The authors present "Billing" ovulation method as natural family planning.

No abstract

Age and weight were determined by direct measure in 30 feed-restricted female rats studied from weaning to first estrus, and compared to well fed controls. At the first estrus the average weight of well fed rats did not differ from that of the feed-restricted groups. Mean ages at vaginal opening and first estrus in the feed-restricted animals were however greater.

Os autores estudaram a época da maturação sexual de ratas submetidas a diferentes graus de desnutrição protéico-calórica.

The present studies were performed to determine the variation in length of the estrous cycle of undernourished female rats. The two groups studied received 4% and 8% protein diets, the first one group ad libitum and the second one controlled in quantity so that the animals of the two groups have the same growth rate.