Changes to your weight, what you eat, how much you exercise, smoking habits and alcohol intake can all be made to increase your chances of becoming pregnant. These factors are known to impact on the fertility of both men and women.
If you are trying to conceive, it is important to be a sensible weight. The best available evidence indicates that being underweight or overweight can impact the fertility of both men and women. In women, excess weight can affect the healthy development of eggs by the ovary and can also affect the implantation of a fertilised egg in the womb. A healthy weight is also needed for the normal production of hormones (oestrogen and testosterone) in both males and females. A healthy weight can increase your chances of becoming pregnant naturally and improve the success of pregnancy while receiving fertility treatment.
If you are trying to conceive, we recommend that you calculate your Body Mass Index (BMI). This can be calculated by dividing your weight in kilograms (kg) by your height in metres squared (your height in metres multiplied by itself). While trying to conceive both you and your partner should have a Body Mass Index (BMI) of between 20 and 24.9. A BMI of above 25 is considered overweight and above 29 is considered obese.
If you have a BMI of more than 29, weight loss of 5% to 10% can significantly increase your success of pregnancy. If you are underweight (BMI of less than 18.5), you are likely to experience irregular periods. Gaining weight can kick-start your ovaries to work properly again and increase your chances of pregnancy. To achieve a healthy weight it is important to eat a balanced diet and exercise regularly.
A healthy, balanced diet is essential when trying to become pregnant. If you are overweight, a healthy diet is essential to achieve weight loss and increase your chances of pregnancy. A healthy diet also reduces your risk of complications during pregnancy such as the development of diabetes and high blood pressure. What you eat before and during pregnancy can also influence the long-term health of your baby. A poor diet can result in low-birth weight and development of heart disease and non-insulin dependent diabetes in adult life. A balanced diet in men is needed to keep sperm production at an ideal level and so increase chances of pregnancy. Here are some tips for healthy eating:
You are also advised to monitor your caffeine intake (coffee, fizzy drinks). Research has shown links between high caffeine levels and an increase in the time it takes to become pregnant and an increased risk of miscarriage. It is recommended for both you and your partner to limit your caffeine intake to less than two cups of coffee per day.
If you are a woman you may also think about supplementing your diet with vitamins and minerals. We recommend women to take folic acid (400ug) while trying to become pregnant and during the first three months of pregnancy. This will reduce the risks of birth defects in your developing baby. Be careful with your intake of Vitamin A as high intake of this vitamin can cause birth defects. Avoid Vitamin A supplements and limit your intake of liver and liver products such as liver pate and cod liver oil supplements.
Regular exercise is needed for a healthy body and mind when trying to conceive. This is particularly important if you have an increased BMI and are trying to achieve a healthy weight. Adults are recommended to take part in 30 minutes of moderate intensity exercise at least 5 times per week. Moderate intensity exercise includes activities such as brisk walking, cycling, tennis and gardening.
Trying for a baby can be a stressful time in your life, regular exercise can help relieve some of this stress by promoting your body to release endorphins ('happy hormones').
Be aware of the dangers of over-exercising. Too much exercise can lead to excessive weight loss and irregular periods.
Smoking affects the fertility of both men and women. If you or your partner are a cigarette smoker you are strongly advised to quit smoking. Available research indicates that the rate of infertility is higher, and the time it takes to become pregnant is longer, in smokers than in non-smokers. In men, cigarette smoke is thought to affect the quality of sperm. In women, smoking has been linked to damage to the ovaries, changes in hormone levels needed for pregnancy and earlier onset of the menopause. If you do become pregnant, smoking is linked with increased risk of miscarriage and low birth weight of the baby.
You may also want to reconsider your alcohol intake while trying to become pregnant. How alcohol influences your fertility remains unclear. However, alcohol has been linked with reduced ovulation and impaired development of a fertilised egg in women. In men, heavy alcohol intake has been linked with decreased testosterone production and quality of sperm.
It is not known how much alcohol you need to drink before it will affect your fertility. Therefore we recommend you to significantly decrease your alcohol intake or to totally avoid drinking alcohol while trying to become pregnant. If you are a woman you should not drink more than 1 or 2 units of alcohol once or twice a week (1 unit = small glass of wine or half a pint of beer). If you are a man, avoid drinking more than 3-4 units a day.
If you want more information or advice on healthy eating, losing weight and quitting smoking, please refer to our fact sheets on these topics, available in the Waterstone Clinic.
Other useful information on the topics discussed above can be found on websites including: