How can low amniotic fluid lead to fetal deformities?

Low amniotic fluid, a condition known as oligohydramnios, can lead to fetal deformities primarily by removing the protective amniotic fluid cushion that shields the fetus from external pressure.12

When this fluid is deficient, the uterine wall and membranes can press directly against the developing fetus. This extrinsic pressure restricts movement and causes secondary bending or changes in shape, resulting in several types of deformities:12

• Limb and Joint Issues: Compression often leads to clubfoot, wryneck, and fixation of joints, such as clubbed hands or arthrogryposes (contracted joints and clawed fingers).12
• Physical Distortions: The pressure can cause flattening of the nose and ears, as well as general distortion of the fetal position.12
• Developmental Impacts: The lack of space and fluid can result in growth retardation and the underdevelopment of vital organs, such as the lungs and gut.2

Additionally, if the condition occurs very early in pregnancy, it may cause firm adhesions between the membranes and the embryo, further contributing to fetal distortion.1