Healthcare providers commonly advise pregnant individuals to stop crossing their legs. This guidance is rooted in specific physiological changes during gestation, aiming to mitigate risks associated with circulation and prevent musculoskeletal discomfort. Understanding the body’s adaptations reveals why this small change in posture is beneficial for well-being.
The Impact on Circulation
Pregnancy significantly alters the circulatory system, making the body more susceptible to issues that leg crossing can exacerbate. Total blood volume increases by up to 50%, which elevates the pressure within the veins, especially in the lower extremities. This pressure is compounded by the growing uterus, which exerts force on the inferior vena cava, the large vein on the right side of the body that returns blood from the legs to the heart.
Crossing the legs at the knee creates localized compression, impeding the return of blood flow to the pelvis and heart. This restriction can worsen common pregnancy-related issues like swelling (edema) in the feet and ankles. It also contributes to the development or worsening of varicose veins, which are already more likely due to hormonal changes relaxing blood vessel walls.
The reduced blood flow slightly elevates the risk of developing a Deep Vein Thrombosis (DVT), a serious concern during pregnancy. While prolonged stillness is the main risk factor for DVT, crossing the legs adds vascular obstruction. Avoiding this position ensures the most unrestricted path for blood flow, helping prevent these circulatory complications.
Joint Stability and Pelvic Discomfort
Beyond circulation, pregnancy introduces hormonal and biomechanical shifts that make crossing the legs structurally challenging. The body produces the hormone relaxin, which softens and loosens ligaments and connective tissues. This effect is most pronounced in the pelvic girdle—specifically the pubic symphysis and sacroiliac joints—to prepare the pelvis for childbirth.
This increased joint laxity, or instability, means that the pelvis is much more vulnerable to misalignment from asymmetrical postures. When one leg is crossed over the other, the pelvis tilts and rotates unevenly, putting a strain on the already loosened ligaments. This uneven weight distribution can irritate the sciatic nerve or exacerbate conditions like Pelvic Girdle Pain (PGP), which is common in pregnancy due to the joint instability.
The uneven posture forces lower back and hip muscles to work harder to stabilize the torso, leading to increased muscle tension. Maintaining a neutral, symmetrical sitting position minimizes stress on hypermobile joints and promotes better alignment. Keeping both feet flat and hips level reduces strain and the likelihood of developing back or hip pain.
Assessing the Safety Question
A common concern is whether crossing the legs can directly harm the developing fetus, but evidence suggests this is not the case. The risks associated with this posture relate primarily to maternal health and comfort, not fetal safety. The baby is protected within the uterus, amniotic fluid, and abdominal wall, meaning the position of the mother’s legs does not compress the fetus.
The advice to uncross the legs centers on preventing maternal complications like DVT and varicose veins, and maximizing comfort. Although restricted blood flow is a concern for the mother, it does not typically impede placental blood flow enough to risk the baby. This measure is precautionary, aimed at promoting the best health and comfort for the pregnant person.
Alternatives for Comfortable Sitting
To maintain a comfortable posture, several alternatives promote better circulation and pelvic alignment. The simplest adjustment is sitting with both feet flat on the floor, keeping knees and ankles uncrossed and hips level. This symmetrical position ensures weight is distributed evenly across the pelvic bones, reducing strain on loosened joints.
Posture and Support
Using props can further enhance comfort and circulation. Placing a footrest or books under the feet elevates them slightly, assisting venous return and reducing swelling. A small cushion or rolled-up towel placed behind the lower back provides lumbar support, encouraging a neutral spine and pelvis.
Movement
It is helpful to consciously change positions and stand up to walk around every 30 to 60 minutes. This is the most effective way to stimulate blood flow and prevent prolonged vein compression.