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Effectiveness of Norplant® implants among Thai women in Bangkok
ELSEVIER
Effectiveness of Norplant@ Implants Among Thai Women in Bangkok S. Chompootaweep,* N. Dusitsint
E. Kochagarn,t
S. Sirisumpan,t
The purpose of the study was to evaluate the efficacy, acceptability, side effects and continuation rates of the implant system in Thai women. A five-year clinical .study of 308 women receiving Norplant@% implants in Bangkok was conducted. Acceptors’ mean age was 29 years, and mean number of children was about two. More than half of the users (63%) finished primary school. The cumulative continuation rates for Norplant@ implants at first, second, third, fourth and fifth years were, respectively, 98%, 91%, 83%, 78% and 71%. Eight out of a total of eleven pregnancies occurred in the fourth and fifth year of use. The cumulative pregnancy rate was 1 .l% for the third year, 2.0% for the fourth year and 4.2% for the fifth year. Desire for future pregnancy was the leading cause for termination of Norplant@ implants use. The five-year cumulative termination rate for planned pregnancy was 9.2%. Disruption of menstrual rhythm, particularly increased bleeding, was the other main reason for termination; however, the prevalence of menstrual irregularities appeared to diminish with time. The cumulative termination rate for menstrual irregularities in the fifth year of the study was 4.4%. The complaints of “other medical reasons” for removal of Nor-plant@ implants were acne, severe headache, and chloasma. The five-year cumulative termination rate for other personal reasons was 7.9%. These personal reasons were husband having vasectomy, husband objection and divorce. It can be seen from this five-year study that Norplant@ implants are well accepted by Thai women. However, the efficacy in preventing pregnancy was not acceptable during the fourth and fifth year of use in this study, which was different from results of other international studies. CONTRACEPTION 1996;53:33-36 KEY
WORDS:
Norplant” implants, contraceptive effective-
ness *Department of Pharmacology. Faculty of Medicine, and tlnstrtute of Health Research, Chulalongkom University, Bangkok, Thailand Name and address for correspondence: Dr. Sumana Chompootaweep. Department of Pharmacologgy, Faculty of Medicrne, Chulalongkorn University, Bangkok 10330, Thailand Submitted for publication May 8, 1995 Rewsed Auoust 7. 1995 Accepted f& pubircation September 27, 1995 Norplant” IS a registered trademark of the Population Councrl, Inc.
0 1996 Elsevier Science Inc. All rights reserved 655 Avenue of the Americas, New York, NY 10010
J. Tang-usaha,t
B. Theppitaksak,t
and
Introduction he Norplant@’ system is a long-acting, lowdose, progestin-only contraception method that has already been approved for clinical use by the Thai National Family Planning Programme, Ministry of Public Health, since March 1986. The drug, levonorgestrel, is delivered by means of six Silastic capsules implanted in the upper arm by a minor surgical technique. It is one of the most modern hormonal fertility regulating methods and has been effective for five years. The clinical trial was conducted at the Institute of Health Research, Chulalongkorn University, Bangkok. The purpose of the study was to evaluate the efficacy, acceptability, side effects and continuation rates of this implant system in Thai women in Bangkok.
T
Methodology The Nor-plant@ system consists of six capsules, each containing 36 mg of levonorgestrel and having a diameter of 2.4 mm and a length of 3.4 cm. The six capsules appear to release levonorgestrel at a rate of approximately 80 ug per 24 h during the first 6-18 months of use. This rate declines over the next few months, and thereafter the capsules deliver approximately 30 ug of levonorgestrel per 24 h. This latter rate of release is maintained for at least 5 years. Enrollment of subjects began in June 1986, and 308 women were recruited by December 1988. Acceptors in the study met the following criteria: healthy women, 18-45 years of age, sexually active, of demonstrable fertility (at least one birth), neither pregnant nor breastfeeding at the time of insertion, and had no standard contraindications to the use of steroids and willing to follow-up on a regular basis. Each acceptor was given a full explanation of the method and informed of its experimental nature by a nurse and/or a clinical staff. Follow-up visits were scheduled for the first week, third month, sixth month, twelfth month and thereafter yearly for 5 years after implants placement. At each visit, the acceptors were given a physical and pelvic examination and had bleeding episodes recorded. Side effects and ISSN 0010.7624/96/$15.00 SSDI 0010.7624(95)00261-6
34
Chompootaweep
et al.
Contraception 1996:53:33-36
the acceptor’s reaction were assessed. They used no other contraceptive during the study. They were recruited from a family planning clinic in the Bangkok Metropolis. The acceptors were charged approximately 8 US dollars each for the service, a subsidized rate set by the National Family planning Programme. Postcards were sent to remind the acceptors 2 weeks before each follow-up appointment. Telephone calls were also used when applicable, and occasionally telegrams were also used in case of missed appointment. Amenorrhea is defined as the absence of menses for three months or longer. Regular cycle is a periodic withdrawal bleeding within 28 * 7 days. Irregular cycles are defined as intermenstrual or prolonged or heavy bleeding at irregular intervals. Diary cards were given and acceptors instructed to record the bleeding patterns daily. At each follow-up visit the bleeding patterns were verified and transferred to investigators’ files. Lost diaries were uncommon and they were replaced with new cards. All the diary cards except four were complete. Life table analysislm3 and descriptive statistics were run on all data where appropriate.
Results Characteristics of the Acceptors The characteristics of the acceptors are given in Table 1. The mean age was 29.1 years with an average parity of 1.9 live births. The mean body weight was 56.9 kilograms. The major occupations of the acceptors were labourer (45.1% ) and housewife (44.8%). More Table
1. Characteristics
of studied women; mean and S.D.
or nercentaee IN = 308) Characteristics of Acceptors
Age (years) Weight (kg) Parity Labourer (%) Housewife
(%]
Primary school (%) Secondary school (%) Reasons for contraception Long-acting method (%) Enough children (%) Sources of information Health personnel 1%) Friend or relative (%) Most recent contraceptive Oral contraceptive (%) Injectable contraceptive (%) Condom (%) IUD (%I
X + S.D. 29.1 f 5.5 56.9 f 10.4 1.9 * 1.0 45.1 44.8 63.3 18.2 39.9 25.0 45.3 44.4 49.0 28.6 8.8 4.9
than half of the users (63%) finished primary school, only 18% finished secondary school. Nearly half of the acceptors (49%) had used oral contraceptives. The other methods used by these acceptors were injectable (28.6%), condom (8.8%) and IUD (4.9%). Reasons for participating in this study were longacting method (39.9%) and having enough children (25%). The Norplant@ implants were recommended by health personnel (45%) and friend or relative (44%), which were the main sources of information; mass communication (TV, radio, news) was cited by only 9 % . Termination and Continuation Reasons for termination and five-year gross cumulative life table rates are presented in Tables 2 and 3, respectively. The cumulative continuation rates of Norplant@ implants at first, second, third, fourth and fifth year were, respectively, 97.6%, 90.7%, 82.9%, 77.9% and 71.0%. One-hundred-eighty-nine of the acceptors completed 5 years of implant use. Seventyfour acceptors terminated for the various reasons presented in Table 2. Forty-five were recorded as lost to follow-up. The total cumulative termination rates for the first, second, third, fourth, and fifth year were, respectively, 2.4%, 9.3%, 17.1%, 22.1% and 29%. Pregnancy Eleven pregnancies occurred in this study. No pregnancy was noted in the first two years. Three pregTable
2. Reasons
for termination
Termination Reasons Completed 60 months of implants Accidental pregnancy Menstrual problems Heavy menstrual flow Spotting Prolonged menstrual flow Planning pregnancy Medical reasons PID Endometrial cyst Severe headache Acne Chloasma Menopause Personal reasons Tubal ligation Husband had vasectomy Husband objection Separation/divorce Husband’s death Removal at other clinic Moving overseas Lost to follow-up
N = 308 use
189 11 5 4 3 25
1 4
1 3 2 4 1 4 2 45
Contraception 1996;53:33-36
Table
Norplant@
Implants
Among
Thai Women
in Bangkok
35
3. Five-year grosscumulative life table rate per 100 acceptors Year
Event
1
Continuation rate Total termination rate Accidental pregnancy Menstrual problems Planning pregnancy Other medical Other personal Number of women-months
2
97.6 2.4
90.7 9.3
-
-
0.34 0.34 1 .oo 0.71 3,448
2.1 4.0 1.8 1.4 6,574
nancies were recorded at the end of the third year, 4 in the fourth year and 4 in the fifth year. All of these accidental pregnancies were intrauterine. Eight pregnancies were terminated at the women’s own request and 3 continued their pregnancies. The cumulative pregnancy rates were 1.1% for the third year, 2.0% for fourth year and 4.2% for the fifth year. With reference to weight, average mean weight of pregnant women was 60.8 kilograms at admission, while the overall mean weight of 308 acceptors was 56.9 kilograms; the difference was not statistically significant (t = 1.0165, p = 0.31). However, when the body mass index (BMI) was used, 45.5% of the pregnant women and only 31.5% of the total study acceptors were categorized as overweight or obese. According to the BMI, the pregnant women group was somewhat heavier th.an the total study group.
Planning
Pregnancy
Desire for future pregnancy was the leading cause for termination of Norpl.ant@ implants use. Twenty-five sets of devices were removed from women for this reason. The cumulative termination rates for planning pregnancy for the first, second, third, fourth and fifth year were, respectively, 0.34%, 4%, 5.1%, 8.0% and 9.2%.
Menstrual
Problems
Disruption of menstrual patterns, particularly heavy menstrual flow, was the other main reason for termination; however, the prevalence of menstrual irregularities appeared to diminish with time. Table 4 Table
3
4
5
82.9 17.1 1.1 3.6 5.1 3.3 4.0 9,431
77.9 22.1 2.0 4.0 8.0 3.0 5.1 11,965
71.0 29.0 4.2 4.4 9.2 3.3 7.9 14,113
shows the bleeding episodes of acceptors during the 5-year study. In the first three months after insertion, 64.8% of acceptors had irregular cycles, 25.9% had amenorrhea, and only 9.3% had regular cycles. By the end of the fifth year, the irregular cycles were found to be only 39.5%. Amenorrhea decreased to 17.3% and regular cycles increased to 43.2%. Twelve sets of devices were removed from women for menstrual problems. The cumulative termination rates for menstrual irregularities at the first, second, third, fourth and fifth year were, respectively, 0.34%, 2.1%, 3.6%, 4.0% and 4.4%.
Other Medical
Reasons
The complaints of other medical reasons for removal of Norplant@ implants were acne, severe headache, and chloasma. The details are described in Table 2. The cumulative termination rates for medical reasons at the first and fifth year were 1.0% and 3.3%, respectively.
Other Personal
Reasons
In our study, we found that “other personal reasons” was another leading cause for removal of implants. A total of 17 women requested removal of Norplant” implants for personal reasons. The cumulative termination rates at the first and fifth year were 0.71% and 7.9%, respectively. Personal reasons were husband having vasectomy, husband objection, divorce, and moving overseas (Tables 2, 3).
4. Bleeding episodesof acceptors during 5 years of study Month N
Amenorrhea (3 months) (%] Irregular cycle (%) Regular cycle (28 * 7 day) 1%) Total
l-3 (3081
lo-12 (278)
22-24
34-36 (219)
46-48
(253)
PW
58-60 (185)
25.9 64.8 9.3 100
23.8 62.8 13.4 100
17.4 54.9 27.7 100
16.0 63.0 21.0 100
17.4 51.2 31.4 100
17.3 39.5 43.2 100
36
Chompootaweep
et al
Discussion In the early 80’s the study of Norplant@ implants was initially conducted in 3 provinces in different parts of Thailand with results showing high acceptability and continuation rates.4 As a result, the Norplant@ system was subsequently implemented by the Thai Ministry of Public Health throughout the kingdom since 1986. Our five-year experience with Norplant@ implants in Thai women living in Bangkok showed a high degree of user satisfaction with a relatively high continuation rate. The cumulative continuation rates at the first and fifth years were 98% and 71%, respectively, higher than those reported by other investigators.5-9 Differences in continuation rates could be explained by different social, cultural and ethnical factors. There could also be differences in the availability and quality of counselling. Eleven pregnancies occurred in our study. The gross cumulative pregnancy rate in the fifth year was 4.2 per 100 acceptors, which was higher than the ICCR study j2.7 per 100 acceptors).” It is interesting that 11 women who became pregnant during Norplant@ implants use had a heavy body weight. Weight was shown to be a factor affecting the effectiveness of Norplant@ implants in one study” in which women weighing less than 50 kilograms had cumulative fiveyear pregnancy rates well below 1 per 100 acceptors. Fatty tissue in heavier women may have an effect on the absorption, distribution and metabolism of the steroid hormone released by the implants and may be one of the major factors that decreases the effectiveness of the Norplant@ system. Mentrual problems in this study were characterized by irregular bleeding, increased frequency and bleeding days. However, abnormal bleeding episodes decreased with the duration of use. The gross cumulative termination rate for menstrual irregularities in this study was only 4.4% at the end of five years of use. This is lower than the rate of 14.1% reported by Sivin et al.” Affandi6 reported a cumulative termination rate of 9.2 per 100 acceptors for menstrual problems after five years of Norplants implants use. In Singapore, Singh et a1.5 reported a 12% five-year cumulative termination rate for menstrual irregularities. Planning pregnancy was the leading cause for discontinuing Norplant@ implants use in this study, with the cumulative termination rate for planning pregnancy of 9.2% at the end of five years. This was similar to the Singapore study’ in which planning pregnancy was the main reason for discontinuation, not the menstrual problems as reported in other studies,6,‘2,‘3 Acne was the main medical reason for removal of
Contraception 1996;53:33-36
Norplant@ implants in our study while Affandi et a1.6 reported that headache was complained of most in all other medical reasons for discontinuation. The fiveyear cumulative termination rate for other medical reasons was 3.3%. It is evident from this five-year study that Norplant@ implants are well accepted by Thai women. However, the efficacy in preventing pregnancy was less acceptable during the fourth and fifth year of use in this study.
Acknowledgments The Norplant@ implants were supplied by the Division of Health, Ministry of Public Health, Thailand. We were also grateful to Mrs. P. Havanond for data analysis and wish to thank Mrs. U. Premanee for preparing the manucript. The expense for publication was supported by Research Affairs, Chulalongkorn University.
References 1. Potter RG. Application of life table techniques to mea-
surement of contraceptive effectiveness. Demography 1966j3:297304. 2. Tietze C. Intrauterine contraception: Recommended procedures for data analysis. Study Fam Plann 1967j18(SUppl.):1-6. 3. Jain AK, Sivin I. Life table analysis of IUDs: Problems
and recommendations. Stud Fam Plann 1977j8~25-47. 4. Satayapan S, Kanchanasinith K, Varakamin S. Percep-
tions and acceptability of Norplant@ implants in Thailand. Stud Fam Plann 1983;14:170-6. 5. Singh K, Viegas OAC, Fong YF, Ratnam SS.Acceptability of Norplant@ implants for fertility regulation in Singapore. Contraception 1992j45139-47. 6. Affandi B, Santoso SSI, Djajadilaga, Hadisaputra W, Moeloek FA, Prihartono J, Lubis F, Samil RS. Five-year experience with Norplant@. Contraception 1987j36: 417-28. 7. Olsson SE, Odlind V, JohanssonEDB, Sivin I. Contraception with Norplant@ implants and Norplantm-2 implants (two covered rods). Contraception 1988j37:6173. 8. Sujuan G, Mingun D, Yuan YD et al. A two-year study
of acceptability, side effects, and effectiveness of Norplant@and NorplantB-2 implants in the People’sRepublic of China. Contraception 1988j38:641-57. 9. PasqualeSA, Brandeis V, Cruz RI, Kelly S, Sweeney M. Norplant@ contraceptive implants. Contraception 1987j36:305-16. 10. World Health Organization. Facts about an implantable contraceptive. B&e WHO 1985j63:485-94. 11. Sivin
I. International
experience
with
Norplant@
and
Norplantm-2 contraceptives. Stud Fam Plann 1988119: 8 l-94. 12. Sivin I, Diaz S, Holma P, Alvarez-Sanchez F, Robertson DN. A four-year clinical study of Norplant@ implants. Stud Fam Plann 1983;14:184-91. 13. Balogh SA, Klavon SL, Basnayake S, Puertollano N, Ramos RM, Grubb GS. Bleeding patterns and acceptability among Norplant@ users in two Asian countries. Contraception 1989;39:541-53.
Effectiveness of Norplant@ Implants Among Thai Women in Bangkok S. Chompootaweep,* N. Dusitsint
E. Kochagarn,t
S. Sirisumpan,t
The purpose of the study was to evaluate the efficacy, acceptability, side effects and continuation rates of the implant system in Thai women. A five-year clinical .study of 308 women receiving Norplant@% implants in Bangkok was conducted. Acceptors’ mean age was 29 years, and mean number of children was about two. More than half of the users (63%) finished primary school. The cumulative continuation rates for Norplant@ implants at first, second, third, fourth and fifth years were, respectively, 98%, 91%, 83%, 78% and 71%. Eight out of a total of eleven pregnancies occurred in the fourth and fifth year of use. The cumulative pregnancy rate was 1 .l% for the third year, 2.0% for the fourth year and 4.2% for the fifth year. Desire for future pregnancy was the leading cause for termination of Norplant@ implants use. The five-year cumulative termination rate for planned pregnancy was 9.2%. Disruption of menstrual rhythm, particularly increased bleeding, was the other main reason for termination; however, the prevalence of menstrual irregularities appeared to diminish with time. The cumulative termination rate for menstrual irregularities in the fifth year of the study was 4.4%. The complaints of “other medical reasons” for removal of Nor-plant@ implants were acne, severe headache, and chloasma. The five-year cumulative termination rate for other personal reasons was 7.9%. These personal reasons were husband having vasectomy, husband objection and divorce. It can be seen from this five-year study that Norplant@ implants are well accepted by Thai women. However, the efficacy in preventing pregnancy was not acceptable during the fourth and fifth year of use in this study, which was different from results of other international studies. CONTRACEPTION 1996;53:33-36 KEY
WORDS:
Norplant” implants, contraceptive effective-
ness *Department of Pharmacology. Faculty of Medicine, and tlnstrtute of Health Research, Chulalongkom University, Bangkok, Thailand Name and address for correspondence: Dr. Sumana Chompootaweep. Department of Pharmacologgy, Faculty of Medicrne, Chulalongkorn University, Bangkok 10330, Thailand Submitted for publication May 8, 1995 Rewsed Auoust 7. 1995 Accepted f& pubircation September 27, 1995 Norplant” IS a registered trademark of the Population Councrl, Inc.
0 1996 Elsevier Science Inc. All rights reserved 655 Avenue of the Americas, New York, NY 10010
J. Tang-usaha,t
B. Theppitaksak,t
and
Introduction he Norplant@’ system is a long-acting, lowdose, progestin-only contraception method that has already been approved for clinical use by the Thai National Family Planning Programme, Ministry of Public Health, since March 1986. The drug, levonorgestrel, is delivered by means of six Silastic capsules implanted in the upper arm by a minor surgical technique. It is one of the most modern hormonal fertility regulating methods and has been effective for five years. The clinical trial was conducted at the Institute of Health Research, Chulalongkorn University, Bangkok. The purpose of the study was to evaluate the efficacy, acceptability, side effects and continuation rates of this implant system in Thai women in Bangkok.
T
Methodology The Nor-plant@ system consists of six capsules, each containing 36 mg of levonorgestrel and having a diameter of 2.4 mm and a length of 3.4 cm. The six capsules appear to release levonorgestrel at a rate of approximately 80 ug per 24 h during the first 6-18 months of use. This rate declines over the next few months, and thereafter the capsules deliver approximately 30 ug of levonorgestrel per 24 h. This latter rate of release is maintained for at least 5 years. Enrollment of subjects began in June 1986, and 308 women were recruited by December 1988. Acceptors in the study met the following criteria: healthy women, 18-45 years of age, sexually active, of demonstrable fertility (at least one birth), neither pregnant nor breastfeeding at the time of insertion, and had no standard contraindications to the use of steroids and willing to follow-up on a regular basis. Each acceptor was given a full explanation of the method and informed of its experimental nature by a nurse and/or a clinical staff. Follow-up visits were scheduled for the first week, third month, sixth month, twelfth month and thereafter yearly for 5 years after implants placement. At each visit, the acceptors were given a physical and pelvic examination and had bleeding episodes recorded. Side effects and ISSN 0010.7624/96/$15.00 SSDI 0010.7624(95)00261-6
34
Chompootaweep
et al.
Contraception 1996:53:33-36
the acceptor’s reaction were assessed. They used no other contraceptive during the study. They were recruited from a family planning clinic in the Bangkok Metropolis. The acceptors were charged approximately 8 US dollars each for the service, a subsidized rate set by the National Family planning Programme. Postcards were sent to remind the acceptors 2 weeks before each follow-up appointment. Telephone calls were also used when applicable, and occasionally telegrams were also used in case of missed appointment. Amenorrhea is defined as the absence of menses for three months or longer. Regular cycle is a periodic withdrawal bleeding within 28 * 7 days. Irregular cycles are defined as intermenstrual or prolonged or heavy bleeding at irregular intervals. Diary cards were given and acceptors instructed to record the bleeding patterns daily. At each follow-up visit the bleeding patterns were verified and transferred to investigators’ files. Lost diaries were uncommon and they were replaced with new cards. All the diary cards except four were complete. Life table analysislm3 and descriptive statistics were run on all data where appropriate.
Results Characteristics of the Acceptors The characteristics of the acceptors are given in Table 1. The mean age was 29.1 years with an average parity of 1.9 live births. The mean body weight was 56.9 kilograms. The major occupations of the acceptors were labourer (45.1% ) and housewife (44.8%). More Table
1. Characteristics
of studied women; mean and S.D.
or nercentaee IN = 308) Characteristics of Acceptors
Age (years) Weight (kg) Parity Labourer (%) Housewife
(%]
Primary school (%) Secondary school (%) Reasons for contraception Long-acting method (%) Enough children (%) Sources of information Health personnel 1%) Friend or relative (%) Most recent contraceptive Oral contraceptive (%) Injectable contraceptive (%) Condom (%) IUD (%I
X + S.D. 29.1 f 5.5 56.9 f 10.4 1.9 * 1.0 45.1 44.8 63.3 18.2 39.9 25.0 45.3 44.4 49.0 28.6 8.8 4.9
than half of the users (63%) finished primary school, only 18% finished secondary school. Nearly half of the acceptors (49%) had used oral contraceptives. The other methods used by these acceptors were injectable (28.6%), condom (8.8%) and IUD (4.9%). Reasons for participating in this study were longacting method (39.9%) and having enough children (25%). The Norplant@ implants were recommended by health personnel (45%) and friend or relative (44%), which were the main sources of information; mass communication (TV, radio, news) was cited by only 9 % . Termination and Continuation Reasons for termination and five-year gross cumulative life table rates are presented in Tables 2 and 3, respectively. The cumulative continuation rates of Norplant@ implants at first, second, third, fourth and fifth year were, respectively, 97.6%, 90.7%, 82.9%, 77.9% and 71.0%. One-hundred-eighty-nine of the acceptors completed 5 years of implant use. Seventyfour acceptors terminated for the various reasons presented in Table 2. Forty-five were recorded as lost to follow-up. The total cumulative termination rates for the first, second, third, fourth, and fifth year were, respectively, 2.4%, 9.3%, 17.1%, 22.1% and 29%. Pregnancy Eleven pregnancies occurred in this study. No pregnancy was noted in the first two years. Three pregTable
2. Reasons
for termination
Termination Reasons Completed 60 months of implants Accidental pregnancy Menstrual problems Heavy menstrual flow Spotting Prolonged menstrual flow Planning pregnancy Medical reasons PID Endometrial cyst Severe headache Acne Chloasma Menopause Personal reasons Tubal ligation Husband had vasectomy Husband objection Separation/divorce Husband’s death Removal at other clinic Moving overseas Lost to follow-up
N = 308 use
189 11 5 4 3 25
1 4
1 3 2 4 1 4 2 45
Contraception 1996;53:33-36
Table
Norplant@
Implants
Among
Thai Women
in Bangkok
35
3. Five-year grosscumulative life table rate per 100 acceptors Year
Event
1
Continuation rate Total termination rate Accidental pregnancy Menstrual problems Planning pregnancy Other medical Other personal Number of women-months
2
97.6 2.4
90.7 9.3
-
-
0.34 0.34 1 .oo 0.71 3,448
2.1 4.0 1.8 1.4 6,574
nancies were recorded at the end of the third year, 4 in the fourth year and 4 in the fifth year. All of these accidental pregnancies were intrauterine. Eight pregnancies were terminated at the women’s own request and 3 continued their pregnancies. The cumulative pregnancy rates were 1.1% for the third year, 2.0% for fourth year and 4.2% for the fifth year. With reference to weight, average mean weight of pregnant women was 60.8 kilograms at admission, while the overall mean weight of 308 acceptors was 56.9 kilograms; the difference was not statistically significant (t = 1.0165, p = 0.31). However, when the body mass index (BMI) was used, 45.5% of the pregnant women and only 31.5% of the total study acceptors were categorized as overweight or obese. According to the BMI, the pregnant women group was somewhat heavier th.an the total study group.
Planning
Pregnancy
Desire for future pregnancy was the leading cause for termination of Norpl.ant@ implants use. Twenty-five sets of devices were removed from women for this reason. The cumulative termination rates for planning pregnancy for the first, second, third, fourth and fifth year were, respectively, 0.34%, 4%, 5.1%, 8.0% and 9.2%.
Menstrual
Problems
Disruption of menstrual patterns, particularly heavy menstrual flow, was the other main reason for termination; however, the prevalence of menstrual irregularities appeared to diminish with time. Table 4 Table
3
4
5
82.9 17.1 1.1 3.6 5.1 3.3 4.0 9,431
77.9 22.1 2.0 4.0 8.0 3.0 5.1 11,965
71.0 29.0 4.2 4.4 9.2 3.3 7.9 14,113
shows the bleeding episodes of acceptors during the 5-year study. In the first three months after insertion, 64.8% of acceptors had irregular cycles, 25.9% had amenorrhea, and only 9.3% had regular cycles. By the end of the fifth year, the irregular cycles were found to be only 39.5%. Amenorrhea decreased to 17.3% and regular cycles increased to 43.2%. Twelve sets of devices were removed from women for menstrual problems. The cumulative termination rates for menstrual irregularities at the first, second, third, fourth and fifth year were, respectively, 0.34%, 2.1%, 3.6%, 4.0% and 4.4%.
Other Medical
Reasons
The complaints of other medical reasons for removal of Norplant@ implants were acne, severe headache, and chloasma. The details are described in Table 2. The cumulative termination rates for medical reasons at the first and fifth year were 1.0% and 3.3%, respectively.
Other Personal
Reasons
In our study, we found that “other personal reasons” was another leading cause for removal of implants. A total of 17 women requested removal of Norplant” implants for personal reasons. The cumulative termination rates at the first and fifth year were 0.71% and 7.9%, respectively. Personal reasons were husband having vasectomy, husband objection, divorce, and moving overseas (Tables 2, 3).
4. Bleeding episodesof acceptors during 5 years of study Month N
Amenorrhea (3 months) (%] Irregular cycle (%) Regular cycle (28 * 7 day) 1%) Total
l-3 (3081
lo-12 (278)
22-24
34-36 (219)
46-48
(253)
PW
58-60 (185)
25.9 64.8 9.3 100
23.8 62.8 13.4 100
17.4 54.9 27.7 100
16.0 63.0 21.0 100
17.4 51.2 31.4 100
17.3 39.5 43.2 100
36
Chompootaweep
et al
Discussion In the early 80’s the study of Norplant@ implants was initially conducted in 3 provinces in different parts of Thailand with results showing high acceptability and continuation rates.4 As a result, the Norplant@ system was subsequently implemented by the Thai Ministry of Public Health throughout the kingdom since 1986. Our five-year experience with Norplant@ implants in Thai women living in Bangkok showed a high degree of user satisfaction with a relatively high continuation rate. The cumulative continuation rates at the first and fifth years were 98% and 71%, respectively, higher than those reported by other investigators.5-9 Differences in continuation rates could be explained by different social, cultural and ethnical factors. There could also be differences in the availability and quality of counselling. Eleven pregnancies occurred in our study. The gross cumulative pregnancy rate in the fifth year was 4.2 per 100 acceptors, which was higher than the ICCR study j2.7 per 100 acceptors).” It is interesting that 11 women who became pregnant during Norplant@ implants use had a heavy body weight. Weight was shown to be a factor affecting the effectiveness of Norplant@ implants in one study” in which women weighing less than 50 kilograms had cumulative fiveyear pregnancy rates well below 1 per 100 acceptors. Fatty tissue in heavier women may have an effect on the absorption, distribution and metabolism of the steroid hormone released by the implants and may be one of the major factors that decreases the effectiveness of the Norplant@ system. Mentrual problems in this study were characterized by irregular bleeding, increased frequency and bleeding days. However, abnormal bleeding episodes decreased with the duration of use. The gross cumulative termination rate for menstrual irregularities in this study was only 4.4% at the end of five years of use. This is lower than the rate of 14.1% reported by Sivin et al.” Affandi6 reported a cumulative termination rate of 9.2 per 100 acceptors for menstrual problems after five years of Norplants implants use. In Singapore, Singh et a1.5 reported a 12% five-year cumulative termination rate for menstrual irregularities. Planning pregnancy was the leading cause for discontinuing Norplant@ implants use in this study, with the cumulative termination rate for planning pregnancy of 9.2% at the end of five years. This was similar to the Singapore study’ in which planning pregnancy was the main reason for discontinuation, not the menstrual problems as reported in other studies,6,‘2,‘3 Acne was the main medical reason for removal of
Contraception 1996;53:33-36
Norplant@ implants in our study while Affandi et a1.6 reported that headache was complained of most in all other medical reasons for discontinuation. The fiveyear cumulative termination rate for other medical reasons was 3.3%. It is evident from this five-year study that Norplant@ implants are well accepted by Thai women. However, the efficacy in preventing pregnancy was less acceptable during the fourth and fifth year of use in this study.
Acknowledgments The Norplant@ implants were supplied by the Division of Health, Ministry of Public Health, Thailand. We were also grateful to Mrs. P. Havanond for data analysis and wish to thank Mrs. U. Premanee for preparing the manucript. The expense for publication was supported by Research Affairs, Chulalongkorn University.
References 1. Potter RG. Application of life table techniques to mea-
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