Factors Affecting Postoperative Ileus after Caesarean Section

By Nazan Usal Tarhan, Hilal Efe, Miray Yucel, Habibe Ayvaci Tasan

Affiliations

1. Department of Obstetrics and Gynaecology, Zeynep Kamil Women's and Children's Diseases Training and Research Hospital, Istanbul, Turkiye

doi: 10.29271/jcpsp.2026.03.310

ABSTRACT
Objective: To identify the factors associated with postoperative ileus (POI) following Caesarean section.
Study Design: A descriptive study.
Place and Duration of the Study: Department of Obstetrics and Gynaecology, Zeynep Kamil Women's and Children's Diseases Training and Research Hospital, Istanbul, Turkiye, between April 2021 and February 2025.
Methodology: A total of 293 women who underwent Caesarean section were evaluated postoperatively. POI was defined as the absence of the first flatus within 24 hours after surgery. Demographic and obstetric characteristics, as well as factors associated with POI, were compared between patients with and without POI.
Results: POI developed in 33 patients (11.3%). Multivariate binary logistic regression showed an increased risk of POI with each 1-unit decrease in preoperative haemoglobin level (RR 1.357, 95% CI = 1.029-1.791, p = 0.031) and with intraoperative drain placement (RR 6.433, 95% CI = 2.326-17.792, p <0.001).
Conclusion: POI can delay postpartum recovery. Preoperative anaemia, history of POI, and intraoperative drain placement are significant risk factors for POI after Caesarean section.

Key Words: Caesarean section, Ileus, Maternal health, Postoperative complications, Postpartum women.

INTRODUCTION

Postoperative ileus (POI) is a temporary, non-mechanical gastrointestinal dysfunction that develops after surgery and is caused by loss of peristalsis. It presents clinically with abdominal distension, abdominal tenderness, and decreased bowel sounds.¹

POI after Caesarean section, the most common obstetric procedure, may result in a prolonged hospital stay, delayed recovery for both mother and child, and increased medical costs. Bleeding greater than 1,000 ml during Caesarean section, multiple pregnancy, corporeal uterine incision, use of topical haemostatic agents, and advanced maternal age have been  reported  as  risk  factors  for  this  complication.² A diagnosis of pre-eclampsia, exposure to general anaes- thesia, estimated blood loss >1 L, and transfusion of blood products were identified as potential risk factors for postcesarean ileus.³

Precautions and practices in the postoperative period for the management of this condition have been frequently studied. It has been reported that a preoperative low-residue diet reduces ileus and pain after Caesarean section.⁴ Early oral feeding within two hours following Caesarean section has been found to speed the restoration to normal bowel function.⁵ Chewing gum within the first hour postoperatively has also  been  shown  to  enhance  recovery.⁶

The postpartum period is an emotional and challenging time in which the mother, in addition to other post-surgical periods, also undertakes the care of the newborn baby. This study aimed to identify risk factors associated with prolonged time  to  first  flatus  in  women  undergoing  Caesa-rean section.

METHODOLOGY

This descriptive study was conducted at the Department of Obstetrics and Gynaecology, Zeynep Kamil Women's and Children's Diseases Training and Research Hospital, Istanbul, Turkiye, between April 2021 and February 2025. Ethical approval was obtained from the Clinical Research Ethics Committee of Zeynep Kamil Women's and Children's Diseases Training and Research Hospital, Istanbul, Turkiye (No. 54; date: 3^rd March 2021). The sample size was calculated using the Open-Epi. For a study with a 95% confidence interval and 80% power,  a  minimum  of  260  participants  was  required.

Women aged 18-45 years who gave birth via Caesarean section at this hospital were included in the study. Women declining participation and those diagnosed with a psychiatric disease or gastrointestinal disease were excluded from the study. Patients were informed about the study and assigned to it on days when the research team was on duty in the maternity ward. A total of 293 postpartum women were included. Patients were evaluated on the first and second postoperative days. The patient’s age was confirmed from official records. Weight and height were measured by the midwife within 1–48 hours of hospitalisation, and these measurements were used to calculate the body mass index (BMI) before surgery. Past medical history and obstetric history were recorded based on the patients’ statements. Data on surgery and anaesthesia were obtained from the surgery and anaesthesia records. Previous abdominal surgery included all intra-abdominal procedures, including Caesarean section. Flatus complications related to previous surgeries were only evaluated in those who had surgery. In the postoperative period following Caesarean section, an independent nurse or physician working on the ward and not involved in the research asked patients to report the time of first passage of flatus. The time to first flatus was obtained from these records and documented accordingly. Postpartum women who did not have their first flatus by the end of the 24^th hour were defined as having POI. Laboratory and other clinical follow-up data were obtained from printed and electronic patient files. Smokers were defined as those who continued smoking during pregnancy.

The distribution of data across groups was evaluated with the Kolmogorov-Smirnov test. Quantitative variables were analysed with the Student’s t-test for data that were normally distributed and with the Mann-Whitney U test for data that were not normally distributed. Categorical variables were analysed using the Pearson chi-square test, and odds ratios (OR) with 95% confidence intervals (CIs) for those found significant between the two groups were also reported. A p-value <0.05 was considered to be statistically significant. Quantitative variables were reported as mean ± standard deviation (SD). Categorical variables were reported as numbers and percentages. The binary logistic regression was performed using the Backward LR method. All of the statistical analyses were performed using IBM SPSS Statistics 17 (IBM SPSS, Turkiye).

RESULTS

A total of 311 eligible patients were invited to the study. Seven patients declined to participate in the study, and five were excluded due to high Postpartum Edinburgh Depression Scale scores. Additionally, six patients were excluded because of a history of gastrointestinal disease. A total of 293 postpartum women were included in the study. Thirty-three (11.3%) developed POI. No differences were observed in age, gravida, parity, number of previous Caesarean sections, maternal weight before pregnancy and before surgery, height, maternal BMI before pregnancy and before surgery, gestational age at birth, fasting time before Caesarean section, operation time, or laboratory variables, except for preoperative and postoperative haemoglobin levels which were significantly lower in patients who developed POI (p = 0.009 and p = 0.029, respectively; Table I).

Univariate analyses revealed that patients who had experienced POI after previous abdominal surgery were significantly more likely to develop POI (p = 0.013). The prevalence of smoking was 12.5% in the POI group and 13.1% in the group without POI. The two groups were statistically similar. Intraoperative and postoperative conditions related to the current Caesarean section were also analysed. Drain placement was associated with a significantly increased risk of POI (p <0.001). Haemorrhage greater than 1,000 cc was observed in 12.1% and 4.6% of the groups with and without POI, respectively.

Table I: Demographic and postoperative characteristics of patients with and without POI.
 

Variables	Cases with POI (n = 33)		Cases without POI (n = 260)		p-values
Age*  (year)	31.4	±6.5	30.0	±5.9	0.216a
Gravida**	3	2-4	2	1-3	0.293b
Parity**	2	1-3	1	0-2	0.010b
Number of CS**	1	1-2	1	0-2	0.103b
Pre-pregnancy weight (kg)**	70	63.5-82.0	68	60-80	0.461b
Weight before surgery**	80	72.5-88.5	80	70-90	0.815b
Pre-pregnancy BMI (kg/m2)**	27.3	24.9-29.1	26.3	22.9-30.2	0.370b
BMI before surgery (kg/m2)**	31.8	±4.6	31.0	±5.0	0.704a
Gestational age at birth**	266	249-273	266	259-273	0.684b
Fasting time before CS (hours)**	8	6-12.0	8	6-12	0.674b
Operation time (minute)**	60	45-65.0	55	45-60	0.285b
Preoperative Hgb (g/dL)**	10.8	±1.3	11.5	±1.4	0.009a
Postoperative Hgb (g/dL)**	9.7	8.9-10.8	10.4	9.4-11.3	0.029b
Creatinine (mg/dL)**	0.55	0.50-0.64	0.52	0.46-0.59	0.225b
*Mean ± standard deviation, **Median (IQR), a Independent Student’s t-test, b Mann-Whitney U test, BMI: Body mass index; CS: Caesarean section, Hgb: Haemo-globin level; POI: Postoperative ileus.

Table II: Medical history, Caesarean section operation, and postoperative characteristics of patients with and without POI.

Variables		Cases with POI (n = 33)		Cases without POI (n = 260)		p-values
		n	%	n	%
Previous abdominal surgery	Yes	20	60.6	143	55.0	0.541
	No	13	39.4	117	45.0
POI in previous abdominal surgery*	Yes	5	15.2	7	3.5	0.013a
	No	28	84.8	251	96.5
Hypertensive diseases of pregnancy	Yes	5	15.2	38	14.6	0.935
	No	28	84.8	222	85.6
Diabetes	Yes	5	15.2	51	19.6	0.539
	No	28	84.8	209	80.4
Smoking	Yes	4	12.5	29	13.1	1.000
	No	28	87.5	192	86.9
Indication for CS	Urgent	18	54.5	118	45.2	0.320
	Elective	15	45.5	142	54.8
Anesthesia method	General	9	27.3	57	21.9	0.488
	Spinal	24	72.7	203	78.1
Incision type	Kerr incision	33	100.0	255	98.1	1.000a
	T or J incision	0	0.0	5	1.9
Complicated uterine incision**	Yes	3	9.1	7	2.7	0.090a
	No	30	90.9	253	97.3
Intra-abdominal adhesion	Present	8	24.2	45	17.3	0.330
	Absent	25	75.8	215	82.7
Urinary tract injury	Present	2	6.1	2	0.8	0.064a
	Absent	31	93.9	258	99.2
Bowel injury	Present	0	0.0	1	0.4	1.000a
	Absent	33	100.0	259	99.6
>1,000 cc haemorrhage	Yes	4	12.1	12	4.6	0.091a
	No	29	87.9	248	95.4
Uterine atony	Yes	3	9.1	10	3.8	0.170a
	No	30	90.9	250	96.2
Surgical intervention for atony	Yes	2	6.1	8	3.1	0.313a
	No	31	93.9	252	96.9
Drain placement	Yes	9	27.3	13	5.0	<0.00a
	No	24	72.7	247	95.0
Blood product transfusion	Yes	4	12.1	5	1.9	0.011a
	No	29	87.9	255	98.1
Postoperative fever	Yes	0	0.0	3	1.2	1.000a
	No	33	100.0	257	98.8
Oliguria in the first 6 hours postoperatively	Yes	1	3.0	8	3.1	1.000a
	No	32	97.2	252	96.9
Fluid balance	In balance	0	0.0	15	5.8	0.199
	Plus	29	87.9	196	75.4
	Minus	4	12.1	49	18.8
Follow-up in ICU	Yes	9	27.3	46	17.7	0.184
	No	24	72.7	214	82.3
aFisher’s exact test, *Cases that had previously undergone surgery were included. **Complicated uterine incision: The situation where the uterine incision extends to the vagina. ICU: Intensive care unit; POI: Postoperative ileus.

Table III: Multivariate binary logistic regression analysis of all cases, including age, BMI before delivery, and any parameter with a p <0.2 in univariate analysis.

Variables	RR	95% CI	p-values
All cases regression analysis
Preoperative Hgb (g/dL)	1.357	1.029-1.791	0.031
Blood product transfusion	5.769	1.227-27.120	0.026
Drain placement	6.433	2.326-17.793	<0.001
Cases that have undergone surgery before
POI in previous abdominal surgery	11.931	2.598-54.796	<0.001
Postoperative Hgb (g/dL)	1.844	1.197-2.842	0.006
Drain placement	9.777	2.441-39.136	0.001
Hgb: Haemoglobin level.

No statistically significant difference was found between the two groups. The need for blood product transfusion was 12.1% in the group with POI and 1.9% in the group without POI, demonstrating a statistically significant difference (p = 0.011; Table II).

Multivariate binary logistic regression analysis showed that, when all cases were evaluated, the relative risk (RR) for the development of POI was 1.357 (95% CI = 1.029-1.791, p = 0.031) for a 1-unit decrease in preoperative haemoglobin level. The RR for the development of POI associated with drain placement and with the need for blood product transfusion during the current operation were 6.433 (95% CI = 2.326-17.793, p <0.001) and 5.769 (95% CI = 1.227-27.120, p = 0.026), respectively.

In the multivariate binary logistic regression analysis including only patients who had previously undergone abdominal surgery, a history of POI in the previous surgery was found to be a significant predictor of POI in the current operation (RR = 11.931, 95% CI = 2.598-54.796; p <0.001). Postoperative Hgb decrease was associated with an RR of 1.844 (p = 0.006), while drain placement was associated with an RR of 13.924 (p <0.001; Table III).

DISCUSSION

This study aimed to determine the risk factors that are effective in prolonging the postoperative flatus time in women who gave birth by Caesarean section. Low preoperative and postoperative haemoglobin levels, history of gastrointestinal disease, and drain placement were determined as factors that increase the risk of POI.

The importance of nutritional interventions in preventing postoperative complications in general surgery cases has been reported. In a clinical nutrition in surgery guideline, some recommendations are as follows: in cases that are scheduled for surgery and not at risk of aspiration, fluid intake may be allowed up to two hours, and solid intake may be allowed up to six hours before surgery. Oral intake can be resumed two hours after surgery.⁷ In Caesarean section cases, it has been reported that practices such as preoperative low-residue diet, early feeding within 2 hours in the postoperative period, and chewing gum after Caesarean section are beneficial in preventing POI.^4,5,8 At the study centre, except in emergencies, Caesarean section is performed after 6 hours of preoperative fasting, and it is not desired to extend this period. Feeding begins 4-6 hours postoperatively. The present study group was not suitable for comparing nutritional practices and fasting duration, and no difference was found between the two groups. In a retrospective case-control study comparing patient-controlled analgesia with intramuscular analgesia after Caesarean section, the incidence of moderate-to-severe adynamic ileus was reported to be higher in the patient-controlled analgesia group (21.8% vs. 13.5%).⁹ Intramuscular analgesia was preferred in all cases included in the study.

In a comparative animal study, it was shown that in rats exposed to haemorrhagic shock, there was impaired smooth muscle contraction and, therefore, intestinal contractility following the inflammatory response.¹⁰ A retrospective cohort study evaluating women who had undergone Caesarean section over six years reported that intraoperative bleeding >1,000 mL was the most significant risk factor associated with postoperative paralytic ileus in multivariate analyses.¹¹ Potential risk factors for the development of ileus following Caesarean section were identified in a retrospective case-control study in cases with and without paralytic ileus within six weeks following cWQWWaesarean section. These factors included the use of magnesium sulphate, general anaesthesia, estimated blooWd loss greater than one litre, and blood product transfusion.³ Severe preoperative anaemia was found to be a risk factor for POI development [OR 2.7 (1.5–5.0), p = 0.001].¹² In the present study, although blood transfusion was significant in univariate analysis, no difference was found in multivariate analysis. However, preoperative haemoglobin level was a risk factor for the development of POI in all cases. Preventing anaemia in pregnancy, which creates a burden of disease, is important for reducing maternal and foetal morbidity and mortality. The World Health Organization (WHO) recommends 30-60 mg/day elemental iron supplementation during pregnancy.¹³ Considering this study, preoperative anaemia is a condition that should be taken into consideration and can be prevented with safe antenatal care.

There are limited studies evaluating the risk of POI occurring in subsequent abdominal surgery. In a 3-stage abdominal surgery performed in ulcerative colitis cases, it has been reported that the development of POI in the first stage does not pose an increased risk for developing POI in the subsequent surgical stage.¹⁴ In the current study, the frequency of experiencing flatus problems in the previous operation was higher in patients who had POI in the last Caesarean section. Studies have focused on the effects of nicotine, a component of cigarettes, on gastrointestinal system motility rather than on the effects of smoking on gastrointestinal motility. Smoking is the most common source of nicotine exposure. Transdermal nicotine administration has been reported to shorten total colonic transit time.¹⁵ Smoking status was assessed in the current study; however, no significant difference was observed between the groups.

Drain placements are used to monitor the discharge of blood, pus, and ascites from body cavities.¹⁶ In a prospective controlled study of gastric cancer patients who underwent total gastrectomy, prophylactic drain placement was shown to delay healing and be associated with delayed bowel movements.¹⁷ In a clinical review on abdominal drains, it was reported that abdominal drain placements may be associated with intestinal obstruction. The importance of removing the drain at the appropriate time in preventing complications was reported.¹⁸ Drains are generally removed without complications, but in rare cases, herniation, evisceration, and knotting of the drain tube may occur.^19,20 Consistent with these studies, drain placement was found to pose a risk in terms of POI development in our study. As a result, it is critical to carefully assess the indications for drain placement, not to extend the follow-up period with the drain beyond what is essential, and to be aware of the problems that may arise during drain placement and removal.

Clinical algorithms in the clinic where the study was con- ducted propose conventional preoperative and postoperative care, as well as precautions to avoid POI. The strength of this study lies in its ability to represent this patient group.

A study evaluating mobilisation within 48 hours postoperatively in major elective surgery cases reported a significant improvement in the composite outcome for every four-minute increase in mobilisation.²¹ Although all of the patients in the current study were mobilised within 4-6 hours after surgery, the intensity of mobilisation within the first 24 hours was not assessed. The present study was not sufficient to evaluate the risk of POI that may be related to the type of anaesthetic method. These are the limitations of the study.

CONCLUSION

POI in postpartum patients can cause delays in recovery, difficulties with activities such as breastfeeding and caring for the newborn, and the development of psychological and social issues. This study determined that preoperative anaemia, history of POI in previous abdominal surgeries, and surgical drain placement are risk factors for the development of POI.

ETHICAL APPROVAL:
Ethical approval was obtained from the Clinical Research Ethics Committee of the Zeynep Kamil Women and Children's Diseases Training and Research Hospital, Istanbul, Turkiye (No. 54; date: 3^rd March 2021). The study was conducted in accordance with the Declaration of Helsinki.

PATIENTS’ CONSENT:
Informed consent was obtained from each patient.

COMPETING INTEREST:
The authors declared no conflict of interest.

AUTHORS’ CONTRIBUTION:
NUT: Conception, acquisition, analysis of data, drafting, and revision of the manuscript.
HE, MY: Acquisition of data and revision of the manuscript.
HAT: Analysis of data, drafting, and revision of the manuscript.
All authors approved the final version of the manuscript to be published.

REFERENCES

1. Asgeirsson T, El-Badawi KI, Mahmood A, Barletta J, Luchtefeld M, Senagore AJ. Postoperative ileus: It costs more than you expect. J Am Coll Surg 2010; 210(2):228-31. doi: 10. 1016/j.jamcollsurg.2009.09.028.
2. Zlakishvili B, Sela HY, Tankel J, Ioscovich A, Rotem R, Grisaru-Granovsky S, et al. Post-cesarean ileus: An assessment of incidence, risk factors and outcomes. Eur J Obstet Gynecol Reprod Biol 2022; 269:55-61. doi: 10.1016/j.ejogrb. 2021.12.019.
3. Hennebery RB, Burke CA, Bank TC, Hoffman MK. Risk factors for postoperative ileus after cesarean delivery. Am J Obstet Gynecol MFM 2022; 4(6):100713. doi: 10.1016/j.ajogmf. 2022.100713.
4. Palaia I, Caruso G, Perniola G, Di Donato V, Brunelli R, Vestri A, et al. The efficacy of preoperative low-residue diet on postoperative ileus following cesarean section. J Matern Foetal Neonatal Med 2023; 36(1):2203795. doi: 10.1080/ 14767058.2023.2203795.
5. Chen D, Lang B, Wu L, Zhou S, Chen S. Early oral feeding within two hours for parturients compared with delayed oral feeding after cesarean section: A systematic review and meta-analysis. BMC Pregnancy Childbirth 2024; 24(1):623. doi: 10.1186/s12884-024-06838-9.
6. Brundha N, Biradar A, Patil N, Yaliwal RG, Biradar P, Gupta N, et al. Chewing gum versus standard care for enhanced bowel recovery after cesarean section: A randomized clinical trial. Cureus 2024; 16(8):e68210. doi: 10.7759/ cureus.68210.
7. Weimann A, Braga M, Carli F, Higashiguchi T, Hubner M, Klek S, et al. ESPEN practical guideline: Clinical nutrition in surgery. Clin Nutr 2021; 40(7):4745-61. doi: 10.1016/j. clnu.2021.03.031.
8. Craciunas L, Sajid MS, Ahmed AS. Chewing gum in preventing postoperative ileus in women undergoing caesarean section: A systematic review and meta-analysis of randomised controlled trials. BJOG 2014; 121(7):793-9; discussion 799. doi: 10.1111/1471-0528.12696.
9. LaRosa JA, Saywell RM Jr, Zollinger TW, Oser TL, Erner BK, McClain E. The incidence of adynamic ileus in postcesarean patients. Patient-controlled analgesia versus intramuscular analgesia. J Reprod Med 1993; 38(4):293-300.
10. Kalff JC, Hierholzer C, Tsukada K, Billiar TR, Bauer AJ. Hemorrhagic shock results in intestinal muscularis intercellular adhesion molecule (ICAM-1) expression, neutrophil infiltration, and smooth muscle dysfunction. Arch Orthop Trauma Surg 1999; 119(1-2):89-93. doi: 10.1007/s0040 20050363.
11. Brunicardi FC, Andersen DK, Billiar TR, Dunn DL, Hunter J, Matthews J, et al. Schwartz’s principles of surgery. McGraw-Hill; 2019. 11^th ed. Available from: httpss://access medicine.mhmedical.com/book.aspx?bookid=2576.
12. Aydinli HH, Aytac E, Remzi FH, Bernstein M, Grucela AL. Factors associated with short-term morbidity in patients undergoing colon resection for Crohn's disease. J Gastrointest Surg 2018; 22(8):1434-41. doi: 10.1007/s11605-018- 3763-4.
13. WHO. Daily iron and folic acid supplementation during pregnancy. (Last updated: 26 July 2024). Available from: httpss://www.who.int/tools/elena/interventions/daily-iron- pregnancy.
14. Le Q, Liou DZ, Murrell Z, Fleshner P. Does a history of postoperative ileus predispose to recurrent ileus after multistage ileal pouch-anal anastomosis? Tech Coloproctol 2013; 17(4):383-8. doi: 10.1007/s10151-012-0942-2.
15. Rausch T, Beglinger C, Alam N, Gyr K, Meier R. Effect of transdermal application of nicotine on colonic transit in healthy nonsmoking volunteers. Neurogastroenterol Motil 1998; 10(3):263-70. doi: 10.1046/j.1365-2982.1998.00 105.x.
     
16. Ramesh BA, Evans JT, Marietta M, BK J. Suction Drains. 2025 Feb 23. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. Available from: httpss:// www.ncbi.nlm.nih.gov/books/NBK557687/.
17. Eleftheriou M, Doulberis M, Pouliakis A, Kareklas D, Toutouzas K, Zografos G, et al. The drain debate: A prospective controlled trial on crite-ria-based prophylactic drain use in total gastrectomy for esophagogastric junctional or gastric cancer (The DRAG Study). Preprints. 2024. 2024121613. doi: 10.20944/preprints202412.1613.v1.
18. O'Connor TW, Hugh TB. Abdominal drainage: A clinical review. Aust N Z J Surg 1979; 49(2):253-60. doi: 10. 1111/j.1445-2197.1979.tb04951.x.
19. Liao CS, Shieh MC. Laparoscopic retrieval of retained intraperitoneal drains in the immediate postoperative period. J Chin Med Assoc 2011; 74(3):138-9. doi: 10.1016/j. jcma.2011.01.030.
20. Shrestha P, Kunwar A, Rijal Y, Aryal S, Adhikari YR, Bhattarai SL, et al. Anchored fallopian tube through the drain tube: A rare case report. Clin Case Rep 2022; 10(5):e05917. doi: 10. 1002/ccr3.5917.
21. Turan A, Khanna AK, Brooker J, Saha AK, Clark CJ, Samant A, et al. Association between mobilization and composite postoperative complications following major elective surgery. JAMA Surg 2023; 158(8):825-30. doi: 10.1001/jamasurg. 2023.1122.