The goal of this clinical trial is to evaluate stress and cardiovascular risk factors in women with preeclampsia in the medical history. The main questions it aims to answer are:

• to improve our understanding of the underlying psychological and physical stress factors in relation to the circulatory risk profile in women with a history of preeclampsia
• to examine the effects of mindfullness based stress reduction (MBSR) or aerobic exercise training on hair cortisol and symptoms of mental stress.

Participants will undergo pre- and post-intervention pre-conceptional standard cardiovascular assessments, head tilt test and give a hair sample. As intervention they will sport or do mindfulness for 3 months.They will be compared with a control group.

Rationale: Approximately one out of three women with pre-term preeclampsia develops a post-traumatic stress disorder or depression after pregnancy. This could be related to the psychological impact of preeclampsia and premature birth resulting in increased perceived stress. It is also possible that preeclampsia and stress levels share a common aetiology, as both appear to correlate with increased cortisol levels and higher sympathetic drive. Approximately 50% of women with a history of preeclampsia have low plasma volume levels, indicating reduced circulatory reserve. Women with a hemodynamic profile characterized by a limited circulatory reserve have increased resting sympathetic tone, and are prone to develop preeclampsia in a subsequent pregnancy. These women also report more complaints of perceived stress. This raises not only the question whether increased perceived stress in women with a history of preeclampsia originates within the brain itself (primary psychological) or whether it is a psychological reflection of underlying reduced circulatory reserves (secondary psychological), but also the question about which intervention is most effective to reduce this perceived stress level. Should the investigators focus more on the emotional coping mechanisms and psychological aspects or should the investigators aim at improving the underlying hemodynamic profile and circulatory reserves to reduce overall sympathetic drive? The investigators hypothesize that 1) both interventions in women with preeclampsia and increased mental stress complaints will result in improved circulatory reserve, lower cortisol levels, lower sympathetic resting tone, and better continuous physiological measures (as measured with a smartwatch during the trial). 2) The aerobic exercise training will additionally improve the women's cardiovascular risk profile.

Objective: To investigate the effects of online mindfulness-based stress reduction (MBSR) therapy and aerobe exercise training on mental stress, physiological stress (hair cortisol) and cardiovascular risk profile in women with a history of preeclampsia and current increased symptoms of mental stress.

Study design: Multicenter randomized trial of two interventions (online mindfulness therapy and aerobic exercise training) and a time control group who undergo neither of the two interventions (wait list group). Possible eligible women will be recruited in two tertiary hospitals (Radboudumc Nijmegen and Maastricht Medical Centre) after referral to these centres for preconceptional cardiovascular assessment after severe preeclampsia in a previous pregnancy. Participants with symptoms of mental stress will be randomly assigned to either one of the two intervention groups or the wait list (3 options) after the Preconceptional Cardiovascular Assessment (PcCA) and Stress Assessment (SA). After 12 weeks of intervention, or in the case of the wait list group, 12 weeks without intervention, another PcCA and SA will take place. Results after 12 weeks will be compared with baseline results. Additionally, in all groups online questionnaires will be filled in 6 months after baseline assessments. Women who were allocated to the wait list group are offered either mindfulness therapy or aerobic exercise training after completing the second PcCA and SA after 12 weeks.

Study population: Primiparous women with an obstetric history of preeclampsia, according to ISSHP definition, who score ≥ 16 on the Perceived Stress Scale (PSS) ≥ 41 on the State-Trait Anxiety Inventory (STAI) or ≥ 10 on the Edinburgh Postnatal Depression Scale (EPDS) during online questionnaires as part of the anamnesis of PcCA will be prompted to join the study. Women with pre-existent diabetes mellitus, autoimmune disease, overt cardiovascular disease, or use of tabacco or medication that might affect the cardiovascular system are excluded from participation. Other exclusion criteria are plans to become pregnant within the time frame of the intervention (12 weeks) at time of baseline assessment.

Intervention: One group receives a 12-weeks standard online MBSR therapy, consisting of 8 weekly group meetings, one day silent retreat, and daily homework. A second group attends a 12-week aerobe training program which consists of HR-controlled training on a cycle trainer at 70-80% individual heart rate reserve (HRR) for 2 to 3 times per week. Finally, the time control (wait list) group will be asked to continue normal activities and lifestyle and won't undergo guided mindfulness therapy or exercise training during the 12 weeks study period.

Main study parameters: The primary endpoint is mental stress, evaluated with validated questionnaires PSS, STAI and EPDS. Secondary endpoints are the results of pre- and post-intervention pre-conceptional standard cardiovascular assessments. These cardiovascular assessments are in Maastricht UMC+ tertiary hospital care as usual after referral for preconceptional evaluation in women with a history of preeclampsia. This assessment includes: biometrics, 30-minutes blood pressure and heart rate measurement, venous blood samples for metabolic syndrome screening, echocardiography and plasma volume assessment. For this specific study the investigators will additionally assess cortisol concentration in hair and evaluate sympathetic activity during a head-up tilt test using non-invasive heart rate variability analysis. During the exercise training, heartbeat monitoring will be measured using smartwatches. Feasibility of the interventions will be evaluate with additional participant survey at follow-up measurement.

Inclusion Criteria:

• Informed consent given
• Age > or = 18 years
• Good understanding of Dutch language
• Preeclampsia in prior pregnancy, defined as the combination of gestational hypertension (≥140/90 mmHg, measured twice, six hours or more apart), and proteinuria (consistently ≥300mg/24 hours) after 20 weeks of pregnancy in previously normotensive women, according to International Society for the Study of Hypertension in Pregnancy (Brown, 2018).
• Normotensive at the time of baseline measurements
• Perceived Stress Scale score ≥ 16 or State-Trait Anxiety Inventory (STAI) score ≥ 41 or Edinburgh Postnatal Depression Scale (EPDS) score ≥ 10

Exclusion Criteria:

• Pre-existent diabetes mellitus, autoimmune disease, HIV positivity or overt cardio-vascular disease.
• Use of medication or supplements that might affect the cardiovascular system
• (Physical) inabilities to complete 12 weeks of moderate exercise training
• Currently involved in psychological therapy or mindfullness training.
• Pregnancy
• Women who intend to become pregnant within 12 weeks after baseline assessment

Only women with obstetric history.

Individual participant data available on request.