Hou 2010.

Methods	Randomized controlled trial
Participants	The study location was Boston, Massachusetts, USA 41 participants were randomized to the intervention group and 41 participants were randomized to the control group The inclusion criteria were women seeking care at Planned Parenthood League of Massachusetts who were sexually active, had voluntarily chosen the pill as their contraceptive method, and were new users of the method. The criteria also included having a personal mobile phone with text‐messaging capabilities and desire to use oral contraceptive pills for at least 6 months The exclusion criteria were contraindications to oral contraceptive pill use, the use of oral contraceptive pills primarily for non‐contraceptive indications, current use of oral contraceptive pills for more than 1 month, intent of pregnancy in the subsequent 12 months, plans to travel outside the cell phone networks of the United States and Canada during the duration of the study, inability to complete the study, and being in situations in which receipt of a text message reminder to take an oral contraceptive pill would endanger the safety and privacy of the woman
Interventions	Intervention: TEXT MESSAGING Participants received daily text‐message reminders. During the 3‐month study period, each participant assigned the intervention received a daily text message, "Please remember to take your birth control pill", sent at a designated time chosen by the participant Control: USUAL CARE Patients in the control group received usual care and were not offered additional medication reminders
Outcomes	The measures of adherence were electronic monitoring and diary self report. The pill packs were modified so that each pack could be inserted into the electronic monitoring device, and each pack was placed in a separate envelope and labeled for the participant to place into the device at the beginning of its cycle. Each woman received an electronic monitoring device called SIMPill (Clinical Technology Advisors, Inc., Acton, MA) for adherence data collection. Each time the participant opened the electronic monitoring device to remove a pill, a short message service signal was sent wirelessly to a main server and a second server. As proof of pill‐taking, each day was examined for at least one record of electronic monitoring device opening on either server. All participants were asked to recharge the electronic monitoring device once a month and received a text message on approximately the 15th of every month of the study reminding them to do so. devices and pill diaries. Each day was examined for at least one electronic monitoring device opening on either server. If 7 or more electronic monitoring device openings in a cycle were recorded, we assumed that the device was functioning for the cycle. If 4 to 6 openings in a cycle were recorded and the patient assessed herself as non‐adherent (missing 3 or more pills a month) on the final questionnaire, then we assumed the device was functioning. However, if 4 to 6 openings were recorded in a cycle but the patient assessed herself as adherent (missing 2 or fewer pills per month), we assumed that the electronic monitoring device was malfunctioning for the cycle and the cycle was dropped from analysis. If 3 openings or less were recorded in a given cycle, it was assumed that the electronic monitoring device was malfunctioning and the cycle was dropped from analysis. The operational definition of a pill‐taking day was from 3:00 AM to 2:59 AM. Only events during the first 21 active pill days of a cycle were used in the analysis. Patients kept a diary of their daily pill taking, which were returned to the clinic at the end of 3 months The patient outcome was pregnancy. It seems that a self reported questionnaire at 3 months was used to obtain information about pregnancy
Notes	―
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomization was computer‐generated with varying blocks of four and six." (pg 634)
Allocation concealment (selection bias)	Low risk	(pg 634) "Randomization was computer‐generated with varying blocks of four and six". Randomization sequences were concealed within opaque, sequentially numbered envelopes until interventions were assigned by a research assistant who did not participate in data analysis
Selective reporting (reporting bias)	Unclear risk	Protocol not available
Other bias	High risk	Authors noted the following limitations: "The lack of a significant difference between the arms could be attributed to the frequent use of alternative reminder systems in the control arm. At the beginning of the study, all women were given routine contraceptive counseling, including the possibility of using reminder methods to help them to remember to take their pill. The high rate of reminder system use in the control arm, particularly electronic systems such as cell phone alarms that mimicked the study intervention, could contribute to the lack of difference between the arms." ‐ (pg 639) "Possible reasons for the lack of pregnancies may be that our participants had a low frequency of sexual activity or correctly used backup methods like condoms when they had poor adherence with oral contraceptive pills. Coital activity and condom use with each sexual act was not assessed. The text‐message arm also reported more frequent condom and emergency contraception use during the study, so the text‐message reminders may have had an unintended effect of reinforcing use of backup methods for women at risk." ‐ (pg 639) "Our study cohort was mostly white, well‐educated, and nulliparous, which may limit the generalizability of these findings to a more diverse population." ‐ (pg 639) "Because we cannot exclude the possibility that participants may open and close the electronic monitoring device without taking their oral contraceptive pill, the electronic monitoring device may be underestimating the actual missed pill rate in the cohort." ‐ (pg 639) "Our wireless technology was limited by mechanical and technological issues as described, but only 42 of the possible 246 cycles (17%) could not be included in analysis compared with 220 of a possible 507 cycles (43%) that could not be analyzed in the study by Potter et al." ‐ (pg 640) "An electronic monitoring device with an embedded memory chip has been tested among oral contraceptive pill users, but data collection was limited by unreturned devices or erased memory chips." ‐ (pg 634)
Blinding of outcome assessment (detection bias) Adherence measure	Low risk	(PRIMARY) ELECTRONIC MONITORING DEVICE ‐ The information was collected by the sending automatic messages to the server
Blinding of outcome assessment (detection bias) Patient outcome	Unclear risk	(PRIMARY) PREGNANCY ‐ It appears that the questionnaire may have been completed by the patient but this is unclear
Blinding of participants (performance bias) Adherence measure	High risk	(PRIMARY) ELECTRONIC MONITORING DEVICE ‐ "Women were told that the device would monitor their pill taking during the study." (pg 635)
Blinding of participants (performance bias) Patient outcome	High risk	(PRIMARY) PREGNANCY ‐ Blinding is impossible as oral contraceptives and pregnancy are linked. Also, this was a subjective questionnaire without the use of an objective measure i.e. blood test/urine test pregnancy confirmation at 3 months
Blinding of personnel (performance bias) Adherence measure	Low risk	(PRIMARY) ELECTRONIC MONITORING DEVICE ‐ Investigators involved in data analysis were blinded to group assignment until primary data analysis was completed (pg 634)
Blinding of personnel (performance bias) Patient outcome	Unclear risk	(PRIMARY) PREGNANCY ‐ It appears that the questionnaire may have been completed by the patient but this is unclear
Incomplete outcome data (attrition bias) Adherence measure	Low risk	(PRIMARY) ELECTRONIC MONITORING DEVICE ‐ 9 participants do not have any usable data. But it not clear which study group they come from. "Fifteen women had data for two cycles as a result of a presumed nonfunctioning device for one cycle (nbeta11), dropping from the study (nbeta3), or stopping oral contraceptive pills during the third cycle (nbeta1). The final 10 women had data for only one cycle either because of a presumed nonfunctioning device for two cycles (nbeta8) or because she stopped her pills during the second cycle (nbeta2)." ‐ (pg 637) According to Figure 1, 1 patient had non‐functioning electronic monitoring device, 3 stopped OCPs, and 1 violated protocol in intervention group. 1 stopped OCPs and 1 violated protocol in control group. However, 21 from the intervention group and 24 from control were presumed to have non‐functioning electronic device during the cycle. Therefore data from 26 participants in the intervention group and 26 from the control group have missing information. Missing outcome data are balanced in numbers across intervention groups, with similar reasons for missing data across groups
Incomplete outcome data (attrition bias) Patient outcome	Unclear risk	(PRIMARY) PREGNANCY ‐ Article contains no information about this measure other than the result; impossible to judge