Protocol for a prospective cohort study for the assessment of sarcopenia in gestational diabetes: the SiGnal-D study

Introduction Sarcopenia is characterised by loss of muscle mass and strength. Although ageing is the most likely risk factor of sarcopenia, sarcopenia is prevalent even in non-elderly people. Type 2 diabetes (T2D) is a risk factor for sarcopenia, as T2D shares with sarcopenia several aetiological factors. Meanwhile, gestational diabetes mellitus (GDM) is characterised by metabolic alterations that resemble those observed in T2D, including increased insulin resistance (present even in physiologic pregnancies). Hence, GDM presents two major risk factors for sarcopenia, that is, dysglycaemia and insulin resistance. Moreover, the number of pregnancies at age >40 years is increasing, which is in an age range in which sarcopenia prevalence is already not negligible. However, data on the prevalence of sarcopenia prevalence in GDM and its effect on pregnancy outcomes are limited. Thus, this study aims to evaluate the prevalence of sarcopenia in women with GDM (and in pregnant women without GDM), identify risk factors and determine its effect on delivery and maternal and fetal outcomes. Methods and analysis For this study, 100 each of women with and without GDM will be recruited. Women will undergo an oral glucose tolerance test within weeks 24–28 for possible GDM diagnosis (in weeks 16–18 for high-risk women). Muscle/physical performance tests will be conducted at weeks 28–32 for possible diagnosis of sarcopenia/presarcopenia. Cognitive function will also be assessed. For all women, information regarding pregnancy progression, along with any complications, will be collected. Collected data will be analysed according to the main objectives of the study: (i) determine the prevalence of sarcopenia/presarcopenia in pregnancy with and without GDM, (ii) identify factors associated with sarcopenia risk, (iii) determine the effect of sarcopenia/presarcopenia on pregnancy outcomes, (iv) explore the relationship between sarcopenia and cognitive function. Therefore, this study will provide information on sarcopenia/presarcopenia prevalence in GDM and, possibly, in pregnancy not complicated by dysglycaemia. Furthermore, the study will provide knowledge on the main factors associated with sarcopenia/presarcopenia in GDM/pregnancy. The identification of such factors will be relevant for an initial guidance for treatments that may prevent sarcopenia in GDM/pregnant women. This will become of even greater interest if sarcopenia/presarcopenia influences pregnancy outcomes, especially in GDM women. Ethics and dissemination The study protocol has been approved by the Comitato Etico Regione Toscana - Area Vasta Nord Ovest (CEAVNO) on 25 July 2024 and by the Local Ethics Committee of the Medical University of Vienna on 17 June 2024. Participants’ enrolment began in May 2025. The results of the study will be presented at national and international conferences and in peer-reviewed journals. Trial registration number ClinicalTrials.gov Identifier: NCT06876090 ; Registration Date: 2025-03-14