Building Your Body for Pregnancy Planning – What Is the Ideal Weight?【Supervised by doctor】

Introduction

Maintaining a weight within the appropriate range is considered conducive to pregnancy, but being outside this range can lead to various complications and make it harder to conceive.

However, just having a weight within the appropriate range does not necessarily guarantee an easier time conceiving. Weight should be seen as one of many indicators of ease of conception.

This article explains the following three points:

• The ideal BMI for pregnancy
• Lifestyle habits that facilitate conception
• Reasons why being outside the appropriate weight range can lead to infertility

Set realistic weight goals and aim to build a body that is conducive to pregnancy.

What is Pregnancy Planning?

Pregnancy planning, abbreviated as “Ninkatsu” in Japanese, refers to activities aimed at achieving pregnancy. This includes actions such as:

• Predicting ovulation days
• Having sexual intercourse on ovulation days
• Discussing pregnancy plans with your partner
• Gathering information about pregnancy
• Visiting infertility clinics
• Deciding on the age to conceive based on life plans

In other words, any actions taken by couples wishing to conceive can be referred to as “Ninkatsu.”

Weight Management During Pregnancy Planning

For weight management during pregnancy planning, it is essential to know the optimal BMI for pregnancy. Compare your BMI with the ideal BMI for pregnancy. Important points will also be explained to help with weight management.

Ideal BMI Value

BMI (Body Mass Index) is a numerical representation of body composition, calculated by dividing your weight in kilograms by your height in meters squared (weight kg ÷ (height m × height m)). You can easily calculate it on the following website, so please feel free to use it.

Reference: CASIO keisan – BMI and Appropriate Weight

For example, if you are 160 cm tall and weigh 55 kg, your BMI would be calculated as 55 ÷ (1.6 × 1.6) = 21.48.

According to the World Health Organization (WHO) standards, a BMI of 18.5 or below is considered underweight, 18.5 to less than 25 is normal weight, 25 to less than 30 is overweight, and 30 or above is obese.

To increase the chances of conception, aim to keep your BMI within the range of 18.5 to 25. Within the appropriate range, a BMI of 19 to 22.9 is associated with the highest pregnancy rates.

It is not good for your BMI to be too high or too low. For a body that is conducive to pregnancy, try to maintain your BMI within the appropriate range as much as possible.

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How to Gain Weight During Pregnancy Planning

• Muscle Training
• Eating Small, Frequent Meals
• Eating Easily Digestible Foods
• Supplementing Calories with Quality Fats

The reason for muscle training is that it positively impacts pregnancy planning. Increasing muscle mass raises body temperature and blood flow, which in turn activates the body’s functions.

If you need to gain weight, you might not be able to eat large amounts at once. In that case, increase the frequency of your meals to supplement your calorie intake.

For those who have trouble eating a lot, weak digestive function might be the issue. Cutting food into small pieces or making soups can aid digestion and make nutrient absorption easier, which is recommended.

Additionally, compared to carbohydrates and proteins, fats have more than twice the calories per gram. Consuming quality fats can help make up for a calorie deficit.

How to Lose Weight During Pregnancy Planning

Aim to keep your BMI within the appropriate range. Being underweight can make it more difficult to conceive. Once your BMI falls within the appropriate range, make an effort to maintain your weight.

Dieting During Pregnancy Planning

• Eating a Balanced Diet While Reducing the Overall Amount
• Losing Weight While Maintaining Muscle Mass
• The Two Weeks After Your Period Ends is an Easier Time to Lose Weight

While dietary restrictions can lead to weight loss, they can also result in an unbalanced diet and potential health issues. Even if your BMI is within the appropriate range, being unhealthy can make it more difficult to conceive. For example, low-carb diets that restrict one nutrient are not ideal during pregnancy planning.

When you lose weight, you also lose muscle mass. To lose weight healthily, combine weight training with your weight loss efforts to slow down muscle loss.

Additionally, basal body temperature can be a good indicator for dieting. The week following the end of your period, when your basal body temperature is low, and the week after that, when your basal body temperature starts to rise, are good times to lose weight.

Underweight, Obesity, and Pregnancy During Planning

Weight during pregnancy planning affects the ease of conception. Here we explain why maintaining an appropriate weight is necessary and the relationship between weight outside the appropriate range and infertility.

The Importance of Maintaining a Healthy Weight

Maintaining an appropriate weight during pregnancy planning is important not only because it makes it easier to conceive but also because being underweight or overweight is believed to affect the baby after pregnancy.

It has been reported that women who were underweight before pregnancy have a higher risk of preterm birth and delivering low birth weight infants compared to women of normal weight.

Source: National Institutes of Biomedical Innovation, Health and Nutrition – Research Report on the Revision and Promotion of Dietary Guidelines for Pregnant Women

Additionally, a BMI of 25 or higher is associated with a higher likelihood of ovulation disorders and decreased egg quality, leading to lower pregnancy rates. After conception, the risk of miscarriage and gestational diabetes also increases.

Maintaining an appropriate weight is important for both the ease of conception and the health of the baby.

The Relationship Between Underweight/Overweight and Infertility

Being underweight or overweight can decrease the chances of conception. This is because the following conditions are more likely to occur in a woman’s body due to being underweight or overweight:

• Ovulation disorders
• Irregular menstruation
• Polycystic ovary syndrome (PCOS)

Here, we will explain in detail how these conditions are related to infertility.

Ovulation Disorders

Ovulation disorders refer to the improper occurrence of ovulation.

Ovulation is essential for conception, as it prepares the egg to meet the sperm. Without proper ovulation, natural pregnancy becomes difficult.

Obesity is closely related to anovulation. Anovulation means that although menstruation occurs, ovulation does not. Additionally, polycystic ovary syndrome (PCOS), which will be explained later, is strongly associated with obesity and can cause ovulation disorders.

There are two main reasons why being underweight can cause ovulation disorders:

• The ovaries’ functions are weakened.
• The amount of estrogen is low.

Being underweight indicates a state of excessive nutritional and energy deficiency. The brain prioritizes survival, thus weakening the function of the ovaries and directing nutrients and energy to vital organs.

The amount of estrogen is proportional to the amount of fat. Therefore, underweight individuals may have difficulty secreting estrogen. One of the roles of estrogen is to prepare for pregnancy by developing and maintaining reproductive organs. A lack of estrogen means that the body cannot adequately prepare for pregnancy, making it harder for underweight individuals to conceive.

Building Your Body for Pregnancy Planning – What Is the Ideal Weight?【Supervised by doctor】

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Irregular Menstruation

Irregular menstruation refers to the absence of a normal menstrual cycle. A normal cycle ranges from 24 to 38 days, with variations within 6 days considered typical.

Both being underweight and overweight can cause irregular menstruation. One possible cause is leptin. Leptin is a hormone that suppresses appetite and also plays a role in regulating reproductive functions. Leptin is produced in fat cells.

In the case of being underweight, there is less fat, and therefore, less leptin is secreted. As a result, reproductive functions cannot be properly regulated, leading to irregular menstruation.

Conversely, in the case of being overweight, it might be expected that more fat would lead to more leptin. However, in an obese state, leptin resistance increases. Leptin resistance means that leptin becomes less effective, making it difficult to regulate reproductive functions. As a result, irregular menstruation becomes more likely.

Polycystic Ovary Syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is one of the causes of ovulation disorders and makes it difficult for eggs to grow properly.

There are two main reasons why eggs have difficulty growing:

• Excessive production of male hormones in the ovaries
• Imbalance of hormones required for ovulation

Obesity is said to increase the production of male hormones. Male hormones inhibit the development of follicles and thicken the tunica albuginea of the ovaries, making ovulation difficult.

When a lot of insulin is secreted, male hormones also increase. Obese individuals often have insulin resistance, meaning insulin becomes less effective. When insulin is less effective, the body compensates by secreting more insulin.

For normal ovulation, a balanced secretion of LH (luteinizing hormone) and FSH (follicle-stimulating hormone) is necessary. However, in polycystic ovary syndrome (PCOS), there is excessive secretion of LH (luteinizing hormone), disrupting the balance and preventing proper ovulation.

Lifestyle During Pregnancy Planning

For a body that is conducive to pregnancy, maintaining a healthy lifestyle is crucial, with a balanced diet and regular exercise being particularly important.

Diet for Weight Management

During pregnancy planning, strive to maintain a balanced diet. Whether you need to gain or lose weight, a balanced diet remains essential.

We will provide a detailed explanation of what constitutes a balanced diet and the nutrients that should be consumed during pregnancy planning.

Recommended Diet for Weight Management During Pregnancy Planning

A balanced diet includes at least two meals a day that consist of a staple food, main dish, and side dish.

This is specified in the “Guidelines for the Diet of Pregnant Women Starting from Pre-Pregnancy” by the Ministry of Health, Labour and Welfare in 2021. Additionally, the definitions of staple food, main dish, and side dish are as follows:

Main Dish (Staple)
Foods that are primarily sources of carbohydrates such as rice, bread, noodles, and pasta.

Main Course
Dishes that are primarily sources of protein, including meat, fish, eggs, soybeans, and soybean products.

Side Dish
Dishes that are primarily sources of vitamins, minerals, and dietary fiber, such as vegetables.

Source: Ministry of Health, Labour and Welfare – Guidelines for the Diet of Pregnant Women Starting from Pre-Pregnancy

Recommended Nutrients During Pregnancy Planning

Folic acid is particularly recommended. Folic acid is a type of vitamin essential for reducing the risk of neural tube defects in babies. The recommended intake of folic acid is 400 μg per day.

Additionally, the following micronutrients should be consumed in greater amounts after pregnancy compared to before pregnancy:

• Vitamin A
• Vitamin D
• Vitamin B1
• Vitamin B2
• Vitamin B6
• Vitamin C
• Calcium
• Magnesium
• Iron
• Zinc

It is challenging to drastically change your diet after becoming pregnant. Therefore, ensure you consume enough of these nutrients in your diet even before pregnancy.

Recommended Exercises During Pregnancy Planning

We recommend squats as they help enhance ovarian function.

Having more muscle in the lower body is believed to increase the secretion of female hormones and improve blood flow to the ovaries. If muscle training is too strenuous, start with activities such as stair climbing or walking.

NIPT (Non-Invasive Prenatal Testing) After Pregnancy is Confirmed

NIPT (Non-Invasive Prenatal Testing) is a test that helps prepare for childbirth while the baby is still in the womb. It can identify congenital diseases caused by genetic abnormalities and determine the baby’s gender.

There are reports that a high maternal BMI at the time of conception is associated with an increased risk of congenital heart defects. It is also believed to increase the risk of other congenital disorders.

NIPT (Non-Invasive Prenatal Testing) is a test that meets the needs of parents who want to prepare the best possible environment for their baby even before birth.

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Conclusion

For pregnancy planning, aim for an appropriate weight first. Having a BMI within the normal range is one indicator of ease of conception.

However, weight is just a guideline. Even if your weight is appropriate, not maintaining a healthy diet or regular exercise can make it more difficult to conceive. Additionally, lacking physical strength or muscle mass can increase the burden of childbirth and childcare.

Start building a body today that can endure pregnancy and childcare.