How to Achieve Your Best Weight for Conception

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Susan Watson

By Susan Watson, a Registered Dietitian

Part 1 - What to do if you are overweight
Part 2 - What to do if you are underweight

Part 1, Overweight - Why is your weight so important?

Your weight prior to conception is very significant, and can play a big role in your rate of conceiving, as well as in complications during pregnancy and labor.

Women that are underweight or overweight have an increased rate of infertility, and a reduced probability of becoming pregnant if receiving assisted reproduction treatments.

These difficulties are sometimes associated with menstrual dysfunction, and anovulation due to hormone imbalances. The menstrual cycle is controlled by hormones. There is also a strong association between preconception weight, and an increased risk of preeclampsia (a complication during pregnancy that is characterized with a raise in blood pressure and can be very serious).

Women that are overweight prior to conception are at an increased risk of developing gestational diabetes, pregnancy-related high blood pressure, miscarriage, preterm birth, and congenital birth defects such as neural tube and heart defects, and gastrointestinal malformations. They also have a higher risk of complications during childbirth, and heavy blood loss after giving birth.

How do I determine what my ideal weight should be?

Your family doctor will use a tool called the Body Mass Index (BMI) to determine if your weight is within your ideal weight range for your age and gender. BMI is a measure of body fat that is based on your height and weight. The BMI calculation is as follows:

BMI = kg/m2 "Kg" is your weight is kilograms and "m2" is your height in meters squared.

A BMI of 25.0 or higher is overweight, and a BMI of 18.4 or lower is underweight. A healthy body weight is considered a BMI between 18.5 and 24.9. This applies for most adults that are between the ages of 18 and 65 years and are not currently pregnant or breastfeeding.

BMI Class
<18.4 Underweight
18.5-25 Normal weight
25> Overweight

Here is a link to an online BMI calculator you can use to quickly check your body weight.

If you would prefer to think of your ideal weight range in terms of kilograms or pounds instead of a BMI number, you can use the following formula:

For example, if you are 165 cm (5 foot 5 inches) tall, your ideal weight range would be 50.4 to 67.8 kg or 111 to 149 lbs. Unfortunately, there are many flaws with using BMI to determine an individual's healthy weight range.

For now, BMI is still the tool used. It provides your doctor with an idea about whether you are at risk when it comes to weight related health complications.

What to do if you are not at your ideal weight:

Calorie restriction or weight maintenance during pregnancy is not recommended for overweight or obese women, as this may be harmful to the baby. Therefore, obtaining a healthy weight prior to getting pregnant is very important.

However, losing weight is not easy and if you want to become pregnant, it is important to ensure your body is getting all the nutrients it needs to prepare for pregnancy. Many of the fad diets that are out there circulating on the Internet or in magazines are too restrictive and promise unrealistic weight loss goals, or use weight loss aids that are not scientifically proven to have any health benefits. If you are looking for a weight loss program or plan, make sure the plan follows these guidelines below:

it is important to ensure your body is getting all the nutrients it needs to prepare for pregnancy

Guidelines for a healthy weight loss plan:

Balanced diet for conception

Lifestyle changes as opposed to diets are the best course of action when wanting to loss weight. And the best changes are those that are sustainable for you in the long-term. Choosing one realistic change at a time also helps make it more sustainable. Once it has become a habit, you can add in another change.

Some changes that can help you manage your weight are:

Setting S.M.A.R.T goals will help you make sustainable changes:

Make sure your goal follows these guidelines.

Goals should be:

S - Specific: clearly outline what you want to do
M - Measurable: how much, and how often
A - Action-oriented: a behavior that you have direct control over
R - Realistic: you should be at least 80% confident that you can achieve this goal
T - Time-framed: have an idea how long it will take for you to achieve this goal

Examples of a S.M.A.R.T goal:

I will start eating 2 cups of vegetables at lunch and supper at least 5 days a week.

Note: "I want to lose 10 lbs." is not a goal because this does not provide you with an action.

A Nutrition FACT!

"Based on self-reported food intakes, individuals in the healthy BMI range and those in the overweight and obese BMI ranges tend to eat the same amount of calories. The difference is in the type of calories that they consume. Individuals in the overweight and obese BMI ranges tend to have diets that are higher in fat and lower in carbohydrates, fruit, and fiber. Those with lower BMI's tend to eat the most finer".

Part 2, Underweight - Why is your weight prior to conception so important?

Your weight prior to conceiving, whether it is under or over the recommended weights, can play a big part in your rate of being able to conceive. This can be associated with hormone imbalances that cause irregular menstruation.

Women that are underweight prior to conception are at an increased risk of having premature, low birth weight, and small-for-gestational-age babies.

Research shows that women with low preconceptions weights are at risk of not gaining adequate weight during pregnancy, which can restrict the fetal growth of the baby.

Another concern is possible inadequate nutrient intake and the effect that this can have on the baby during the early weeks of pregnancy.

How to determine what your ideal weight should be

Ideal weight ranges are determined using a calculation that measures body fat. This tool is called the Body Mass Index (BMI). This tool applies for adults that are between the ages of 18 and 65 years, and are not currently pregnant or breastfeeding.

BMI Class
<18.4 Underweight
18.5-25 Normal weight
25> Overweight

What to do if you are underweight

Obtaining a healthy weight prior to becoming pregnant is very important for your health, and the health of your baby once you do conceive. This will help ensure that your body has what it needs right from the start to grow and support a healthy baby.

Being underweight may put you at risk of nutritional deficiencies such as protein, iron, calcium, folate, vitamin D, and vitamin B12. If you eat a diet that has little to no fat in it, you may also become deficient in fat soluble vitamins such as vitamin A, E, D and K. Deficiencies in these nutrients may cause your bones to become fragile and can lead to osteoporosis. They may also weaken your immune system, and lead to anemia. On top of the effects they may have on you, these nutrient deficiencies may lead to birth defects for your baby, and your baby may also develop the same deficiencies.

However, gaining weight does not mean filling your plate with unhealthy high calorie snack foods. While eating these foods may lead to weight gain, it does not address the nutrient deficiencies mentioned above. You want to make sure that the foods you are consuming will give your body the right nutrients that it needs, and that you are gaining weight in a way that supports your health.

Changing your pattern of eating, and your food choices is not an easy task.

Making small changes that are easy for you to incorporate into your every day life, and to the foods you are already eating will be the best way to help you achieve a healthy weight prior to conception.

Steps to take

Here are some healthy lifestyle tips, and meal ideas to help you gain weight that reinforces your health for conception:

Eat three meals a day

A healthy balanced meal includes foods from at least three of the following food groups:

Balanced nutrition for conception

Eat three balanced snacks a day

This will help you keep your energy up and ensure you are meeting your nutrient requirements. A healthy balanced snack includes foods from at least two of the food groups mentioned above. Some ideas for healthy snacks are:

Eat frequently

Aim to eat a meal or snack every 3 to 4 hours, and include a snack before you go to bed. If you find that you tend to feel full fast, eating frequently can help you reach your calorie and nutrient needs for the day.

Avoid "empty calories"

Such as soda pop, chips, and ice cream. Instead, focus on nutrient dense foods, like nuts, avocados, whole grains, legumes, eggs, milk. Do not choose the "reduced fat" or "light" options of healthy foods.

Drink beverages between meals and snacks

Or save them until after you have finished eating. This will help ensure that you do not fill up on these before having the chance to get enough calories and nutrients from food.

Include a protein source with each meal and snack

The milk and alternatives and meat and alternatives food groups offer some great choices for protein sources. Add protein throughout your day by:

An Example of Healthy Balanced Menu For Achieving Your Ideal Weight For Conception


Some women are predisposed to being underweight, and find it difficult to gain weight. In this instance, your focus should be on ensuring that you are receiving adequate nutrition by eating a balanced diet that consists of three meals and three snacks a day, as outlined above.

If you follow the tips above and do not see an increase in your weight, do not despair. You have provided your body with proper nutrition and this will help keep you and your future son or daughter healthy!

Are you trying to get to your ideal weight? Has it been hard? Got a question? Leave a comment below.

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  1. Christy Oct 24, 2016
    I have been trying so hard to maintain an idea weight to no avail. I am over weight
  2. Kay Nov 03, 2016
    I have always been underweight and I've tried everything to gain weight, but I realized that I get full quickly and cannot eat more than 4 times a day (meals).
  3. CCheryl Nov 08, 2016
    I do not know if I'm pregnant. I had sex with my hubby on the week of ovulation and in the days leading up to the week. On the 20th, I'll take a test to see if I am expecting. Cross your fingers, everone....
  4. Calify Nov 21, 2016
    I usually have a 30 day cycle. I had my period on the 9th of November and had sexual intercourse with my fiance between the 17th to 21st of this month. I want to know my chances of becoming pregnant.
    1. Christina (OC Team): If you use your Ovulation Calculator account to track your cycle, you will see a prediction of your fertile window. If you had sex within your fertile window, you have a chance at becoming pregnant. - (Nov 22, 2016)
  5. Ruchi Feb 05, 2017
    We have been TTC for 4 months. This month, I was pretty sure that I had conceived. I had all the symptoms and saw lot of changes happening in my body. I was 4 days late with my period, which made me all the more sure to pick a HPT on 7th day. Unfortunately, I got my period on the 5th day. I don't know what symptoms those were. I have never felt any such symptoms earlier. I have learned through other forums that at times, you do bleed like a period in early pregnancy. I was expecting myself to be 5 weeks along from my last LMP. Should I still take a test and check?

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