This will be a proof-of-concept randomised control trial (RCT) study, where 100 pregnant women will be recruited in the first trimester of pregnancy and followed-up until delivery. It aims to test these following hypotheses:

1. pregnancy is a window of opportunity to implement good lifestyle habits of physical activity and exercise as pregnant women are in regular contact with health professionals and are likely motivated and be more confident to carry out these activities according to the guidelines
2. this integrated programme will effective in a healthcare setting, and will bring Singapore's "Guidelines on Physical Activity and Exercise in Pregnancy" guidelines to implementation
3. with enhanced self-efficacy and motivation, the proportion of women engaging in adequate physical activity during pregnancy will increase to meet recommended guidelines.

In Singapore, where national initiatives such as Healthier SG aim to promote active lifestyles, nearly one-third of pregnant women are affected by overweight or obesity (BMI ≥ 23 kg/m²), increasing health risks for both mother and child. These women are typically less physically active than their lean counterparts, a gap that often widens during pregnancy, leading to excessive gestational weight gain and postpartum weight retention that heighten long-term metabolic and cardiovascular risks. Culturally tailored, region-specific strategies are needed to support healthy behaviours during pregnancy. We propose an integrated eHealth prenatal programme offering personalised guidance, credible information, and improved communication with healthcare professionals to overcome existing barriers and promote sustained physical activity-a critical yet under-addressed priority in Asia.

This will be a proof-of-concept randomised control trial (RCT) study, where 100 pregnant overweight/obese women (BMI 23 kg/m2 or above) will be recruited from KK Women's and Children's hospital in the first trimester of pregnancy with consent form completion after meeting the inclusion criteria. After the first baseline visit, all participants will be followed-up in the second and third trimester of the pregnancy.

All participants recruited will be randomised into one of two groups through block-randomization of size 2 to reduce bias and achieve balance in the allocation of participants to intervention arms. All participants will receive standard routine antenatal care, along with an educational leaflet on physical activity and exercise during pregnancy and a wearable tracker. The intervention group will receive the e-IMPACT programme in three parts led by exercise physiologist from the Singapore Sport and Exercise Medicine Centre @ KKH in the first, second and third trimester of pregnancy.

This study will evaluate behavioural, psychological, and health-related outcomes among pregnant participants. Physical activity will be objectively measured using a Fitbit tracker to record steps, activity duration, moderate-to-vigorous physical activity, and energy expenditure, and subjectively using the Pregnancy Physical Activity Questionnaire (PPAQ) to assess self-reported activity, sedentary time, and energy expenditure (MET-min/day). Participants' self-efficacy and motivation to engage in exercise during pregnancy will be assessed at baseline and post-intervention using the Pregnancy Exercise Self-Efficacy Scale (P-ESES) and the Behavioural Regulation in Exercise Questionnaire (BREQ-2). Feasibility, acceptability, and scalability of the e-IMPACT programme will be evaluated through a process evaluation guided by the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework, incorporating feedback from both participants and exercise physiologists. Exploratory outcomes will include sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI), antenatal anxiety and depression measured by the Edinburgh Postnatal Depression Scale (EPDS), and health-related quality of life measured by the EuroQol-5 Dimension (EQ-5D). Gestational weight gain will be determined from medical records, using the first and last recorded gestational weights.

Inclusion Criteria:

1. Pregnant women (First trimester at least 4 weeks gestation)
2. Age 21 years and above
3. BMI 23 kg/m2 and above
4. Physically fit to participate in moderate intensity exercise
5. Singleton pregnancy

Exclusion Criteria:

1. Women who have severe chronic disease such as chronic kidney disease, hypertension, asthma OR
2. Obstetric or medical complications which might preclude women in normal levels of physical activity or exercise during pregnancy.
3. Women who participated in other weight management programmes, or physical activity intervention studies recently (past 6 months) or concurrently
4. Difficulty in understanding the English language

Only participants who self-identify as women and are currently pregnant are eligible to participate.

Individual participant data (IPD) will not be shared due to the sensitive nature of the dataset, which involves pregnant participants and potentially identifiable health and obstetric information.

Although all data will be de-identified, there remains a risk of participant re-identification given the small sample size and the unique combination of demographic and pregnancy-related variables.

Furthermore, consent for open data sharing was not obtained from participants, and sharing IPD beyond the study team would therefore not comply with the approved ethics protocol.

Aggregated results and summary statistics will be shared through publications and conference presentations, in accordance with ethical approval and data protection regulations.