The experience of infertility can have a major impact on individuals, families and relationships, as most people have life plans that involve children. In addition, it can result in a considerable cost to both individuals and health services. The aetiology of infertility is complex, with many factors affecting an individuals risk of infertility. Age is an important determinant, especially for women, with increasing age strongly correlated with decreasing fertility for women older than 30 years.1 Due to social changes over the past few decades, many women/couples in New Zealand are delaying the start of their families, with the median age of childbearing now around 30 years.2 Concurrent with this trend of delayed childbearing, there have been changes in the frequency of health conditions that may have a negative impact on fertility. These include increases in obesity and sexually transmitted infections such as Chlamydia trachomatis,3,4 which have most likely impacted on the number of women experiencing infertility. There is already evidence that childlessness is increasingly common in women aged more than 40 years; in the 2006 New Zealand Census, 16.7% of women over 40 years were childless and this is projected to rise to over a quarter by the next census in 2018.5,6Despite the importance of infertility and social changes that may be impacting on its prevalence, population-based estimates are limited to one study, a cohort born in Dunedin, New Zealand, in 1972/3, who were last interviewed when aged 37-39 years.7 Just over a quarter (26.0%) of these 458 women had ever tried to conceive for at least 12 months, or needed medical help to conceive. This estimate is higher than the few comparable studies in high-income countries and the commonly quoted statistic of 1 in 6 couples experiencing infertility;8,9 one probable reason for the higher proportion in the Dunedin study being that information was obtained on more than one occasion.Given the paucity of information on infertility prevalence and the use of treatment services in New Zealand, a population-based survey of women aged 25-50 years was undertaken in Otago and Southland. From this survey data the aim was to estimate the prevalence of infertility, describe both the uptake of infertility services and the frequency of infertility resolution, and examine factors associated with infertility.MethodPopulation and data collectionA random sample of 2,200 women aged 25-50 years was drawn from the general and Mori electoral rolls in the Otago and Southland electorates in December, 2010. Women were invited to participate in a survey on fertility and infertility using a computerised questionnaire. This method has been shown to be particularly useful when studying sensitive issues.10,11 A link to the secure online questionnaire was provided in the letter, as well as a pre-paid return slip allowing participants to alternatively request a telephone interview or decline to participate. Non-responders were sent one reminder letter and, if there was still no response, where possible they were contacted by telephone after searching for their details in the public telephone directory. Remaining non-responders were sent a brief paper-based questionnaire with a final reminder letter.The online fertility questionnaire was adapted from three surveys: The US Fertility and Family Growth Survey; the North East of Scotland Fertility Study; and the Dunedin Multidisciplinary Health and Development Study.11-13 Demographic questions were refined for the New Zealand context. Data were collected between June and December, 2011.The Southern Regional Ethics Committee granted ethical approval for this survey in November 2010 (reference number LRS/10/EXP/054).Measures of infertility and childlessnessInfertility measures were those widely used, based on (a) length of time trying to conceive, which historically was 24 months but is now more commonly 12 months (the period generally waited before intervening clinically), and/or (b) seeking medical help to conceive.8 Successful resolution of infertility was considered as having a live birth during or after the first infertile period. Women aged 40 years or more with no previous births, whose infertility was not resolved with a live birth, were defined as having primary unresolved infertility. Childlessness, a commonly used demographic fertility measure,14 is distinct from the above as it is independent of a womans fertility history. It is defined as never having had a live birth and was determined among all participants aged 40 years or more. Childlessness was considered involuntary if the woman reported trying to conceive and/or wished she had had a child, and otherwise considered voluntary. Involuntary childlessness has multifactorial aetiology, including women who have not had the opportunity to form relationships and those who have primary unresolved infertility.The denominator for the infertility analyses included all women who had ever conceived or had tried to conceive. For the analyses of resolution of first infertility, the denominator was women who had tried for 12 months or more and/or sought medical help to conceive. For childlessness, the denominator was all women over the age of 40 years, irrespective of whether they had ever tried to conceive.Demographic variablesAge at the time of participation, ascertained from the electoral roll, was grouped into 5-year age bands. Mori descent was also ascertained from electoral roll data. Self-identified ethnicity was collected from participants using Census New Zealand questions and, where multiple ethnicities were reported, the womans ethnicity was prioritised into one group in the following order: Mori; Pacific; Asian; Other; or otherwise European.15 Area-level relative deprivation decile, calculated using 2006 Census data (NZDep06 score),16 was determined for each participant using the mesh block area code associated with the residential address. Deprivation deciles were then grouped as follows: Low (deciles 1-3); medium (deciles 4-7); and high (8-10). Highest educational qualification, household income, body mass index (BMI) and smoking status were collected via the questionnaire. BMI was grouped according to the World Health Organization guidelines as: Underweight (<18.5 kg/m2); normal (18.5-24.9 kg/m2); overweight (25.0-29.9 kg/m2); obese class I (30.0-34.9 kg/m2); obese class II (35.0-39.9 kg/m2); or obese class III (\u226540.0 kg/m2).17Statistical analysesData were analysed in STATA 12.1/SE. The demographic characteristics of participants and, where information was available, non-participants were described. The prevalence of infertility according to various definitions was calculated with 95% confidence intervals (CI). Service seeking behaviours, diagnoses, help received, and outcomes were described for the participants first episode of infertility and were summarised across multiple episodes of infertility. All differences between categorical data were tested using Pearsons \u03c72 tests.Infertility (using a definition of 12 months or more duration and/or seeking medical help to conceive) was examined by demographic factors, using Poisson regression to measure the relative risk (RR) of infertility, ever seeking medical help and the likelihood of resolving the first episode of infertility.ResultsParticipation and demographic profileOf 2,200 women drawn from the sampling frame, 174 were found to be ineligible and a further 154 did not receive the survey as they were no longer at their registered address and could not be located, giving an estimated eligible total of 1,872. After the initial invitation and two further attempts to contact non-responders, 1,125 completed questionnaires were received, including 63 from women who completed the shorter paper-based version, a response rate of 60.1% (1,125/1,872). There was lower participation amongst those aged 25-29 years, those of Mori descent and those from high deprivation areas (all p\u22640.05). The demographic profile of participants and non-participants is shown in Table 1.Table 1: Demographic characteristics of participants and non-participants \r\n \r\n \r\n \r\n \r\n \r\n Participants,\r\n n (%)\r\n \r\n Non-participants,\r\n n (%)*\r\n \r\n \u03c72 test P-value\r\n \r\n \r\n \r\n Total\r\n \r\n 1,125\r\n \r\n 901\r\n \r\n \r\n \r\n \r\n \r\n Age group (years)*\r\n \r\n 25-29\r\n \r\n 215\r\n \r\n (19.1)\r\n \r\n 210\r\n \r\n (23.3)\r\n \r\n \r\n \r\n \r\n \r\n 30-34\r\n \r\n 159\r\n \r\n (14.1)\r\n \r\n 98\r\n \r\n (10.9)\r\n \r\n \r\n \r\n \r\n \r\n 35-39\r\n \r\n 208\r\n \r\n (18.5)\r\n \r\n 177\r\n \r\n (19.6)\r\n \r\n \r\n \r\n \r\n \r\n 40-44\r\n \r\n 277\r\n \r\n (24.6)\r\n \r\n 203\r\n \r\n (22.5)\r\n \r\n \r\n \r\n \r\n \r\n 45-50\r\n \r\n 266\r\n \r\n (23.6)\r\n \r\n 213\r\n \r\n (23.6)\r\n \r\n 0.047\r\n \r\n \r\n \r\n Current relationship status\u2020\r\n \r\n Living with male partner\r\n \r\n 837\r\n \r\n (74.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Male partner, not cohabiting\r\n \r\n 49\r\n \r\n (4.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Living with female partner\r\n \r\n 5\r\n \r\n (0.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Not in a relationship\r\n \r\n 151\r\n \r\n (13.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Mori descent*\r\n \r\n Yes\r\n \r\n 109\r\n \r\n (9.7)\r\n \r\n 133\r\n \r\n (14.8)\r\n \r\n \r\n \r\n \r\n \r\n No\r\n \r\n 1,016\r\n \r\n (90.3)\r\n \r\n 768\r\n \r\n (85.2)\r\n \r\n <0.001\r\n \r\n \r\n \r\n Prioritised ethnic group\u2020\r\n \r\n European\r\n \r\n 981\r\n \r\n (87.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Mori\r\n \r\n 78\r\n \r\n (6.9)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Pacific peoples\r\n \r\n 3\r\n \r\n (0.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Asian\r\n \r\n 20\r\n \r\n (1.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Other\r\n \r\n 15\r\n \r\n (1.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Deprivation (NZDep06)*\r\n \r\n Low (deciles 1-3)\r\n \r\n 512\r\n \r\n (45.5)\r\n \r\n 338\r\n \r\n (37.5)\r\n \r\n \r\n \r\n \r\n \r\n Medium (deciles 4-7)\r\n \r\n 429\r\n \r\n (38.1)\r\n \r\n 335\r\n \r\n (37.2)\r\n \r\n \r\n \r\n \r\n \r\n High (deciles 8-10)\r\n \r\n 184\r\n \r\n (16.4)\r\n \r\n 228\r\n \r\n (25.3)\r\n \r\n <0.001\r\n \r\n \r\n \r\n Highest qualification level\u2020\r\n \r\n High school or less\r\n \r\n 436\r\n \r\n (38.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Post high school, not university\r\n \r\n 255\r\n \r\n (22.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n University\r\n \r\n 338\r\n \r\n (30.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Annual household income\u2020\r\n \r\n Low (\u2264 $30,000)\r\n \r\n 124\r\n \r\n (11.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Medium ($30,001-$70,000)\r\n \r\n 392\r\n \r\n (34.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n High (>$70,000)\r\n \r\n 479\r\n \r\n (42.6)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Smoking status\u2020\r\n \r\n Current smoker\r\n \r\n 148\r\n \r\n (13.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Past smoker\r\n \r\n 307\r\n \r\n (27.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Non smoker\r\n \r\n 593\r\n \r\n (52.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Body mass index (BMI), kg/m2\u2020\r\n \r\n Underweight, <18.5\r\n \r\n 14\r\n \r\n (1.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Normal, 18.5-24.9\r\n \r\n 484\r\n \r\n (43.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Overweight, 25.0-29.9\r\n \r\n 233\r\n \r\n (20.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class I, 30.0-34.9\r\n \r\n 139\r\n \r\n (12.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class II, 35.0-39.9\r\n \r\n 74\r\n \r\n (6.6)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class III, \u226540.0\r\n \r\n 31\r\n \r\n (2.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n- These data were not available for non-participants.* Data on non-participants were derived from the electoral roll.\u2020 Due to women not always answering all questions in the questionnaire, these variables have missing data and, therefore, the total responses are less than 1,125. The prevalence of infertilityOf the 1,125 participants, 974 (86.6%) had ever tried to become or had been pregnant; the proportion who had done so increased markedly with age, from 63.3% in those aged 25-29 years to 94.2% in those aged 35-39 years (p<0.001). Of those in the 25-29 year age group, 70.2% intended to have (more) children in the future, a significant proportion of women in their thirties also reported future fertility intentions (34.2% and 11.5% in those aged 30-34 and 35-39 years, respectively). This decreased to 3.9% in the 40-44 year-olds, with no one older than this intending to conceive in the future.The measures of infertility and childlessness are shown in Table 2.Of those women who had tried to become or had become pregnant, 211 (21.7%, 95% CI 19.1-24.4%) had ever tried to conceive for 12 months or more; just over half (55.4%, 117/211) of those women having tried for 24 months or more. Including those women who had sought medical help for conceiving increased the 12-month estimate of infertility to 25.3% (22.6-28.1%). Of the 476 women over the age of 40 years at the time of participation who had tried to conceive, nine (1.9%, 0.9-3.6%) had primary unresolved infertility. However, substantially more (13.8%) of all 518 women aged 40 years or more were childless; 35 (6.8%, 4.8-9.3%) were considered involuntarily and 36 (7.0%, 4.8-9.5%) voluntarily childless.Table 2: The prevalence of infertility and childlessness\r\n \r\n \r\n \r\n Definition\r\n \r\n N\r\n \r\n n\r\n \r\n %\r\n \r\n (95% CI)\r\n \r\n \r\n \r\n Ever tried to conceive for 12 months or more\r\n \r\n 974\r\n \r\n 211\r\n \r\n 21.7\r\n \r\n (19.1-24.4)\r\n \r\n \r\n \r\n Ever tried to conceive for 24 months or more*\r\n \r\n 911\r\n \r\n 117\r\n \r\n 12.8\r\n \r\n (10.7-15.2)\r\n \r\n \r\n \r\n Ever sought medical help to conceive\r\n \r\n 974\r\n \r\n 171\r\n \r\n 17.6\r\n \r\n (15.2-20.1)\r\n \r\n \r\n \r\n Ever tried for 12 months or more and/or sought medical help to conceive\r\n \r\n 974\r\n \r\n 246\r\n \r\n 25.3\r\n \r\n (22.6-28.1)\r\n \r\n \r\n \r\n Primary unresolved infertility\u2020\r\n \r\n 476\r\n \r\n 9\r\n \r\n 1.9\r\n \r\n (0.9-3.6)\r\n \r\n \r\n \r\n Involuntary childlessness\u2021\r\n \r\n 518\r\n \r\n 35\r\n \r\n 6.8\r\n \r\n (4.8-9.3)\r\n \r\n \r\n \r\n Voluntary childlessness\u2021\r\n \r\n 518\r\n \r\n 36\r\n \r\n 7.0\r\n \r\n (4.9-9.5)\r\n \r\n \r\n \r\n * Only 911 women who had conceived or tried to conceive answered the full questionnaire allowing definitions to be calculated using a 24-month period.\u2020Limited to women aged 40 years or more who had ever tried to become or had been pregnant.\u2021 Limited to women aged 40 years or more, irrespective of whether they had attempted or had previously conceived.Uptake of services for infertility and infertility outcomesThere were 235 who women who had at least one episode of infertility (using the 12 months trying and/or sought medical help to conceive definition) and completed all service use questions. Figure 1 summarises the first experience of infertility for these women. This initially shows those with self-defined difficulty, followed sequentially by services sought and received. Whether this first episode of infertility ended with a live birth has been indicated at each stage for those women who did not progress to the next stage of the care pathway.Figure 1: Access to services, uptake of treatment and resolution for the first experience of infertility \r\n* Defined as 12 months or more trying and/or seeking medical help to conceive.\u2020 Includes 11 referred women (11.3% of the 98 referred) who conceived before seeing specialist, 10 of whom eventually had a live birth and one who did not.\u2021 Includes four women who conceived before starting any treatment, all of whom eventually had a live birth. Of the 235 infertile women, 37 (15.7%) did not consider that they had a fertility problem for their first episode of infertility. All of these 37 women eventually conceived, with 29 having a live birth.Of the 198 women who reported having difficulties, 144 sought help by initially consulting a non-specialist, and 10 by consulting a specialist directly. Of the women who saw a non-specialist medical provider, over half reported receiving advice (81, 57.5%) and just over two-thirds (98, 69.5%) were referred to specialist services.A total of 97 women saw a specialist. Male factors were the most common cause of their infertility (33.3%), followed by ovulation disorder (23.7%), unknown cause (21.5%) and endometriosis (18.3%). Twenty of these 97 women reported not having any treatment, although four reported getting pregnant before any treatment could be started. The remaining 77 women received treatment for their first episode of infertility, the most frequent treatments being drugs (47.5%), in vitro fertilisation (IVF) (36.4%), surgery (27.3%) and artificial insemination (AI)/intra-uterine insemination (IUI) (22.1%). It is possible that the prevalence of treatment with surgery has been inflated by women reporting surgery as a treatment when it may have been for diagnostic purposes (eg, laparoscopy).For 99 (42.1%) of the 235 women, their first episode of infertility ended with a live birth, another 79 had a live birth after this attempt; ie, they reported a pregnancy ending in a live birth, which they self-defined as a subsequent fertility event\u2014this may have involved a change of partner and/or a break from trying to conceive. Therefore, in total 178 (75.7%) women had a live birth subsequent to their initial infertility. Those who were aged 35 or more years when they first experienced infertility were significantly less likely to have resolved it than those aged less than 35 years (57.1% vs 79.0% respectively, p=0.005).When considering all episodes of infertility, 166 (70.6%) infertile women had sought non-specialist and/or specialist medical help at least once, and treatment was received by 89 (37.9%) infertile women.Factors associated with infertility, service use for infertility and resolution of infertilityUnadjusted analyses revealed statistically significant associations between having experienced infertility and relationship type, age, education and BMI (all of which were at the time of survey participation) (all p<0.05) (Table 3). Women aged 25-29 and 45-50 years had a lower prevalence of infertility, especially compared to women aged 40-44 years at the time of the survey. However, after simultaneously adjusting for these factors, age group was no longer a significant determinant of infertility risk.The adjusted relative risk of infertility was reduced (RR 0.50, 95% CI 0.28-0.90) amongst women who were single or in a same-sex relationship compared with women in a heterosexual relationship at the time of the survey. Women who were underweight were 2.61 (1.43-4.79) times more likely to report infertility compared with women with a normal BMI, while women in the obese class II and class III categories had 1.78 (1.19-2.65) and 2.01 (1.19-3.37) times the risk respectively. Women who had a university level qualification had 1.19 (1.04-1.35) times the risk of infertility than those without.After investigating the likelihood of seeking medical help for infertility, using the determinants listed in Table 3 for modelling, only two significant factors were found: Education and income. However, these models (and that for resolution of infertility) were of limited power, having just 235 cases. Infertile women with a university-level qualification were slightly more likely than those without to seek non-specialist care (RR 1.10, 1.01-1.21). Household income predicted seeking specialist help; those with low and medium incomes were less likely to do so than those in the high-income bracket (RR 0.70 [0.39-1.26] and RR 0.67 [0.49-0.90] respectively).Only two factors were associated with the resolution of the first episode of infertility in the adjusted model: Reported age at the onset of the first infertility experience and deprivation. Those aged 35 years or more when they first experienced infertility were less likely (RR 0.71, 95% CI 0.53-0.96) to resolve their infertility compared with those aged less than 35 years. For each level of deprivation there was a modest but significant decrease in infertility resolution (RR 0.89, 0.80-1.00), such that those in the highest deprivation deciles (deciles 8-10) were 22% less likely to resolve their infertility compared with those in the lowest deprivation deciles (deciles 1-3).Table 3: Unadjusted and adjusted relative risk of infertility* by selected demographic factors and risk determinants \r\n \r\n \r\n \r\n Determinants (measured at time of participation)\r\n \r\n Number of women who experienced infertility* (Prevalence, %)\r\n \r\n Unadjusted\r\n \r\n Adjusted\u2020\r\n \r\n \r\n \r\n RR\r\n \r\n (95 CI%)\r\n \r\n P-value\r\n \r\n RR\r\n \r\n (95 CI%)\r\n \r\n P-value\r\n \r\n \r\n \r\n Relationship type\r\n \r\n Heterosexual\r\n \r\n 216\r\n \r\n (27.4)\r\n \r\n Reference\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Same-sex/no relationship\r\n \r\n 15\r\n \r\n (13.6)\r\n \r\n 0.50\r\n \r\n (0.31-0.81)\r\n \r\n 0.005\r\n \r\n 0.50\r\n \r\n (0.28-0.90)\r\n \r\n 0.020\r\n \r\n \r\n \r\n Age group (years)\r\n \r\n 25-29\r\n \r\n 19\r\n \r\n (14.0)\r\n \r\n 0.52\r\n \r\n (0.32-0.83)\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 30-34\r\n \r\n 38\r\n \r\n (27.5)\r\n \r\n 1.02\r\n \r\n (0.71-1.45)\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 35-39\r\n \r\n 53\r\n \r\n (27.0)\r\n \r\n Reference\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 40-44\r\n \r\n 79\r\n \r\n (30.2)\r\n \r\n 1.12\r\n \r\n (0.83-1.50)\r\n

The experience of infertility can have a major impact on individuals, families and relationships, as most people have life plans that involve children. In addition, it can result in a considerable cost to both individuals and health services. The aetiology of infertility is complex, with many factors affecting an individuals risk of infertility. Age is an important determinant, especially for women, with increasing age strongly correlated with decreasing fertility for women older than 30 years.1 Due to social changes over the past few decades, many women/couples in New Zealand are delaying the start of their families, with the median age of childbearing now around 30 years.2 Concurrent with this trend of delayed childbearing, there have been changes in the frequency of health conditions that may have a negative impact on fertility. These include increases in obesity and sexually transmitted infections such as Chlamydia trachomatis,3,4 which have most likely impacted on the number of women experiencing infertility. There is already evidence that childlessness is increasingly common in women aged more than 40 years; in the 2006 New Zealand Census, 16.7% of women over 40 years were childless and this is projected to rise to over a quarter by the next census in 2018.5,6Despite the importance of infertility and social changes that may be impacting on its prevalence, population-based estimates are limited to one study, a cohort born in Dunedin, New Zealand, in 1972/3, who were last interviewed when aged 37-39 years.7 Just over a quarter (26.0%) of these 458 women had ever tried to conceive for at least 12 months, or needed medical help to conceive. This estimate is higher than the few comparable studies in high-income countries and the commonly quoted statistic of 1 in 6 couples experiencing infertility;8,9 one probable reason for the higher proportion in the Dunedin study being that information was obtained on more than one occasion.Given the paucity of information on infertility prevalence and the use of treatment services in New Zealand, a population-based survey of women aged 25-50 years was undertaken in Otago and Southland. From this survey data the aim was to estimate the prevalence of infertility, describe both the uptake of infertility services and the frequency of infertility resolution, and examine factors associated with infertility.MethodPopulation and data collectionA random sample of 2,200 women aged 25-50 years was drawn from the general and Mori electoral rolls in the Otago and Southland electorates in December, 2010. Women were invited to participate in a survey on fertility and infertility using a computerised questionnaire. This method has been shown to be particularly useful when studying sensitive issues.10,11 A link to the secure online questionnaire was provided in the letter, as well as a pre-paid return slip allowing participants to alternatively request a telephone interview or decline to participate. Non-responders were sent one reminder letter and, if there was still no response, where possible they were contacted by telephone after searching for their details in the public telephone directory. Remaining non-responders were sent a brief paper-based questionnaire with a final reminder letter.The online fertility questionnaire was adapted from three surveys: The US Fertility and Family Growth Survey; the North East of Scotland Fertility Study; and the Dunedin Multidisciplinary Health and Development Study.11-13 Demographic questions were refined for the New Zealand context. Data were collected between June and December, 2011.The Southern Regional Ethics Committee granted ethical approval for this survey in November 2010 (reference number LRS/10/EXP/054).Measures of infertility and childlessnessInfertility measures were those widely used, based on (a) length of time trying to conceive, which historically was 24 months but is now more commonly 12 months (the period generally waited before intervening clinically), and/or (b) seeking medical help to conceive.8 Successful resolution of infertility was considered as having a live birth during or after the first infertile period. Women aged 40 years or more with no previous births, whose infertility was not resolved with a live birth, were defined as having primary unresolved infertility. Childlessness, a commonly used demographic fertility measure,14 is distinct from the above as it is independent of a womans fertility history. It is defined as never having had a live birth and was determined among all participants aged 40 years or more. Childlessness was considered involuntary if the woman reported trying to conceive and/or wished she had had a child, and otherwise considered voluntary. Involuntary childlessness has multifactorial aetiology, including women who have not had the opportunity to form relationships and those who have primary unresolved infertility.The denominator for the infertility analyses included all women who had ever conceived or had tried to conceive. For the analyses of resolution of first infertility, the denominator was women who had tried for 12 months or more and/or sought medical help to conceive. For childlessness, the denominator was all women over the age of 40 years, irrespective of whether they had ever tried to conceive.Demographic variablesAge at the time of participation, ascertained from the electoral roll, was grouped into 5-year age bands. Mori descent was also ascertained from electoral roll data. Self-identified ethnicity was collected from participants using Census New Zealand questions and, where multiple ethnicities were reported, the womans ethnicity was prioritised into one group in the following order: Mori; Pacific; Asian; Other; or otherwise European.15 Area-level relative deprivation decile, calculated using 2006 Census data (NZDep06 score),16 was determined for each participant using the mesh block area code associated with the residential address. Deprivation deciles were then grouped as follows: Low (deciles 1-3); medium (deciles 4-7); and high (8-10). Highest educational qualification, household income, body mass index (BMI) and smoking status were collected via the questionnaire. BMI was grouped according to the World Health Organization guidelines as: Underweight (<18.5 kg/m2); normal (18.5-24.9 kg/m2); overweight (25.0-29.9 kg/m2); obese class I (30.0-34.9 kg/m2); obese class II (35.0-39.9 kg/m2); or obese class III (\u226540.0 kg/m2).17Statistical analysesData were analysed in STATA 12.1/SE. The demographic characteristics of participants and, where information was available, non-participants were described. The prevalence of infertility according to various definitions was calculated with 95% confidence intervals (CI). Service seeking behaviours, diagnoses, help received, and outcomes were described for the participants first episode of infertility and were summarised across multiple episodes of infertility. All differences between categorical data were tested using Pearsons \u03c72 tests.Infertility (using a definition of 12 months or more duration and/or seeking medical help to conceive) was examined by demographic factors, using Poisson regression to measure the relative risk (RR) of infertility, ever seeking medical help and the likelihood of resolving the first episode of infertility.ResultsParticipation and demographic profileOf 2,200 women drawn from the sampling frame, 174 were found to be ineligible and a further 154 did not receive the survey as they were no longer at their registered address and could not be located, giving an estimated eligible total of 1,872. After the initial invitation and two further attempts to contact non-responders, 1,125 completed questionnaires were received, including 63 from women who completed the shorter paper-based version, a response rate of 60.1% (1,125/1,872). There was lower participation amongst those aged 25-29 years, those of Mori descent and those from high deprivation areas (all p\u22640.05). The demographic profile of participants and non-participants is shown in Table 1.Table 1: Demographic characteristics of participants and non-participants \r\n \r\n \r\n \r\n \r\n \r\n Participants,\r\n n (%)\r\n \r\n Non-participants,\r\n n (%)*\r\n \r\n \u03c72 test P-value\r\n \r\n \r\n \r\n Total\r\n \r\n 1,125\r\n \r\n 901\r\n \r\n \r\n \r\n \r\n \r\n Age group (years)*\r\n \r\n 25-29\r\n \r\n 215\r\n \r\n (19.1)\r\n \r\n 210\r\n \r\n (23.3)\r\n \r\n \r\n \r\n \r\n \r\n 30-34\r\n \r\n 159\r\n \r\n (14.1)\r\n \r\n 98\r\n \r\n (10.9)\r\n \r\n \r\n \r\n \r\n \r\n 35-39\r\n \r\n 208\r\n \r\n (18.5)\r\n \r\n 177\r\n \r\n (19.6)\r\n \r\n \r\n \r\n \r\n \r\n 40-44\r\n \r\n 277\r\n \r\n (24.6)\r\n \r\n 203\r\n \r\n (22.5)\r\n \r\n \r\n \r\n \r\n \r\n 45-50\r\n \r\n 266\r\n \r\n (23.6)\r\n \r\n 213\r\n \r\n (23.6)\r\n \r\n 0.047\r\n \r\n \r\n \r\n Current relationship status\u2020\r\n \r\n Living with male partner\r\n \r\n 837\r\n \r\n (74.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Male partner, not cohabiting\r\n \r\n 49\r\n \r\n (4.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Living with female partner\r\n \r\n 5\r\n \r\n (0.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Not in a relationship\r\n \r\n 151\r\n \r\n (13.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Mori descent*\r\n \r\n Yes\r\n \r\n 109\r\n \r\n (9.7)\r\n \r\n 133\r\n \r\n (14.8)\r\n \r\n \r\n \r\n \r\n \r\n No\r\n \r\n 1,016\r\n \r\n (90.3)\r\n \r\n 768\r\n \r\n (85.2)\r\n \r\n <0.001\r\n \r\n \r\n \r\n Prioritised ethnic group\u2020\r\n \r\n European\r\n \r\n 981\r\n \r\n (87.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Mori\r\n \r\n 78\r\n \r\n (6.9)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Pacific peoples\r\n \r\n 3\r\n \r\n (0.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Asian\r\n \r\n 20\r\n \r\n (1.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Other\r\n \r\n 15\r\n \r\n (1.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Deprivation (NZDep06)*\r\n \r\n Low (deciles 1-3)\r\n \r\n 512\r\n \r\n (45.5)\r\n \r\n 338\r\n \r\n (37.5)\r\n \r\n \r\n \r\n \r\n \r\n Medium (deciles 4-7)\r\n \r\n 429\r\n \r\n (38.1)\r\n \r\n 335\r\n \r\n (37.2)\r\n \r\n \r\n \r\n \r\n \r\n High (deciles 8-10)\r\n \r\n 184\r\n \r\n (16.4)\r\n \r\n 228\r\n \r\n (25.3)\r\n \r\n <0.001\r\n \r\n \r\n \r\n Highest qualification level\u2020\r\n \r\n High school or less\r\n \r\n 436\r\n \r\n (38.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Post high school, not university\r\n \r\n 255\r\n \r\n (22.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n University\r\n \r\n 338\r\n \r\n (30.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Annual household income\u2020\r\n \r\n Low (\u2264 $30,000)\r\n \r\n 124\r\n \r\n (11.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Medium ($30,001-$70,000)\r\n \r\n 392\r\n \r\n (34.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n High (>$70,000)\r\n \r\n 479\r\n \r\n (42.6)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Smoking status\u2020\r\n \r\n Current smoker\r\n \r\n 148\r\n \r\n (13.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Past smoker\r\n \r\n 307\r\n \r\n (27.3)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Non smoker\r\n \r\n 593\r\n \r\n (52.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Body mass index (BMI), kg/m2\u2020\r\n \r\n Underweight, <18.5\r\n \r\n 14\r\n \r\n (1.2)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Normal, 18.5-24.9\r\n \r\n 484\r\n \r\n (43.0)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Overweight, 25.0-29.9\r\n \r\n 233\r\n \r\n (20.7)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class I, 30.0-34.9\r\n \r\n 139\r\n \r\n (12.4)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class II, 35.0-39.9\r\n \r\n 74\r\n \r\n (6.6)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Obese class III, \u226540.0\r\n \r\n 31\r\n \r\n (2.8)\r\n \r\n -\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n- These data were not available for non-participants.* Data on non-participants were derived from the electoral roll.\u2020 Due to women not always answering all questions in the questionnaire, these variables have missing data and, therefore, the total responses are less than 1,125. The prevalence of infertilityOf the 1,125 participants, 974 (86.6%) had ever tried to become or had been pregnant; the proportion who had done so increased markedly with age, from 63.3% in those aged 25-29 years to 94.2% in those aged 35-39 years (p<0.001). Of those in the 25-29 year age group, 70.2% intended to have (more) children in the future, a significant proportion of women in their thirties also reported future fertility intentions (34.2% and 11.5% in those aged 30-34 and 35-39 years, respectively). This decreased to 3.9% in the 40-44 year-olds, with no one older than this intending to conceive in the future.The measures of infertility and childlessness are shown in Table 2.Of those women who had tried to become or had become pregnant, 211 (21.7%, 95% CI 19.1-24.4%) had ever tried to conceive for 12 months or more; just over half (55.4%, 117/211) of those women having tried for 24 months or more. Including those women who had sought medical help for conceiving increased the 12-month estimate of infertility to 25.3% (22.6-28.1%). Of the 476 women over the age of 40 years at the time of participation who had tried to conceive, nine (1.9%, 0.9-3.6%) had primary unresolved infertility. However, substantially more (13.8%) of all 518 women aged 40 years or more were childless; 35 (6.8%, 4.8-9.3%) were considered involuntarily and 36 (7.0%, 4.8-9.5%) voluntarily childless.Table 2: The prevalence of infertility and childlessness\r\n \r\n \r\n \r\n Definition\r\n \r\n N\r\n \r\n n\r\n \r\n %\r\n \r\n (95% CI)\r\n \r\n \r\n \r\n Ever tried to conceive for 12 months or more\r\n \r\n 974\r\n \r\n 211\r\n \r\n 21.7\r\n \r\n (19.1-24.4)\r\n \r\n \r\n \r\n Ever tried to conceive for 24 months or more*\r\n \r\n 911\r\n \r\n 117\r\n \r\n 12.8\r\n \r\n (10.7-15.2)\r\n \r\n \r\n \r\n Ever sought medical help to conceive\r\n \r\n 974\r\n \r\n 171\r\n \r\n 17.6\r\n \r\n (15.2-20.1)\r\n \r\n \r\n \r\n Ever tried for 12 months or more and/or sought medical help to conceive\r\n \r\n 974\r\n \r\n 246\r\n \r\n 25.3\r\n \r\n (22.6-28.1)\r\n \r\n \r\n \r\n Primary unresolved infertility\u2020\r\n \r\n 476\r\n \r\n 9\r\n \r\n 1.9\r\n \r\n (0.9-3.6)\r\n \r\n \r\n \r\n Involuntary childlessness\u2021\r\n \r\n 518\r\n \r\n 35\r\n \r\n 6.8\r\n \r\n (4.8-9.3)\r\n \r\n \r\n \r\n Voluntary childlessness\u2021\r\n \r\n 518\r\n \r\n 36\r\n \r\n 7.0\r\n \r\n (4.9-9.5)\r\n \r\n \r\n \r\n * Only 911 women who had conceived or tried to conceive answered the full questionnaire allowing definitions to be calculated using a 24-month period.\u2020Limited to women aged 40 years or more who had ever tried to become or had been pregnant.\u2021 Limited to women aged 40 years or more, irrespective of whether they had attempted or had previously conceived.Uptake of services for infertility and infertility outcomesThere were 235 who women who had at least one episode of infertility (using the 12 months trying and/or sought medical help to conceive definition) and completed all service use questions. Figure 1 summarises the first experience of infertility for these women. This initially shows those with self-defined difficulty, followed sequentially by services sought and received. Whether this first episode of infertility ended with a live birth has been indicated at each stage for those women who did not progress to the next stage of the care pathway.Figure 1: Access to services, uptake of treatment and resolution for the first experience of infertility \r\n* Defined as 12 months or more trying and/or seeking medical help to conceive.\u2020 Includes 11 referred women (11.3% of the 98 referred) who conceived before seeing specialist, 10 of whom eventually had a live birth and one who did not.\u2021 Includes four women who conceived before starting any treatment, all of whom eventually had a live birth. Of the 235 infertile women, 37 (15.7%) did not consider that they had a fertility problem for their first episode of infertility. All of these 37 women eventually conceived, with 29 having a live birth.Of the 198 women who reported having difficulties, 144 sought help by initially consulting a non-specialist, and 10 by consulting a specialist directly. Of the women who saw a non-specialist medical provider, over half reported receiving advice (81, 57.5%) and just over two-thirds (98, 69.5%) were referred to specialist services.A total of 97 women saw a specialist. Male factors were the most common cause of their infertility (33.3%), followed by ovulation disorder (23.7%), unknown cause (21.5%) and endometriosis (18.3%). Twenty of these 97 women reported not having any treatment, although four reported getting pregnant before any treatment could be started. The remaining 77 women received treatment for their first episode of infertility, the most frequent treatments being drugs (47.5%), in vitro fertilisation (IVF) (36.4%), surgery (27.3%) and artificial insemination (AI)/intra-uterine insemination (IUI) (22.1%). It is possible that the prevalence of treatment with surgery has been inflated by women reporting surgery as a treatment when it may have been for diagnostic purposes (eg, laparoscopy).For 99 (42.1%) of the 235 women, their first episode of infertility ended with a live birth, another 79 had a live birth after this attempt; ie, they reported a pregnancy ending in a live birth, which they self-defined as a subsequent fertility event\u2014this may have involved a change of partner and/or a break from trying to conceive. Therefore, in total 178 (75.7%) women had a live birth subsequent to their initial infertility. Those who were aged 35 or more years when they first experienced infertility were significantly less likely to have resolved it than those aged less than 35 years (57.1% vs 79.0% respectively, p=0.005).When considering all episodes of infertility, 166 (70.6%) infertile women had sought non-specialist and/or specialist medical help at least once, and treatment was received by 89 (37.9%) infertile women.Factors associated with infertility, service use for infertility and resolution of infertilityUnadjusted analyses revealed statistically significant associations between having experienced infertility and relationship type, age, education and BMI (all of which were at the time of survey participation) (all p<0.05) (Table 3). Women aged 25-29 and 45-50 years had a lower prevalence of infertility, especially compared to women aged 40-44 years at the time of the survey. However, after simultaneously adjusting for these factors, age group was no longer a significant determinant of infertility risk.The adjusted relative risk of infertility was reduced (RR 0.50, 95% CI 0.28-0.90) amongst women who were single or in a same-sex relationship compared with women in a heterosexual relationship at the time of the survey. Women who were underweight were 2.61 (1.43-4.79) times more likely to report infertility compared with women with a normal BMI, while women in the obese class II and class III categories had 1.78 (1.19-2.65) and 2.01 (1.19-3.37) times the risk respectively. Women who had a university level qualification had 1.19 (1.04-1.35) times the risk of infertility than those without.After investigating the likelihood of seeking medical help for infertility, using the determinants listed in Table 3 for modelling, only two significant factors were found: Education and income. However, these models (and that for resolution of infertility) were of limited power, having just 235 cases. Infertile women with a university-level qualification were slightly more likely than those without to seek non-specialist care (RR 1.10, 1.01-1.21). Household income predicted seeking specialist help; those with low and medium incomes were less likely to do so than those in the high-income bracket (RR 0.70 [0.39-1.26] and RR 0.67 [0.49-0.90] respectively).Only two factors were associated with the resolution of the first episode of infertility in the adjusted model: Reported age at the onset of the first infertility experience and deprivation. Those aged 35 years or more when they first experienced infertility were less likely (RR 0.71, 95% CI 0.53-0.96) to resolve their infertility compared with those aged less than 35 years. For each level of deprivation there was a modest but significant decrease in infertility resolution (RR 0.89, 0.80-1.00), such that those in the highest deprivation deciles (deciles 8-10) were 22% less likely to resolve their infertility compared with those in the lowest deprivation deciles (deciles 1-3).Table 3: Unadjusted and adjusted relative risk of infertility* by selected demographic factors and risk determinants \r\n \r\n \r\n \r\n Determinants (measured at time of participation)\r\n \r\n Number of women who experienced infertility* (Prevalence, %)\r\n \r\n Unadjusted\r\n \r\n Adjusted\u2020\r\n \r\n \r\n \r\n RR\r\n \r\n (95 CI%)\r\n \r\n P-value\r\n \r\n RR\r\n \r\n (95 CI%)\r\n \r\n P-value\r\n \r\n \r\n \r\n Relationship type\r\n \r\n Heterosexual\r\n \r\n 216\r\n \r\n (27.4)\r\n \r\n Reference\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n Same-sex/no relationship\r\n \r\n 15\r\n \r\n (13.6)\r\n \r\n 0.50\r\n \r\n (0.31-0.81)\r\n \r\n 0.005\r\n \r\n 0.50\r\n \r\n (0.28-0.90)\r\n \r\n 0.020\r\n \r\n \r\n \r\n Age group (years)\r\n \r\n 25-29\r\n \r\n 19\r\n \r\n (14.0)\r\n \r\n 0.52\r\n \r\n (0.32-0.83)\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 30-34\r\n \r\n 38\r\n \r\n (27.5)\r\n \r\n 1.02\r\n \r\n (0.71-1.45)\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 35-39\r\n \r\n 53\r\n \r\n (27.0)\r\n \r\n Reference\r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n \r\n 40-44\r\n \r\n 79\r\n \r\n (30.2)\r\n \r\n 1.12\r\n \r\n (0.83-1.50)\r\n