Is cycling safe during pregnancy?

Cycling during pregnancy requires some nuance. Stationary cycling — on an exercise bike or indoor trainer — is safe throughout all three trimesters and is an excellent form of low-impact cardiovascular exercise. Outdoor cycling on roads or paths carries a progressively increasing risk of falls as the bump grows and balance shifts, and becomes less advisable from around the second trimester.

The NHS recommends staying active during pregnancy, and cycling is a valid way to do this. The key is understanding how the risk profile changes as pregnancy progresses.

Stationary cycling: safe throughout pregnancy

An exercise bike or indoor cycling trainer is one of the safest cardiovascular options during pregnancy. There is no fall risk, no traffic, no unpredictable terrain, and the seated position is comfortable and manageable even into the third trimester.

Stationary cycling is appropriate for all fitness levels, low-impact on the joints, and easy to adjust in intensity. Many pregnant women who were outdoor cyclists transition to a stationary bike from the second trimester and find it a very practical alternative.

Indoor cycling classes (spin classes) are generally safe in early and mid-pregnancy for women who were already attending them. The high intensity of some spin classes may need to be moderated — use the talk test as a guide (you should be able to speak in short sentences). Bike setup should be adjusted as the bump grows to ensure a comfortable, upright position that does not require bending over the bump.

Outdoor cycling: fine early, increasing caution later

Outdoor cycling is generally safe in the first trimester for experienced cyclists. The considerations that make it progressively more of a concern as pregnancy advances are:

Balance changes. The growing bump shifts the centre of gravity forward and alters balance. This makes it harder to handle unexpected situations — sudden stops, uneven surfaces, obstacles — and increases the risk of falls.

Relaxin and joint laxity. The hormone relaxin, which loosens the ligaments in preparation for birth, also affects the ankles, knees, and hips, making joints slightly less stable under load.

Abdominal protection. In the event of a fall, the bump is vulnerable to impact. Even a relatively minor cycling fall that would have been inconsequential before pregnancy carries more risk when pregnant.

Bike fit. As the bump grows, the riding position that previously felt natural becomes increasingly awkward. Leaning over the handlebars puts strain on the lower back; handlebar height may need raising. At some point — usually mid-third trimester — the bump simply makes a road cycling position uncomfortable.

Practical guidance for outdoor cycling

  • If you continue outdoor cycling in the second trimester, stick to well-maintained, low-traffic routes without technical features
  • Avoid mountain biking, gravel riding on rough terrain, and cycling in heavy traffic
  • Wear a properly fitted helmet at all times
  • Be honest with yourself about whether your balance feels as reliable as it did before pregnancy
  • Most women who cycle outdoors during pregnancy transition to a stationary bike or stop by 20–28 weeks

Adjusting the bike as your bump grows

Whether on a stationary bike or riding outdoors, bike fit matters increasingly as pregnancy progresses:

  • Seat height: A higher seat position reduces how far you need to lean forward and is more comfortable as the bump grows
  • Handlebar height: Raising the handlebars to a more upright position reduces strain on the lower back and is easier on the bump
  • Saddle: A wider, well-cushioned saddle is more comfortable in pregnancy as the pelvis widens

How much cycling is appropriate?

The NHS recommends 150 minutes of moderate activity per week during pregnancy. Moderate-intensity cycling — a pace at which your breathing is elevated but you can still hold a conversation — counts toward this. Sessions of 20–45 minutes on a stationary bike five days a week is a practical way to meet this recommendation.

Avoid sustained high-intensity cycling in the heat; overheating is a concern in all vigorous exercise during pregnancy.

When to stop and seek advice

Stop cycling and contact your midwife if you experience:

  • Chest pain or palpitations
  • Dizziness, light-headedness, or feeling faint
  • Abdominal pain or cramping
  • Vaginal bleeding or fluid leakage
  • Significant shortness of breath at a pace that previously felt manageable
  • Pelvic pain, particularly with a rocking motion on the saddle (can indicate pelvic girdle pain)
  • Any fall — contact your midwife even if you feel fine