Inclusion Criteria:  Singleton pregnancy Vertex presentation Speak, read and understand Danish  Exclusion Criteria:  Gestational age < 37+0 weeks Gestational age > to 41+6 weeks High-risk pregnancies (including risk factors: eclampsia, pre-eclampsia, diabetes, gestational diabetes, hypertension (above 140/90), and hypotension (below 90/60), Intrauterine growth restriction (IUGR), polyhydramnious, and oligohydramnious). Pre-gestational body mass index (BMI) above 40 kg/m2 Use of fetal scalp-electrode during the experiment Use of pacemakers and other electronic implants Severe arrhythmia Present musculoskeletal illnesses (including myopathy and arthritis). Chronic pain within last 6 months (Pelvic girdle pain (PGP) to a mild degree (VAS 0-6 cm) is accepted in the experiment. Severe degree (VAS 6-10 cm) (e.g. bedridden or difficulty walking) especially within 24 hours before birth is excluded). Present/previous neurologic illnesses (including epilepsy, migraine, and sclerosis). Present medicated mental disorders (including dementia, personality disorders, bipolar, ADHD, and anxiety). Dermatological disorders (including skin allergy, tattoos or scars on the locations of electrodes) Use of other long-acting pain relief before the experiment (including Epidural, Morphine less than 16 hours before experiment), Acupuncture, Paracetamol (less than 8 hours before experiment), Cocktail (less than 8 hours before experiment), nitrous oxide (less than one hour before experiment), sterile water injection (less than two hours before experiment). Use of TENS 48 hours before the trial Drug addiction defined as the use of cannabis, opioids or other drugs. Smokers Lack of ability to cooperate