In women, progesterone levels are relatively low during the preovulatory phase of the menstrual cycle, rise after ovulation, and are elevated during the luteal phase, as shown in diagram below. Progesterone levels tend to be < 2 ng/ml prior to ovulation, and > 5 ng/ml after ovulation.
Results for this Gallup poll are based on telephone interviews conducted Aug. 7-Dec. 29, 2013, on the Gallup Daily tracking survey, with a random sample of 3,445 adults, aged 18-34, living in all 50 U.S. states and the District of Columbia, who report they are currently living at home with their parents.
This still remains the parent's choice. Provided the parent has lived with the child for at least six months and one day, the parent can always choose to claim his or her child for purposes of the earned income credit. In a tiebreaker situation between two unmarried parents, the tiebreak goes to the parent who lived with the child for the longest.