Here is the design of a clinical trial:

Official Title: Healthy for my Baby- A Randomized Controlled Trial Assessing a Preconception Clinically Integrated Technological Intervention to Improve the Lifestyle of Overweight Women and Their Partners

Included conditions:
- Overweight and Obesity
- Pregnancy Complications
- Health Behavior
- Life Style
- Preconception Care

Study Armgroups:
- {'label': 'Intervention', 'type': 'EXPERIMENTAL', 'description': 'Healthy for my Baby Intervention', 'interventionNames': ['Behavioral: Healthy for my Baby']}
- {'label': 'Control', 'type': 'OTHER', 'description': 'Usual care', 'interventionNames': ['Other: Usual Care']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Healthy for my Baby', 'description': 'Participants will start the preconception intervention by meeting with a health professional for a motivational interview session on healthy lifestyle habits. Following this interview, participants will have access to a mobile phone application that will allow them to track daily lifestyle modification goals. After a month, they will meet the health professional for a second motivational interview and review their progression. Participants will continue to make lifestyle changes through the preconception period by accomplishing smart goals followed daily in the mobile phone application.\n\nIf the woman becomes pregnant, the couple will participate in two more in-person motivational interviews, a month apart. The mobile application will be put in pregnancy mode, and participants will adapt their daily lifestyle goals for the pregnancy. Participants will continue to make lifestyle changes throughout pregnancy by accomplishing smart goals followed daily in the mobile phone application.', 'armGroupLabels': ['Intervention']}
- {'type': 'OTHER', 'name': 'Usual Care', 'description': 'Participants in the control group will receive standard advice on healthy lifestyle habits as provided by their usual care provider. They will receive standard medical care in preconception and pregnancy.\n\nTo improve compliance with the study follow-up, participants in this group will have access to a simplified version of the mobile application that contains a fertility calendar and a research visit calendar. This version of the application does not include lifestyle goals or any information on healthy lifestyle habits.', 'armGroupLabels': ['Control']}

Primary Outcomes:
- {'measure': "Women's diet quality in preconception measured with the Canadian-Healthy Eating Index- 2007", 'description': "Women's C-HEI score will be measured with two or three online 24 hour dietary recalls (R24W tool) at each time point. Value range 0-100 with a higher score indicating better diet quality. The change of the score in time during the preconception period will be compared between the groups.", 'timeFrame': '0, 2, 4, and 6 months'}

Please estimate the sample size based on the assumption: 
The assumptions include a significance level (alpha) of 5%, a power of 80%, and a 20% attrition rate.
Sample Size Calculation
          Since no minimally clinically important effect size has been defined for the HEI score, our effect size has been estimated as a plausible effect of the intervention based on the preliminary results of the Obesity Fertility trial (71), which demonstrated a 12.5 Â± 13.0 points increase in the average HEI score of women with obesity and infertility after a 6-month lifestyle intervention (unpublished data). An increase of 12 points in the average HEI score was also observed in breast cancer survivors with obesity who received a 6-month dietetic intervention (75). To detect a 10% difference in the average HEI score between groups with a 13-point standard deviation, an alpha value of 5% and 80% power, we will need to recruit 27 women per group (76). To account for a 20% attrition rate (77), a total of 68 women and their partners will be recruited.