhesions and bowel obstruction — Abdominal surgery is associated with long-term risks from development of clinically significant adhesions. Adhesions can be completely asymptomatic or can cause significant morbidity and mortality related to bowel obstruction, infertility, or organ injury during repeat abdominal surgery. Formation of adhesions is common after cesarean birth, and the extent and density increase with increasing numbers of repeat cesarean births: the reported prevalence of adhesions is 12 to 46 percent of women at their second cesarean and 26 to 75 percent of women at their third cesarean [83-88], but the prevalence of small bowel obstruction is much lower [89-91]. In a population-based cohort study, the risk of small bowel obstruction among women with a cesarean birth was 16.3 of 10,000 person-years versus 6.4 of 10,000 person-years in women without (odds ratio [OR] 2.54, 95% CI 2.15-3.00), and an increasing number of cesarean births was associated with an increasing risk of small bowel obstruction (OR 1.61, 95% CI 1.46-1.78, per additional cesarean birth) [92].

There is no convincing evidence to support use of adhesion barriers or closure of the peritoneum to prevent complications from adhesions after cesarean birth. (See "Cesarean birth: Surgical technique and wound care", section on 'Adhesion barriers' and "Cesarean birth: Surgical technique and wound care", section on 'Reapproximation of the peritoneum'.)

Subfertility — There is no convincing evidence of a causal relationship between cesarean birth in a first pregnancy and subfertility [93] or cesarean surgical technique and subfertility [94]. The effect of multiple cesareans on fertility has not been evaluated. However, there is some evidence that subfertile women are more likely to deliver by cesarean and that women who deliver by cesarean take longer to conceive future pregnancies [95].

In a 2013 systematic review including 18 cohort studies and almost 600,000 women, women who underwent a cesarean birth had 10 percent fewer subsequent pregnancies than women who delivered vaginally [96]. In a 2018 meta-analysis, women who had cesarean birth had a 60 percent increase in subfertility compared with those who had a vaginal birth (OR 1.60, 95% CI 1.45-1.76), but subfertility was not defined [97]. This association appears to be due to confounding factors that affected both the need for cesarean birth and the choice of subsequent pregnancy [98,99].

Unexplained stillbirth — The effect of cesarean birth on future stillbirth is controversial. A 2015 systematic review and meta-analysis reported a significant positive association between cesarean birth and antepartum stillbirth in a second pregnancy (pooled hazard ratio 1.40, 95% CI 1.10-1.77) [100]. The absolute risk difference was 0.1 percent; therefore, 1000 cesarean births would need to be avoided to prevent one additional antepartum stillbirth. The analysis excluded the largest published study, which included almost 1.8 million singleton second births in women with no underlying medical conditions and fetuses with no structural or chromosomal abnormalities and found no association between previous cesarean and future term fetal demise [101]. This study was excluded from the analysis because it included intrapartum stillbirths, which may have a different etiology. In this study, the fetal death rates at term in those with and without a previous cesarean birth were 0.7 and 0.8 per 1000 births, respectively. In the entire cohort of over 11 million singleton births (second and subsequent births), the fetal death rates at term for women with and without a previous cesarean were 0.4 and 0.6 per 1000 births, respectively.

An association between unexplained stillbirth and a prior cesarean birth observed in some studies may be due to residual confounding, but it is possible that scar tissue from a previous cesarean birth may lead to abnormal placental function leading to stillbirth.

Preterm birth — Cesarean birth appears to have no more than a minimal increase in risk for subsequent preterm birth. In a meta-analysis of 10 cohort studies involving 10 million women, compared with vaginal birth, women delivering by previous cesarean had a 12 percent increase in risk of preterm birth overall in subsequent deliveries (adjusted risk ratio [RR] 1.12, 95% CI 1.01-1.24) and a trend toward increased risk for very preterm birth (birth at 28 to 32 weeks: adjusted RR 1.16, 95% CI 0.80-1.68) [102]. Future studies should further evaluate this possible association and possible causative factors (eg, incision placement, method of delivering fetus from a low station, previous attempt at operative vaginal delivery).

Adverse effect on gut microbiota in the newborn

Allergic disease, obesity, infection in offspring — During the first few months of life, colonization of the gut microbiota in newborns appears to be impacted by the mode of delivery [103,104]. It has been hypothesized that neonatal exposure to maternal flora during vaginal birth reduces the risk of developing allergic disorders (allergic rhinoconjunctivitis, asthma, food allergy), childhood/adolescent obesity, and infection-related hospitalization in early childhood. In support of this hypothesis, an association between cesarean birth and development of these disorders has been observed, particularly after planned cesarean birth or intrapartum cesarean birth before membrane rupture [105-112].

Role of vaginal seeding — In an attempt to restore normal neonatal colonization of cesarean-born neonates, a cotton gauze or cotton swab inoculated with maternal vaginal fluid has been used to wipe the mouth, nose, or skin of the newborn infant (called vaginal seeding). However, both the safety and effectiveness of this practice are unproven.

The American College of Obstetricians and Gynecologists and others recommend that clinicians and patients avoid this practice, unless as part of an institutional review board-approved research protocol [113-115].

Neurodevelopmental outcome of offspring — In a meta-analysis of observational studies examining cesarean birth and neurodevelopmental and psychiatric disorders in the offspring, compared with vaginal birth, cesarean birth was associated with increased odds of autism spectrum disorders (OR 1.33, 95% CI 1.25-1.41) and attention deficit hyperactivity disorder (OR 1.17, 95% CI 1.07-1.26) [116]. Risks were similar for emergency and planned procedures. More research is needed to understand if these associations are true and, if true, the reasons for the associations. Confounders and ascertainment bias could account for the association in these observational studies [117].

FUTURE DELIVERY

Trial of labor after a cesarean — After a cesarean birth, the surgeon should describe the uterine incision clearly in the operative note and begin a discussion with the patient about the feasibility of a trial of labor in a future pregnancy. (See "Choosing the route of delivery after cesarean birth".)

Repeat cesarean birth — Issues relating to repeat cesarean birth are discussed separately. (See "Repeat cesarean birth".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Cesarean birth".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: C-section (cesarean delivery) (The Basics)")

●Beyond the Basics topics (see "Patient education: C-section (cesarean delivery) (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●Routine postoperative hemoglobin testing is unnecessary in asymptomatic patients after planned cesarean birth, as the information does not lead to improved outcomes. Routine evaluation of postdelivery hemoglobin is probably unwarranted after uncomplicated intrapartum cesarean birth. (See 'Maternal monitoring' above.)

●Patient-controlled opioid analgesia followed by oral nonsteroidal anti-inflammatory drugs provides adequate pain relief for most women. (See 'Pain management' above.)

●If inserted, removal of the bladder catheter as soon as possible postpartum minimizes the risk of infection. (See 'Bladder catheter' above.)

●Breastfeeding can be initiated in the delivery room. The usual drugs/procedures associated with cesarean birth are not a contraindication to breastfeeding. (See 'Breastfeeding' above.)

●Early ambulation (when the effects of anesthesia have abated) and oral intake (within six hours of delivery) are encouraged, as well as chewing gum. Women may slowly increase aerobic training activities, depending on their level of discomfort and postpartum complications. Pelvic floor muscle exercises can reduce urinary incontinence, if present. (See 'Ambulation/diet' above.)

●Wound dressings can be removed at 6 hours and certainly within 24 hours, and patients may shower within 48 hours of surgery. (See 'Wound care' above.)

●The frequency of short-term complications after primary cesarean birth is: ileus (10 to 20 percent), endometritis (6 to 11 percent), wound complications (1 to 2 percent), hemorrhage requiring transfusion (2 to 4 percent), surgical injury (0.2 to 0.5 percent), and thrombotic events (246 per 100,000). (See 'Complications' above.)

●Neonatal risks include iatrogenic prematurity, respiratory problems, and birth injury. (See 'Fetal and neonatal risks' above.)

●The major long-term risks of cesarean birth are abnormal placentation (previa, accreta) and uterine rupture during a trial of labor in future pregnancies (see 'Abnormal placentation' above and 'Uterine rupture in a subsequent pregnancy' above). The risk of abnormal placentation increases with an increasing number of cesarean births. The rate of bowel obstruction after cesarean birth ranges from 0.5 to 9 per 1000 cesarean births, with the highest risk in women who have undergone multiple cesarean births. (See 'Adhesions and bowel obstruction' above.)

●Long-term abdominal scar complications include numbness, pain, and endometriosis. Uterine scar complications include cesarean scar pregnancy and postmenstrual spotting. (See 'Scar complications' above.)

●Cesarean birth does not appear to be an independent risk factor for future unexplained stillbirth or subfertility. (See 'Unexplained stillbirth' above and 'Subfertility' above.)