Abstinence versus contraceptive use:
the effect on pregnancy rates
(Part II of “Examining the argument that provision of contraception leads to increased abortion rates“)
In part one of this post, we examined the fallacy that provision of contraceptives increases the number of abortions. We presented strong evidence that couples do not abstain when no contraceptives are available. Now we turn to a related question about the efficacy of abstinence as a goal for reducing unintended pregnancy rates.
It is clearly true that if couples did abstain from sex when contraceptives were not available, unintended pregnancies would be less frequent and abortions would surely decline. But how many people would have to abstain to achieve the fertility reduction achieved by couples using contraceptive methods? Are such levels of abstinence realistic?
Two imagined states:
Contraceptives-upon-Demand and Never-Never Land…
Let us imagine two states—call them Contraceptives-upon-Demand (CUD) and Never-Never Land (NNL)—each with a population of 1,000 couples who do not want to become pregnant this year. In Contraceptives-upon-Demand, everyone uses condoms and, just like condom users everywhere, not everyone uses condoms effectively and consistently. Based on the typical use failure rate for condoms, in CUD 180 women would have unintended pregnancies in a year. In Never-Never Land, there are no contraceptives, so abstinence is the only way to prevent pregnancy. How many couples in Never-Never Land would have to abstain to achieve the same rate of pregnancy as condom—using CUD? 788 out of 1,000. 
Now if the women in CUD used more effective methods of contraception like oral contraceptives (OCs) or intrauterine devices (IUDs), they would have far fewer pregnancies than when they were relying on condoms alone—90 pregnancies in a year if women used OCs and just 2 pregnancies if women used IUDs.  Back in NNL, 89% of the 1,000 couples would have to abstain for the year to match the oral contraceptive pregnancy rate in CUD, and all but two of the couples would have to abstain in order to match the pregnancy rate of those using IUDs in CUD.
There is no place or program that has achieved these levels of abstinence. Among all women, teenagers may be the most likely to be able to abstain because few are married or in steady relationships, and the frequency of intercourse is lower than for women in their twenties and thirties. But even teenagers enrolled in abstinence programs have not achieved a 79% abstinence rate. The programs that most effectively promote abstinence-only messages have not been shown to reduce sexual activity among teens and achieve only about a 50% abstinence rate. (See Cagampang et al., 1997; Kirby, 2007; and Trenholm et al., 2007.)
…and two actual states: California and Texas
Returning to our state examples, we could have called Contraceptives-upon-Demand and Never-Never Land, California and Texas. In 1988, both California and Texas had among the highest teen pregnancy rates in the country. California has had a state family planning program since the 1970s. In 1997, California expanded access to contraceptives to nearly all teenagers as part of the Family PACT Program. Family PACT now serves almost 1.8 million low-income women and men each year, including over 300 thousand teenagers.
Texas has no state family planning program but does have contraceptives available through its Title X program. But Title X in Texas serves only an estimated 15% of women in need (much lower than the national average of 27%). Access to contraceptive services is poor in Texas: a 17-year-old who wants to use contraceptives in Texas would have to find Title X services and even then would need her parents’ permission to get contraceptives. Public Health Institute data show the effects of these two approaches on the teen birth rate.
Couples do not consistently abstain from intercourse when they do not have contraceptives—witness the sharply different trends in teen births in California and Texas, the preponderance of women using no contraceptive method who present at abortion clinics, and the stated willingness of couples to go without birth control if they do not have a method on hand. Contraceptive methods are not perfect but even the least effective methods, like condoms, provide a sharp reduction in the risk of pregnancy compared to using no method of contraception at all.
The debate over public support for family planning should be based in evidence. The evidence is strong that expanding access to effective contraceptive methods is the best approach to reducing unintended pregnancy and the demand for abortion.
- This is just a crude calculation which actually underestimates the percentage of couples who would have to abstain. We took the typical use pregnancy rate for each contraceptive method and calculated what percentage of couples could continue to have sex without contraception (at an 85% annual pregnancy rate) to achieve the same number of pregnancies. It underestimates abstinence rates because 85% refers to the percentage of women who have at least one pregnancy within a year. Couples who do not abstain can have more than one pregnancy each year, especially if some pregnancies end in abortion.
- IUD is assumed to be the Mirena.
Top image ©Tetra Images/Corbis; bottom image ©Radius Images/Corbis