Aerobe Cycling Training in Women With Unexplained Recurrent Pregnancy Loss

Aerobe Cycling Training in Women With Unexplained Recurrent Pregnancy Loss

In 50% of women with recurrent pregnancy loss (RPL) miscarriages are unexplained, therefore no therapeutic intervention is possible. In a pilot study, women with unexplained RPL showed less endometrial NK cells (eNK) compared to women with a previously uncomplicated pregnancy. It is known that eNK cells are important for embryo implantation during early pregnancy. Investigators presume that high sympathetic activity in these women is related to eNK cell number, function and phenotype and that exercise is an effective intervention to lower sympathetic activity and to influence the immune system, as especially peripheral NK cells have been assumed to be responsive to physical training. The investigators hypothesize that moderate exercise can lower the adrenergic tone of the sympathetic nervous system hereby influencing endometrial NK cells in women with RPL and eventually pregnancy outcome.

Inclusion Criteria:

• RPL defined as 2 or more unexplained pregnancy losses from the time of conception until 24 weeks of gestation, known cause for the miscarriages are the presence of thyroid abnormalities, anti-phospholipid syndrome, uterine malformation, and abnormal parental karyotype according to international guideline.
• Couples should not be aiming to conceive during the time course of the exercise intervention.

Exclusion Criteria:

• Age above 40 years
• BMI above 40
• Current use of immunosuppressive or biological drugs
• Current use of hormone conceptive
• HIV positivity
• Current or recent (<2 weeks) symptomatic genital infection such as chlamydia, gonorroa, or pelvic inflammatory disease
• Pre-existent diabetes mellitus, autoimmune disease or overt cardiovascular disease
• Vaccination (i.e Covid) within 1 month prior to or during sampling and intervention
• New pregnancy at time of measurements, breastfeeding
• Current or recent (<2-3 months ago) pregnancy
• (Physical) inabilities to follow moderate aerobe cycling training
• Participants who are not capable of signing the informed consent