Antiseptic Vaginal Preparation for Reducing Infection Morbidity at Caesarean Section: A Randomised Controlled Trial

Background

Caesarean section (CS) is one of the most commonly performed obstetric surgical procedures worldwide and remains an essential intervention for reducing maternal and perinatal morbidity and mortality when medically indicated. Globally, CS rates have increased substantially over the past two decades and currently account for more than 21% of all births, with projections suggesting a rise to approximately 29% by 2030 [1]. Despite its lifesaving benefits, caesarean delivery is associated with significantly higher maternal morbidity compared with vaginal birth, particularly postoperative infectious complications [2].

Post-caesarean maternal infection is a major contributor to maternal morbidity and mortality globally, especially in low- and middle-income countries. Caesarean delivery increases the risk of postpartum infection by five- to twenty-fold compared with vaginal delivery [3]. Common infectious morbidities following CS include puerperal sepsis, endometritis, postoperative fever, urinary tract infection, and surgical site infection (SSI) [4]. Severe complications such as septic shock, pelvic abscess, necrotizing fasciitis, bacteraemia, and septic pelvic thrombophlebitis may occur and can result in prolonged hospitalization, infertility, chronic pelvic pain, increased healthcare costs, and maternal death [5]. Maternal infections account for approximately 10% of maternal deaths worldwide [6].

The pathogenesis of post-caesarean infection is closely linked to contamination of the uterine cavity and surgical wound by endogenous vaginal and cervical microorganisms during surgery [7]. The risk is heightened in women with prolonged labour, ruptured membranes, repeated vaginal examinations, prolonged operative time, obesity, anaemia, and emergency caesarean section [8]. Although prophylactic antibiotics have significantly reduced postoperative infectious morbidity, infection rates remain high in many resource-limited settings despite adherence to standard preventive protocols [9]. Furthermore, indiscriminate antibiotic use contributes to the growing burden of antimicrobial resistance, creating the need for additional effective and affordable preventive strategies [10].

Preoperative vaginal cleansing with antiseptic agents has emerged as an adjunctive measure aimed at reducing bacterial colonization within the genital tract before uterine incision [11]. Povidone-iodine and chlorhexidine are the most commonly used agents because of their broad-spectrum antimicrobial activity, availability, and low cost [12]. Several randomized controlled trials and systematic reviews have demonstrated that vaginal preparation before caesarean section reduces postoperative endometritis, febrile morbidity, and wound infection [13][14]. Consequently, the World Health Organization recommends vaginal cleansing for women undergoing caesarean section, particularly those in labour or with ruptured membranes [15].

However, uncertainty persists regarding the superior antiseptic agent for vaginal preparation before caesarean section. While some studies suggest that povidone-iodine is more effective in reducing postoperative infectious morbidity, others report comparable or better outcomes with chlorhexidine [16][17]. Additionally, there is limited evidence from sub-Saharan Africa comparing both agents, despite the disproportionately high burden of post-caesarean infection in the region. This gap in knowledge limits evidence-based recommendations for selecting the optimal antiseptic agent in low-resource settings.

This study was therefore justified by the need to identify the more effective vaginal antiseptic agent for reducing post-caesarean maternal infectious morbidity. The study aimed to compare the effectiveness of 5% povidone-iodine and 0.3% chlorhexidine vaginal preparation in reducing post-caesarean infections among women undergoing caesarean section.

Methodology

Study Area

This study was conducted at the Department of Obstetrics and Gynaecology, Ladoke Akintola University of Technology Teaching Hospital (LAUTECH-TH), Ogbomoso, Oyo State, Nigeria. The Obstetrics and Gynaecology Department records an average of 2,500 deliveries annually, with a caesarean section rate of approximately 35%.

Study Design

This study was a hospital-based, single-blind randomised controlled trial conducted over six months.

Study Population

The study population comprised pregnant women scheduled for caesarean section at LAUTECH Teaching Hospital, Ogbomoso, during the study period who provided informed consent

Exclusion Criteria

Participants were excluded if they had a known hypersensitivity or allergy to chlorhexidine or povidone-iodine, had active herpes simplex virus infection, had gynaetresia, were immunocompromised, including patients with HIV infection, diabetes mellitus, malnutrition, or those receiving long-term corticosteroid therapy.

Instrument for Data Collection

Data were collected using a structured pro forma adapted from a previous related study. The instrument was designed to obtain information relevant to the study objectives.

Sample Size Determination

The minimum sample size was determined using Zhong's formula for calculating the sample size of a clinically equivalent randomised controlled trial for dichotomous variables [18].

N= sample size for each group,

Z =standard normal deviate for a one- or two-sided x,

δ₀ = a clinically accepted margin,

Substituting for,

Z_1-α = 1.96 (where α = 0.05)

Z_1-β = 0.845 (where β= 0.20)

δ₀ = 10

P = 7.5 (from a study by Nisreen et al.) [19]

N = 2 × (28.05)² ×0.0694

N = 2 ×786.80 ×0.0694

N =109.21 ≈ 109

Providing 10% attrition, 109/10 ≈11

N = 120.

Therefore, a minimum of 120 participants was recruited into each study arm, giving a total sample size of 240 participants.

Sampling Technique, Randomization, and Study Procedure

Participant Recruitment and Randomization

Eligible participants were recruited consecutively from the antenatal and labour wards after counselling and obtaining written informed consent. Participants were randomly assigned to either the povidone-iodine vaginal cleansing group or the chlorhexidine vaginal cleansing group using computer-generated randomization. Allocation concealment was achieved using sealed opaque envelopes. The study was single-blinded, as participants were unaware of the intervention administered.

Intervention Procedures

Group 1: Preoperative Vaginal Cleansing with 5% Povidone-Iodine

Within five minutes before abdominal skin preparation and following administration of spinal anaesthesia, participants were positioned dorsally with legs supported. Sterile gloves were worn, and two sterile gauze swabs held with sponge-holding forceps were soaked in 5% povidone-iodine solution (WOSAN Solution®, Jawasil; NAFDAC No. A4-0939).

The vaginal walls were cleansed for approximately one minute using a rotational motion from the vaginal apex to the introitus, ensuring adequate coverage of the anterior, posterior, and lateral vaginal walls. Following the procedure, urethral catheterization was performed. Gloves were changed before routine abdominal preparation with chlorhexidine and methylated spirit. Caesarean sections were performed.

Group 2: Preoperative Vaginal Cleansing with 0.3% Chlorhexidine

Participants randomized to this group underwent the same procedure as described for Group 1, except that 0.3% chlorhexidine solution (Savlon®, Johnson & Johnson; NAFDAC No. 04-1289) was used for vaginal cleansing.

Postoperative Care and Follow-up

After surgery, sterile gauze dressings were applied to the wound site and secured with adhesive plaster. Participants were advised to keep the dressing dry. Dressings were routinely changed on the third postoperative day or earlier if soaked. Wounds were assessed during admission and at discharge.

Participants with suspected surgical site infection had wound swabs collected for microscopy, culture, and sensitivity testing. Those with symptoms suggestive of endometritis had endocervical swabs taken for microbiological evaluation.

All participants received prophylactic intravenous ceftriaxone at induction of anaesthesia and were monitored daily during admission for signs of puerperal sepsis and surgical site infection. Follow-up assessments were conducted at two, three, and four weeks postpartum.

Outcome Measures

Primary Outcome

The primary outcome measure was the proportion of participants who developed post-caesarean endometritis.

Secondary Outcomes

Secondary outcome measures included: Postoperative fever; Surgical site infection; Local adverse reactions such as vaginal itching or burning sensation; Anaphylactic reactions to the study agents.

Subgroup analyses were performed among participants with established risk factors for puerperal sepsis, including prolonged labour, ruptured membranes, and emergency caesarean section.

Definition of Clinical Outcomes

Post-caesarean Endometritis

Defined as a temperature ≥38°C occurring at least 24 hours after surgery in association with foul-smelling lochia, lower abdominal pain, and/or uterine tenderness.

Surgical Site Infection

Defined by the presence of erythema, purulent discharge, or wound breakdown.

A modified Southampton Wound Infection Scoring System was used for grading wound infection severity as follows:

Grade 0: Normal healing without signs of inflammation;

Grade I: Normal healing with mild bruising or erythema;

Grade II: Erythema with additional signs of inflammation;

Grade III: Serosanguinous wound discharge;

Grade IV: Purulent wound discharge;

Grade V: Purulent discharge with wound dehiscence.

Measures to Reduce Bias

To minimize systematic bias and inter-observer variation, all participating resident doctors received standardized training before commencement of the study. Training covered participant recruitment, randomization procedures, vaginal cleansing techniques, wound assessment, and the use of the Southampton wound infection scoring system.

Uniform protocols were used for skin preparation, vaginal cleansing, caesarean section procedures, specimen collection, and postoperative assessment across both study groups. Potential confounding variables were controlled through matching and standardised perioperative management.

Data Management and Statistical Analysis

Data obtained from participants and case records were entered into a structured pro forma, cleaned, coded, and analysed using IBM SPSS Statistics version 27.

Continuous variables were summarized using means and standard deviations, while categorical variables were presented as frequencies and percentages. Associations between categorical variables were assessed using the Chi-square test. Relative risks and 95% confidence intervals were calculated for outcome variables. Statistical significance was set at a p-value of less than 0.05. Findings were presented using tables and charts where appropriate.

Ethical Considerations

Ethical approval for the study was obtained from the Ethics Review Committee of LAUTECH Teaching Hospital, Ogbomoso (Approval Number: LTH/OGB/EC/2023/385). Written informed consent was obtained from all participants before enrolment. Participants were informed about the purpose, benefits, and potential risks of the study, and confidentiality of all information obtained was maintained throughout the study.

Participants were assured of their right to decline participation or withdraw from the study at any stage without any adverse consequences to their care.

The study was registered with the Pan-African Clinical Trial Registry (PACTR) under the registration number: PACTR202411605053903.

Results

Two hundred and forty participants were recruited for this study. Fifteen were excluded from the analysis because they were lost to follow-up. One hundred and ten were in the chlorhexidine group, and one hundred and fifteen were in the povidone-iodine group. Per-protocol analysis was employed in this study.

Table 1 compares sociodemographic characteristics between participants in the povidone-iodine and chlorhexidine groups. The mean ages of participants were comparable between groups (30.35 ± 5.00 years vs 31.14 ± 4.84 years), with no statistically significant difference (t = -1.314, p = 0.191). Most participants in both groups were aged between 21 and 40 years.

The majority of participants were married, accounting for 80.0% in the povidone-iodine group and 81.8% in the chlorhexidine group. Educational status was similarly distributed, with over half of the participants having secondary education and approximately two-fifths having tertiary education. Yoruba ethnicity predominated in both groups, while artisans constituted the largest occupational category.

There were no statistically significant differences between the two groups regarding age distribution, marital status, educational level, tribe, or occupation (p > 0.05). This indicates that both study groups were sociodemographically comparable at baseline.

Table 2 compares the obstetric characteristics of participants in the povidone-iodine and chlorhexidine groups. Most participants in both groups had low parity (0–3), accounting for 72.2% and 69.6%, respectively. The majority also had term pregnancies, while preterm and post-term pregnancies were less common. Approximately two-thirds of participants in both groups were booked for antenatal care and underwent emergency caesarean section. Membrane rupture was present in about 62% of participants in both groups. There were no statistically significant differences in parity, gestational age, booking status, type of caesarean section, or membrane rupture between the two groups (p > 0.05).

Table 3 compares obstetric characteristics between participants in the povidone-iodine and chlorhexidine groups. The most common indications for caesarean section in both groups were previous caesarean scar (≥2 previous scars) and failed vaginal birth after caesarean section (VBAC). Prolonged labour/poor progress and non-reassuring foetal status were also notable indications. However, there was no statistically significant difference in the indications for caesarean section between the two groups (p = 0.204).

Most surgeries lasted 60 minutes or less in both groups, while approximately one-third lasted more than 60 minutes. Senior registrars performed most of the surgeries in both groups. Additionally, the majority of participants had hospital stays of seven days or less following surgery. No statistically significant differences were observed between the two groups regarding duration of surgery, cadre of surgeon, or duration of hospital stay (p > 0.05)

Table 4 compares the incidence of post-caesarean maternal infection between the povidone-iodine and chlorhexidine groups. Overall, post-caesarean maternal infection was lower among participants in the povidone-iodine group (9.2%) compared with the chlorhexidine group (18.4%), although the difference was not statistically significant (p = 0.072).

Surgical site infection (SSI) occurred in 2.5% of participants in the povidone-iodine group and 6.7% in the chlorhexidine group. The relative risk showed a slightly increased risk in the chlorhexidine group (RR = 1.073; 95% CI: 1.022–1.127), although this difference was not statistically significant (p = 0.812).

Puerperal sepsis was significantly lower in the povidone-iodine group (6.7%) compared with the chlorhexidine group (11.7%) (p = 0.018). Participants in the chlorhexidine group were approximately five times more likely to develop puerperal sepsis than those in the povidone-iodine group (RR = 5.509; 95% CI: 1.157–26.237).

Table 6 shows no statistically significant difference in post-caesarean maternal infections between the povidone-iodine and chlorhexidine groups for both elective and emergency caesarean sections (all p-values >0.05). In elective procedures, chlorhexidine showed slightly higher rates of puerperal sepsis (RR=1.984, 95% CI: 0.749–2.885) and surgical site infection (RR=1.872, 95% CI: 0.444–2.895). Similarly, in emergency caesarean sections, chlorhexidine had higher puerperal sepsis (RR=1.716, 95% CI: 0.239–2.147) and surgical site infection rates (RR=1.041, 95% CI: 0.015–2.088).

Discussion

This study compared the effectiveness of povidone-iodine and chlorhexidine vaginal cleansing in reducing post-caesarean infectious morbidity. The findings demonstrated that women who received povidone-iodine vaginal cleansing had lower overall rates of post-caesarean maternal infection compared with those who received chlorhexidine. Importantly, puerperal sepsis, which represented the primary outcome of this study, occurred significantly less frequently in the povidone-iodine group. These findings suggest that povidone-iodine may provide superior prot-ection against ascending genital tract infections following caesarean section.

The observed reduction in puerperal sepsis among women who received povidone-iodine is consistent with previous studies and meta-analyses reporting the effectiveness of preoperative vaginal antisepsis in lowering postoperative endometritis rates after caesarean delivery. Roeckner et al. reported that 1% povidone-iodine was the most effective vaginal antiseptic for preventing post-caesarean endometritis in a network meta-analysis [12]. Similarly, Caissutti et al. found that vaginal cleansing before caesarean delivery significantly reduced postoperative endometritis, particularly among women in labour or with ruptured membranes [11]. The antimicrobial activity of povidone-iodine against a broad spectrum of aerobic and anaerobic organisms may explain its superior efficacy in reducing puerperal sepsis.

Although surgical site infection (SSI) rates were lower in the povidone-iodine group, the difference between the two antiseptics was not statistically significant. This finding agrees with the randomized comparator-controlled trial by Lakhi et al., which reported similar wound infection rates between chlorhexidine and povidone-iodine vaginal preparation groups [16]. Likewise, Ramadan et al. observed no significant difference in postoperative wound infection rates between the two antiseptic agents [13]. The absence of statistical significance in SSI reduction in this study may be related to the relatively low incidence of wound infections overall, reducing the power to detect meaningful differences.

The lower overall maternal infection rate observed among women who received povidone-iodine supports evidence from several systematic reviews demonstrating the value of vaginal antisepsis before caesarean delivery. Fadlalmola et al. concluded that povidone-iodine was associated with fewer postoperative infections compared with other antiseptic solutions [14]. Marrapodi et al. also demonstrated that vaginal cleansing significantly reduced postoperative infectious morbidity after caesarean section [20]. These findings collectively reinforce recommendations supporting routine vaginal preparation before caesarean delivery, especially among women with established risk factors for infection.

Subgroup analysis based on membrane status revealed that women with ruptured membranes had higher rates of puerperal sepsis and SSI in the chlorhexidine group compared with the povidone-iodine group, although these differences were not statistically significant. This trend aligns with the findings of Temming et al., who demonstrated that vaginal cleansing before unscheduled caesarean delivery reduced infectious morbidity among women exposed to prolonged labour and ruptured membranes [17]. Ruptured membranes increase the risk of ascending bacterial contamination; therefore, antiseptic agents with stronger broad-spectrum activity may provide greater protection in this population.

Similarly, women who underwent emergency caesarean section experienced higher infection rates in the chlorhexidine group than in the povidone-iodine group. Emergency procedures are commonly associated with prolonged labour, repeated vaginal examinations, and delayed surgery, all of which increase bacterial exposure and postoperative infection risk. Previous evidence indicates that vaginal cleansing is particularly beneficial in emergency caesarean sections [11][17]. The lower infection rates observed with povidone-iodine in this subgroup, therefore, support its usefulness in high-risk obstetric settings.

The present study also assessed secondary outcomes, including postoperative fever, local adverse reactions, and anaphylactic reactions. No serious adverse effects attributable to either antiseptic agent were observed. This finding is comparable to previous studies demonstrating the safety of both povidone-iodine and chlorhexidine when used for vaginal preparation before caesarean section [16,21]. Although chlorhexidine is often preferred for its sustained antimicrobial activity, povidone-iodine remains inexpensive, widely available, and highly effective against polymicrobial vaginal flora implicated in puerperal infections.

Interestingly, some studies have reported contrasting findings favouring chlorhexidine. Garcia-So et al. demonstrated greater bactericidal activity with chlorhexidine vaginal preparation compared with povidone-iodine [17,21]. Likewise, some systematic reviews suggested that chlorhexidine-based preparations may reduce SSI rates more effectively than povidone-iodine under certain surgical conditions [22,23]. However, these studies frequently focused on skin antisepsis rather than vaginal cleansing, and variations in concentration, preparation technique, and study populations may account for differences in outcomes.

The strengths of this study include the comparability of baseline sociodemographic and obstetric characteristics between the two groups, thereby minimizing confounding. Additionally, subgroup analyses among women with ruptured membranes and emergency caesarean sections provided clinically relevant insight into high-risk populations that are particularly vulnerable to post-caesarean infections.

Limitations of this study were that it was a single centre trial and about 15 participants were lost to follow-up with analysis done per-protocol.

Conclusion

This study demonstrated that vaginal cleansing with povidone-iodine before caesarean section was associated with lower rates of puerperal sepsis, surgical site infection, and overall post-caesarean maternal infection compared with chlorhexidine. The reduction in puerperal sepsis was statistically significant, suggesting that povidone-iodine may be more effective in preventing postoperative infectious morbidity.

Routine preoperative vaginal cleansing with povidone-iodine may therefore be considered an effective strategy for reducing post-caesarean maternal infections, particularly in high-risk obstetric populations.

The benefit appeared more pronounced among women with ruptured membranes and those undergoing emergency caesarean section.

Declaration

Ethical Approval

Ethical approval was obtained from the Ethics Review Committee of LAUTECH Teaching Hospital, Ogbomoso (Approval No. LTH/OGB/EC/2023/385). Written informed consent was obtained from all participants, and confidentiality and the right to withdraw were ensured. The study was registered with the Pan-African Clinical Trial Registry (PACTR202411605053903).

Funding Statement

Self-financed

Conflict of Interest

None declared

Availability of Sata and Materials

All data from this study can be obtained from the corresponding author upon a reasonable request.

Acknowledgement

I acknowledge resident doctors in our research team and the authors cited in this study