Antenatal care (ANC) is a critical measure to reduce maternal and perinatal morbidity and mortality. However, there are issues of too many visits and cumbersome procedures of ANC in many maternity hospitals of China. In the past year, the COVID-19 pandemic has brought huge impacts on the health systems, but also gives a valuable chance to review healthcare delivery strategies. Reduced-visit antenatal care models combined with remote monitoring have been recommended and implemented at most hospitals in China during the pandemic, particularly for low-risk pregnant women. However, due to limited evaluations of the cost-effectiveness, policymakers remain confused on how to appropriately integrate online delivery strategies with routine models to improve ANC quality and efficiency sustainably at scale.

This is a single-blind, randomized controlled trial, conducted among low-risk pregnant women at Peking University Third Hospital in Beijing, to evaluate the effectiveness, acceptability, and cost of a reduced-visit ANC model combined with online monitoring compared to the routine ANC model. Participants will be randomly assigned in a 1:1 ratio to receive 12 routine ANC visits or the new ANC model consist of 9 outpatient visits and three online services with remote monitoring on their weight, heart rate, blood pressure, urinary protein, blood glucose, and fetal movement. CSOG-recommended ANC services will be provided to all participants. According to the study objectives and hypotheses, the primary outcome is adverse maternal and perinatal outcomes for non-inferiority analysis, and the secondary outcomes are acceptability and cost for superiority analysis.

Main project problem Is it possible to develop a reduced-visit antenatal care model for low-risk pregnant women, which is more convenient and lower-cost while has same protection for maternal and fetal health compared with routine care? Goals and objectives This project aims to evaluate the acceptability, cost and effectiveness of a reduced-visit antenatal care model combined with online monitoring for low-risk pregnant women, so as to provide evidence for improving antenatal care delivery strategies.

Methods Design, settings and participants A randomized controlled trial will be conducted at the obstetric outpatient department of a tertiary hospital in Beijing between 2022 and 2024. Pregnant women meeting the following criteria are eligible: at 20-34 years old, at <8 weeks of gestation, being registered and scheduled for antenatal care and delivery at this hospital, and without adverse pregnancy-related or medical conditions prior to registration.

Randomization and blinding Pregnant women who complete the first antenatal examination will be assessed for eligibility and recruited by an obstetric nurse. After informed consent is obtained, participants will be randomly assigned to either experimental or control groups using a computer program by an independent statistician blinded to participants' characteristics and health conditions. Obstetricians and nurses provide assigned antenatal care. The outcome assessors and data statistical analysts will be blinded to antenatal care allocation.

Intervention and control methods Participants in the control group will be scheduled for routine 12 clinic visits for antenatal examinations. Participants in the experimental group will be scheduled for 9 clinic visits and additional 3 times of services provided through an online medical service platform. Home self-monitoring for weight, heart rate, blood pressure, urinary protein, blood glucose, and fetal movement is recommended in experimental group, according to the guideline of the Chinese Society of Obstetrics and Gynecology (CSOG) . Such a combination is generally in line with the WHO and CSOG recommendations. Participants developing any complications during pregnancy will be treated according to the conventional clinical pathway, regardless of their grouping.

Data collection and evaluation Participants will be followed up until delivery. Antenatal care time, type and practices will be recorded in detail. Effectiveness, as the primary outcome, will be evaluated by comparing maternal and perinatal outcomes between the two groups. The health outcomes can be extracted from medical records, including maternal, fetal, and neonatal complications, cesarean delivery, preterm, birthweight, Apgar scores, etc. The secondary outcomes include acceptability and cost of the new antenatal model. Acceptability will be measured by comparing satisfaction with antenatal care and pregnancy-related stress. We will measure pregnant women's expectations with prenatal care at 8 weeks of gestation and measure their satisfaction with prenatal care after each visit/contact, using the Patient Expectations and Satisfaction with Prenatal Care (PESPC) instrument. Pregnancy-related stress will be measured at 12, 26 and 36 weeks of gestation by the Pregnancy Stress Rating Scale (PSRS) which has been well validated and widely used (Chen, 2015). Cost of both routine and reduced-visit antenatal care models will be measured from the perspective of both service providers and pregnant women. For a pregnant woman during whole pregnancy, the cost of providing routine antenatal care is calculated by multiplying the average time spent by clinicians and nurses by their average hourly income, and the cost of obtaining antenatal care is calculated by summing the following items: (a) Direct medical cost; (b) Direct non-medical costs, including transportation expenses, accompanying expenses, accommodation expenses, etc. for obtaining prenatal health care services; (c) Indirect costs, calculated by multiplying the working hours delayed by the participants and their families due to antenatal care throughout pregnancy by their normal average hourly income.

Sample size The sample size can be calculated based on expected effectiveness which is considered as the most important endpoint. Given the estimated composite rate of 15% for maternal and perinatal adverse outcomes, a sample size of 1762 patients (881 in each group) would be required with 5% (two-sided) type I error, 80% power, and 10% attrition using a 5% non-inferiority margin.

Statistical Analysis Both intention-to-treat and per-protocol analyses will be performed to account for participants with protocol violations. Satisfaction with antenatal care, pregnancy-related stress, cost, and health outcomes will be compared by arm using independent t-test or one-way analysis of variance for continuous variables and χ2 test or Fisher's exact test for nominal variables. If appropriate, non-inferiority tests will be used by taking a one-sided test of 2.5%, a non-inferiority value of 5%. Multivariable adjusted analyses will be performed to detect the differences more accurately after adjusting for baseline characteristics.

Cost-effectiveness analysis A cost-effectiveness analysis comparing the two ANC models will be conducted by estimating the incremental cost-effectiveness ratios (ICERs) from the perspective of both providers and pregnant women. ICERs are computed by dividing the incremental costs with the differences between the intervention and control groups in primary and secondary outcomes. A sensitivity analysis will be conducted to assess the sensitivity of the cost-effectiveness results with respect to variations in key parameters, including cost.

Expected results and products By the trial, we expect to evaluate the acceptability, cost and effectiveness of the reduced-visit antenatal care model combined with online monitoring. The model will be widely recommended as an alternative method to delivery antenatal care if meeting expectation.

Inclusion Criteria:

• Aged 19-34 years, ≤8 weeks of gestation, registered and scheduled for ANC and delivery at Peking University Third Hospital, and documented as low risk.

Exclusion Criteria:

• Includes any of the following pregnancy-related or medical conditions: pregnancies by in vitro fertilization, multifetal gestation, BMI ≥28, diabetes, hypertension disorders, thyroid diseases, circulatory diseases, respiratory diseases, nephropathy, inflammatory bowel disease, hepatopathy, coagulopathies, immunodeficiency conditions, mental health disorders, genetic disorders, >2 pregnancy losses, history of preterm delivery at <37 weeks of gestation or stillbirth, and other conditions judged by obstetricians as high-risk pregnancy.

Requested data for public purpose or research transparency will be provided via the corresponding author after 36 months following trial completion.

Requested data for public purpose or research transparency will be provided via the corresponding author after 36 months following trial completion.

Requested data for public purpose or research transparency will be provided via the corresponding author. The e-mail address is weiyuanbysy@163.com.

ANC allocation will be concealed from investigators who will enroll and assign the participants. Participants and care providers will not be masked to the allocation because of the nature of the ANC, while the outcome assessors and data statistical analysts will be blinded.