Efficacy of a combined contraceptive regimen consisting of condoms and emergency contraception pills

A large number of studies have found that the consistent and correct use of condoms is by far the most important factor in preventing both pregnancy [1‐8] and sexually transmitted disease (STD) [9, 10], including HIV [11]. However, a limited but growing body of research literature indicated that most of these studies were conducted from a disease-prevention perspective, neglecting the fact that condoms were originally created as a method to prevent unwanted pregnancy [12].

To our knowledge, few relevant randomized and controlled clinical trials were conducted to test the efficacy of latex condom in China. In Shanghai, more than 20% of married women at reproductive age relied on male latex condoms to protect against unintended pregnancy and STDs in 2008 [13]. And recently, more and more women at reproductive age choose latex condoms as a contraception method. This rate rose to 31.04% in 2012 [14]. Since this is the major contraceptive method for married women in Shanghai, the contraceptive efficacy of latex condom needs to be further tested.

Considering ethical issues, it is hard to carry out clinical trials in which volunteers do not use condoms. Therefore, we created a contrast between the control group with male condoms only and the intervention group with a combined contraceptive method consisting of condoms and emergency contraceptive pills (ECPs). ECPs are certainly not 100% effective, but when taken within 72 hours of unprotected sex, timely emergency contraception may reduce women’s risk of unintended pregnancy by 89–95% [15]. Moreover, there is no known harm to the woman, the course of her pregnancy, or the fetus if ECPs are accidentally used [16, 17].

Therefore, a follow-up study to this study was designed to evaluate and contrast the effectiveness of the combined regimen with the method using condoms only in preventing pregnancy.

Male condoms in various forms have been used for centuries [18]. Latex male condoms have been mass-produced since the mid-1800s [19], and since the 1930s, latex condoms have been available to prevent both pregnancy and sexually transmitted disease [20]. Up till now, condoms are one of most popular contraceptive methods and are widely used in many nations for contraception. This randomized and controlled study had several strengths in the efficacy evaluation between two groups. It provides considerable evidence that male condom use remains a highly effective contraceptive method for a period of one year if consistently and correctly used. In this study, over the course of the whole year, the cumulative gross pregnancy rates in the intervention group and the condom only group were, respectively, 2.17% and 1.25%. The Pearl Index intervention group and condom only group were, respectively, 2.21% and 1.26%.The results of our study indicated a low pregnancy rate (2.17% and 1.25%, respectively). However, when we reviewed much of the literature, we found that the reported pregnancy rates for condom users involve a broader range. Some studies showed that the clinical failure rate of male latex condoms rarely exceeded 2% [21‐23]. But other studies found that the pregnancy risk with condoms is high (18.4% in Thailand, 29.5% in Uganda, and 23.3% in Zimbabwe) [3]. After reviewing and discussing the relevant literature, we found the lower pregnancy rates (2.17% and 1.25%, respectively) of our study are primarily due to the study design. Those studies with high pregnancy rates were always inferred from cross-sectional survey studies. But in the randomized and controlled studies in which latex condoms were usually used as the control methods compared with other methods, the pregnancy rate is at a low level, just like in our study. In a relevant study, the pregnancy rate of the six-cycle consistent-use of latex condoms was 1.0% [5]. Another completed randomized controlled trial of condom use reported that the pregnancy rate was 1.2 per 100 women using latex condoms in six-months of consistent use (subjects used condoms in every instance of sexual intercourse) [24]. The similarity between those trials and our study represents a ‘correct’ use of condoms, including consistent and correct condom use.

Some studies [25, 26] indicated that the participants should be educated in correct condom use, but others indicated that education is not related with correct condom use and that the benefits of written instructions are limited and do not fully teach correct condom use [27]. Our study suggested that providing one-on-one training and counseling to subjects about condom use might be crucial to encouraging the consistent and correct use of condoms. Before the study, we asked the subjects: “Do you know how to use condoms correctly?” If the answer was “no,” we explained and gave detailed training on the usage of condoms after interviewing. If the answer was “yes” or “not sure,” we let the subject describe how to use a condom and checked points according to the subject’s description by drawing a “√” at the mentioned point (the point included: a. a condom should be used for every instance of sexual intercourse; b. check if condom is broken before using it; c. exhaust the air from the top bubble; d. hold the base of the condom while drawing the penis out of the vagina; e. if breakage, leakage, or slippage occurs, an emergency method should be used). But the results make us regret that there were 92% and 88.5%, respectively, among our subjects who didn’t know how to use condoms completely correctly. Other studies also obtained a similar result. In a study conducted in Africa [28], taking all criteria together, only 11% of participants performed a correct condom use demonstration. It is obvious that subjects need more information and guidance about how to correctly and consistently use condoms and how to manage breakage, slippage and other relative problems. During the project, therefore, we conducted much training to teach subjects (the couples together) correct condom use and also emphasized the importance of consistent use. After the training, we conducted a small test to test whether they could answer the questions right or not, meanwhile, we provided condoms and penis moulds to subjects so they could demonstrate the process of condom use until they could do it correctly. Finally, we found that the one-on-one training and counseling was truly helpful to the subjects. The lower pregnancy rates (2.17% and 1.25%, respectively) of our study may support the idea.

At the beginning of the study, we assumed that the combined contraceptive regimen consisting of condoms and emergency contraception pills would be helpful to improve the contraceptive effect. However, the log-rank test results show that there wasn’t significant difference between the intervention group and the condom only group in preventing pregnancy in our study, and the Cox regression also illustrated that the contraception regimen show no effect on pregnancy rate. This may result from the situation that pregnancies reported with condom use are almost always due to inconsistent and incorrect use and not to defective condoms [29] and that failure of the condom itself is rare (the reported breakage or slippage rate of condoms is 7.9%) [30]. In our study, there were 4.76% and 5.88% respectively subjects who discontinued participation in the study because of condom reasons, such as condom breakage or discomfort. Among the 26 pregnancies (17 in the intervention group and nine in the control group), only five pregnancies were due to condom-related reasons. As has been shown from this and the other relevant studies mentioned above, once a person starts using condoms regularly, correctly, and consistently, condoms may play a more significant role in pregnancy prevention and in reducing the pregnancy rate to a very low level. So it is not strange that a significant difference between the two groups was not found in this study.

In this study, we carried out a follow-up study to collect detailed information on the subjects and adopted cumulative life table rates to calculate pregnancy occurrence and other variables. The result of this study is expected to provide useful information on the contraceptive effectiveness of condoms and the combined regimen consisting of condoms and ECPs. In this population, it seemed that the combined contraceptive regimen did not improve contraceptive effectiveness. However, this study also found that the rates of non-use of condoms and incorrect use of condoms among our subjects were relatively low because of one-on-one training and counseling. Thus, we don’t know whether the combined contraceptive regimen can improve contraceptive effectiveness among a population who has a high rate of non-condom use and/or incorrect use of condoms. Therefore, further studies need to be conducted in different populations and with different methods.

This study provides considerable evidence that male condom use remains a highly effective contraceptive method for a period of one year if consistently and correctly used. Providing training and counseling to subjects about condom use might be crucial to encouraging the consistent and correct use of condoms. Subjects need more information and guidance about how to correctly and consistently use condoms, which contributes to increasing the contraception efficacy of condoms.