In recent years, the family planning program has been one of the priority national policies adopted in the field of government health services. As contraceptive methods, such as the safe period and intrauterine devices which apply the principle of the menstrual cycle, have been popularized among women practicing
family planning, attention has been increase toward the menstrual cycle.
Studies on the menstrual cycle have often been conducted, but their criteria have mostly limited to groups of patients in hospitals or girl students; moreover, data have been collected according to the memory of the last few menstruations or by
asking them to check their menstrual record for a limited period. As a result, such statistical reports could not be expected to be representative of all facts arising in the menstrual cycle of the general population.
Therefore, it seemed to the author that this extensive study on the menstrual cycle among housewives in Korean rural communities utilizing accurate recording of data collected over an extended period would be most significant not only as an academic study but also in supporting the national family planning program.
Hence, the present investigation was undertaken to find out the individual menstruation of rural married women in terms of cycle, regularity and duratinon of flow throughout the extended period of observation, and to analyze the findings in terms of age and season.
Materials and Method
The basic universe of the study was Koyang Gun. Since Koyang Health Center has long been a rural demonstration center and since the Department of Preventive Medicine and Public Health, Yonsei University College of Medicine had established a unit to demonstrated the family planning program in this area, the villagers were familiar and cooperative toward the public health program and research activities.
Therefore, unbiased appraisal could be anticipated in collecting accurate data with the cooperation of the residents.
For the sample design, the family record of every household in the area had been prepared and this record was checked by conducting the field survey. Households were then divided into clusters of 50 based upon proximity of dwelling, and the number of eligible women(eligibility being defined as a marred housewife under 45 years of age). In each group cluster were further subdivided into two. Finally, the universe contained 277 clusters by sub-universe (Myun), and in order to minimize sampling error 53 cluster were decided on for the sample size. 1,609 eligible women were involved tin this sample.
These 1,609 eligible women were interviewed; During home visits, and calendars for recording their menstruation were distributed. In order to check the records, four field workers were employed to interview the clients every one month. The clients were asked to fill in their records, but when some clients failed to do so, field workers checked and recorded uncompleted previous cycles during regular home visits. Therefore, the records were expected to be reliable.
The field study was conducted during the period from June, 1965 to June, 1966, and information on 5,148 cycle from 1,609 clients was collected excluding periods of drop-out due to refusal to be interviewed, of failure to interview, hospitalization, and migration.
Results and Discussion
1,474 clients out of 1,609 eligible women excluding 135 drop-outs were classified into three groups according to the menstrual status. Accordingly, 570 clients whose menstrual cycles were regarded as normal anovulatory cycle were classified as Group
Ⅰ, 452 clients who had one or more anovulatory cycles as Group Ⅱ, and 452 women whose menstruation had not been observed during the period as Group Ⅲ.
Distribution of Menstrual Cycle
Among the total of 3,875 cycles in Group Ⅰ and 1,273 cycles in Group Ⅱ, 29days interval was the most frequent followed by 30,31 and 28 dyas in turn. The mean of the total cycles was calculated to be 30.8 days Group Ⅰ, and 31.8 days in Group Ⅱ.
Therefore, it was considered that the menstrual cycle of Korean rural women formed a peak at 29 days interval leaning toward the longer side. It was of interest that in spite of the preconception that 28 days might be the most prevalent, this interval ranked fourth in frequency in this study.
In gorup Ⅰ, 80% of the total cycles were distributed in range between 26 and 37 days interval, and in Group Ⅱ, 80% of them were distributed in the range between 26 and 49 days interval.
3,670 cycles out of the total number of cycles in Group Ⅰ, excluding those with less than 20 days interval or more than 50 days, were classified according to age groups. The mean was calculated to be 32.4 days in the 20-24 age group, 31.3 in the
25-29 age group, 31.1 in the 30-34 age group, 30.4 in the 35-39 age group, 30.4 in the 40-44 age group. Accordingly, it was considered that longer intervals were found in younger age groups.
Variation of Consecutive Menstrual Cycles
Comparing two consecutive cycles by means of a valued run (positive or negative difference between two consecutive cycles) frequent variations in individual cycles of eligible women observed. In Group Ⅰ, only 10.7% of the total number of valued
runs were found to be 0(i.e. consecutive cycles were the same), 33.9% had interval of ±1 days. Therefore, it could be considered that intervals ranging within ±6days reflected a normal variation.
The greatest fluctuations in consecutive cycles were observed in the younger age groups and in the spring.
Duration of Menstrual Flow
Among a total of 6,518 menstruations covered by this study the most frequent duration of menstrual flow was 5 days, followed by 4,3 and 6 days in turu. The mean was calculated to be 4.6 days.
It was then concluded that in Group Ⅰ and Ⅱ the duration of menstruation was between 4 and 7 days in 74.8% of menstruations recorded and between 1 and 3 days for 21.9% of menstruations. Only 3.3% could be classified in the long duration category with menstruation lasting more than 7 days. The category could be
considered to abnormal.
For individual women, it seemed to the author that the duration of flow among the women over 35 years of were shorter than that of younger age group.
A study of 1,609 married women under the age of 45 was conducted in Kouang Gun to investigate their menstruation in terms of cycle, regularity, and duration of flow. The following conclusion have been drawn;
1. The intervals of normal menstrual cycle was from 26 to 37 days.
2. The most frequent intervals of menstrual cycle was 29 days followed by 30,31, and 28 in turn, the mean being 30.8 days.
3. The older age groups-reflected a shorter interval.
4. The younger age groups reflected the shortest interval in summer and the longest interval in winer.
5. The intervals within the normal range of variation in two consecutive cycle was 23 to 35 days.
6. The variation of intervals was notable in the younger age group, particularly, in 20-24 age group.
7. The noticeable variation in fluctuation of two consecutive cycles was observed in the spring.
8. the normal duration of menstrual flow was from 3 to 7 days, the mean being 407±1.3 days.
9. The older age group reflected a longer duration of menstrual flow.
This study was significant in establishing the normal range of menstrual cycle for Korean rural women. These findings could be useful not only for diagnosis and treatment of abnormal menses, but also in family planning education in order to determine the safe period.