Why can pressure from the uterine wall cause clubbed hands or feet when amniotic fluid is low?

When amniotic fluid is deficient—a condition known as oligohydramnios—the protective, cushioning environment surrounding the fetus is lost.

In a normal pregnancy, amniotic fluid allows the fetus to move freely and maintains space within the uterus. When this fluid decreases significantly, the uterine wall and the fetal membranes can press directly against the developing baby. This mechanical pressure distorts the fetus's position and restricts its movement, which can lead to physical deformities such as clubfoot or wryneck. Essentially, the lack of fluid removes the buffer that prevents the uterine wall from exerting external pressure on the developing limbs and skeletal structures, resulting in these congenital malformations.1