The carat (ct) is a unit of mass equal to 200 mg (0.2 g; 0.007055 oz) and is used for measuring gemstones and pearls. The current definition, sometimes known as the metric carat, was adopted in 1907 at the Fourth General Conference on Weights and Measures, and soon afterwards in many countries around the world.
Depending on your cycle length the most fertile days in the cycle varies: If you have 28 days between periods ovulation typically happens on day 14, and the most fertile days are days 12, 13, and 14. If you have longer cycles, say 35 days between periods, ovulation happens on day 21 and the most fertile days are days 19, 20, and 21.
You should add the day of and the day after ovulation to this fertile period just to be sure you don't miss chance at conceiving in case you miscalculate. So all in all, your most fertile days to conceive is a 7 day window. The best position for getting pregnant is the missionary position. This allows for the deepest penetration for sperm to be deposited closest to the cervix or opening of the uterus and allows gravity to be in your favor.