The question of whether a person’s hip shape influences their ability to give birth is common, often confusing external appearance with functional anatomy. While the internal shape of the pelvis is a factor in labor, external contours like “hip dips” are unrelated to the internal capacity needed for a baby to pass through the birth canal. This distinction between outer appearance and inner structure is important for understanding the mechanics of delivery.
What Exactly Are Hip Dips
Hip dips, sometimes called “violin hips,” are the inward indentations that appear on the outer sides of the body, below the hip bone and above the thigh. This feature is purely a variation of normal human anatomy, not an indicator of health or fitness. The indentation is caused by the underlying bone structure, specifically where the skin is tethered to the deeper bone of the greater trochanter, the prominent knob at the top of the femur. The prominence of these dips is influenced by the width of the pelvis and the way muscle and subcutaneous fat are distributed. Genetics determine the shape of the pelvis and thigh bones, making hip dips a natural and common feature.
Pelvic Anatomy and the Birth Canal
The true functional area for childbirth is the lesser pelvis, a bony ring that forms the birth canal, distinct from the external hip shape. This passage is structurally divided into three planes: the inlet, the mid-pelvis, and the outlet. The dimensions and shape of these internal planes are what determine the capacity for a baby’s head to successfully navigate the passage. Historically, pelvimetry was used to measure these diameters, and four main pelvic types—gynecoid, android, anthropoid, and platypelloid—describe variations in the internal shape. The rounded gynecoid pelvis is generally considered the most favorable shape for vaginal birth, but many successful deliveries occur with other pelvic types.
Why Hip Dips Do Not Affect Delivery
The superficial characteristic of hip dips has no bearing on the dimensions of the internal pelvic passage required for birth. Hip dips reflect external factors, such as the angle of the femur head and the placement of fat stores, which are completely separate from the internal capacity of the bony birth canal. The idea that externally wide hips indicate a more capable pelvis is a common misconception, as external hip width is determined by the flare of the iliac crests, which are above the true birth canal. A person with prominent hip dips may have a structurally ideal pelvis, while someone with smooth hips might have a less accommodating internal pelvis. The ability to deliver vaginally depends on the relationship between the baby’s head size and the internal pelvic diameters, not on the outer aesthetic of the hips.
Real Factors Influencing Labor Progress
The actual ease and progression of labor are influenced by a complex interplay of factors, often summarized by the five P’s: power, passage, passenger, position, and psyche. “Power” refers to the strength and effectiveness of uterine contractions and the mother’s pushing efforts. The “passage” is the bony pelvis and soft tissues of the birth canal, which must be able to accommodate the baby. The “passenger” is the baby, and its size, lie, and presentation—especially the position of the head—are highly influential. The “position” of the laboring person and their ability to move, along with their mental state or “psyche,” also significantly affect labor progression. Hormones released due to fear or anxiety can slow contractions, demonstrating the mind’s impact on the physical process of birth.