P-641 A prospective observational case series on the effects of a very low-calorie ketogenic diet (VLCKD) in overweight and obese infertile women
Authors: Nicolosi A  E , Piontini A , Ferraro C , Bergomas F , Riccaboni A , Viganò P , Edgardo S , Maìra C , Irene M , Giorgia D  S , Marco R , Polenghi G , Vigna L 
Published: July 2024

Study question

What is the compliance level of overweight/obese infertile patients to VLCKD? Is therapeutic adherence associated with weight loss and increased pregnancy rates?

Summary answer

Compliance level to VLCKD was surprisingly high. Participants experienced weight loss and pregnancy rates improved.

What is known already

Obesity and overweight are associated with infertility. They can adversely affect the hypothalamic-pituitary-gonadal axis, compromise oocyte quality and reduce endometrial receptivity. In addition, obesity exposes women at increased risk of obstetric complications. Although not always consistent, some evidence suggests a beneficial effect of diet in this setting, both for natural conception and in the context of ART. However, these studies also show low compliance, with many patients failing to lose enough weight to be clinically significant. VLCKD is a more aggressive approach to treating severe obesity and may represent a more effective option for these patients.

Study design, size, duration

This case-series prospective study has been performed at Unit of Obesity and Occupational medicine, Fondazione Ca’ Granda IRCCS Ospedale Maggiore Policlinico Milano between May 2019 and September 2023 and involved 42 infertile women aged ≤ 40 years, affected by overweight-obesity (BMI 27.5-35), but without other relevant systemic pathologies.

Participants/materials, setting, methods

Treatment firstly included 3 months of VLCKD followed by 12 months of Low-Calorie Diet (LCD). The occurrence of any natural pregnancy led to the discontinuation of treatment. These cases were counted as successes. Throughout the study period, patients underwent regular dietary and anthropometric evaluations.

Main results and the role of chance

Of the 42 recruited patients, 36 adhered to the VLCKD. The median treatment duration was 5.5 months [Interquartile Range (IQR) 3-9]. The compliance rate was 86% (95% CI: 72-93%). A significant reduction in BMI was observed: at recruitment, patients had a median BMI of 36.6 [IQR 33.4-39.9], and at the end, it was 29.5 [IQR 27.3-32.7], with a weight loss of 19.9 kg [IQR 12.7-24.4]. Regarding pregnancy, 8 women (22%) achieved a natural pregnancy, while of the remaining 28 patients, 25 underwent ART treatments. Among these, 16 achieved pregnancy (13 by homologous cycles, two donor cycles, and one with ovulation induction). In total, 24 women achieved pregnancy. The intention-to-treat success rate was 57% (95% CI: 42-71%), and the protocol success rate was 67% (95% CI: 50-80%).

Limitations, reasons for caution

The case-series study design, by definition, does not require a control group and this could be considered a “weakness”. However, it should be noted that patients were likely to be highly motivated to lose weight and health-conscious, thus creating a sample group with distinctive characteristics.

Wider implications of the findings

The use of VLCKD in obese infertile women allows high compliance to be achieved. The probability of pregnancy also appears very promising. VLCKD could be considered as a first approach for the treatment of obese women who do not have contraindications to ketosis.

Trial registration number

not applicable