January 2007 Vol 7 correct A.indd Oman is an Islamic country on the Arabian Peninsula in the Middle East. The popula-tion of Oman is about 2.5 million with the bulk concentrated in the north and the south of the country. Prior to 1970 there were only one small mis- sionary hospital and a few clinics scattered over the country. Oman has witnessed great strides in devel- opment during the last thirty years. The hospital bed space grew from only 12 beds in 1970 to 5,200 beds and about 120 health centers in 2000. With the improve- ments in health care, infant mortality has decreased from 110 per 1000 in 1970 to 17 per 1000 in 2000.1 The 1993 census of Oman suggests a wide-based age pyramid, with the majority of the population un- der the age of 20. This large young population base is likely to herald a ‘baby boom’, and a doubling of the population in 14 years is expected.2,3,4,5 As a response the Ministry of Health started to institute a number of birth spacing initiatives in the early 1990s.1 Com- prehensive studies are needed to appraise the effect of such programmes. At the turn of this century, the population of the world surpassed 6.1 billion. This means that the number of people has more than doubled in the past 50 years. However, population growth has leveled off in most industrialized countries and in some countries has even begun to decline.6,7 Although debilitating dis- eases such as malaria and acquired immune deficiency SULTAN QABOOS UNIVERSITY MEDICAL JOURNAL DECEMBER 2006 VOL 6, NO. 2 SULTAN QABOOS UNIVERSITY© 1 Department of Mathematics and Statistics, Sultan Qaboos University, Sultanate of Oman, 2 Department of Studies and Research, Ministry of Health, Sultanate of Oman, 3 Department of Behavioral Medicine, Sultan Qaboos University, Sultanate of Oman *To whom correspondence should be addressed. Email: atsu@squ.edu.om A Study of Fertility Patterns of Ever Married Women in Oman *Atsu S S Dorvlo1, Charles S Bakheit1, Asya Al-Riyami2, Magdi Morsi2, Samir Al-Adawi3 ABSTRACT Objective: To examine the relation between age, education, residence and fertility rate and change in fertility rate between 994/95 and 999/2000. Methods: The data for the study was extracted from the Oman National Health Survey, 2000. The birth histories data was used to extract data on woman years and births in the periods 990 to 994 and 995 to 2000. Results: The marital fertility rate in 999/2000 was 7.2 births. The rates for rural and urban dwellers were 8.07 and 6.75 respectively in 999/2000. Corresponding rates in 994/95 (8.65, 8.30 and 9.69 respectively) were significantly higher than those in 999/2000 for all categories, indicating a reduction in rates. In both periods the higher the education level of the mother the lower her fertility. Conclusion: Educa- tion was a strong determinant of fertility. This study confirms that the higher the education of the woman the lower her fertility and that fertility is on the decline in Oman. Keywords: Fertility rate, marital fertility, reproductive history, woman years العمانيات النساء اخلصوبة عند مناذج دراسة فيما ومعرفة ، أخرى جهة من (التحضر) والتمدين والعمر التعليمِ جهة، ومستوى معدالت اخلصوبة الزوجية من امللخص: الهدف: إيجاد العالقة بني مان عُ صحة مسح من الدراسة معطيات الطريقة: أخذت .2000/1999 وسنة (املرجع) 95/ 1994 سنة بني تغيّرتْ قد الزوجية اخلصوبة كانت إذا .2000 1995 إلى ومن ،1994 1990 إلى من الفترات في ــاء النس ووالدات أعمار ملعرفة ــتعمل تس كانت تأريخ الوالدة بيانات .2000 ــنة لس الوطني /1999 6.75 على التوالي في (8.07 و ــة واملدين ــكان الريف س معدالت كانت 7.12 والدة. 2000/1999 كان في الزوجي اخلصوبة ــدل مع النتائــج: 2000/1999 ــنة س معدالت من أعلى وهي التوالي) 8.30 و9.69 على ,8.65) 95/1994 فكانت منهما في لكل اخلصوبة ــدالت ــا مع أم . (2000 تعليمَ ــةِ أن الدراس هذه د اخلالصة: تُؤكّ اخلصوبة. في احملددة العوامل القوية من التعليم كان املعدالت. تلك انخفاض في إلى ــير يش مما األصناف، لكلّ انخفاض. في وان اخلصوبة أقل ، اخلصوبة كانت كلما عاليا كان املرأةِ كلما املرأة. عمر ، التناسل تأريخ ، الزوجية اخلصوبة ، اخلصوبة املفردات املفتاحية: معدل O R I G I N A L S T U D Y AT S U S S D O R V L O , C H A R L E S S B A K H E I T, A S YA A L - R I YA M I , M A G D I M O R S I A N D S A M I R A L - A D AW I 34 disease are likely to mitigate the current estimate of population growth,8 the trend in developing countries, including Arab countries, suggests the existence of various factors favoring rapid population growth. Var- ious studies have given conflicting reports on popula- tion growth in the Islamic world.1,2,3,4,5,11,12,13,14 To our knowledge, no such studies have come out of Oman. In a paternalistic society such as Oman, women have traditionally played domestic and gender roles that are strongly associated with women’s biological imperatives.14,15 However, the recent acculturation and the spread of education in the country have ushered in new roles and opportunities for women.16 Despite cultural constraints, women in Oman have infiltrated positions that were once considered male domains.17 In education, females appear to be performing better than their male counterparts.18 It is apparent that such newly found social status has impacted on fertility rates. Studies from developing countries suggest that education appears to be an antidote to high birth rates, since fertility is highly influenced by the level of educa- tion of women.19,20 The relationship between education and fertility has yet to be clearly established in Oman. Previous studies have also suggested that there are sig- nificant differences between fertility in urban and rural areas in many developing countries.21 Similar studies are needed to examine the fertility rate between rural and urban populations in Oman so that effective fam- ily planning strategies can be contemplated. The aim of this paper is three-fold: (i) to examine the marital fertility rate, which is the general fertil- ity rate for ever married women in Oman; (ii) to as- sess the impact of education and dwelling on fertility; and (iii) to examine whether the rate of fertility has changed over time. DATA The data for this study were derived from the Oman National Health Survey-2000 (NHS-2000), which Al- Riyami22 conducted nationally from September 1999 to March 2000. The Oman National Health Survey was a comprehensive survey that generated information on, among other things, patterns and determinants of morbidity and mortality, reproductive health and the prevalence of some common diseases. A multi-stage stratified probability-sampling plan was used to select respondents that covered the 10 re- gions of Oman. Suleiman et al.1 reported the details of the design. The Ministry of Health of Oman con- ducted the NHS-2000 with support from UNICEF and UNFPA. A questionnaire administered by trained personnel was used in collecting the various pieces of information. Some parts of the questionnaire were filled from documents provided by respondents. The reproductive health questionnaire consisted of six modules – a woman’s background, reproductive histo- ry, maternal health, family planning knowledge, social status and AIDS awareness. The reproduction module on which the current article was based obtained in- formation on the number of children and the dates of birth of all children ever born. For the present analysis the relevant variables from that survey included the date of birth, age, dwelling and level of education. This study focused on only ever-married Omani women and hence the rates discussed in this article are called marital fertility rates, which are in effect the general fertility rates for ever-married women. In Oman 37% of all women are single, 52% are married and about 3% are divorced (NHS-2000). Over 84% of all women in the age group 25 to 49 are married, while 8% of women between 15 and 19 are married. Since the database contained the birth dates of all children ever born to the women, two secondary data sets were generated; the first, called 1999/2000 data, used the actual interview date as the reference date in computing the number of children and woman years. The second data set, called 1994/95 data, as- sumed a hypothetical survey date that was five years earlier than the actual interview as the reference date. Women who were 15 to 49 in 1999/2000 were 10 to 44 in 1994/95. Therefore to compare the same set of cohorts in 1994/95 with similar cohorts in 1999/2000, only women who were 20 – 49 during the interview in 1999/2000 were included in that part of the computa- tions [Tables 5 and 6]. Besides, women who had died between 1994/95 and 1999/2000 were not included in the 1994/95 data, though they would have been in- cluded if the interview had actually taken place then. Excluded also from the 1994/95 computations were all women who were married between 1994/95 and 1999/ 2000 as they were not married before the hypothetical interview in 1994/95. That is, data on 15-49 year olds in 1999/2000 were used in computing the estimates reported in Tables 3 and 4, while 15 to 44-year olds in 1999/2000 were used for estimates reported in Tables 5 and 6. The data were analyzed using the statistical pack- age StatXact. Nonparametric ANOVA was used to 35 A S T U D Y O F F E R T I L I T Y PAT T E R N S O F E V E R M A R R I E D WO M E N I N O M A N compare the rates. M E T H O D O F E S T I M A T I N G F E R T I L I T Y R A T E S The marital fertility rate, MFR, is computed using the method described in the next section. Readers are referred to Schmertmann and Caetano23 for more details. Since there may be only one data set for the estimations the degree of accuracy of the estimate is usually not possible to determine. Bootstrap24 meth- ods were used to compute the 95% confidence bounds for the estimates of the fertility rates. Note that these bounds are not symmetric about the mean as normal- ity was not assumed. 3.1 Estimation of fertility by last T woman-years method Suppose X is the number of years between the time of marriage and the interview date for a particular woman, that is, X = interview date – marriage date. This woman will be deemed to be susceptible to hav- ing a child in these X+1 years. In this conservative so- ciety, sexual activity usually starts at marriage. Assum- ing a truncation time of T years, this woman would contribute Z equal to minimum (X+1, T) woman years of susceptibility to child bearing. If this woman was Y years old at the time of the survey then these Z wom- an years of susceptibility are distributed one woman year each for the years Y, Y-1, Y-2,-Y-Z. In addition, if this woman had provided k births during the Z years, these births would be counted against the particular years. For example, consider a woman 25 years old at the time of the survey that was married at age 19 and had births at ages 22 and 24. She would provide one woman-year of susceptibility to each of ages 19, 20, 21, 23 and 25 and provide a birth and a woman year to each of the ages 22 and 24 (W1, Tables 1 and 2). An- other woman (W2) who was married at 20 and had no children by age 22, when she was interviewed, would contribute only 3 woman years. See Tables 1 and 2 for more illustrations. The estimator of the fertility rate for a particular year is the number or sum of births in that year di- vided by the number or sum of all woman years for that age [Table 2]. In this formulation a decision needs Table 1: Sample data from birth histories of 5 women Years from interview date 0-1 1-2 2-3 3-4 4-5 5-6 6-7 Woman 1 25 (24) 23 (22) 21 20 [19] Woman 2 22 21 [20] Woman 3 23 22 21 20 19 [18] Woman 4 (24) 23 22 (21) [20] Woman 5 24 (23) [22] NB: (23) indicates birth at age 23, [20] indicates marriage at 20 Table 2: Distribution of woman years by age at risk for 5 women, T=5 Age at Risk W1 W2 W3 W4 W5 Total Births at Age Woman Years Rate 18 [1]* 0 0 0 19 [1]* 1 [1]* 0 1 0/1 20 1* [1] 1 1 0 3 0/3 21 1 1 1 (1) 1 4 1/4 22 (1) 1 1 1 [1] 1 5 1/5 23 1 1 1 (1) 1 4 1/4 24 (1) (1) 1 2 3 2/3 25 1 0 1 0/1 1.37 NB: (1) indicates a woman year and a birth. 1 indicates one woman year. [1] indicates marriage year and a woman year; * indicates the year is not contributed because of truncation AT S U S S D O R V L O , C H A R L E S S B A K H E I T, A S YA A L - R I YA M I , M A G D I M O R S I A N D S A M I R A L - A D AW I 36 to be made on how far back (T years) from the inter- view date to truncate the data. If T=1 is used then the method is equivalent to the “birth last year” method.23 The truncation time, T, equal to 5 years, is usually taken since it is not too far from the interview date to make the results outdated. The fertility rate of any group is obtained as the sum of the ratio of number of births to number of woman years over the individual years/ages. For example the fertility rate of these five women will be 1.37. R E S U L T S The women in this data set were between 14 and 49 years old. Their average age was 31 years with a stand- ard deviation of 7.8 years. Seventy-three percent lived in the urban areas while 23% lived in the rural areas. On average the women in this sample were married by age 17 years and the average number of children born was 5. M A R I TA L FE RTI L I T Y R ATE S I N OM A N , 9 9 9 / 2 0 0 0 I N TE RV I E W DATE DATA Table 3 shows the estimates of the marital fertility rates of Omani women aged 15 to 49 years by cate- gories. The marital fertility rate (MFR) based on the 1999/2000 survey date was 7.12. The 95% confidence interval was (6.90, 7.37). Obermeryer14 reported that between 1950 and 1990 Oman had a constant total fer- tility rate of 7.2. According to a recent report the total fertility rate has declined to 4.8 in 2000 (NHS-2000). Note that the marital fertility rate is the total fertility rate for only married women as the base group. Hence it is expected that the marital fertility rate will be high- er than the total fertility rate. There was a marked dif- ference between the MFR for the rural dwellers and the urban dwellers (p-value<0.01). The rate for the ru- ral dwellers was 1.3 births more than that of the urban dwellers. Education also had a marked effect on the fertility rates (p-value<0.01). The more educatation Omani women achieved the lower the rates. The col- lege or university educated had a rate of 4.75 births while the lowest educated achieved a rate of almost 8 births. M A R I TA L FE RTI L I T Y R ATE S I N OM A N , A S SUMI N G 9 94 / 95 I N TE RV I E W DATE Assuming a 1994/95-interview date the marital fertil- ity rate for Oman was 8.65 with 95% confidence limits (8.36, 8.95) [Table 4]. The fertility rate was higher in the rural areas than in the urban areas. The rates were 9.69 in the rural areas compared to 8.30 in the urban areas. As in 1999/2000 results, education had an in- verse relationship with fertility. The difference be- tween the rates for the no-education group of women and the college or university educated women was 4.3 births. The rates in 1994/95 were higher than the cor- responding rates in 1999/2000. C OMPA R I S O N O F FE RTI L I T Y R ATE S F O R 9 94 / 95 A N D 9 9 9 / 2 0 0 0 Table 5 gives the fertility rates in 1994/95 compared with those in 1999/2000. It should be noted that only women who were between 20 and 49 during the 1999/ 2000 interviews were used for the computations for the 1994/95 estimates while the estimates for 1999/ 2000 were restricted to women who were between 15 and 44 years old, in order that the same groups could be compared. For Oman as a whole, the fertility rate reduced by about 1.8 births, from 8.65 in 1994/95 to 6.86 in 1999/2000. There was a reduction for all age cohorts. There was a drop of almost two births in the urban areas and 1.6 in the rural areas in this time interval. The standardized fertility ratios in the Table 3: Bootstrap estimates of marital fertility using data on 15-49 year olds in 1999/2000 Sample size No. of births up to T=5 No. of woman years Estimate of fertility 95% Lower Confidence Limit 95% Upper Confidence Limit Oman 2037 2338 9482 7.12 6.90 7.37 Urban 1492 1612 6934 6.75 6.47 7.01 Rural 545 726 2548 8.07 7.60 8.48 No Education 747 817 3703 7.70 7.22 8.22 Up to Primary 680 843 3221 7.03 6.65 7.45 Prep-Secondary 488 547 2037 6.17 5.68 6.82 College-University 122 131 521 4.75 4.06 5.49 37 A S T U D Y O F F E R T I L I T Y PAT T E R N S O F E V E R M A R R I E D WO M E N I N O M A N last column of the table, quantified the general reduc- tions in the rates from 1994/95 to 1999/2000.25 All the education categories showed big drops in rates. The education classification in 1999/2000 was retained for their status in 1994/95 since this classification was not available for the 1994/95 data. Table 6 shows the rates by age cohorts. Again all categories experienced de- creases in the fertility rates. The biggest drops were in the 35-44 cohorts. D I S C U S S I O N Studies of fertility from different parts of the Arab world suggest that since the late 1970s there has been a steady decline in fertility.26 However, such decline is not uniform.26,27,28,29,30,31 In Yemen, where women begin childbearing at a relatively early age and a large pro- portion of ever-married women reach high parity at a relatively fast pace, the fertility rate exceeds seven children per woman of reproductive age.23 In contrast, in North Africa women are characterized by delays in the onset of and a slow pace of childbearing; and a smaller proportion of ever-married women reach high parity with a fertility rate of less than 5 births per woman.23 While a woman’s fertility has been suggested to be inversely related to her level of education,20 this issue has so far not been sufficiently investigated in the Arab world32. The present data suggest that in Oman the higher the education of a woman, the lower the fertility rate, which tend to agree with similar stud- ies cited earlier. This largely supports previous stud- ies that empowerment of women with education is a strong catalyst for a successful campaign for health related matters.26 The high fertility rates in developing countries place heavy financial burdens on families with the resultant negative effect on economic growth and quality of life. Table 4: Bootstrap estimates of marital fertility using data on 15-44 year olds in 1994/95 Sample size No. of births up to T=5 No. of woman years Estimate of fertility 95% Lower Confidence Limit 95% Upper Confidence Limit Oman 1675 2499 7598 8.65 8.36 8.95 Urban 1224 1778 5579 8.30 7.97 8.64 Rural 451 721 2019 9.69 9.07 10.26 No Education 729 1205 3558 9.54 9.10 10.01 Up to Primary 594 920 2689 9.25 8.11 10.24 Prep-Secondary 280 304 1084 5.71 5.17 6.26 College-University 72 70 267 5.25 4.32 6.37 Table 5: Estimates of Age Specific Fertility Rates for Oman for 1994/95 and 1999/2000 and the corre- sponding Standardized Fertility Ratios 1994/95 1999/2000 Standardized Fertility Ratio with 1994/95 as base year No. of births Woman Years Marital Fertility No. of births Woman Years Marital Fertility Oman 2499 7598 8.65 2288 8882 6.86 0.80 Urban 1778 5579 8.30 1574 6469 6.44 0.79 Rural 721 2019 9.69 714 2413 8.13 0.84 No Education 1205 3558 9.54 773 3193 7.42 0.78 Up to Primary 920 2689 9.25 838 3161 6.76 0.81 Prep-Secondary 304 1084 5.71 546 2017 6.21 0.94 College-University 70 267 5.25 131 511 4.75 0.91 NB: Educational status as at 1999/2000 used for 1994/95 classification AT S U S S D O R V L O , C H A R L E S S B A K H E I T, A S YA A L - R I YA M I , M A G D I M O R S I A N D S A M I R A L - A D AW I 38 Like elsewhere, Oman has traditionally had high fer- tility rates under the impression that some children may not survive into adulthood.2,33 With very limited or almost non-existent medical services prior to 1970, mortality rates, both for mother and child, were very high in Oman. However with improved medical facili- ties after 1970 and the resultant increase in life expect- ancy, coupled with high fertility, population growth increased rapidly.3 Children are also perceived as gifts from God, and this perception might also encourage high fertility. This could entail difficulties in employ- ment provision, infrastructure development and serv- ice delivery, particularly in education and health.34,35 The above explains to some extent the high fertility rates reported in this study. However there are indi- cations that the rates are decreasing. The standard- ized fertility ratios indicated a general decrease from 1994/95 to 1999/2000 within all cohorts. The older women had higher decreases. Although this should be a welcome beginning, more concerted effort is need- ed to target women who are not yet benefiting from modern education. As family planning is sometimes viewed with suspicion in many traditional societies,36 its implementation needs to be handled with cultural sensitivity and skill for it to be acceptable. The current emphasis of family planning programs should be on educating families to increase the intervals between births rather than focus on reducing the number of children. This apparently is more compatible with socio-cultural teaching especially in the Middle East. For such programs to work, less educated women will have to be especially targeted, as these are the groups with the highest fertility rates. L I M I T A T I O N S O F T H E S T U D Y Some limitations associated with the data analyzed in this paper have potential implications on the interpre- tation of the findings. A common problem with retro- spective studies is the reliability of recall.37 The older women may not be able to remember accurately infor- mation related to the birth of older children. Secondly, this study hinges on the idea that there is a clear di- chotomy between urban and rural areas, both socially and geographically. In Oman the urban-rural divide is not very clear. Most urban dwellers have very strong ties with the rural areas, which they visit almost on a weekly basis. Also many urban residents tend to marry from the rural areas. This notwithstanding, the present data show that there are discernible differences in fer- tility rates between rural and urban areas in Oman. Thirdly, the term education tends to pose difficulties in the Arab/Islamic world where many individuals do receive a traditional education known as ‘madrasa’, leading to a literacy or at least cursory knowledge of the Koran.38 However, information about whether the present cohort acquired a madrasa education was not elicited. In addition, the level of education as elicited from the present sample is likely to have missed other important variables such as quality and skills acquisi- tion. Future studies ought to explore the contribution of traditional education and other skills to fertility. This study has explored the relationship between marital fertility rates and the level of education, age and urbanization, and assessed whether the rate of fertility has changed over time. In general the fertility rates were high but a decline was noted since the rates in 1994/95 were significantly higher than the rates in 1999/2000. Despite these caveats, the impact of educa- Table 6: Estimates of Age Specific Fertility Rates for Oman for 1994/95 and 1999/2000 and the corre- sponding Standardized Fertility Ratios by cohorts Cohorts 1994/95 1999/2000 Standardized Fertility Ratio with 1994/95 as base yearNo. of births Woman Years Marital Fertility No. of births Woman Years Marital Fertility 15-19 362 1125 1.47 198 739 1.17 0.78 20-24 686 1874 1.83 655 1991 1.64 0.90 25-29 660 1855 1.78 624 2123 1.47 0.83 30-34 511 1582 1.60 471 1881 1.25 0.78 35-39 226 881 1.26 280 1586 0.87 0.69 40-44 54 281 0.71 60 562 0.46 0.57 39 A S T U D Y O F F E R T I L I T Y PAT T E R N S O F E V E R M A R R I E D WO M E N I N O M A N tion, age and urbanization on fertility rates were found to be significant. A C K N OW L E D GE ME N TS This study was supported by internal grant IG/SCI/ DOMS/01/05 from Sultan Qaboos University. We are grateful to the Ministry of Health, Sultanate of Oman for providing us with the data. 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