Risk Factors for Unintended Pregnancy in Women: A Nested Case-Control Study


Abdorrahim Afkhamzadeh ORCID 1 , Khaled Rahmani ORCID 1 , Moharam Felehgary 2 , Fariba Farhadifar 1 , Obeidollah Faraji 1 , *

1 Social Determinants of Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Sciences, Sanandaj, Iran

2 Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran

How to Cite: Afkhamzadeh A , Rahmani K, Felehgary M, Farhadifar F, Faraji O. Risk Factors for Unintended Pregnancy in Women: A Nested Case-Control Study, Shiraz E-Med J. 2020 ; 21(1):e89984. doi: 10.5812/semj.89984.


Shiraz E-Medical Journal: 21 (1); e89984
Published Online: November 19, 2019
Article Type: Research Article
Received: January 28, 2019
Revised: July 8, 2019
Accepted: July 13, 2019


Background: Unintended pregnancies impose a large financial burden on national resources and health.

Objectives: This study aimed to determine the risk factors associated with unintended pregnancies in women aged 15 to 45 in Sanandaj, Kurdistan, Iran.

Methods: This nested case-control study was conducted in the second half of 2016 (a period of six months) on 800 pregnant women aged 15 to 45. Overall 240 subjects were placed in the unintended pregnancy group (case group) and 560 subjects in the intended pregnancy group (control group). The data were analyzed using STATA 12 software. Logistic regression analysis was done to investigate the final effect of the studied variables.

Results: In multivariate analysis, the significant relationship was found between unintended pregnancy and some studied variables, including mother’s age (> 25) (odds ratio (OR): 1.69; 95% CI: 1.07 - 2.41), child gender in the current pregnancy (female) (OR: 2.85; 95% CI: 1.94 - 4.17), higher family income (OR: 0.47; 95% CI: 0.31 - 0.74), a history of unintended pregnancy (OR: 5.07; 95% CI: 3.08 - 8.55), abortion or curettage history (OR: 2.78; 95% CI: 1.47 - 5.10), having not good communication with spouse (OR: 9.09; 95% CI: 2.73 - 17.38), attending family planning classes (OR: 1.54; 95% CI: 1.05 - 2.29), and higher previous pregnancies (OR: 4.62; 95% CI: 2.79 - 7.79).

Conclusions: Our results showed some preventable factors such as mother’s age, child gender in the current pregnancy and family income may be related to the unintended pregnancy. Using the study results may help health policymakers in designing interventional programs.

1. Background

Unintended pregnancy is a global problem that often leads to legal or illegal abortion. Preventing unintended pregnancy and minimizing the number of abortion are the key priorities associated with maternal and child health and one of the main objectives of public health policies throughout the world (1, 2). The purpose of reducing unintended pregnancy is mentioned in the WHO report entitled “healthy people in 2000”, but the measures and objectives to achieve this goal have only focused on increasing access to contraceptives. Although increased access to contraceptives is an important tool to reduce unintended pregnancies, it is insufficient for solving unintended pregnancy problem (3). On the other hand, changing the demography policies in Iran in recent years towards increasing childbearing can influence unintended pregnancies. It seems that this policy change has reduced access to free-of-charge contraceptives in health centers across the country (4).

Unintended pregnancies in the world in 2014 were estimated to be 41%, and 50% of these pregnancies led to abortion (5, 6). More than one-third of abortions are unsafe and 95% of them occur in developing countries (7). In various studies, the rate of unintended pregnancies in Iran has been reported to be 24.1% and 18.6% in 2000 and 2005, respectively (8). Although most occurred abortions in Iran have not been reported due to legal restriction, informal statistics show that 1000 unhealthy and unsafe abortions occur daily in Iran (9).

Unintended pregnancy is important and considerable for two reasons; one is to avoid excessive population growth and the other one is its negative effects on the mothers’ and children’s health. The rapid growth of the population in the world and especially in some developing countries has many negative effects on the social, economic, and cultural development of countries (10). Unintended pregnancies are associated with negative consequences for both mother and child, including receiving late prenatal care, physical and sexual violence, postpartum depression, suicide, anxiety during pregnancy, low birth weight, lower mother’s self-care behaviors such as the lack of using supplements, vaccinations and nutrition, higher rates of risky behaviors of mothers such as smoking, alcohol and drug abuse, negligence and shortcomings in the care and upbringing of the child, child abuse, behavioral problems in children, decreased employment opportunities, economic and educational problems of families (11-16).

Unintended pregnancies impose a large financial burden on national resources and health. Economic, social, and medical burden of such pregnancies is huge, such that direct medical expenditures of those pregnancies have been estimated to be about 5 billion dollars in the U.S in 2003 and 299 million dollars in England in 2010 (17).

Several risk factors have been expressed in relation to unintended pregnancy in different studies in which factors such as low educational level of mothers, maternal age, inaccessibility or non-use of contraception, ineffective use of contraceptive methods, changing contraceptive methods, lack of national contraception guidelines and unintended pregnancies management, and lack of implementation of these guidelines, mothers’ suffering from chronic diseases such as diabetes, Spouses’ sexual and domestic violence, physical activity and obesity can be mentioned (3, 18-25).

2. Objectives

Given the high prevalence of unintended pregnancies in the country and its negative consequences for mothers’ and children’s health, this study was carried out to identify potential risk factors related to the unintended pregnancies in women aged 15 to 45 in Sanandaj, Kurdistan, Iran.

3. Methods

This was a nested case-control study conducted in the second half of 2016 (a period of six months). Cases were 240 women with unintended pregnancies based on their states that selected among 800 pregnant women who referred to Be’sat Hospital and health centers for prenatal care or childbirth in Sanandaj, Kurdistan, Iran. The rest of 800 women (560 women) that had intended pregnancies were chosen as the controls.

The data were collected through a checklist prepared by the researchers, including demographic information such as age, marriage age, number of children, socioeconomic status, and specific information about family planning methods and pregnancy status such as prior contraception methods, unintended pregnancy history, abortion and curettage history, the way of receiving contraception method via face to face interviews by the researcher collaborator (medical intern) and midwives in health centers that had already been justified by the researcher. To develop the checklist, the views of 15 related professionals (obstetricians, midwives, faculty members of public health, gynecology, and obstetrics groups) were also obtained.

The data were analyzed using STATA 12 software. To describe the data, descriptive statistics were used. Then potential relationship between unintended pregnancy and each of studied variable was analyzed by chi-square. In multivariate analyses, in order to control potential confounders, logistic regression was performed for the variables with a significance level of less than 0.2. Adjusted odds ratio and 95% CI were calculated for each factor.

Because of ethical considerations, all the subjects were told that their participation in the study was voluntary and they were assured that their participation would have no risk for them and the inform consent form was also completed by them. In addition, the study was ethically reviewed by the Ethics Committee of Kurdistan University of Medical Sciences and was approved with the code: IR 1390/130.

4. Results

In this study, a total of 800 women in two groups, including 240 cases and 560 controls were investigated with the mean ± standard deviation age of 30.27 ± 7.1 and 27.7 ± 5.4 years, respectively. Among all participants, 60% of cases and 40% of controls, used traditional contraceptive methods, whereas 12% and 21% of the cases and controls used modern contraception methods (oral contraceptive methods and intrauterine device), respectively. Other characteristics of studied participants are summarized in Table 1.

Table 1. Characteristics of Studied Participants (N = 800)a
VariableCases, N = 240Controls, N = 560P Value
Mother’s age< 0.001
< 2581 (33)205 (37)
> 25231 (67)283 (63)
High-risk pregnancy, y< 0.001
18 - 35159 (66)507 (90)
< 18 or > 3581 (44)53 (10)
Number of previous pregnancies< 0.001
155 (23)265 (47)
254 (22)177 (32)
> 3131 (55)118 (21)
Number of children< 0.001
< 1121 (51)482 (86)
> 1119 (49)78 (14)
Child gender in the current pregnancy< 0.001
Male72 (30)294 (52)
Female168 (70)266 (48)
Mother’s education level< 0.001
Illiterate43 (18)40 (7)
Less than diploma120 (50)239 (43)
Diploma51 (21)188 (34)
University graduate26 (11)93 (16)
Husband’s education level< 0.001
Illiterate22 (9)18 (3)
Less than diploma110 (46)197 (35)
Diploma69 (29)190 (34)
University graduate39 (16)155 (28)
Family income0.004
Low151 (63)311 (55)
Average65 (27)203 (36)
High24 (10)46 (9)
Contraception method0.001
Traditional108 (45)321 (57)
Modern132 (55)239 (43)
Choosing contraception method0.009
Herself131 (55)350 (62)
Husband45 (19)114 (20)
Physician49 (20)64 (12)
Other15 (6)32 (6)
Unintended pregnancy history< 0.001
Yes113 (47)62 (11)
No127 (53)498 (89)
Curettage or abortion history< 0.001
Yes76 (32)101 (18)
No164 (68)459 (82)
Spouse communication< 0.001
Good112 (47)426 (76)
Sometimes good100 (42)130 (23)
Not good28 (11)4 (1)
Attending at training classes< 0.001
Yes131 (55)408 (73)
No152 (45)152 (27)
Psychiatric problems history< 0.001
Yes45 (19)24 (4)
No195 (81)536 (96)

aValues are expressed as No. (%).

In univariate analysis, statistical significant relation observed between unintended pregnancy and some variables such as mother’s age, high risk pregnancy (years), number of previous pregnancies, child gender in current pregnancy, women’s education, family income, contraceptive method, method of choosing contraception, unintended pregnancy history, curettage or abortion history, relationship with spouse, attending at family planning classes, and psychiatric problems history had a significant relationship with unintended pregnancy (P ≤ 0.05) (Table 1).

In contrast, in multivariate analysis, a significant relationship was found between unintended pregnancy and some studied variables, including mother’s age(> 25) (odds ratio (OR): 1.69; 95% CI: 1.07 - 2.41), child gender in the current pregnancy (female) (OR: 2.85; 95% CI: 1.94 - 4.17), higher family income (OR: 0.47; 95% CI: 0.31 - 0.74), history of unintended pregnancy (OR: 5.07; 95% CI: 3.08 - 8.55), abortion or curettage history (OR: 2.78; 95% CI: 1.47 - 5.10), having not good communication with spouse (OR: 9.09; 95% CI: 2.73 - 17.38), attending family planning classes (OR: 1.54; 95% CI: 1.05 - 2.29), and higher previous pregnancies (OR: 4.62; 95% CI: 2.79 - 7.79) (Table 2).

Table 2. Logistic Regression for Association of Unintended Pregnancy and Studied Variables
OR (95% CIP ValueOR (95% CI)P Value
Mother’s age
< 251-1-
> 251.61 (1.16 - 2.23)0.041.69 (1.07 - 2.41)0.02
Family income
Average0.51 (0.29 - 0.78)0.0010.47 (0.31 - 0.74)0.001
High0.82 (0.43 - 1.71)0.60.86 (0.45 - 1.64)0.6
Child gender in current pregnancy
Female2.58 (1.87 - 3.56)< 0.0012.85 (1.95 - 4.17)< 0.001
Unintended pregnancy history
Yes5.73 (3.11 - 8.79)< 0.0015.07(3.08 - 8.55)< 0.001
Curettage or abortion history
Yes2.62 (1.41 - 5.59)< 0.0012.78 (1.47 - 5.10)0.002
Spouse communication
Sometimes good9.73 (2.81 - 18.31)< 0.0019.09 (2.73 - 17.38)< 0.001
Not good2.49 (1.47 - 3.61)< 0.0012.23 (1.56 - 3.20)< 0.001
Attending at family planning classes
No2.23 (1.63 - 3.06)< 0.0011.54 (1.05 - 2.29)0.03
High risk pregnancy, y
18 - 351-1-
< 18 or > 354.87 (3.31 - 7.19)< 0.0011.75 (0.99 - 3.10)0.05
Number of children
< 11-1-
> 16.07 (4.29 - 8.61)< 0.0012.05 (1.04 - 4.05)0.04
Number of previous pregnancies
21.47 (0.96 - 2.24)0.071.82 (1.15 - 2.87)0.01
> 35.35 (3.65 - 7.84)< 0.0014.62 (2.79 - 7.79)< 0.001

Abbreviations: CI, confidence interval, OR, odds ratio.

Mother’s view about unintended or intended pregnancy have been significantly changed when they were informed their child gender so that 32 of them changed their view from intended to unintended pregnancy (28 girls, 4 boys) and also 72 women changed their view from unintended to intended pregnancy (5 girls, 67 boys) (P < 0.001).

5. Discussion

In this study, we investigated potential risk factors for unintended pregnancy in women referred to a tertiary hospital and health centers of Sanandaj, Kurdistan, Iran. The obtained results showed there is a significant relationship between unintended pregnancy and mother’s age, child gender in the current pregnancy, family income, unintended pregnancy history, abortion or curettage history, spouse communication, attending family planning classes, number of children, and the number of previous pregnancies.

According to the results, the mother’s age had a significant relationship with unintended pregnancy so that the mother’s age increased the likelihood of unintended pregnancy increased too. This finding was consistent with the studies carried out in the U.S. in 2006 (26) and in Tanzania in 2008 (27), but it was not consistent with the results of studies conducted in South Asia in 2011 (18) and Thailand in 2013 (19). The inconsistency could result from differences in the populations under study, data collection time, and research methods. The relationship between mothers’ older age and the increase of unintended pregnancy might be due the fact that through the increase of age, more time would pass since marriage, and the start of having sexual relationship which would increase the possibility of facing unintended pregnancy or it might be because women prefer pregnancy at younger ages and after achieving the favorite dimension of the household at these ages, they consider the next pregnancies as unintended.

Another factor for unintended pregnancy was the child gender in the current pregnancy. Women whose child’s gender was female were more willing to consider their pregnancy unintended and also if the gender of their child was specified to be a girl, their opinion changed from intended to unintended pregnancy. The conducted studies in India in 2005 (28) and a review study in 2008 (5) reported such a result. In traditional communities and developing regions, including Kurdistan, due to less cultural and economic development than the developed regions of the world, there is a lot of discrimination between different genders in terms of achieving social and occupational positions and this issue can be a justification for women to change their perspective towards their pregnancies if the child gender is identified and their willingness to the male child.

The results of the study showed that there was a relationship between the lower-income of family and unintended pregnancy. Similar results were achieved in the studies conducted in 2006 in the U.S. (26) and in 2010 in Iran (29). This is probably due to the lack of awareness and lower access to contraceptive methods in low-income women. Moreover, owing to bad economic and income status, such women have problems in supplying the costs of pregnancy and child-rearing and thus they address their pregnancy as unintended.

The results of the study showed the relationship between unintended pregnancy history and the increase of unintended pregnancy. This result was similar to the results of studies conducted in 2007 in China (30), and in 2003 in the U.S. (31). It is likely because of the fact that women who have already had a history of unintended pregnancy, have experienced all its stress, mental, and emotional pressures and are aware of the problems of facing it; moreover, such women have already had special behavioral, social, and economic circumstances and they have the same problems now; so they consider their present pregnancy as unintended.

Another result of the study was the relationship between unintended pregnancy and abortion or curettage history. The result was consistent with the findings of the conducted studies in 2008 in Iran (32) and in 2007 in China (33). The result can be due to the fact that mothers who have already experienced abortion are worried about the unfortunate consequences of pregnancy for their children and themselves, and since abortion in Iran is illegal, illegitimate, and non-customary; this issue enhances the probability to experience unsafe abortion and the appearance of physical and mental problems for mothers.

There was a relationship between couple communication problems and unintended pregnancy such that women who did not have a good relationship with their husbands mainly addressed their pregnancy unintended. The result is consistent with the findings of the study carried out in the U.S. in 2013 (34). The reason may be that such women are not satisfied with their lives and they think it is very probable to break up with their spouses in the future and consequently, concern about bringing up and growing their children.

Another result of the study was the relationship between attending family planning classes and unintended pregnancy; thus women’s absence in training classes further led to unintended pregnancy. The result was consistent with the findings of the studies conducted in 2005 and 2006 in Iran (35, 36). It is probably because of the fact that lack of presence in such classes by women causes less awareness and information and insufficient use of preventive methods and ultimately leads to unintended pregnancy.

The results also indicated the relationship between the number of children and unintended pregnancy was consistent with the findings of the studies carried out in 2011 in South Asia (18) and in 2005 and 2006 in Iran (36, 37); therefore, as the number of children increased the probability of unintended pregnancy increased too. This shows families tendency towards having fewer children so that they consider their pregnancy as unintended with increased number of pregnancy.

There is also a relationship between unintended pregnancy and the number of previous pregnancies so that by increasing the number of previous pregnancies the percentage of unintended pregnancy increases too. The results of studies conducted in the U.S. in 2006 (26) and in Iran in 2008 (32) confirm this issue. It may be said that as the number of mothers’ pregnancies increases because of ignoring medical issues such as birth spacing, mother’s anemia, and physical weakness, the risk of unintended pregnancy increases.

In univariate study, although the relationship between some variables such as women’s education, spouse education, contraceptive method, the way of selecting contraception, and psychiatric problems history and unintended pregnancy was evaluated, there was no relationship between the above-mentioned variables and unintended pregnancy in multivariate analysis. Nevertheless, the relationship between these variables and unintended pregnancy has been reported in various studies (27, 38-41), which may be due to the differences in sample size, cultural, social, and economic background of the environment where the studies were carried out and their research methods.

Even though this study was carried out in a large population and on many factors affecting unintended pregnancy, some other important and effective factors such as obesity, smoking, chronic diseases, spouse’s violence, and physical activities were not examined and it is recommended that the effect of such factors be measured in future studies.

Preventing unintended pregnancy by establishing appropriate strategies for comprehensive sexual health education, increasing access to contraceptive, paying attention to high-risk pregnancies, providing information about safe abortion, providing comprehensive post-abortion care, providing legal and safe abortion services, counseling, and caring before pregnancy and abortion, emphasizing the role of men in family planning programs, developing evidence-based clinical guidelines that fits culture to reduce unintended pregnancy may be managed.

5.1. Conclusions

The present study showed that there is a relationship between unintended pregnancy and several factors such as mother’s age, child gender (female) in the current pregnancy, number of children, number of previous pregnancies, and woman’s communication with her husband and so on; therefore, preventing unintended pregnancy requires comprehensive and long-term interventions.

Recent demographic policies in Iran have focused on the increase of population, decrease of family planning program budget, and the increase of legal constraints for cares associated with contraception and abortion, which will increase concern about the increase of unintended pregnancy due to high cost of contraceptive equipment and reduction of access to such services and also will increase unsafe and safe abortions. This raises the necessity to pay more attention and to prioritize the unintended pregnancy problem and its solution.




  • 1.

    Falk G, Falk L, Hanson U, Milsom I. Young women requesting emergency contraception are, despite contraceptive counseling, a high risk group for new unintended pregnancies. Contraception. 2001;64(1):23-7. doi: 10.1016/s0010-7824(01)00225-6. [PubMed: 11535209].

  • 2.

    United Nations Population Fund (UNFPA). Achieving the ICPD goals: Reproductive health commodity requirements 2000-2015. UNFPA; 2005.

  • 3.

    Taylor D, Levi A, Simmonds K, Board of the Society of Family P. Reframing unintended pregnancy prevention: A public health model. Contraception. 2010;81(5):363-6. doi: 10.1016/j.contraception.2010.01.023. [PubMed: 20399941].

  • 4.

    Hosseini-Chavoshi M, Abbasi-Shavazi MJ, McDonald P. Fertility, marriage, and family planning in Iran: Implications for future policy. Popul Horiz. 2016;13(1):31-40. doi: 10.1515/pophzn-2016-0005.

  • 5.

    Singh S, Sedgh G, Hussain R. Unintended pregnancy: Worldwide levels, trends, and outcomes. Stud Fam Plann. 2010;41(4):241-50. doi: 10.1111/j.1728-4465.2010.00250.x. [PubMed: 21465725].

  • 6.

    Brown SS, Eisenberg L; Institute of Medicine; Committee on Unintended Pregnancy. The best intentions: Unintended pregnancy and the well-being of children and families. National Academy Press; 1995.

  • 7.

    Ghazizadeh S, Lessan-Pezeshki M, Khatami M, Mahdavi M, Razeghi E, Seifi S, et al. Unwanted pregnancy among kidney transplant recipients in Iran. Transplant Proc. 2005;37(7):3085-6. doi: 10.1016/j.transproceed.2005.07.060. [PubMed: 16213313].

  • 8.

    Khajehpour M, Simbar M, Jannesari S, Ramezani-Tehrani F, Majd HA. Health status of women with intended and unintended pregnancies. Public Health. 2013;127(1):58-64. doi: 10.1016/j.puhe.2012.08.011. [PubMed: 23200101].

  • 9.

    Ahmadnejad S, Ahmadnejad E, Fayazjahani F, Jafari G, Koohkan Talebkhan Z, Ghorbanipoor M, et al. [A review to abortion and reproductive health law in Middle East Islamic region]. Med Law J. 2011;5(16):161-78. Persian.

  • 10.

    Short RV. The future fertility of mankind: Effects on world population growth and migration. Reprod Fertil Dev. 2001;13(5-6):405-10. doi: 10.1071/rd01107. [PubMed: 11833937].

  • 11.

    Moos MK, Bartholomew NE, Lohr KN. Counseling in the clinical setting to prevent unintended pregnancy: An evidence-based research agenda. Contraception. 2003;67(2):115-32. doi: 10.1016/s0010-7824(02)00472-9. [PubMed: 12586322].

  • 12.

    Mohllajee AP, Curtis KM, Morrow B, Marchbanks PA. Pregnancy intention and its relationship to birth and maternal outcomes. Obstet Gynecol. 2007;109(3):678-86. doi: 10.1097/01.AOG.0000255666.78427.c5. [PubMed: 17329520].

  • 13.

    Dott M, Rasmussen SA, Hogue CJ, Reefhuis J, National Birth Defects Prevention S. Association between pregnancy intention and reproductive-health related behaviors before and after pregnancy recognition, National Birth Defects Prevention Study, 1997-2002. Matern Child Health J. 2010;14(3):373-81. doi: 10.1007/s10995-009-0458-1. [PubMed: 19252975].

  • 14.

    Ishida K, Stupp P, Serbanescu F, Tullo E. Perinatal risk for common mental disorders and suicidal ideation among women in Paraguay. Int J Gynaecol Obstet. 2010;110(3):235-40. doi: 10.1016/j.ijgo.2010.03.027. [PubMed: 20472235].

  • 15.

    Gipson JD, Koenig MA, Hindin MJ. The effects of unintended pregnancy on infant, child, and parental health: A review of the literature. Stud Fam Plann. 2008;39(1):18-38. doi: 10.1111/j.1728-4465.2008.00148.x. [PubMed: 18540521].

  • 16.

    Hayatbakhsh MR, Najman JM, Khatun M, Al Mamun A, Bor W, Clavarino A. A longitudinal study of child mental health and problem behaviours at 14 years of age following unplanned pregnancy. Psychiatry Res. 2011;185(1-2):200-4. doi: 10.1016/j.psychres.2010.05.019. [PubMed: 20576294].

  • 17.

    Trussell J. The cost of unintended pregnancy in the United States. Contraception. 2007;75(3):168-70. doi: 10.1016/j.contraception.2006.11.009. [PubMed: 17303484].

  • 18.

    Raj A, McDougal L. Associations of intimate partner violence with unintended pregnancy and pre-pregnancy contraceptive use in South Asia. Contraception. 2015;91(6):456-63. doi: 10.1016/j.contraception.2015.03.008. [PubMed: 25769441]. [PubMed Central: PMC4442030].

  • 19.

    Sriprasert I, Chaovisitsaree S, Sribanditmongkhol N, Sunthornlimsiri N, Kietpeerakool C. Unintended pregnancy and associated risk factors among young pregnant women. Int J Gynaecol Obstet. 2015;128(3):228-31. doi: 10.1016/j.ijgo.2014.09.004. [PubMed: 25456969].

  • 20.

    Ali MM, Cleland J, Shah IH. Condom use within marriage: A neglected HIV intervention. Bull World Health Organ. 2004;82(3):180-6. [PubMed: 15112006]. [PubMed Central: PMC2585927].

  • 21.

    Marston C, Cleland J. Relationships between contraception and abortion: A review of the evidence. Int Fam Plan Perspect. 2003;29(1):6-13. doi: 10.1363/ifpp.29.006.03. [PubMed: 12709307].

  • 22.

    Schreiber CA, Whittington S, Cen L, Maslankowski L. Good intentions: Risk factors for unintended pregnancies in the US cohort of a microbicide trial. Contraception. 2011;83(1):74-81. doi: 10.1016/j.contraception.2010.06.012. [PubMed: 21134507].

  • 23.

    Chor J, Rankin K, Harwood B, Handler A. Unintended pregnancy and postpartum contraceptive use in women with and without chronic medical disease who experienced a live birth. Contraception. 2011;84(1):57-63. doi: 10.1016/j.contraception.2010.11.018. [PubMed: 21664511].

  • 24.

    Cripe SM, Sanchez SE, Perales MT, Lam N, Garcia P, Williams MA. Association of intimate partner physical and sexual violence with unintended pregnancy among pregnant women in Peru. Int J Gynaecol Obstet. 2008;100(2):104-8. doi: 10.1016/j.ijgo.2007.08.003. [PubMed: 17963763].

  • 25.

    Xaverius PK, Tenkku LE, Salas J. Differences between women at higher and lower risk for an unintended pregnancy. Womens Health Issues. 2009;19(5):306-12. doi: 10.1016/j.whi.2009.06.002. [PubMed: 19733800].

  • 26.

    Finer LB, Zolna MR. Unintended pregnancy in the United States: incidence and disparities, 2006. Contraception. 2011;84(5):478-85. doi: 10.1016/j.contraception.2011.07.013. [PubMed: 22018121]. [PubMed Central: PMC3338192].

  • 27.

    Calvert C, Baisley K, Doyle AM, Maganja K, Changalucha J, Watson-Jones D, et al. Risk factors for unplanned pregnancy among young women in Tanzania. J Fam Plann Reprod Health Care. 2013;39(4). e2. doi: 10.1136/jfprhc-2012-100389. [PubMed: 23902713]. [PubMed Central: PMC3786620].

  • 28.

    Chaudhuri S. The desire for sons and excess fertility: A household-level analysis of parity progression in India. Int Perspect Sex Reprod Health. 2012;38(4):178-86. doi: 10.1363/3817812. [PubMed: 23318167].

  • 29.

    Mortazavi F, Damghanian M, Mataghi Z, Shariati M. [Women's experience of unwanted pregnancy: A qualitative study]. Behbood J. 2011;15(6):492-503. Persian.

  • 30.

    Zhou Y, Xiong C, Xiong J, Shang X, Liu G, Zhang M, et al. A blind area of family planning services in China: Unintended pregnancy among unmarried graduate students. BMC Public Health. 2013;13:198. doi: 10.1186/1471-2458-13-198. [PubMed: 23497130]. [PubMed Central: PMC3599835].

  • 31.

    Kuroki LM, Allsworth JE, Redding CA, Blume JD, Peipert JF. Is a previous unplanned pregnancy a risk factor for a subsequent unplanned pregnancy? Am J Obstet Gynecol. 2008;199(5):517 e1-7. doi: 10.1016/j.ajog.2008.03.049. [PubMed: 18468575]. [PubMed Central: PMC2728620].

  • 32.

    Amani F, Bashiri J, Nahan Moghaddam N, Tabarraie Y. [Application of logistic regression model in surveying effective causes of unwanted pregnancy]. Qom Univ Med Sci J. 2010;4(1):32-6. Persian.

  • 33.

    Wang H, Long L, Cai H, Wu Y, Xu J, Shu C, et al. Contraception and unintended pregnancy among unmarried female university students: A cross-sectional study from China. PLoS One. 2015;10(6). e0130212. doi: 10.1371/journal.pone.0130212. [PubMed: 26091505]. [PubMed Central: PMC4474598].

  • 34.

    Visger JM. Predictors of psychosocial adaptation to pregnancy among urban African-American primiparas. Wayne State University; 2013.

  • 35.

    Poorheidary M, Khosravi A, Shamaiian-Razavi N, Hamidzadeh A. [A comparison of prenatal maternal care between wanted and unwanted pregnancies]. Knowl Health. 2011;5(4):7-13. Persian.

  • 36.

    Pourheidari M, Souzani A, Shamaiian-Razavi N. [The prevalence of unwanted pregnancy in mothers and its determinants in the Shahrood city]. Payesh. 2006;6(1):63-70. Persian.

  • 37.

    Khoosheh Mehri G, Ebrahim Taheri G, Hatami Z, Safari M. [Prevalence of unwanted pregnancy and associated factors among pregnant women attending health centers south of Tehran]. J Nurs Midwifery. 2007;16(59):26-32. Persian.

  • 38.

    Foster DG, Bley J, Mikanda J, Induni M, Arons A, Baumrind N, et al. Contraceptive use and risk of unintended pregnancy in California. Contraception. 2004;70(1):31-9. doi: 10.1016/j.contraception.2004.01.012. [PubMed: 15208050].

  • 39.

    Tabeshfar Z, Holakouie Naieni K, Chaman R, Malekafzali H, Eshraghian MR, Fararooei M. [Factors affecting unwanted pregnancies in urban areas of Kohgiloyeh and Boyer Ahmad province in 2008]. Armaghane Danesh. 2011;16(3):282-90. Persian.

  • 40.

    Maxson P, Miranda ML. Pregnancy intention, demographic differences, and psychosocial health. J Womens Health (Larchmt). 2011;20(8):1215-23. doi: 10.1089/jwh.2010.2379. [PubMed: 21671765].

  • 41.

    Bahk J, Yun SC, Kim YM, Khang YH. Impact of unintended pregnancy on maternal mental health: A causal analysis using follow up data of the Panel Study on Korean Children (PSKC). BMC Pregnancy Childbirth. 2015;15:85. doi: 10.1186/s12884-015-0505-4. [PubMed: 25881099]. [PubMed Central: PMC4387588].

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