Introduction

First menstrual period otherwise called menarche (Ganong 2003) is the last but a very important stage of puberty in females ( Wronka and, Pawlinska-Chmara 2005). It serves as both an indicator of onset of ovarian function and a predictor of ovulatory frequency (Bernstein 2002). It is influenced by a number of factors including percentage body fat and is therefore a sensitive indicator of environmental conditions during childhood (Wronka and, Pawlinska-Chmara 2005). Though birth weight is not significantly related to age at menarche, girls who were relatively long and thin (>49cm, <3kg) at birth were found to attain menarche six months earlier than girls who were short and light (<49cm, < 3kg)( Adair2001). Furthermore age at menarche was positively correlated with their mother’s age at menarche (Bernstein 2002), which suggests a genetic input. In a more recent study, timing of puberty in general shows high genetic correlation, but environmental factors had stronger influence on menarche, pubarche and adrenarche (Van den Berg 2006 ) ^.

Though many studies especially in developed countries have noted a decline in age at menarche (Herman-Giddens 2006, Silva  and Padez 2006) same cannot be said with certainty for our environment because of paucity of documented evidence. A lot of women in this environment are psychologically ill prepared for this all-important event and this could constitute serious embarrassment and confusion especially when it starts outside the home.

The purpose of this study therefore, was to determine some baseline characteristics of menarche in our environment, emotional implications and level of preparedness for this important event. This would serve as a reference data for future studies considering the current secular trend of menarcheal age.

Materials and Methods

This is cross-sectional study of female students of University of Nigeria, Enugu and Nsukka campuses, Enugu state University of science and technology, and Institute of management and technology Enugu using pre-tested self-administered structured questionnaires. It was carried out during a six weeks period in the 2006/1007 academic session.  Three thousand female students aged between 16 and 20 years were selected using systematic sampling of every second female student queued for submission of school fees’ slips and registration for 2006/07 academic session. After an informed oral consent, and ethical clearance from the relevant authority, we obtained the following information; age at onset of menarche, duration of menarche, reaction and feeling at onset of menarche, prior knowledge and sources of information about menarche before its onset and location on the first day of menarche. Menarche is said to be delayed when first menses occurs after 16 years of age, while premature menarche refers to when first menses occurs before 10 years of age (ACOG 2001).  

The data were analyzed by simple percentage and descriptive statistics using Statistical Package for Social Sciences (SPSS) software version 11 (SPSS Inc: 2001).

Results

Two thousand seven hundred and twenty four questionnaires were completed satisfactorily and returned given a response rate of 90.8%. The mean age of respondents was 18.2 ± 2.7 years (Range 16 – 20 years). Ninety eight percent of the respondents were unmarried. All were Christians.

Forty eight (1.8%) respondents could not recall their exact age at menarche. The mean age at menarche for the remaining 2676 respondents was 12.9 ± 1.1 years (Range 9 – 19years). Out of this, 96 (3.6%) and 48 (1.8%) respondents had delayed menarche and premature menarche respectively as shown in table I. The commonest range of duration of  bleeding at menarche was 2 – 4 days (63.9%) followed by 5 – 8 days (26.5%) while 7.9% and 1.8% of respondents had bleeding at menarche lasting 1 day and more than 8 days respectively .This is shown in table II. The distribution of respondents with respect to their location at onset of menarche is shown in table III. 68.3% were at home,24.2% in the classroom,3.5% in the church and 1.8% of the respondents were inside the market or in a vehicle.

Table 1: Distribution of respondents by menarcheal age.

 Table 2: Duration of bleeding at menarche

Table 3:  Location at onset of menarche.

Majority (48.5%) of the respondents felt embarrassed at onset of menarche despite prior knowledge of the condition. One thousand three hundred and twenty (1320) (45.8%) felt normal emotionally at the onset of menarche because of prior knowledge. However, 5.7% of respondents had no prior knowledge at its onset and therefore felt embarrassed. This is illustrated in table IV. The source of information about menstruation in one thousand three hundred and sixty two (50.0%) of respondents was their mothers; teachers/lecturers contributed 21.7% while the house – helps were the source in 4 (0.4%) of respondents. This is shown in table V.

Table 4: Emotional Feeling at onset of Menarche.

Table 5 : Sources of information about menstruation.

Discussion 

The mean age at menarche of 12.9 years in this study is lower than 13.3years (Modebe 1987)   and 13.1years (Ezem 2006) reported for Igbos of South East Nigeria. It is equally lower than other related studies in other non Igbo tribes of Nigeria 13.57years (Mathur and, Toriola 1982) , 13.45 years(Toriola and Salokun 1991) and 13.19years (Ikaraoha etal 2005). The decline in menarcheal age for both the Igbos and non Igbo speaking tribes of Nigeria therefore, can be said to be in line with the reported secular trend towards younger menarcheal age (Silva and Padez 2006).In this study, the trend toward younger menacheal age when compared with other studies shows a decline at the rate of about 5month per decade.Prior to that a rate of decline of about 4months per decade has been reported. (Modebe 1987), an indication of improving socioeconomic conditions. This is also supported by the finding that only 0.2% of respondent had their menarche before age of ten in 1995 (Nwobodo etal, 1995) as compared to 1.8% in this study. It is also important to note that fluctuating socioeconomic conditions in our environment affects’ a sustained decline as evidenced by the menarcheal age of 14.19years reported in 1995 (Nwobodo etal,1995 )  for Igbos  and13.9 years reported in 1997( Abioye- Kuteyi etal 1997) for the non –Igbo speaking tribe of Nigeria.  Furthermore, the mean menarcheal age in this study is higher than 12.8 years in Americans,( Zacharias  and Rand  1976, ACOG 2001), 12.88 years in Brazilians(Silva and Padez 2006) but lower than 14.3 years in Malawians.(Lema etal 2002). These variations in the age at menarche in different environment are probably nutritional (Herman-Giddens etal 1997). This is supported by the findings that poor nutrition may delay menarche from age 12 – 13 years to about 19 years though a 2 year delay is probably more common ( Kulin etal 1982).

In order to determine the effect socioeconomic and environmental factors on the age at menarche, comparism with results obtained in rural areas would have been more appropriate. If that was done, the average age at menarche may likely to be higher than we reported. However attempts to do that were abandoned as information obtained was very scanty and inconclusive due to poor educational background of the respondents. Furthermore, a previous study among Igbos did not notice any significant effect of socio-economic class on the age at menarche (Nwobodo etal, 1995). The wide range of menarcheal age of 9 – 19 years in this study may be a reflection of the varying socio-economic and genetic background of the students. The average duration of 2-4days found in this study is not different from findings from other studies (Ezem 2006).

Prior knowledge of menstruation did not prevent embarrassment in the majority of the respondents (48.5%), In another study done in 2000, although majority had prior knowledge up to 84% were not psychologically prepared ( Abioye- Kuteyi 2000), which may cast doubt on the quality of the information received prior to menarche. That house-helps were sources of information in some respondents while some others never had prior information may indict some parents who never had time or are shy of discussing reproductive  health matters with their wards. If our children get only scanty information about menarche and menstruation, one wonders the quality of sex education they will obtain and their preparedness to cope with some situations in the   adolescent period. The socio-cultural peculiarities of our environment still have strong influence on our parents irrespective of educational attainment. This makes them reluctant to exhaustibly discuss reproductive health matters with their wards.

The factors that modulate the complex relationship in the hypothalamo-pituitary- ovarian axis that allows gross variation in the timing of menarche are unclear, thus further studies should be encouraged in this regard. There is also need for periodic review of the characteristics of menarche in our environment so as to monitor its trend over time. Parents should devote more time to their female wards as well as be more open to them in reproductive health matters. This will ensure adequate psychological preparation for menarche and other reproductive health issues.

 References

1. Abioye- Kuteyi E A , Ojofeitimi, E O, Aina O I etal. 1997. The influence of socioeconomic and nutritional status on menarche in Nigerian school girls. Nutr-Health 11(3): 185-95.
2. Abioye- Kuteyi E A. 2000. Menstrual knowledge and practices amongst secondary school girls in lle lfe, Nigeria .The Journal of the Royal Society for the Promotion of Health 120: 23-26.
3. Adair LS. 2001. Size at Birth Predicts Age at Menarche. Pediatrics 107 (4): 59.
4. American College of Obstetricians and Gynecologists. ACOG 2001. Pediatric Gynecologic Disorders: ACOG Technical Bulletin No. 201. In: The 2001 Compendium of Selected Publications. Washington, DC: 680 – 685.
5. Bernstein L. 2002. Epidemiology of endocrine-related risks factors for breast cancer. J Mammary Gland Biol Neoplasia 7 (1):3 – 15.
6. Ganong WF. 2003. Physiology of Reproduction in Women. In: DeCherney AH, Nathan L, editors. Current Obstetrics & Gynecologic Diagnosis & Treatment 9^th edition, USA: McGraw-Hill. 130 – 152p.
7. Herman-Giddens ME, Slora EJ, Wasserman RC et al. 1997. Secondary sexual characteristics and Menses in young girls seen in office practice: A study from the Pediatric Research in office settings network. Pediatrics 99(4): 505 – 512.
8. Herman-Giddens ME. .2006. Recent data on pubertal milestones in United States children: the secular trend toward earlier development.Int J Androl 29:241-246.
9. Kulin HE, Bwibo N, Mutie D Santner S. 1982. The effect of chronic childhood malnutrition on pubertal growth and development. American J Cli Nut 36: 527 – 536.
10. Lema VM, Mpang V, Makanani BS.. 2002. Socio-demographic characteristics of adolescents’ post-abortion patients in Blantyre, Malawi. East Afr  Med J 79(6): 306 – 310.
11. Mathur DN, Toriola AL. 1982. Age at menarche in Nigerian athletes. Brit J Sports Med 16: 250 – 252.
12. Nwobodo ED, Orisakwe E, Amilo G et.al1995. Menarche Age of Nigerian Igbos. Orient Journal of Medicine 7(1&2): 23 – 25.
13. Silva HP, Padez C. 2006. Secular trends in age at menarche among Caboclo populations from Para, Amazonia, Brazil: 1930-1980. Am J Hum Biol 18(1): 83 – 92.
14. Toriola AL, Salokun SO. 1991. Age at menarche of Secondary School Girls. Trop J Obstet  Gynaecol 9(2): 7 – 9.
15. Van den Berg SM, Setiawan A, Bartels M, Polderman TJ, etal. Individual Differences in Puberty Onset in Girls: Bayesian Estimation of Heritabilities and Genetic Correlations.Behav Genetic 36:261-270.
16. Wronka I, Pawlinska-Chmara R. 2005. Menarcheal age and socio-economic factors in Poland. Ann Hum Biol32 (5): 630 – 638.
17. Zacharias L, Rand WM. 1976. Development and Growth in American girls: The statistics of menarche. Obstet Gynecol 31: 325