SOURCE: CDC/NCHS, National Survey of Family Growth, 2011–2013.
Contraceptive methods ever used: These data are based on a series of yes or no questions asking the female respondent if she has ever used each of 19 different contraceptive methods.
The following are the contraceptive methods included in this series: the pill; condom; partner’s vasectomy; Depo-Provera injectable; withdrawal; fertility awareness-based methods (e.g., rhythm method or natural family planning); contraceptive patch; contraceptive ring; emergency contraception; hormonal implant; IUD; cervical cap; diaphragm; female condom or vaginal pouch; foam; jelly or cream; suppository or insert; Today sponge; and other method.
Probability of first birth by selected ages: The probability that an individual has had a first birth by various ages was calculated using a life table methodology.
This methodology uses age-specific rates to calculate how many individuals of a cohort will experience an event (i.e., first birth) during an interval.
These additional cases were included to increase sample size because some teenagers aged 15–19 who have not experienced these events may do so before age 20, and adults aged 20–24 have completed their teen years and can provide information on whether they experienced these events in their teen years.