The primary aim of the study is to evaluate if weight management intervention for obese women (BMI≥30<35 kg/m2) prior to IVF improves the outcome assessed as live birth per participating woman, as compared to women where no intervention was made.

1. There will be two groups of patients.

   1. The first group (n=167) will receive weight management intervention during up to four months prior to IVF treatment.The group randomized to intervention will start an intensive weight reduction plan. The aim of the weight reduction is to reach as close to normal BMI (<25.0 kg/m2) as possible during a time of approximately 4 months. The purpose of the dietary intervention is to create a negative energy balance to induce weight loss. The intervention starts with 12 weeks of a low calorie liquid formula diet (LCD) and thereafter, diet re-introduction and weight control stabilization until IVF treatment begins. Should the patient for some reason be unable to fulfil the LCD-treatment, she will anyhow have an individualized dietary counselling to help her loose weight until the time for her IVF-treatment.
   2. The second group (n=167) will start their IVF-treatment directly without other intervention than written advice about the benefits of weight reduction and exercise. The group randomized directly to IVF-treatment will start the treatment as soon as possible after randomization, preferably within that menstrual cycle.

2. Tertiary aim is a follow-up 2 years after randomization to the study with questionnaires to the couple in both the intervention and the control groups. A special questionnaire will cover the weights of the couple and if the woman has had any pregnancies or live births after concluding the study. For the women having achieved a live birth in the index-cycle of IVF the number of children and also follow-up of the children will be performed by assessing medical records from pediatric clinic (if applicable) and child health care centres covering birth data, general health and weight of the children at birth and at the assessment date. Eating -habits and -patterns and quality of life parameters will be assessed with the same three questionnaires that were filled in after randomization.

Inclusion criteria

• Indication for IVF/ICSI for the couple
• Woman's age >18< 38 years at randomization
• First, second or third IVF/ICSI treatment
• BMI > or = 30.0 <35.0 kg/m2
• Willing to participate and to sign informed consent

Exclusion Criteria:

• Diabetes mellitus treated with insulin
• Oocyte or sperm donation planned
• Preimplantation genetic diagnosis (PGD) treatment planned
• Azoospermia known at randomization
• Patient not having adequate knowledge of Swedish (to understand patient information and questionnaires)
• QEWP-R questionnaire indicating binge eating disorder for the woman
• Previous participation in the study