INTER-ACT: prevention of pregnancy complications through an e-health driven interpregnancy lifestyle intervention – study protocol of a multicentre randomised controlled trial

Maternal pre-pregnancy weight is related to pregnancy- and birth outcomes. An excessive weight before conception increases the risk for pregnancy- and birth related complications such as gestational diabetes mellitus (GDM), pregnancy-induced hypertension (PIH), caesarean section (CS), or a large-for-gestational age (LGA) infant [1‐4]. Besides, excessive gestational weight gain (EGWG), i.e. a gestational weight gain (GWG) higher than the recommended GWG by the Institute Of Medicine (IOM) [5], is also associated with these perinatal complications [6‐8]. Both the pre-pregnancy BMI and gestational weight gain (GWG) are thus considerable risk factors of pregnancy and birth complications. Between 2009 and 2014, the Flanders Study centre Perinatal Epidemiology (SPE) collected data of almost 400.000 singleton pregnancies in Flanders, Belgium, on the combined association of GWG and pre-pregnancy BMI with the prevalence of the composite outcome of pregnancy and birth complications (i.e. at least one of four perinatal outcomes PIH, GDM, CS and/or LGA infant). The prevalence of the composite perinatal outcome was 26% in women with a normal BMI and an adequate GWG; 34% in women with a normal BMI but with an excessive GWG; and 66% in women with class III obesity (BMI ≥ 40) and excessive GWG [SPE, 2016 in progress]. A Norwegian study reported similar findings. Haugen et al. [9] found that normal weight and overweight women with EGWG had an increased risk for PIH, preeclampsia, CS, high birth weight (>4500 g) and LGA infant. Moreover, women of all BMI classes and with EGWG, except underweight women, had an increased risk of more than 2 kg postpartum weight retention (PPWR) at 18 months postpartum [9]. Conversely, a more recent study from Xiong et al. reported an increased likelihood of CS in underweight or normal weight women with EGWG compared to overweight or obese women EGWG [10]. Thus, these results highlight the importance of adequate GWG in all BMI groups.

Based on the guidelines of the Institute of Medicine (IOM) [5], one in three women in Flanders, Belgium, has excessive GWG: 25% in normal pre-pregnancy BMI, 58% in pre-pregnancy overweight, and 54% in pre-pregnancy obesity [11]. Half of the women with excessive GWG do not return to their pre-pregnancy weight after delivery, resulting in a doubled risk for pregnancy- and birth related complications in the next pregnancy [12]. Retention of the excessive weight gained during pregnancy (i.e. PPWR) can result in obesity and an increased risk of chronic disease in later life [13‐17]. Additionally, maternal obesity negatively affects the health of the offspring in childhood and in adulthood, by increasing the risk of obesity and the related risks of non-communicable diseases. Maternal obesity might therefore result in a vicious circle of obesity throughout generations [4, 18, 19].

Several lifestyle interventions have been implemented during pregnancy in an attempt to reduce GWG and prevent pregnancy- and birth related complications. Although these interventions showed moderate beneficial effects on GWG, they had no significant impact on pregnancy- and birth related complications [20], potentially due to the limited time window [21, 22]. Therefore, the international community of health experts has called for strategies that already intervene in the pre-conception period in order to timely acquire a healthy lifestyle and weight loss [1]. However, such strategies are still scarce [20], possibly due to unpredictability of becoming pregnant and not being linked to the health care system preconceptionally [23]. The few existing studies, though, show promising results in intervening during the preconception period [24‐27]. An opportunity to overcome the barrier of reaching women in their preconception period, is to commence interventions already in the postpartum period and continuing until the next pregnancy. Such interpregnancy interventions could potentially be a unique strategy to acquire a healthy lifestyle before a subsequent pregnancy starts.

Effective lifestyle interventions for weight management among postpartum women are usually based on a combination of diet and physical activity [28‐30]. Ideally, such lifestyle interventions go beyond education or advice alone and integrate behavioural change techniques such as goal setting, self-monitoring and feedback [25, 31]. Mobile applications are excellent tools to incorporate such behavioural change techniques for intervention efforts promoting a healthy lifestyle [32] that have been found effective in health behaviour change and weight loss [33].

The interpregnAncy Coaching for a healthy fuTure (INTER-ACT) intervention is an e-health driven and face-to-face combined coaching program that is implemented between two pregnancies and during the subsequent pregnancy of women with an excessive GWG in the previous pregnancy. The main aim of this study is to assess the effectiveness of the INTER-ACT intervention on the composite outcomes score (GDM, PIH, CS, LGA) in the next pregnancy. This will be evaluated through a randomised controlled trial with an intervention- and control arm.