Effect of Copper on the Healing of Obstetric Wounds

This is a double blind randomised controlled pilot study to assess feasibility of copper impregnated wound dressings and maternity pads for the healing of obstetric wounds. All women having a caesarean section or with perineal sutures after a vaginal delivery will be recruited from the antenatal clinic (in case of an elective caesarean section) or from the maternity wards within Croydon Health Services. All women will be given a patient information sheet describing the study prior to consent and will be giving adequate time to read the information before signing the Informed consent. Participants will be followed up via a telephone questionnaire 7, 14 and 30 days after the delivery.

Randomisation:

After inclusion all participants will be randomised for a wound dressing or maternity pad with (study group) or without copper (control group). The two sets of wound dressings and pads will be marked "A" or "B". Both the clinician and the participant will be blinded to the randomised group. Only the manufacturer will be aware of which group contains copper.

Copper impregnated dressings:

As soon as possible, but within 12 hours after primary closure of the caesarean section incision, the randomised study dressing will be applied. The two study dressings were equivalent to the dressing normally used within this Trust, except the foam of one set of dressings was impregnated with 3% copper oxide ions. The two sets of wound dressings were marked "A" and "B" and both the women and clinician were blinded to the randomised group. According to local protocol the wound dressing will be left intact for 7 days following surgery and will be renewed if necessary.

Copper impregnated maternity pads As soon as possible, but within 12 hours after suturing, women will be asked to wear the study maternity pads, which will be provided. The two sets of study maternity pads will be equivalent to the currently recommended pads, except that one set of pads will have a thin top layer of non-woven polyester fibres with 3% copper oxide ions permanently attached to it. Women will be asked to use the pads for 14 days.

Patient data, history and physical examination:

Demographic data such as age, ethnicity, height and weight will be collected as well as obstetric data and delivery details. Past medical history such as concomitant (chronic) diseases and the use of medications will be obtained. Wound infection will be assessed via a telephone questionnaire after 7, 14 and 30 days after delivery. The data will be stored in a secure room within Trust facilities. All electronic data will be stored within password protected IT system within the Trust, which is only accessible by the clinical and research team.

Questionnaire:

For the assessment of surgical site infection, the Post Discharge Questionnaire used by the HPC surgical site infection surveillance will be used, which is according to the worldwide used definition of surgical site infection by the CDC.

Statistical analysis Statistical analysis will be performed using SPSS version 20.0 or higher. Infection rates in the perineal tear group and the caesarean section group will be analysed seperately. The infection rates in the study group (with copper) will be compared to the control group and possible risk factors for infection will be explored. the Chi-Square will be used to analyse categorical variables and the T-test or Mann Whitney-U test will be used to analyse continuous variables. Multivariable logistic regression will be used to investigate risk factors for development of infection.

Sample size calculation Since the effect of copper on infection rates is currently unknown, we will conduct a pilot study for 12 months.

Inclusion criteria

• Aged 18 or over
• Delivered by caesarean section (emergency or elective), or vaginally, sustaining a perineal tear or episiotomy which needed to be sutured
• Ability to understand and read the content of the patient information sheet (in English, via an interpreter if needed and possible)
• Ability to give informed consent

Exclusion criteria

• Inability to give consent
• Fetal or neonatal death or poor neonatal outcome
• Obstetric anal sphincter injuries
• Included in another study on postpartum infection
• Wilson's disease
• Allergy to copper