What causes hips to widen?

The width of a person's hips is determined by a complex interplay of skeletal structure, genetics, hormones, and soft tissue, not just body fat. Understanding what causes hips to widen can help demystify these natural body changes throughout a person's life.

Quick Summary

Several factors contribute to hip widening, including hormonal changes during puberty and pregnancy, genetic inheritance that dictates bone structure, and fat distribution influenced by hormones and lifestyle. Gradual bone remodeling throughout life and certain medical conditions can also play a role.

Key Points

• Hormones Drive Change: Puberty and pregnancy-related hormonal fluctuations, particularly estrogen and relaxin, are major causes of hip widening, affecting both bone structure and fat storage.

• Genetics Set the Blueprint: Your skeletal structure is primarily determined by genetics, influencing the final shape and width of your pelvis after puberty.

• Fat Distribution is Hormonal: Hormones dictate where your body stores fat. Estrogen causes fat to accumulate around the hips and thighs, while declining estrogen during menopause can shift fat toward the waist.

• Aging Involves Bone Remodeling: Pelvic bones naturally and gradually widen throughout adulthood in both men and women, independent of weight gain.

• Medical Conditions Exist: In some cases, conditions like lipoedema, which causes abnormal fat buildup, can lead to disproportionate hip widening.

The Hormonal Impact on Body Shape

Changes in hormone levels are a primary driver of how the body develops and changes, with significant effects on hip width. This is especially true for those with higher estrogen levels.

Puberty: The Primary Driver of Pelvic Growth

During puberty, the body undergoes a series of transformative changes to develop secondary sex characteristics.

• Estrogen: In females, the increase in estrogen levels signals the pelvic bones to grow wider and flatter, creating a larger and more rounded birth canal. This skeletal change, which is mostly complete by the end of puberty, contributes significantly to hip width.
• Testosterone: In contrast, males experience an increase in testosterone, which primarily promotes shoulder widening and a more angular body frame, rather than significant pelvic expansion.

Pregnancy and the Hormone Relaxin

Pregnancy is another major hormonal event that causes temporary hip widening. The hormone relaxin, produced early in pregnancy, softens and loosens the ligaments and joints in the pelvis. This allows the pelvic bones to spread apart, providing more space for the growing baby and preparing the birth canal for delivery.

• During Pregnancy: The ligaments at the sacroiliac joints and the pubic symphysis relax, causing the hips to expand, sometimes by a few centimeters.
• Post-Pregnancy: After birth, relaxin levels decrease, and the ligaments begin to tighten again. While hips usually return close to their pre-pregnancy size, a slight permanent widening of 1–2 cm is common.

Genetics and the Foundation of Your Frame

Your genetic makeup plays a foundational role in determining your overall body frame, including the size and shape of your pelvic bones. The concept of being "big-boned" is largely a myth, but inherited genetic traits do dictate the dimensions of your skeleton.

• Inherited Traits: If your relatives have wider hips, it is very likely you will as well. Genetics determines not only your overall pelvic width but also subtler features, like the angle of your femur, which can influence hip appearance.
• Unchangeable Foundation: Unlike fat or muscle, the final structure of your adult pelvis is set after puberty. It is a fundamental part of your body that cannot be altered by lifestyle changes alone.

Body Composition and Fat Distribution

Changes in body composition, specifically fat and muscle, can significantly alter the appearance of your hip size. Hormones influence where fat is stored on your body, a process that changes throughout your life.

• Fat Storage: For women, estrogen promotes fat storage in the hips, thighs, and buttocks, contributing to a pear or hourglass shape.
• Menopause: As estrogen levels decline during menopause, women's fat distribution often shifts, with fat migrating from the hips and thighs to the waist and abdomen, similar to the typical male fat distribution pattern.
• Exercise and Diet: While you cannot 'spot-reduce' fat from a specific area, overall fat loss through diet and exercise will reduce fat stored around the hips. Building the muscles in the gluteal area can also change the shape and appearance of the hips.

The Effect of Aging

Pelvic width is not static after puberty. Research shows that the pelvic bones continue to remodel and widen gradually throughout adult life in both men and women.

• Bone Remodeling: This gradual widening, which can add inches to the waist and hip circumference over decades, is a natural part of the aging process and independent of overall weight gain.
• Adapting to Pressure: Some experts hypothesize that this remodeling is a response to the lifelong pressures endured by the pelvis, potentially as a way to maintain stability as bones weaken with age.

Comparison of Factors Affecting Hip Widening

Factor	Primary Mechanism	Timing	Permanent Change?	Influence Level
Puberty	Estrogen-driven pelvic bone growth.	During teenage years.	Yes, permanent skeletal change.	High
Pregnancy	Relaxin hormone loosens pelvic ligaments.	During and after pregnancy.	Usually slight permanent change.	High
Genetics	Inherited bone structure and body frame.	Lifelong.	Yes, determines maximum potential width.	High
Fat Distribution	Hormonal and lifestyle influence on fat storage.	Throughout adulthood.	Dependent on diet, exercise, and hormonal shifts.	Moderate to High
Aging	Gradual bone remodeling over time.	Throughout adult life.	Yes, a slow, progressive change.	Moderate
Lipoedema	Abnormal fat and tissue buildup due to medical condition.	Can begin at puberty or other hormonal changes.	Yes, requires specific management.	Varies

Medical Conditions Affecting Hip Shape

While most hip widening is natural, certain medical conditions can cause unusual fat accumulation in this area.

• Lipoedema: This is a chronic condition that causes an abnormal, symmetrical buildup of fat and connective tissue, primarily in the legs, hips, and buttocks. Unlike simple weight gain, lipoedema fat is resistant to diet and exercise and can be painful. It affects women far more often than men and is often triggered by hormonal events like puberty or pregnancy.
• Other Conditions: In rare cases, other disorders can affect hip joint health and appearance, though they don't typically cause the symmetrical "widening" associated with natural development. If you suspect a medical condition, a consultation with a doctor is essential.

Conclusion: A Natural and Multifaceted Process

Hip widening is a natural and normal biological process driven by several factors, from the hormones of puberty and pregnancy to the genetics inherited from your family. While a person's weight and fat distribution can certainly influence hip appearance, the underlying bone structure is the primary determinant of ultimate hip width. Instead of focusing on altering what is often a genetically determined trait, the healthiest approach is to embrace your body's natural shape and focus on overall well-being through balanced nutrition and regular exercise. For those concerned about conditions like lipoedema, professional medical advice can provide clarity and effective management strategies.

Exercises for Toning the Hip Area

1. Squats: A fundamental exercise that targets the glutes, hamstrings, and quads, which contribute to a toned lower body appearance.
2. Glute Bridges: Performed on your back, this exercise strengthens the glutes and hamstrings.
3. Side Leg Lifts: Lying on your side, lift your top leg. This targets the abductor muscles, which can tone the outer hip area.
4. Lunges: Excellent for overall lower body development and muscle definition.
5. Band Walks: Using a resistance band around your ankles or thighs, walk sideways to activate and strengthen the gluteus medius and minimus.

For more information on lipoedema, please see this authoritative source: NHS Inform - Lipoedema.

Frequently Asked Questions

Can I prevent my hips from widening naturally?

No, natural hip widening caused by puberty or aging is a normal physiological process and cannot be prevented through diet or exercise, as it is related to bone structure.

Do hips widen during pregnancy permanently?

While the pelvic ligaments soften and loosen during pregnancy, causing temporary widening, they do tighten afterward. However, a slight permanent increase in hip width (1-2 cm) is common.

How can diet and exercise affect hip size?

Diet and exercise can reduce overall body fat, which may decrease fat stored in the hip area. Targeted exercises can also tone the gluteal and thigh muscles, altering the appearance of the hips.

Is it normal for a man's hips to widen?

Yes, it is normal for a man's pelvis to experience some gradual widening as part of the aging process, though it is a much less pronounced effect compared to female puberty.

What is the difference between lipoedema and weight gain on the hips?

Lipoedema is a medical condition causing abnormal fat buildup that is resistant to diet and exercise and is often painful. Weight gain on the hips is simply fat accumulation that can be reduced with weight loss.

Does giving birth via C-section affect hip widening differently?

No, hip widening during pregnancy is caused by hormones like relaxin, which prepare the body for childbirth regardless of whether the delivery is vaginal or by C-section. Some women may experience slightly less widening if a C-section occurs before labor begins.

Can transgender individuals experience hip widening?

Yes, transgender women undergoing feminizing hormone therapy may experience fat redistribution to the hips, thighs, and buttocks. Conversely, transgender men on testosterone will see a reduction in gynoid fat.