Overweight women may #conceive more regularly if they exercise
Overweight and obese women trying to conceive may find that exercise may help them to get pregnant faster.
A new study claims to be the first to find that the effect of physical activity on fertility varied by body mass index; Researchers followed more than 3,500 Danish women aged 18 to 40 trying to conceive over the course of a year. They all reported being in a stable relationship with a male partner and not receiving any fertility treatments. Participants estimated the number of hours per week they had spent exercising in the past year, as well as the intensity of their workouts.
Over the course of the study, nearly 70% of all women became pregnant. The researchers found that moderate exercise, such as walking, cycling, or gardening, was associated with getting pregnant more quickly for all women, regardless of weight. Women who spent more than five hours per week doing moderate exercise were 18% more likely to become pregnant during any given menstrual cycle than women who performed moderate exercise for less than an hour each week.
However, normal-weight and very lean women who reported high levels of vigorous exercise, such as running or aerobics, took longer to get pregnant. Those who exercised vigorously for more than five hours each week had a 32% lower chance of becoming pregnant during a given cycle than women who did not exercise vigorously at all. But there was no association between vigorous exercise and the time it took overweight or obese women (BMI of 25 or greater) to become pregnant.
Because amount and intensity of exercise was self-reported, participants could have underestimated or overestimated their activity levels The results also don’t mean that exercise was responsible for the results. But in general overweight and obese women have higher rates of infertility issues and a variety of pregnancy complications. Fat is also metabolically active and oestrogens and too much oestrogen can suppress other hormones responsible for ovulation. This can lead to cycle irregularity and even amenorrhea, or lack of menstruation. Having too little body fat may be a factor for some women. Competitive female athletes and very underweight women, for example, are known to experience menstrual irregularities.
Exercise may also affect the fertilized egg’s ability to implant in the uterus. One previous study of women undergoing in vitro fertilization found a higher risk of implantation failure among women who did a lot of running or bicycling.
Fertil Steril March 16,2012.