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Overweight and trying to get pregnant: will this affect my chances?

Being overweight could affect your chances to become pregnant, especially if this is your first pregnancy. The chances of conceiving during each cycle are reduced by 8 percent if you are overweight and by 18 percent if you are obese (having an abnormal accumulation of body fat, usually 20 percent or more over your ideal body weight).  If this is not a first pregnancy, these numbers climb even higher to about 16 percent if you are overweight and 34 percent if you are obese.

At one time, it was thought that obesity only affected your ability to conceive if you had irregular menstrual cycles. New medical evidence now shows that even overweight women with regular cycles are affected. The risk of infertility appears to increase with the degree of obesity; the greater the weight the larger the problem. There is a solution however. By following a weight loss and regular exercise programme, you can get ovulation started again and improve your chances of becoming pregnant. Even a modest weight loss can pay off. Studies have shown that a weight loss of 10 – 20 percent of body weight helped to regulate menstrual cycles and increased the chances of ovulation. (Yes, you can menstruate and not ovulate.) 

Being overweight is one possible symptom of a condition called polycystic ovarian syndrome (PCOS). In PCOS, the ovaries don't produce enough of the hormones that stimulate the egg to mature and be released. Another symptom of PCOS is the over production of the hormone insulin, which normally helps the body use and store sugars and starches from food. Too much insulin causes the body to release an excess of male hormones called androgens. High levels of androgens can interfere with ovulation and make it difficult for you to get pregnant. Other possible symptoms of PCOS include irregular or non-existent periods, excess hair growth and acne. If you think you may be affected, see your doctor.

Being overweight may make it more difficult to have a baby if you decide to go through in vitro fertilisation (IVF). It is a possibility that the embryo's ability to implant in the uterus will be impaired resulting in lower conception rates and higher miscarriage rates. The exact medical reasons for this is unknown, but the good news is that by losing the extra pounds before you try IVF will dramatically improve your chances of conceiving and having a healthy pregnancy.
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More questions

The best timing for pregnancy testing is once you miss your period.
Ectopic pregnancies are fertilized eggs which implant themselves outside of the uterus. They must be terminated and can indicate future fertility issues.
Ovulation is the period during which you can conceive. Tracking ovulation can be tricky, but you can increase your chances of conceiving through math, prediction kits, or simple scientific observation.
Implantation bleeding is not a common experience, but some women do report small amounts of blood with or without cramping roughly a week or less before their anticipated period.
Pregnancy tests are only as good as the execution. Read all instructions to avoid getting inaccurate results on a home pregnancy test.
The best over the counter kits measure luteinizing hormone (LH).
There are many things that you can do to increase your chances of getting pregnant.
How STD’s can affect your pregnancy, your baby and how you should deal with them during pregnancy.
Taking care of your body before and during pregnancy
Ovulation occurs just about two weeks after the first day of your period.