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Tackle excess weight

Losing 5 percent to 10 percent of your body weight if you’re overweight, defined as a body mass index (BMI)score of 25 to 29.9, can help jump-start ovulation.

A recent U.K. study, presented at the European Society for Human Reproduction and Embryology meeting in 2009, found that a 5 percent decrease in BMI—regardless of starting weight—resulted in a significant increase in blood flow to the womb, which can help trigger egg release from the ovaries and implantation.

Weight loss boosts insulin sensitivity, which in turn improves levels of many reproductive hormones, Chavarro says. It also decreases levels of inflammatory markers, which can interfere with ovulation and implantation. On the other hand, being too thin also can disrupt ovulation. If you want to be in what the Harvard team calls “the fertility zone,” aim for a BMI of 20 to 24.