Impact of Exercise Prescription on Obstetric and Neonatal Outcomes

A prospective, longitudinal, single-arm, intervention (prospective cohort) study was conducted in the Obstetric Department of Hospital of Coimbra, Portugal, for a total period of 18 months after a one-year recruitment period between February 2024 and January 2025, with data collection continuing until the final participant had given birth.

Clinical monitoring for high-risk pregnancies takes place solely in a hospital setting. This includes at least monthly visits and standardized trimester ultrasounds, with supplementary scans schedule as needed for fetal development and well-being based on the underlying conditions.

All pregnant patients attending their first obstetric consultation for either Endocrinology/Obstetric (if diagnosis of gestational diabetes or obesity with previous bariatric surgery) or Hypertension/Obstetric (if chronic hypertension) were recruited for the trial.

Study participants were enrolled via screening referrals initiated by both internal or external healthcare providers.

At the first visit, pregnant women were notified of an upcoming telephone contact from the research team. After clinical record verification, a phone interview was conducted to explain the project and collect demographic, anthropometric and obstetric data. After confirming the absence of exercise contraindications, researchers assessed the participants' pre-pregnancy healthy lifestyle habits.

Subsequently, participants received proactive counselling on the exercise modalities most effective for their specific pathologies, including guidance on the intensity, frequency and duration required for optimal health outcomes. This intervention included information on local exercise facilities and access to digital platforms (YouTube Channel - Active Pregnancy) featuring safe, evidence-based activities tailored for pregnancy. Prescriptions were individualized, incorporating patient preferences to determine the most suitable activity types and schedules.

Participants were equipped with a smartwatch to monitor physical activity, specifically tracking heart rate, step count, distance and average speed throughout the pregnancy. They were instructed to activate the device's 'training' mode at the commencement of each exercise session. Subsequently, activity data were synced to a dedicated mobile application for later extraction and analysis from the research team.

Follow-up telephonic consultations were conducted every 3-6 weeks to promote exercise adherence. During these calls, the research team characterized the participants' previous activity levels and adjusted prescriptions based on individual tolerability and evolving interests. These contacts persisted until delivery, the emerge of a medical contraindication or at the participants request.

Informational posters were displayed throughout the institution to highlight the primary advantages of prenatal physical activity. These materials included a link to dedicated social media platform design specifically for this study, intended to educate patients, dispel prevalent myths such as the unsubstantiated link between exercise and miscarriage or preterm birth and provide localized information on community exercise facilities and safe home-based workout routines.

The study was conducted in accordance with the Declaration of Helsinki and applicable national regulations for healthcare research and was approved by the Ethics Committee of the Institution (PI OBS.SF.112-2023). Informed consent was obtained from all individual participants. All materials and clinical appointments were provided without any costs for the participants, and all data were collected by healthcare professionals and processed anonymously to ensure participant confidentiality.

Inclusion criteria

• Pregnant women aged 16 years or older with a confirmed diagnosis of gestational diabetes (fasting blood glucose greater than 92 mg/dL in first trimester; or values in the oral glucose tolerance test in second trimester greater than 92/180/153 mg/dL, respectively at 0 hours, 1 hour after glucose ingestion, and 2 hours after)
• Pregnant women aged 16 or older with chronic hypertension or a history of bariatric surgery and pre-pregnancy Body Mass Index (BMI) above 30Kg/m2.
• Eligibility further required consistent clinical adherence defined as attending all schedule appointments with the obstetric team without unjustified absences

Exclusion criteria

• multiple gestations
• risk of preterm labor
• history of premature delivery due to a non-maternal cause
• persistent vaginal bleeding
• placenta previa beyond 28 weeks' gestation
• cervical insufficiency
• any limiting systemic, respiratory or cardiovascular disease.