Contraceptive use and associations with intimate partner violence among a population-based sample of New Zealand women

Authors


: Dr Janet Fanslow, Social and Community Health – School of Population Health, University of Auckland, Private Bag 92019, Auckland, New Zealand. Email: j.fanslow@auckland.ac.nz

Abstract

Aim:  To outline the use of contraception among a representative sample of New Zealand women, and explore associations with intimate partner violence (IPV), and contraception and condom use.

Methods:  Face-to-face interviews were conducted with a random sample of 2790 women who had ever had sexual intercourse, aged 18–64 years old in two regions (urban and rural) in New Zealand. Analyses were conducted using logistic regression and Wald χ2 tests.

Results:  Almost all women had used contraception at some point in their life, and almost one half of all women 18–49 years were currently using methods of contraception. Contraceptive use and methods varied significantly by location. Women who had ever experienced IPV were significantly more likely to report having ever used contraception, compared with women who had not experienced IPV (91% vs 85.2%). While having a partner who refused to use or tried to stop women from using a method of contraception was rare, it was significantly more common among women who had ever experienced IPV (5.4% vs 1.3%).

Conclusions:  Most women have used contraception at some point. Women who have ever experienced IPV were: more likely to have used contraception than women who have not experienced IPV, and to have had partners who refused to use condoms or prevented women from using contraception. Partner refusal may be a key indicator of IPV. These findings emphasise the importance of family violence screening at routine health consultations.

Introduction

Decisions around contraception are an important aspect of women's reproductive health.1 At present, however, there are limited data about women's use of contraception per se, factors that influence women's contraceptive choices, and about male partner's influence on women's use of contraception. The most recent information on contraception in New Zealand involving a representative sample of women comes from a 1995 survey.2 Additionally, in this era of increasing prevalence of certain sexually transmitted infections, regular and reliable information about condom use within the New Zealand population is necessary to inform policy and programs.3,4

As recognition of the prevalence of intimate partner violence (IPV) in the population has grown,5 there has been increasing interest in understanding how violence and coercion within relationships impact on use of contraception, unintended pregnancy and abortion.6,7 Most research to date comes from the USA. Research from a four-state pregnancy monitoring system showed that up to 70% of women who experienced violence in relationships had unwanted or mistimed pregnancies.8 Other studies showed that women in violent relationships were less likely to use condoms, or ask partners to use condoms, because of increased risk of verbal or emotional abuse when compared with women in non-violent relationships.9 Abused women were also found to be at significantly higher risk for sexually transmitted infections.10,11

Qualitative studies highlight challenges that women involved in abusive relationships experience in negotiating issues associated with sexuality and fertility. Abused women reported that they felt they could not avoid intercourse with their abusers, despite fears of pregnancy, and in some case were denied access to contraception (eg methods being found by abusive partners and destroyed). Some women reported that their partner's viewed use of contraception as a license for women to be ‘unfaithful’. Many women sought tubal ligations as a method of contraception that did not require partner consent.12 There has been limited research in New Zealand around these issues, although a recent study found significantly higher prevalence of family violence among women seeking abortion services, compared to the general population.13

To extend our understanding of the relationship between IPV and women's use of contraception in New Zealand, there is a need for further research to study a broad cross-section of women, including those who do not present within the health system.6 Improved understanding of these relationships may enhance our identification of risk factors, which in turn can inform development of effective intervention strategies.5

This article provides information on use of contraception in a population-based sample of New Zealand women, as well as identifying differences in contraceptive use between women who have experienced intimate partner violence and those who have not. To conclude, findings of the study are placed in the context of international data, and recommendations for clinical practice and future research are outlined.

Methods

Sampling strategy, participants and response rate

The survey was conducted by the School of Population Health at the University of Auckland, as part of the New Zealand Violence Against Women Study (a replication of the World Health Organization (WHO) Multi-country Study).14 A random sample of women aged 18–64 years was obtained from Auckland, the largest city (population 1.2 million), containing 26.8% of the total New Zealand population of women aged 15–64 years, and north Waikato, a rural region, containing 2.8% of the total population of women aged 15–64 years. Potential participants were contacted by door-knocking at randomly selected households, following a population-based cluster sampling scheme. The starting point for each cluster consisted of a randomly selected street and dwelling number. From the starting point, interviewers in Auckland approached every fourth house, and interviewers in the Waikato approached every 2nd house until ten households per cluster had been reached. Non-residential (eg commercial, retail or industrial buildings) and short-term residential properties (eg hotels, motels, boarding houses) were excluded.

In households with more than one eligible respondent, one woman was randomly selected, for safety and confidentiality reasons. If the woman selected was available, consent was sought and an interview arranged, otherwise contact details were obtained. A minimum of three return visits were made to each household at different times on different days to maximise the chance of obtaining an interview. Some interviewers made up to nine repeat visits.

In total, 6174 addresses were approached. Of these 57 did not have a dwelling (ineligible precontact); 784 (12.8%) households refused, indefinitely postponed, did not speak English or Mandarin/Cantonese or were unable to be contacted. Of the remaining 5333 houses, 1563 did not have eligible women (ineligible post contact). From the 3770 households with eligible women, 2855 women aged 18–64 years were interviewed. An 88.3% household response rate and a 75.8% eligible woman response rate were obtained, resulting in an overall response rate of 66.9%. In this paper, we report data from 2790 women who had ever had sexual intercourse (Auckland n = 1389, North Waikato n = 1401).

Questionnaire

The base questionnaire was developed by the Core Technical Team of the WHO Multi-Country Study on Violence Against Women15 and was adapted for use in New Zealand.

Data management

All questionnaires were checked for completeness, and participants were recontacted if necessary to obtain missing data. All data were double entered in Epi-Info (CDC, Atlanta, GA, USA), checked and cleaned. Questions with open-ended ‘other’ responses were reviewed to ascertain if existing coding categories applied, or new categories emerged.

Definitions

‘Intimate partners’ included male current or ex-partners (married or had lived with), or current regular male sexual partners. Current or most recent partner refers to the woman's current or last male intimate partner. Physical violence included: having been slapped or had something thrown at them that could hurt; having been pushed, shoved, or had their hair pulled; having been hit with a fist or something else, having been kicked, dragged or beaten up, having been choked or burnt on purpose, or having been threatened with, or had used against them a gun, knife or other weapon. Sexual violence included being physically forced to have sexual intercourse; having sexual intercourse because she was afraid of what her partner might do, or being forced to do something sexual that she found degrading or humiliating.

‘Lifetime’ IPV victims had experienced at least one incident of physical or sexual violence by an intimate partner in her lifetime. ‘Current’ IPV victims had experienced at least one incident of physical or sexual violence by an intimate partner within the 12 months prior to the survey.

Contraceptive use was assessed as: ever use of contraception (tried in any way to delay or avoid getting pregnant), current use of contraception, main method of contraception currently used (one method only allowed), current partner's knowledge of contraception use, current/most recent partner's refusal to use/attempt to stop her from using contraception, and the partners’ means of communicating disapproval.

Regardless of the main method of current contraception, questions were also asked about use of condoms ever in the current/most recent relationship, use of condoms at last intercourse, women's request to most recent partner to use condoms (ever), partner's refusal to use condoms, and partner's means of communicating disapproval.

Analyses

Percentages with confidence intervals are presented. Logistic regression and Wald χ2 tests were used to test for significant differences. Data from both rural and urban sites are combined in logistic regressions, unless site-specific differences were identified. All analyses allow for the sample design. Analyses for questions related to current contraception were restricted to 18–49 year olds.

Safety and ethics

All interviews were conducted in private (no children older than two years). All participants were provided with a list of support agencies. WHO ethics and safety recommendations for research on IPV were followed.16 Ethics approval was granted by the Human Subjects Ethics Committee of the University of Auckland (reference number 2002/199).

Results

Sample description

The mean age of women in the study sample was 41.7 years (SD = 7.5). The great majority of women had used contraception at some point in their life (see Table 1). More women in the rural area had ever used contraception, compared to women in the urban area (89.8% and 83.6%, respectively, P < 0.001). Almost half of women aged 18–49 years were using contraception at the time of the study (45% urban, 48.5% rural), and almost all reported that their partner knew they used contraception (97.3% urban, 98.3% rural). Around 3% of all sexually active women reported that their current partner had ever refused to use contraception.

Table 1.  Sample description
 nUrban % (95% CI)Rural % (95% CI)P-value
  1. CI, confidence interval; IPV, intimate partner violence.

Ever use of contraception279083.6 (80.9–86.5)89.8 (88.1–91.5)0.0001
Current use of contraception205245.0 (41.3–48.6)48.5 (44.9–52.1)0.178
Partner knows of contraceptive use 53497.3 (94.6–100)98.3 (96.8–99.8)0.505
Partner ever refused to use contraception27803.6 (2.4–4.8)2.4 (1.5–3.3)0.113
Ever IPV266433.1 (30.1–36.2)38.8 (36.0–41.6)0.007
Current IPV27905.2 (4.0–6.5)5.1 (3.7–6.6)0.936
Ever use of condom with current partner277764.6 (61.2–68.0)67.5 (64.7–70.3)0.186
Use of condom at last sex183231.4 (27.7–35.1)18.0 (15.5–20.6)< 0.0001
Ever asked partner to use condom276741.4 (38.3–44.5)36.1 (33.3–38.9)0.013
Partner refused to use condom at least once108115.1 (11.9–18.4)10.6 (8.0–13.2)0.030

A significantly greater percentage of women living in the rural region reported ever having experienced IPV (38.8%), compared to those women living in the urban region (33.1%, P = 0.007). Five per cent of women in both rural and urban sites had experienced IPV within the 12 months prior to the survey. Regardless of previous reports of contraception use, women were asked about condom use ever with their current or most recent male partner. In the urban region, 64.6% had ever used a condom with their current/most recent partner, and, of these women, 31% had used a condom the last time they had sex. Forty-one per cent of women reported having ever asked their current/most recent partner to use a condom and of these women, 15% reported that their partner had refused on at least one occasion. In the rural region, 67.5% had ever used a condom with their current/most recent partner, and of these women, 18% reported that they had used a condom the last time they had sex. Thirty-six per cent of women reported having ever asked their current/most recent partner to use a condom and of these women, 10.6% reported that their partner had refused on at least one occasion. Compared to the rural region, a significantly greater percentage of women in the urban region had ever asked a partner to use a condom (P = 0.01) and reported that the partner had ever refused (P = 0.03).

Method of contraception currently used

Table 2 shows the main methods of contraception currently used. In the urban region, the most commonly used methods were pill/tablet (37.5%), condoms (25%), intrauterine device (IUD) (12.1%) followed by female sterilisation (7.7%), male sterilisation (7.5%) and injectables (7%). In the rural area, the method mix is slightly different. Although the pill/tablet is still the most commonly used (29.6%), male sterilisation comes second (22.4%), followed by condoms (15.3%), female sterilisation (13.3%), IUDs (9.5%) and injectables (5.7%). Sterilisation (male and female) was used more frequently in the rural site, while pills/tablets and condoms were used more frequently in the urban site.

Table 2.  Main current contraception method, by site n = 960
 Urban% (95% CI)Rural% (95% CI)
  1. CI, confidence interval.

Pill/Tablets37.5 (32.2–42.7)29.6 (25.2–34.0)
Condoms25.0 (20.8–29.3)15.3 (12.1–18.5)
Male sterilisation7.5 (5.0–10.1)22.4 (18.2–26.7)
Female sterilisation7.7 (5.3–10.1)13.3 (10.1–16.5)
Intrauterine device12.1 (8.5–15.7)9.5 (6.9–12.1)
Injectables7.0 (4.4–9.6)5.7 (3.6–7.7)
Implants (norplant)0.2 (0.0–0.5)0.9 (0.0–1.9)
Diaphragm/Foam/Jelly0.2 (0.0–0.5)0.4 (0.0–0.9)
Other2.8 (1.2–4.3)2.9 (1.4–4.5)

Use of contraception and IPV

Table 3 shows the relationship between contraception use and IPV. A significantly greater percentage of women who had ever experienced IPV had ever used contraception (91% compared with 85.2%, P < 0.0001). There was no significant difference in current use of contraception between women aged 18–49 years who had experienced IPV in the 12 months before the survey and those who had not.

Table 3.  Use of contraception by intimate partner violence (IPV)
  1. CI, confidence interval.

Contraception use evernLifetime IPV: Yes % (95% CI)Lifetime IPV: No % (95% CI)P-value
266491.0 (89.2–92.9)85.2 (83.0–87.3)< 0.0001
Current use of contraceptionnCurrent IPV: Yes % (95% CI)Current IPV: No % (95% CI)P-value
205243.8 (34.1–53.5)46.7 (44.0–49.4)0.58

Partner's refusal and IPV

As seen in Table 1, approximately 3% of women reported that their current/most recent partner had ever refused/tried to stop her from using a method of contraception. Moreover, Table 4 shows that partner refusal was significantly more common among women who had ever experienced IPV (5.4% compared with 1.3%, P < 0.0001). Women who had not experienced IPV and whose partner refused reported that their partners told them that he did not approve (80%) or that he took or destroyed the method (8%). In contrast, partners of women who had experienced IPV showed disapproval of contraceptive use by telling the woman he disapproved (58%), shouting/getting angry (15.3%), threatening to beat the woman (5.1%), beating or physically assaulting the woman (8.5%), or taking or destroying the method (13.6%) (data not shown).

Table 4.  Partner refusal by intimate partner violence (IPV)
 nLifetime IPV: Yes % (95% CI)Lifetime IPV: No % (95% CI)P-value
  1. CI, confidence interval.

Partner's refusal to use contraception26585.4 (3.8–6.9)1.3 (0.7–1.8)< 0.0001
Asked partner to use condom264556.3 (52.8–59.8)35.4 (32.9–37.9)< 0.0001
Partner's refusal to use a condom102221.1 (17.1–25.1)6.8 (4.7–8.9)< 0.0001

More than half the women who had ever experienced IPV had asked their current or most recent partner to use a condom, compared to only 35.4% of women who had never experienced IPV (P < 0.0001). There were no significant difference in use of condom at last sexual intercourse between women who had experienced violence within the last 12 months versus those who had not (data not shown). Partner's refusal to use a condom was significantly more common for women who had experienced IPV (21.1% compared with 6.8%, P < 0.0001).

Discussion

This study outlines the use of contraception among a large representative sample of New Zealand women, and is the first in New Zealand to explore associations between use of contraception and intimate partner violence. Almost all women had ever used contraception, and women's location (urban/rural) was significantly associated with method of contraception used. This is consistent with previous research in New Zealand and other developed countries.2,17 Women who had experienced IPV were significantly more likely to have ever used contraception. In addition, since at any one point in time, almost one half of women of child-bearing age currently use contraception, discussions related to contraception provision may provide an opportunity for health-care professionals to assess and provide brief intervention for IPV.

Women in rural locations were more likely to report having ever experienced IPV, yet these women may have less opportunity for health-care intervention, for example, greater reliance on sterilisation in rural areas obviates on-going needs to access contraception. As women in rural locations may have greater difficulty accessing health services,18 greater efforts to resource existing prevention efforts, as well as to develop intervention responses that are not reliant on health-care provider or specialist IPV providers, may need to developed.

One-third to one-half of women had ever asked their current/most recent male partner to use a condom, with more victims of IPV having asked their partner to use a condom. This suggests that women may have a heightened awareness of their risk of STIs and/or unintended pregnancy. This finding is consistent with most WHO study sites where women whose current or most recent partner was violent were more likely to have asked their partner to use a condom, and to report that their partner had ever refused to use a condom, than were women in non-violent relationships.14 However, unfortunately, women who have experienced IPV were also more likely to have partners who refused to use/or to let the woman use any method of contraception, and were more likely to have partners who refused to use a condom. This suggests that partner refusal to use a condom, or let the woman use contraception may be key indicators of IPV. The methods partners used to communicate disapproval of contraceptive use were more violent for women who had experienced IPV compared with communication methods used by partners of women who had not experienced IPV. This has the potential to impact on women's ability to avoid unintended pregnancy and sexually transmitted infections, and emphasises the importance of family violence screening at routine health consultations, including those for contraception and sexual health checks.

Lastly, international research in demography and reproductive health uses the concept of unmet need for family planning as a useful indicator of whether contraceptive services are meeting women's need for family planning.19 Future research should explore not only the relationship between IPV and use of contraception but also explore women's reproductive intentions to ascertain whether an unmet need for family planning is associated with IPV.

Strengths of the study include use of a large-scale sample of women, representative of 30% of New Zealand women, suggesting that the study may be broadly generalisable to the population as whole. Additionally, the face-to-face interview methodology employed, utilising trained interviewers, is likely to have enhanced disclosure on sensitive topics such as reproductive health and intimate partner violence. The study's comparability to the WHO Multi-country Study speaks to the scientific rigour of the data collected, as well as allowing for international comparison. Finally, the ability of the study to identify urban and rural differences has implications for service delivery and policy planning. Weaknesses of the study include reliance on retrospective reports, which may lead to underreporting, both of experience of IPV and of contraceptive use. Additionally, associations between IPV and contraceptive use reported are for lifetime exposure to IPV, rather than relationship specific. As a consequence, and as a general limitation of cross-sectional studies, it is not possible to demonstrate a causal link from the findings, rather they provide an indication of the associations between contraception and IPV. Nonetheless, the study signals important directions for future practice.

This study provides previously unavailable information about contraception use reported by a large sample of New Zealand women. The findings suggest that partner refusal to use condoms/or preventing women from using contraception may be a key indicator of IPV. These findings emphasise the importance of family violence screening at routine health consultations.

Acknowledgements

We would like to acknowledge the women who participated in this study. The following are also acknowledged: project manager: Cherie Lovell; project assistants: Margaret (Meg) Tenny and Clare Murphy; data manager: Vivien Lovell; and Auckland and Waikato interview teams; data entry staff. We thank the Advisory Group who provided important support for the study. Funding for this project was provided by the Health Research Council of New Zealand (02/207). This study replicates the WHO Multi-country Study on Women's Health and Domestic Violence (WHO/EIP/GPE/99.3).

Ancillary