CHRISMED Journal of Health and Research

: 2022  |  Volume : 9  |  Issue : 1  |  Page : 9--17

Determinants of interpregnancy intervals among women in rural communities in delta state, Southern Nigeria

Rolle Remi Ahuru1, Iseghohi Judith Omon2, Henry Akpojubaro Efegbere3,  
1 Centre of Excellence in Reproductive Health Innovation, University of Benin, Benin City, Nigeria
2 Department of Economics and Statistics, Faculty of Social Sciences, University of Benin, Benin City, Nigeria
3 Department of Community Medicine, College of Medical Sciences, Edo University Iyamho, Benin City, Nigeria

Correspondence Address:
Rolle Remi Ahuru
C/O of Darkup Koplama Procurement Department, University of Benin Teaching Hospital, PMB 111, Benin City, Edo State


Aim: To guarantee safe motherhood, women are advised to adequately space their deliveries. The World Health Organization advocated for a birth interval between 3 and 5 years, yet closed birth spacing continues to be a problem in Nigeria, resulting in poor infant, child, and maternal health. This study explored the determinants of three classes of birth interval (too short, adequate, and too long) among 534 women drawn from three rural communities in Delta State, Southern Nigeria. Methods: The study is an analytical cross-sectional household survey which used a pretested structured questionnaire to elicit information from 534 women in their homes. Extracted data were analyzed with Stata version 13.0. Frequency and simple proportion were used to describe the characteristics of the women. Bivariate analysis was undertaken to show the association between birth intervals and various sociodemographic factors. Determinants of birth interval were measured by multivariate logistic regression. Statistical significance was set at P < 0.05. Results: The mean maternal age is 35.3 years (standard deviation = 7.3 years). According to the results, 74.2% (396/354) of the women reported short birth interval (<24 months), 13.7% (73/534) reported adequate birth interval, and 12.2% (65/534) reported too long birth interval. According to the multivariate logistic regression, short birth interval is significantly influenced by education, media exposure, use of contraceptive, unmet need of contraceptive, and age at marriage. Adequate birth interval is determined by education and unmet need of contraceptive. Long birth interval is predicted by education and ideal birth spacing. Conclusion: In order to encourage adequate birth spacing, education and employment opportunities should be expanded for women in the study area, and the use of modern contraceptive should be encouraged.

How to cite this article:
Ahuru RR, Omon IJ, Efegbere HA. Determinants of interpregnancy intervals among women in rural communities in delta state, Southern Nigeria.CHRISMED J Health Res 2022;9:9-17

How to cite this URL:
Ahuru RR, Omon IJ, Efegbere HA. Determinants of interpregnancy intervals among women in rural communities in delta state, Southern Nigeria. CHRISMED J Health Res [serial online] 2022 [cited 2022 Nov 30 ];9:9-17
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Nigeria's rapid population growth rate has been noted by past studies as a challenge in her development efforts.[1],[2] High population growth rate in excess of the gross domestic product growth rate may mean that several Nigerians may be denied resources for sustainable livelihood. In 2006, Nigeria's population figure was put at 167 million and she was ranked the sixth most populated country in the world.[2] It is reported that Nigeria is the most populated African nation and the most populated black nation on the earth.[3] Current estimates put Nigeria's population estimate at 190,886 million people.[4] Its population growth rate of 2.68% is about the highest in Africa, and projection based on this puts Nigerian population at 359 million people in 2050.[2],[5] Based on this population estimate, Nigeria will be the third most populated nation globally, next only to India and China.

High Nigerian population growth rate is, in turn, explained by its high fertility rate.[6] Although, its fertility rate has declined over the years from 6.3 births per woman in the period 1981–1982 to 6.0 in 1990 to 5.7 in the period 2003–2013, and recently, it is 5.3.[2],[7] High Nigerian fertility, in turn, results from a high number of women graduating into the reproductive age, the preference for large family size, and too closed birth interval.

The World Health Organization (WHO) defines birth interval as the time period from live birth to a successive pregnancy, and the recommended period is at least 24 months (2 years). In the literature, birth interval can be too short (<24 months), adequate (24–59 months), and too long (≥60 months).[8],[9],[10] Too closed birth spacing (<2 years) has been linked to negative maternal and child health outcomes including low birth weight, small for gestational age, preterm birth, genital malformations, and early neonatal death.[9],[11],[12],[13],[14],[15],[16] A 2002 study conducted among women in both low-and-middle-income countries revealed that the neonatal mortality rate was, respectively, 102% and 27% higher for children with birth intervals of 9–14 months and 15–20 months compared to children born 27–32 months.[11] The analysis of birth intervals is of interest in the Nigerian context since it can provide further insight into the mechanisms underlying changes in fertility. Among mothers, closed birth interval is associated with maternal nutritional depletion, placenta previa, and incomplete healing of cesarean section scars, poor lactation, and cross infection among siblings.[16] However, systematic review has shown that mothers who adopt too long birth interval are susceptible to labor dystocia and more likely to suffer preeclampsia.[16] Optimal birth intervals could, therefore, help avert some of these poor maternal and child health outcomes.

Although a handful of Nigerian studies has explored the determinants of birth interval, these studies predominantly focused on short birth interval.[2],[17] This present study adopted a dynamic approach by investigating determinants of the three classes of birth interval (too short, adequate, and too long). Nigeria is a multilingual country with diverse culture and religious belief, which influence both the use of contraceptive, fertility, and birth interval. In the light of the foregoing, predictors of birth interval in Nigeria are contextually bound, and as such, extrapolation of findings of the study from one setting may not hold for other settings. Past Nigerian studies focused on South East, with no previous study that covered South-South, Nigeria.[2],[17] This study explored the determinants of birth interval among reproductive-age women in three rural communities in Delta State, Southern Nigeria. The communities are patriarchal in nature, with male dominance and female subjugation as the norm. The women in the study communities have limited reproductive health right, which may affect their choices of birth interval. The results of the study may be useful to policymakers and health planners with the goal to improve child spacing among rural Nigerian women.


Study communities

This study is a cross-sectional household survey conducted in three rural communities in Ughelli North Local Government Area (LGA) in Delta State, Southern part of Nigeria. Ughelli North is one of the LGAs in Delta State. It lies between 9° 45' N and 8° 43' E with a landmass of 818 square km. The population census of 2006 puts the population figure at 321,028, with a population density of 460.1 people per square km. While women constitute 49.9% of the population, people within the age bracket 15–64 years constitute 57.6%. Administratively, the LGA comprises 11 wards with many communities situated in each ward. The inhabitants of the area are predominantly the Urhobo with other minority ethnic groups such as Okpe, Itsekiri and Ijaw. Men in the area are mainly engaged in fish farming and crop plantation. The women are mainly petty traders. There is a high level of illiteracy in the area, and the rate of poverty is also high.

Sample size determination and sampling procedure

This was an analytical cross-sectional study. Multistage sampling technique was employed in selecting respondents for the study. Simple random sampling technique was used to select three out of the eleven political wards. The selected wards were Agbarha-Otor ward, Agbarho ward 2, and Evwereni ward. Simple random sampling technique was used to select one community in each of the wards. The sample size was calculated using 12% modern contraceptive prevalence rate reported by the most recent National Demographic and Health Survey, using the Cochrane's sampling formula for a single proportion [INSIDE:1] giving rise to a minimum sample size of 162.[7],[18] Assuming an attrition rate of 10%, the sample size was raised to 178 per community and a total of 534 for the three communities (178 × 3). In each of the communities, household survey was conducted in which the entire houses were numbered and households were listed. Households with at least one qualified woman were marked for the survey. The targeted population was all women of reproductive ages with at least two live births. The eligibility criteria were within the reproductive ages, either married or in a consensual union, and must have resided in the communities for a minimum of 12 months. In houses where more than one qualified woman was on the ground at the time of the survey, simple balloting was used to select one of them. This was done until the required sample sizes of 178 respondents were surveyed in each of the communities.

Research instrument

An interviewer-administered questionnaire was used in collecting the data. The questionnaire was formulated by the researchers based on the objective of the study, and was drawn from literature and previous studies. The questionnaire comprises mainly closed-ended questions, in which respondents were provided with response options. The questionnaire was structured into five sections. Sections 1 and 2, respectively, focused on respondent's characteristics and husband's information. Section 3 focused on reproductive characteristics which include birth interval. Section 4 focused on the use of contraceptive, and section 5 focused on barriers to contraception. The questionnaire comprises a total number of 39 structured questions and was formulated in English and translated into the local dialect (Urhobo). The questionnaire was pretested by administering it to eight women in a nearby community called Gana, which shared similar socioeconomic characteristics with the research communities. Adjustments were made based on the results of the pilot test by rephrasing questions which were hazy to respondents and completely removing those ones that seem irrelevant.

Data collection procedure

Trained field research assistants were used to administer the questionnaire. Research assistants were graduates of management and social sciences discipline, and were conversant with the study area, and understood English, Pidgin English, and Urhobo (mother tongue of residents of study area). Research assistants were given 2 days' training on the content of the questionnaire, ethics of the research, and field conduct. The questions were fielded in English language, Pidgin English, and Urhobo, and the questionnaire was administered through face-to-face interviews. The interview took place in household settings, hence the privacies of respondents were ensured throughout. The household survey was carried out from January to June 2019.

Ethical approval and consent to participate

Approval to conduct the study was obtained from the University of Benin Ethics Review Committee. Permission to conduct the study was sought from the community leaders where the survey was conducted. Approval was also sought from the heads of the individual households where participants were drawn from. Finally, informed consent was obtained from the women. The purpose of the research was explained to participants. Participants were made to sign a consent form, which showed they understood what was explained to them, and that they partook in the survey voluntarily. Data collection procedure adhered to ethical process of anonymity, informed consent, and confidentiality. No specific contact information was obtained from the women, as they were identified with unique numbers.

Dependent variables

The dependent variable for this study is birth interval. Birth interval is the time interval in months between two live births.[2],[7],[16] This was measured by evaluating the length of time between the previous birth and the immediate last birth and then subtracting the length of time of the pregnancy which resulted in the last birth, given that most women may not recall the exact date of their conception. The women were asked the age of their second to the last child when their last child was born. They were also quizzed on the duration of the pregnancy that gave birth to the last child. Birth interval was obtained as the difference between the age of the second and the last child when the last child was born less than the duration of the pregnancy that gave rise to the last child.[16] To subscribe to binary classification, we categorized birth interval into three groups: (i) short birth interval (<24 months), (ii) adequate birth interval (24–59 months), and (iii) long birth interval (≥60 months).

Explanatory variables

Exposure to media was generated with frequency of listening to the radio, watching television, and reading newspaper. The response options were everyday, at least once a week, less than once a week, and not at all. The responses were aggregated to generate a three-category measure of exposure to the media: high/moderate/no exposure. In addition, the following variables were examined: maternal age 15–24/25–29/30–34/35–39/40–49; age at marriage 15–19/≥20; age at first birth 15–19/≥20; maternal education formal/nonformal education; husband education formal/nonformal education; employment status working/not working; ideal family size 1–3/4–6/≥7; forms of marriage monogamy/polygamy; hierarchy in a polygamous marriage first wife/second wife/third wife/≥4; number of living children 2 children/3–4 children/5–6 children/at ≥7 children; use of contraceptive modern versus traditional/no use; and unmet need for contraceptive yes/no. These factors were included based on previous studies which examined the factors associated with birth interval.[2],[9],[14],[17],[19]

Data analysis

Extracted data were cleaned, coded and entered into excel format, and uploaded on Stata. All analyses were done with Stata version 13.0 for Windows. Analyses were undertaken at three stages. In the first stage, frequency and simple proportion were used to describe the characteristics of the women. In the second stage, bivariate analysis using Chi-square was used to test for a significant association between various classes of birth interval and the various sociodemographic characteristics. In the third stage, multivariate logistic regression models were estimated. After bivariate analysis, variables with P ≤ 0.1 and other plausible variables were further analyzed using multivariate logistic regression to control for confounding. Variables with P ≤ 0.5 were considered significantly associated with birth intervals.


Sociodemographic characteristics of respondents

The women in the study were aged between 15 and 49 years with a mean age of 35.3 years (standard deviation [SD] = 7.3). The mean age at first birth was 18.1 (SD = 2.3). The mean age at marriage was 17.3 (SD = 2.4). A higher proportion of the women (137, 25.7%) were within the age group of 30–34 years. Most of the women had no formal education (137, 74.3%), and majority of husbands/partners were also formally educated (423, 79.2%). Most of the women reported 0–2 children and ideal family size of 1–3. Majority of the women were in polygamous marriage (420, 78.7%), and those of them in polygamous marriage were mostly the second wife (81, 71.1%). Most of the women reported <2 years as the ideal birth spacing (251, 47%). Majority of the women were working (399,80.6%), but analysis of details of employment showed that they were engaged in the informal sector, which comprised petty trading, farming, teaching, and hairstylist [analysis not shown in [Table 1]]. Majority of the women had no media exposure (420, 78.7%). Majority of the women either were not using any form of modern contraceptive or were using traditional method (381, 71.3%). Most of the women reported unmet need for contraceptive (394, 73.8%) [Table 1].{Table 1}

Bivariate analysis

The result revealed that 74.2% (396/534) had short birth internal, 13.7% (73/534) had adequate birth interval, and 12.2% (65/534) had long birth interval. Women aged 15–24 years (19.7%) and 40–49 years (15.4%) had the highest coverage of adequate birth interval. Women who got married within 15–19 years (34.9%) and who had their first child within 15–19 years (15.4%) reported the highest coverage of adequate birth interval. In addition, mothers with formal educational qualifications (34.9%) and those whose husbands had formal educational qualifications (25.9%) had the higher coverage of adequate birth interval. Women who reported 5–6 living children (46.3%) and those whose ideal family size is 4–6 (18.6%) had the highest coverage of adequate birth interval. Furthermore, women in polygamous marriage (21.9%), those who were third and fourth wives in the hierarchy of polygamous marriage (28.6%), those who reported ideal birth interval ≥60 months (43.2%), and those employed (18.0%) had the highest coverage of adequate birth interval. Women who reported moderate media exposure (40.8%), those using modern contraceptive method (44.4%), and those who had no unmet need for modern contraceptive (46.4%) had the highest coverage of adequate birth interval. All the sociodemographic characteristics were significantly associated with birth interval (P < 0.05) at the bivariate analysis as presented in [Table 2].{Table 2}

Determinants of short birth interval (<24 months)

[Table 3] shows the odds ratios estimated from the multivariate analyses of factors associated with short birth interval among the women. The statistically significant results are reported below. Women who reported formal education qualification (adjusted odds ratio [aOR] = 0.42, 95% confidence interval [CI]: 0.82–53.72, P < 0.05) had a 58% reduction in short birth interval compared to those with nonformal education. Those whose husbands have formal education qualification (aOR = 0.29, 95% CI: 2.31–61.78, P < 0.01) were significantly less likely to have short birth interval compared to those whose husbands had no formal education. Those who reported high media exposure (aOR = 0.36, 95% CI: 0.08–2.89, P < 0.05) were significantly less likely to have short birth interval compared to those with no media exposure. Women who reported the use of modern contraceptive (aOR = 0.66, 95% CI: 1.17–4.82, P < 0.05) had a 34% reduction in short birth interval compared to those who either did not use contraceptive or were making use of traditional methods. Those who reported they have no unmet need for contraceptive (aOR = 0.21, 95% CI: 0.67–4.27, P < 0.05) had a 79% reduction in short birth interval compared to those with such needs. In reference to those who got married within the age group of 15–19 years, those who got married at ≥20 years (aOR = 1.39, 95% CI: 0.59–3.30, P < 0.05) were 1.39 times as likely to have short birth interval. Compared to unemployed women, those employed (aOR = 0.29, 95% CI: 2.31–61.78, P < 0.001) were significantly less likely to have short birth interval.{Table 3}

Determinants of optimum (adequate) birth interval (24–59 months)

[Table 3] shows the odds ratios estimated from the multivariate analyses of factors significantly associated with adequate birth interval among the study participants. In reference to mothers without formal education, those who reported formal education (aOR = 1.89, 95% CI: 0.39–4.38, P < 0.05) were approximately two times as likely to have adequate birth interval. In reference to women whose partners do not have formal education, those whose partners were formally educated (aOR = 2.37, 95% CI: 1.17–4.82, P < 0.05) were approximately two times as likely to have adequate birth interval. Women who had no unmet need for contraceptive (aOR = 3.39, 95% CI: 1.01–11.17, P < 0.05) were approximately three times as likely to have adequate birth interval compared to those who have such needs. Compared to unemployed women, those employed (aOR = 2.72, 95% CI: 0.43–3.06, P < 0.001) were approximately three times as likely to have adequate birth interval.

Determinants of long birth interval (≥60 months)

[Table 3] shows the odds ratios estimated from the binary logistic regression of factors associated with long birth interval among the women. In reference to mothers who reported no formal education, those who had formal educational qualifications (aOR = 0.62, 95% CI: 1.00–6.85, P < 0.05) had a 38% reduction in long birth interval. Women who reported ≥60 months as ideal birth spacing (aOR = 4.06, 95% CI: 1.25–13.24, P < 0.05) were 4.06 times as likely to have long birth spacing compared to those who reported <24 months.


The study explored the determinants of three classes of childbirth interval (too short, adequate, and too long) among 534 women across three rural communities in Delta State, Southern Nigeria. The result showed that 74.2% (396/534) of the women reported short birth intervals (<24 months). This report concurs with the finding by Bassey et al. in which 65.9% of the women had short birth intervals (<24 months) and Aleni et al. in which 52.4% of the women had short birth interval, but contradicts finding by Hendrick et al. in which only 24.6% of the women had short birth interval (<33 months).[12],[16],[17] The proportion of women that have short birth interval is higher than the 23% reported by the most recent National Demographic and Health Survey.[7] Therefore, intervention program should be implemented in the study area that educates mothers on the benefits of adequate child spacing.

According to the results, women who got married after 20 years were more likely to have short birth interval (<24 months) compared to those who got married at 15–19 years. This may be due to the fact that late marriage may put pressure on women to realize their targeted fertility. Furthermore, the fear of reaching menopause may compel women with delayed marriages into more frequent childbirth. In their study, Courtney and Rob reported that shorter period for childbearing and the desire to attain fertility expectations may compel women into short birth intervals.[19]

The results showed that women who were formally educated were less likely to have too short birth interval, and more likely to have adequate and long birth intervals. This finding concurs with findings from other studies both for Nigeria and elsewhere.[2],[9] Maternal education influences every aspect of women's reproductive health behavior. There are several pathways through which education can influence birth spacing behaviour. First, education enhances people's awareness of available contraceptive services.[4],[20] Second, educated women are more likely to have the resources to pay for contraceptive services. Third, educated mothers have confidence which enables them to dialog with health-care providers. Fourth, education reduces power imbalance at the home front which enables a woman to negotiate with the husband on appropriate birth spacing. Fifth, educated men can easily understand and give their wives support on appropriate birth spacing. Sixth, higher education attainment improves a woman socioeconomic status and open doors for higher employment opportunities, hence resulting in adequate birth interval.[9]

The results showed that employed women were less likely to have short birth interval, but more likely to have adequate birth intervals. The fact that employed women were more likely to adequately space their childbearing reflects their desire to cater to their children and time engagement in pursuing self-fulfilling goals and ambition.[9] In Nigeria, there are limited numbers of maternity leaves for employed women, hence employed mothers are compelled to adequately space child delivery. Courtney and Rob remarked that jobless women without education and career often take to childbearing as an alternative to job opportunities.[19]

We found out that media exposure significantly influenced childbirth interval. In clear terms, women who were exposed by watching television, reading the newspaper, or listening to the radio reported longer birth interval. This finding corroborates that of Kaggwa et al., who reported that Malian women living in communities with high media exposure were more likely to use modern contraceptive and reported longer birth intervals.[21]

The result revealed that women who used modern contraceptive were less likely to have short birth interval, while those who had no unmet need for contraceptive were more likely to have adequate birth interval. In the literature, the use of contraceptive has been advocated as one of the most powerful predictors of birth spacing.[6],[16],[22] The use of modern contraceptive has been advocated as strategies for controlling unwanted pregnancy, achieving optimal birth spacing, and promotion of good health for both mothers and babies. As expected, this was demonstrated in our study. Only 24.3% of the women in our study used modern contraceptives before the next pregnancy, hence the high proportion of short birth intervals. Our finding concurs with a Nigerian study,[17] Uganda study;[16] study for Bangladesh[23] and Northern Iran,[24] but contradicts findings from studies conducted for Uganda and Zimbabwe,[19] and Democratic Republic of Congo.[24] The aforementioned studies could not identify a significant association between the use of contraceptive and childbirth spacing.

Despite the utility of the findings from the study, five limitations are noteworthy. First, the report analyzed in this study is obtained through verbal reports; hence, there is difficulty validating such verbal reports. Second, because the data are cross sectional, we could not explore the intertemporal relationship between the various sociodemographic factors and interpregnancy interval. Third, prominently, the analyses utilized cross-sectional data; hence, only associations and no causal relationships could be established. Fourth, respondents may have given socially desirable responses. Fifth, there may be recall bias.

 Conclusion and Implication for Practice

The study explored the determinants of various classes of birth interval among 534 rural women in Delta State, Southern Nigeria. Majority of the women had short birth intervals. The results revealed that being formally educated, being employed, reporting high media exposure and the use of modern contraceptive improves the chances for adequate birth spacing. Based on the findings of the study, the following recommendations are suggested:

Policymakers should expand both education and employment opportunities for rural Nigerian women. Employment opportunities can be expanded through vocational education skills, offering cheap lines of credit to rural women engaged in businesses and using specialized quota for female employment. Education opportunities can be expanded for women through the use of special cutoff for female tertiary education and free tuition at primary and secondary levelsHealth education programs that focus on the benefit of adequate birth spacing should be launched in the study area. Health-care workers should use the medium of antenatal care attendance to educate mothers on the benefit of optimal birth spacing. Health programs using local dialect should be launched in the study areaWomen in the study area should be educated on the benefits of getting married at optimum age brackets that are neither “too early” nor “too late.” While early marriage may expose women to maternal morbidity and mortality, late marriage forces women into too frequent and closed birth spacing to realize fertility expectations and escape menopauseContraceptive services should be made available and offer at highly subsidized rates in all primary health-care centers in rural parts of Nigeria. The unmet need for contraceptive reported in this study is high and may serve as barriers to the use of contraception among the women.

Availability of data and materials

The dataset used and analyzed during the current study is available from the corresponding author on a reasonable request.


The author wishes to appreciate all the research assistants who helped in gathering the data.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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