contraceptivesResearchBlogging.orgTeen pregnancy and birth rates can be a tricky subject.  Maybe it’s just me but parents want to be involved in the type of sexual education their kids get but passively rely on schools and public health initiatives to actually do the teaching.  This has led to battles between abstinence only and comprehensive sex ed. Put 2,000 kids in a school with a single sex ed option and watch the parents come out of the woodwork.  The big three issues of birth control methods, sexually transmitted infections (STIs)  and pregnancy stand as polarizing subjects.  Some parents decry the teaching of these issues because it will encourage early sexual encounters, others will say that the coverage of these subjects need to be open and thorough.  I firmly believe that all three of these subjects should be taught to kiddos starting at an age that precedes the mean onset of sexual activity, mostly because sexuality and misinformation is hard to hide in our uber-accessible internet society.  It used to be that Playboy was behind the counter, but now sexual imagery is touted everywhere from the Disney Channel to the vast expanses of the internet.

Using self survey data a team from Columbia University set out to determine how sexual activity and pregnancy risk have correlated since the survey began in 1991.  As is reported in vast amounts of the literature the sexual activity stayed very stable throughout the 90’s and early 2000’s except in black teens where there was a significant drop in the sex rate.

High School Student Sexual Activity

This means that the rate of pregnancies for high school kids should fluctuates based on how well they use contraceptives since the amount of sex isn’t changing to a large amount.  So how have our kids been doing?  A team from Columbia University set out to find this out by determining the significance of behavioral risk to high school pregnancy.  The team created the Pregnancy Risk Index (PRI) which measures three variables: sexual activity, contraceptive method used at last sexual intercourse, and failure rates for each contraceptive method used. The PRI is essentially a method of determining the risk that a female will get pregnant in 1 year.

The PRI measurement the team came up with correlated very well with the actual pregnancy and birth rates of high school students so we can use this as an indicator of how safe our sexually active kids are being.  Females that haven’t had sex get a 0 on the scale and those that have had sex get a correlating score based on the failure rate of their chosen method of contraception (no contraception scored an 85 out of 100).  So the risk of pregnancy for all sexually active females is simply a factor of the method of contraceptive (and its rate of failure).

PRIThings don’t look too bad, throughout the 90’s the risk of pregnancy fell but then in 2003 an upward trend started for all race/ethnic classes.  True it is not a significant amount but if the trend continues then it could become a significant measurement.  Now let’s take a look at the type of contraceptives used.

Figure 3. Trends in prevalence of contraceptive use at last sex among high school females by race/ethnicity, YRBS, 1991–2007.

Figure 3. Trends in prevalence of contraceptive use at last sex among high school females by race/ethnicity, YRBS, 1991–2007.

No surprises here guys.  Condom use skyrocketed in throughout the 90’s as other methods used declined.  Then as we approach 2007 the trend of condom use changes and begins to decline. This correlates very well with the rise in PRI we see the closer we get to the 2007 numbers.

Obviously this has implications over the type of policy we use in our schools.  The authors made reference to the HIV scare that began around the same time this data begins and how large public awareness campaigns most likely contributed to the explosion in condom use, the decrease in pregnancy and the slight decrease in overall sexual activity.  As the information campaign wanes and the public becomes less vigilant we see the drop in condom use and the corresponding rise in pregnancy risk.

This should have a significant impact in how we structure our sexual education programs in the USA.  We see that the rate of sexual activity did not decrease when abstinence only policies began to become popular in the early oughts but at the same time we see a rise in pregnancy risk (and dare I saw the same rise in STIs, but that is for another paper and another post).  Teaching about pregnancy, methods of contraception, and possibly most importantly STI prevention should be a cornerstone in the education process.  These numbers (as well as many other independent surveys) show that it is a myth that comprehensive education raises the number of youths having sex and on the contrary it is an important factor in reducing pregnancy in our high schoolers.  We should make a commitment to teaching our kids these issues.  We send our kids to school to learn, so let’s not neglect this subject.

I’m briefly going to cover the methods of the survey and the weaknesses that are inherent to the process.

Every two years since 1991 the Youth Risk Behavior Surveillance (YRBS) is administered in schools and the kids self report whether they have had sex in the last 3 months and the method of contraception used.  Kids lie, maybe because they don’t believe the answers are confidential or just because their embarrassed but the numbers have always fallen into a plane of reasonable measures which lends creedence to the fact that the answers are a reliable assessment of the actual state of the issues (or that kids reliably lie on a consistent scale).

One large deficiency that is not covered by the survey are the teens who drop out of school and are at the most risk of pregnancy.  Not much can be done to collect this data and if the kids are already outside the scope of the school then a change in policy will not affect the information and consequently the pregnancy risk that they run.  The dropout rate has stayed consistent since these numbers have been collected so that factor does not skew the results.

John S. Santelli, M.D., M.P.H., Mark Orr, Ph.D., Laura D. Lindberg, Ph.D.,, & and Daniela C. Diaza (2009). Changing Behavioral Risk for Pregnancy Among High School Students in the United States, 1991-2007 Journal of Adolescent Health, 45 (1), 25-32 DOI: 10.1016/j.jadohealth.2009.04.017