The goal of this clinical trial is to learn which antibiotic regimen works best to prevent infection in pregnant women whose waters break early (preterm, pre-labour rupture of membranes, or PPROM) and assess the health outcomes of babies born to pregnant women who have received these antibiotics.

PROMOAT aims to answer the question: Which antibiotic or combined antibiotic regimen most effectively prevents infection in pregnant women with PPROM < 37+0 weeks' gestation.

Researchers will compare three antibiotic regimens already used in clinical practice to prevent infection in pregnant women with PPROM.

Participants will be randomly allocated to the antibiotic regimen they will follow for seven days, or until birth (whichever is earlier). All antibiotics will be taken orally.

Neonatal health outcomes will be collected at 42 weeks postmenstrual age and maternal birth and postpartum care outcomes assessed at 42 days postpartum.

Questionnaires will capture maternal mood at time of consent and at 42 days postpartum. Antibiotic tolerance will be assessed at the time antibiotic treatment is ceased.

This trial will be undertaken as part of the PLATIPUS trial (NCT06461429).

PROMOAT aims to determine which of the most common antibiotic regimens are most effective in preventing infection in pregnant people with PPROM to improve health outcomes for their infants. PROMOAT is a pregnancy domain within the PLATIPUS adaptive platform trial (NCT06461429).

Preterm prelabour rupture of membranes (PPROM) precedes 30-40% of spontaneous preterm births and is an important cause of maternal and neonatal infection. Membrane rupture provides an entry point for microbes from the vagina to ascend into the uterine cavity, exposing the mother and the fetus to infectious pathogens leading to poor maternal and neonatal outcomes. Mothers with PPROM are at increased risk of haemorrhage, hysterectomy, sepsis, intensive care admission and death. Preterm infants exposed to in-utero infection are at higher risk of poor short- and long-term outcomes, including neonatal sepsis, neurodevelopmental delay, cerebral palsy, chronic lung disease and death.

Neonatal sepsis is the third most common cause of newborn deaths (~340,000 per year) and prevention is a major research priority, Neonatal sepsis due to pathogens acquired after PPROM may present in the first days of life and result in bacteraemia, pneumonia and meningitis. The most common pathogens associated with early-onset neonatal sepsis are Streptococcus agalactiae (aka Group B Streptococcus: GBS), Escherichia coli and Ureaplasma sp. Mortality is highest in the most immature infants, with a 54% case fatality rate in infants born before 24 weeks' gestation.

The goal in managing pregnancies complicated by PPROM is to prolong the pregnancy to enable fetal maturity without an increased risk of infection (acquired while the fetus remains in utero). Antibiotic prophylaxis has been shown to increase latency to birth but there is limited evidence to guide antibiotic choice to prevent infection in PPROM.

In PROMOAT, pregnant women with PPROM will be randomly assigned to receive one of the three intervention arms:

• Erythromycin
• Azithromycin, or
• Erythromycin and Amoxicillin.

Health outcomes will be assessed using the PLATIPUS Ordinal Outcome Scale, at 42 weeks' postmenstrual age or discharge home, whichever is earliest.

A short questionnaire at Day 7 (or birth, whichever is earlier) will measure compliance and antibiotic tolerance. A maternal and family health questionnaire will be collected at Day 42 postpartum.

PLATFORM ELIGIBILITY

Participants must meet all core PLATIPUS platform inclusion criteria:

• Considered to be at risk of birth before 37 weeks gestation (spontaneous and provider-initiated)
• Receiving pregnancy care at a participating site (hospital) at the time of eligibility assessment and
• Meet eligibility criteria for one or more platform domains.

Participants will be excluded from participation if they meet any core PLATIPUS platform exclusion criteria:

• Inability to consent for themselves
• Perinatal death is deemed to be imminent and inevitable during the next 24 hours (at time of screening).

Pregnant women and people who meet ALL of the core platform inclusion criteria and none of the exclusion criteria will be considered for PROMOAT-specific eligibility.

PROMOAT-SPECIFIC ELIGIBILITY

Platform-eligible participants must meet all PROMOAT-specific inclusion criteria:

1. Women with singleton or multiple pregnancies complicated by preterm prelabour rupture of membranes (PPROM) < 37+0 weeks' gestation as determined by the treating clinician and standard criteria:

   • Maternal history consistent with loss of fluid per vagina
   • Evidence of a pool of fluid in the vagina on sterile speculum examination
   • +/- positive testing for IGFBP-1 (Actim PROM) or PAMG-1 (Amnisure) AND

2. Are eligible for at least two treatment arms within the domain

3. The fetus/fetuses are alive at randomisation

4. The pregnancy is continuing and active neonatal management is planned.

Participants will be excluded from participation if they meet core PLATIPUS platform exclusion criteria:

• Inability to consent for themselves OR
• Perinatal death is deemed to be imminent and inevitable during the next 24 hours (at time of screening).

Participants will be excluded from participation if they meet any PROMOAT-specific exclusion criteria:

1. Antibiotic treatment for > 24 hours administered with the aim of preventing infection from PPROM
2. Suspected maternal or fetal infection (chorioamnionitis)
3. Maternal or fetal indication for immediate birth
4. Established preterm labour (cervical dilatation ≥ 3cm AND regular contractions)
5. No appropriate antibiotic available within domain intervention arms due to allergy, contraindications, drug interactions, drug availability, or previous history of antibiotic-resistant infection/s
6. Women with a previous infant affected by GBS sepsis
7. Major congenital fetal anomaly.

Platform-eligible participants who meet all PROMOAT-specific inclusion criteria and none of the PROMOAT-specific exclusion criteria will be eligible to participate in PROMOAT.

Data sharing will align with PLATIPUS (NCT06461429) policy. Version 1, Apr-2024

Once data unblinding no longer compromises the integrity of the trial, a de-identified data set collected for the analysis of domains within PLATIPUS will be made available.

Conditions

1. All domains in which the participant is co-enrolled are closed to recruitment* (*Where one or more domains in which a participant is co-enrolled are not yet closed to recruitment, the participant's data may be provided, without the treatment code, to prevent unblinding in unfinished domains).
2. Primary domain conclusions/analyses have been published, AND
3. The 2-year follow-up of participants within the domain/s of interest is/are complete.

Supporting materials (Core Protocol, Domain-Specific Appendices, Data Dictionaries and Domain-Specific Statistical Analysis Plans) will be available.

Contact: University of Melbourne - info@platipustrial.org.

This is estimated to be approximately six months following the completion of the two-year follow-up of domain participants.

To be determined. Access requests will be subject to review by trial subcommittees. The Trial Steering Committee will approve or disapprove requests. A Data Transfer Agreement and Authorship Agreement signed by relevant parties and evidence of ethical approval will be required.

All parties will be blinded to the assigned intervention.