Body Weight and Fertility: Why It Matters

Maintaining a healthy body weight is not just about appearance or general wellness. Maintaining a healthy body weight plays a key role in optimal reproductive health and fertility for people of all genders. Whether you're planning to conceive naturally or with assistance, understanding how weight impacts fertility can help guide better decisions for your body and future family.

The Importance of a Healthy BMI for Conception

BMI, or Body Mass Index, is a commonly used measure to assess whether your weight is within a healthy range. A BMI between 18.5 and 24.9 is typically considered optimal for fertility. However, BMI does not tell the full story. Muscle mass, fat distribution, metabolic health, and individual variations should all be considered when evaluating fertility potential.

How Body Weight Affects Fertility

Our reproductive system is closely linked to our overall health, and body weight is one of the most influential factors. Both excess weight and being underweight can disrupt the hormonal balance necessary for healthy reproductive function.

High Body Weight and Fertility

Excess weight, particularly when it results in a high BMI can:

• Disrupt hormonal balance: Hormones imbalance from excess fat tissue can interfere with ovulation. Women with high BMI may experience irregular and infrequent menstrual cycles (oligo-ovulation) or may not have menstrual periods at all (anovulation), which can make it harder to conceive.
• Lower success rates with fertility treatments: Research shows that individuals with higher BMI often have reduced success rates with fertility treatments like IVF and ICSI. The body may not respond as effectively to fertility medications, and procedures like ultrasound scanning and egg retrieval may be more challenging.
• Increase pregnancy complications: Higher BMI is associated with increased risk of gestational diabetes, hypertension (high blood pressure), miscarriage, preterm birth, blood clots in legs and lungs and complications during labor and delivery.
• Impact on male fertility: In men, obesity can negatively affect testosterone levels, sperm count, motility, and DNA integrity in sperm. These factors can make natural conception more difficult and impact fertility treatment outcomes.

Low Body Weight and Fertility

Being underweight can also negatively affect fertility:

• Ovulation issues: A low BMI can signal the body that it is not receiving enough energy to support a pregnancy. As a result, ovulation may become irregular or stop altogether, a condition known as hypothalamic amenorrhea.
• Hormonal imbalances: Insufficient body fat can reduce the production of hormone oestrogen, essential for reproductive, bone and cardiovascular health.
• Increased risk during pregnancy: Individuals who are underweight at the time of conception may face challenges with fetal growth, preterm birth, and nutritional deficiencies during pregnancy.
• Effect on male fertility: Although less studied than obesity, underweight men may also experience lower sperm quality, reduced libido, and hormonal imbalances.

Weight and the Health of the Baby

Your weight not only affects your ability to conceive, but it can also influence your baby's health and development:

• Preconception weight: Higher or lower than average BMI before pregnancy can affect how a baby grows in the womb.
• Pregnancy weight gain: Those who begin pregnancy at a healthy weight and maintain appropriate weight gain during pregnancy are more likely to experience fewer complications.
• Long-term effects: There is growing evidence that a parent's weight at the time of conception can influence their child’s risk of developing obesity, diabetes, and other metabolic conditions later in life.

Steps to Optimise Body Weight for Fertility

Improving your weight does not require drastic measures. Sustainable, safe, and supportive approaches are key:

1. Set Realistic Goals

Work with a healthcare provider to determine a healthy weight range based on your unique body composition and fertility goals. Even a modest weight loss of 5 to 10 percent can significantly improve fertility in those with higher BMI.

2. Prioritise Balanced Nutrition

Focus on nutrient-dense foods that support hormone production and reproductive health:

• Plenty of fruits and vegetables
• Whole grains
• Lean proteins (plant-based and animal sources)
• Healthy fats like avocados, nuts, and olive oil
• Adequate hydration

Avoid restrictive or extreme diets, which can harm fertility. Instead, aim for sustainable eating habits.

3. Undertake Regular Moderate Exercises

Engage in physical activity that you enjoy. Regular moderate exercises improve metabolic health, reduces stress, and supports hormonal balance. Aim for at least 150 minutes of moderate-intensity activity per week, such as walking, swimming, or cycling.

4. Reduce Stress

Chronic stress can compound the effects of weight-related fertility issues. Practice stress-reducing techniques like mindfulness, yoga, deep breathing, or speaking with a therapist. Emotional wellbeing supports both physical health and fertility.

5. Sleep Well

Poor sleep can disrupt hormone production and appetite regulation. Prioritising quality sleep (7-9 hours per night) can aid weight management and overall reproductive health.

6. Seek Support

Whether you're trying to gain weight, lose weight, or simply improve your overall health, professional guidance can make the journey safer and more effective. Support from fertility specialists, nutritionists, and counsellors can provide a comprehensive plan tailored to your needs.

JIVA Fertility's Approach

At JIVA Fertility, we understand that every body is different. Maria Kolotourou, our specialist Dietitian-Nutritionist, can guide patients through safe, effective, and compassionate nutrition strategies. Her work focuses on sustainable changes that support hormone health, energy balance, and emotional wellbeing. She will be able to offer:

• Individualised assessments to understand your unique health profile
• Personalised nutrition optimisation plans that are safe and realistic
• Holistic care for individuals and couples

We support people of all genders and body types, recognising that fertility optimisation is not one-size-fits-all. Our team provides compassionate, medically sound care designed to help you move forward with confidence and hope.

Final Thoughts

Body weight is just one piece of the fertility puzzle, but it is a powerful one. Whether you are just beginning to think about pregnancy or are already on a fertility journey, taking steps to reach and maintain a healthy weight can improve your chances of success, and support a healthier pregnancy.

You are not alone. At JIVA Fertility, we are here to guide you with care, respect, and expertise every step of the way.

For more information check out in-detailed FAQ on Body Weight and Fertility or to speak with a fertility Consultant or a Dietitian-Nutritionist, contact us today.

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