Infertility in Australia circa 1980: an historical population perspective on the uptake of fertility treatment by Australian women born in 1946-51
Danielle Herbert, The University of Queensland, School of Population Health, Public Health Building, Herston QLD 4006 Australia. Fax: (07) 3365 5540; e-mail: firstname.lastname@example.org
Objective: To estimate the prevalence of lifetime infertility in Australian women born in 1946-51 and examine their uptake of treatment.
Methods: Participants in the Australian Longitudinal Study on Women's Health born in 1946-51 (n=13,715) completed up to four mailed surveys from 1996 to 2004. The odds of infertility were estimated using logistic regression with adjustment for socio-demographic and reproductive factors.
Results: Among participants, 92.1% had been pregnant. For women who had been pregnant (n=12738): 56.5% had at least one birth but no pregnancy loss (miscarriage and/or termination); 39.9% experienced both birth and loss; and 3.6% had a loss only. The lifetime prevalence of infertility was 11.0%. Among women who reported infertility (n=1511), 41.7% used treatment. Women had higher odds of infertility when they had reproductive histories of losses only (OR range 9.0-43.5) or had never been pregnant (OR=15.7, 95%CI 11.8-20.8); and higher odds for treatment: losses only (OR range 2.5-9.8); or never pregnant (1.96, 1.28-3.00). Women who delayed their first birth until aged 30+ years had higher odds of treatment (OR range 3.2-4.3).
Conclusions: About one in ten women experienced infertility and almost half used some form of treatment, especially those attempting pregnancy after 1980. Older first time mothers had an increased uptake of treatment as assisted reproductive technologies (ART) developed.
Implications: This study provided evidence of the early uptake of treatment prior to 1979 when the national register of invasive ART was developed and later uptake prior to 1998 when data on non-invasive ART were first collected.
Australian women born in 1946-51 were in their prime reproductive years in the late 1960s and early 1970s and the majority of births occurred for these women from age 20 to 29 years.1 Specifically, in 1965 the total fertility rate (TFR) was three children per woman but by 1975 the TFR dropped to 2.2 children and the median age of mothers for all births was 25.8 years. For infertile couples in the 1970s, the availability of children for adoption became limited due, in part, to women being able to control their fertility with the oral contraceptive pill and abortion.2–4 As demonstrated by the timeline of significant population and fertility treatment events in Australia (Table 1), a diagnosis of infertility was possible for this generation of women but the availability of treatment was limited. Prior to the availability of clinics that specialised in assisted reproductive technologies (ART), infertility treatment was provided through gynaecological clinics and focused on female factor infertility. For infertile women, treatment included: tubal, endometrial or ovarian surgery, basal temperature charts and measurement of ovarian hormones.5
Table 1. Timeline of significant population and fertility treatment events in Australia.
| ||1938||Infertility clinic opened: Sydney5|
| ||1940||Infertility clinic opened: Melbourne5|
|ALSWH participants born in 1946-51||1946||Infertility clinic opened: Adelaide5|
|↓||1948||Infertility clinic opened: Brisbane5|
|↓||1949||Infertility clinic opened: Perth5|
|ALSWH participants born in 1946-51||1951|| |
|Oral contraceptive pill available3||1961|| |
| ||1962||Ovulation induction treatment introduced: Sydney5|
| ||1967||Infertility clinic opened: Hobart5|
|Therapeutic abortion legalised in Victoria (Menhennitt ruling)4||1969|| |
|Median age of mothers: 25.6 years1||1970|| |
|ALSWH cohort aged: 19-24 years|| || |
|Therapeutic abortion legalised in New South Wales (Levine ruling)4||1971|| |
| ||1972||First donor sperm bank: Adelaide5|
| || ||First IVF clinic: Melbourne7|
| || ||Hormonally stimulated cycles began2|
| ||1973||First two IVF pregnancies in the world but lost <1 week: Melbourne28|
|Median age of mothers: 25.8 years1||1975|| |
|ALSWH cohort aged: 24-29 years|| || |
| ||1978||First IVF child in the world is born, Louise Brown: United Kingdom8|
| ||1979||First ongoing IVF pregnancy in Australia20|
|Median age of mothers: 26.6 years1||1980||First IVF child in Australia is born, Candice Reed: Melbourne9|
|ALSWH cohort aged: 29-34 years|| || |
| || ||New IVF clinics: Sydney, Adelaide, Brisbane, Perth2,7|
|National Perinatal Statistics Unit begins collation of ART data from 1979+20||1983||First birth from donor eggs2|
| || ||Eight IVF clinics in operation20|
| ||1984||First birth from frozen embryos2|
| || ||New IVF clinic: Newcastle (pers. com.)|
|Median age of mothers: 27.3 years1||1985|| |
|ALSWH cohort aged: 34-39 years|| || |
| ||1987||14 IVF clinics in operation20|
|Government introduced limited public funding (Medicare) for ART27||1990||SUZI technique introduced to treat male factor infertility10,13|
| ||1993||ICSI technique introduced11,13|
| || ||23 IVF clinics in operation13|
|Government removed six cycle limit for Medicare funded ART27||2000|| |
|Medicare Safety Net introduced27||2004|| |
|ICSI added to Medicare funded ART29||2006||35 fertility centres in operation (plus associated clinics totals 68)23|
From 1962, the specialised ART available to Australian women born in 1946-51 was limited to ovulation induction and further limited by geographical access to a small number of clinics.5 Modern ART includes in vitro fertilisation (IVF), but this method was only successfully developed worldwide in the late 1970s.6,7 The first IVF child in the world, Louise Brown, was born in the UK in 19788 and the first IVF child in Australia (third in the world), Candice Reed, was born in 1980.9 Up to the late 1980s, treatment for male partners who had a low or zero sperm count was limited to the use of donor sperm.5 Technological advances in treatment for male factor infertility did not occur for a decade after the first IVF birth.10–13 The introduction of the techniques of subzonal insemination (SUZI) in 1990 and, the more successful, intracytoplasmic sperm injection (ICSI) in 1993 revolutionised ART in Australia and facilitated infertile couples to have their own genetic child and avoided using donor sperm.14
Lifetime infertility and comprehensive reproductive histories for Australian women prior to the successful development of IVF in 1980 have not been studied. The Australian Longitudinal Study on Women's Health (ALSWH) provides a unique opportunity to explore a historical population perspective on infertility. The objective of this study is to identify the prevalence of lifetime infertility in Australian women born in 1946-51 and their use of treatment relative to the successful development of in vitro fertilisation (IVF) in 1980.
Study design and setting
The ALSWH is a broad-ranging longitudinal examination of the impact of reproductive, physiological and social factors on women's health. Participants respond to mailed surveys. In 1996, Australian women from three age cohorts (born in 1921-26, 1946-51 and 1973-78) were selected from the national health insurance (Medicare) database, which contains names and addresses of all Australian citizens and permanent residents. Random sampling of the population was undertaken with intentional over-sampling of women from rural and remote areas. The methodology for the ALSWH has been described fully elsewhere and the study had ethical clearance from the Universities of Queensland and Newcastle.15,16
Women born in 1946-51 were aged 45-50 years at survey 1 (S1, 1996, n=13,715) and they were resurveyed in 1998 (aged 47-52 years at survey 2 (S2), n=12,338), in 2001 (aged 50-55 years at survey 3 (S3), n=11,200), and in 2004 (aged 53-58 years at survey 4 (S4), n=10,905). The response rates for S1 participants (n=13715) to each survey were: four surveys (S1,S2,S3,S4), 70.0%; three surveys (S1,S2,S3; S1,S2,S4; S1,S3,S4), 13.4%; two surveys (S1,S2; S1,S3; S1,S4), 10.6%; and S1 only, 6.0%.
Outcome measures: (1) infertility; (2) treatment.
Women were asked a series of fertility-related questions at S3 only (n=11,200). The format of the lead-in question was: “Some women have experienced difficulties in becoming pregnant. Have you ever had any of the following problems with fertility?” Six questions followed and requested a yes/no response: (1) “You tried unsuccessfully to get pregnant? (for 12 months or more)”; (2) “You were diagnosed as infertile by a doctor?”; (3) “Your partner was diagnosed as infertile by a doctor?”; (4) “You had treatment for infertility?”; (5) “Your partner had treatment for infertility?”; (6) “None of these”. Women who responded “yes” to questions (1) to (5) were grouped as having “had infertility”; remainder as “no infertility” including “yes” responses to question (6). The format of question (1) on infertility is consistent with the clinical definition of infertility, i.e. more than 12 months without spontaneous conception17. Among women with infertility, those who responded “yes” to questions (4) or (5) were grouped as having “used treatment” for infertility; remainder as “not used treatment.”
Socio-demographic factors at each survey included: age at participation in the survey, marital status (single, married, de-facto, ex-partnered [i.e. separated/divorced/widowed]), occupation status18 (manual/other/no paid job, trade/service, professional), highest qualification (junior high school, senior high school, trade/certificate/diploma, university); area of residence based on postcode19 (major city, inner regional, outer regional/remote).
Reproductive histories for each respondent were developed from responses to S1 and S4 and included women who had been pregnant but never given birth to a child or women who had never been pregnant. At S1 only, women were asked “How many times have you?” followed by four separate questions: a) “been pregnant”; b) “had a miscarriage”; c) “had a termination”; d) “given birth to a child”; and response options: never, once, twice, three times, four or more times. At S4, women who had ever given birth were asked to write the year of birth of each child. Additional births reported for the first time at S4 (i.e. births occurring after S1) were included. Responses were categorised into three pregnancy outcome groups: miscarriage (b), termination (c) and birth (d). Respondents who had more than one type of pregnancy outcome were described with combination reproductive histories, e.g. birth+miscarriage. The summary category of “pregnancy loss” included miscarriage (spontaneous loss) and termination (induced loss). The year of birth of each child was used to develop the age at first and last birth for women who had given birth. The year of birth was also used to develop the timing of births relative to the successful development of IVF in Australia in 1980: before IVF, <1980; early IVF, 1980-1984; later IVF, 1985+.
To take account of the over-sampling of women living in rural and remote areas, results reported as percentages were based on weighted data, and logistic regression models adjusted for area of residence. Logistic regression models were used to identify the factors associated with having reported infertility and used treatment. Data analysis was conducted using SAS software, Version 9.1.3 SP2 of the SAS System for Windows (Copyright© 2002-2003 SAS Institute Inc., Cary, NC, US).
For women born in 1946-51 (n=13,715), 92.1% had ever been pregnant and 7.9% had never been pregnant (Table 2). For women who had ever been pregnant (n=12,738): 56.5% had given birth and never had a pregnancy loss; 39.9% had given birth and had at least one pregnancy loss; 3.6% had pregnancy losses but had never given birth to a child. Almost three-quarters (73.4%) of women who gave birth had a total of two (44.5%) or three (28.9%) children. The majority of women had their first birth in their 20s and their last birth in their late 20s or early 30s. From 1985, 192 (2.4%) women aged >34 years gave birth for the first time. Among nine women who gave birth after 1996 (S1), three gave birth for the first time when they were aged >45 years (further details are excluded to maintain confidentiality).
Table 2. Lifetime reproductive histories for Australian women born in 1946-51.
|Miscarriage + termination||0.4||0.4|
|Birth + miscarriage||23.2||25.2|
|Birth + termination||8.6||9.3|
|Birth + miscarriage + termination||5.0||5.4|
| || ||35-39||3.2||35-39||13.1|
| || ||40+||0.6||40+||3.3|
| ||100.0|| ||100.0|| ||100.0|
The lifetime prevalence of infertility reported among women born in 1946-51 was 11.0%. Among women who had ever had infertility (n=1,511), the cause was diagnosed as being due to: female factors, 16.7%; male factors, 7.6%; both female and male factors, 2.8%; but for the majority the cause remained unexplained, 72.9%. Women with infertility who had used treatment (n=570) were those diagnosed with: female factors, 26.3%; male factors, 7.3%; or both female and male factors, 5.4%; but for the majority (60.9%) their infertility was unexplained.
The socio-demographic and reproductive factors of women who had infertility (n=1,511) are described in Table 3. Women had higher odds of infertility if they had reproductive histories with pregnancy losses (miscarriage and/or termination) and never given birth; had never been pregnant; or had experienced both birth and miscarriage. Among women who had given birth, those who had less than three children, especially a single child, had higher odds of reporting infertility. Women who delayed their first birth until 35+ years or last birth after 30+ years had higher odds of infertility. Women who had their first birth during the years 1980 to 1984 (early IVF development) and last birth from 1985 onwards (later IVF development) also had higher odds of reporting infertility.
Table 3. Socio-demographic and reproductive factors of Australian women born in 1946-51 who reported infertility.
| 45-46||37.8||39.4|| || || || |
| 47-48||38.7||37.0|| || || || |
| 49-50a||23.5||23.6||0.4|| || ||0.9|
| Single||4.2||1.1|| ||0.05||(0.02-0.10)||<0.0001|
| Marrieda||74.6||80.0|| || ||1.00|| |
| De-facto||5.7||4.9|| ||0.52||(0.38-0.71)||<0.0001|
| Manual/othera||21.3||13.8|| || || || |
| Trade/service||41.7||43.1|| || || || |
| Professional||37.0||43.1||<0.0001|| || ||0.05|
| Manual/other||26.7||21.1|| || || || |
| Trade/servicea||17.9||18.1|| || || || |
| Professional||44.7||52.6|| || || || |
| No partner||10.7||8.2||<0.0001|| || ||0.4|
| Junior high schoola||47.1||41.0|| || || || |
| Senior high school||17.4||17.9|| || || || |
| Trade/cert./diploma||19.6||20.6|| || || || |
| University||15.9||20.5||<0.0001|| || ||0.3|
|Area of residence|
| Major citya||83.8||83.5|| || || || |
| Inner regional||11.0||11.6|| || || || |
| Outer reg./remote||5.2||4.9||0.7|| || ||0.5|
|Reproductive factors Reproductive histories|
| Birth onlya||55.4||41.5|| ||1.00|| || |
| Miscarriage only||0.4||2.9|| ||43.5||(25.6-74.1)||<0.0001|
| Termination only||1.8||2.9|| ||9.02||(5.64-14.4)||<0.0001|
| Miscarriage+termination||0.3||0.9|| ||14.7||(5.99-36.2)||<0.0001|
| Birth+miscarriage||22.4||27.8|| ||1.69||(1.46-1.96)||<0.0001|
| Birth+termination||9.0||5.0|| ||0.68||(0.52-0.90)||0.008|
| Birth+miscarriage+termination||4.7||4.6|| ||1.08||(0.78-1.49)||0.6|
| No pregnancy||6.0||14.4||<0.0001||15.7||(11.8-20.8)||<0.0001|
|Number of children|
| 0||8.4||21.1|| ||c|| || |
| 1||8.2||17.6|| ||3.93||(3.01-5.14)||<0.0001|
| 2||41.5||35.2|| ||1.57||(1.31-1.88)||<0.0001|
| 3a||27.3||18.9|| ||1.00|| || |
| 4 or more||14.6||7.2||<0.0001||0.67||(0.52-0.86)||0.002|
|Age at first birth|
| 15-19||12.3||4.6|| ||0.80||(0.59-1.08)||0.1|
| 20-24a||40.7||22.3|| ||1.00|| || |
| 25-29||26.9||29.8|| ||1.54||(1.28-1.85)||<0.0001|
| 30-34||8.9||13.6|| ||1.38||(0.99-1.92)||0.06|
| 35-39||2.5||5.9|| ||1.93||(1.07-3.48)||0.03|
| 40+||0.2||2.4|| ||3.96||(1.47-10.6)||0.006|
| No birth||8.5||21.4||<0.0001||c|| || |
|Age at last birth|
| 15-19||1.0||0.6|| ||0.82||(0.38-1.79)||0.6|
| 20-24||15.0||8.1|| ||0.88||(0.68-1.15)||0.3|
| 25-29a||35.2||21.3|| ||1.00|| || |
| 30-34||26.6||26.9|| ||1.56||(1.23-1.97)||0.0002|
| 35-39||11.2||15.5|| ||1.60||(1.09-2.37)||0.02|
| 40+||2.5||6.2|| ||2.11||(1.21-3.67)||0.009|
| No birth||8.5||21.4||<0.0001||c|| || |
|Year of first/last birthd|
| Before/Before IVFa||61.8||40.4|| ||1.00|| || |
| Before/Early IVF||17.8||16.1|| ||1.29||(1.01-1.63)||0.04|
| Before/Later IVF||4.8||6.2|| ||1.91||(1.22-2.98)||0.004|
| Early/Early IVF||3.7||6.5|| ||1.11||(0.75-1.64)||0.6|
| Early/Later IVF||2.5||4.9|| ||1.96||(1.21-3.17)||0.006|
| Later/Later IVF||1.7||5.7|| ||1.08||(0.56-2.07)||0.8|
| No birth||7.7||20.2||<0.0001||c|| || |
Among women with infertility (n=1,511), 41.7% used treatment. Women had higher odds of using treatment for infertility if they were: younger; had a reproductive history of pregnancy loss and never given birth or had never been pregnant (Table 4). Women who delayed their first birth until aged 25+ years also had higher odds of using treatment.
Table 4. Socio-demographic and reproductive factors of Australian women born in 1946-51 who used infertility treatment.
| 45-46||36.3||43.8|| ||1.58||(1.15-2.15)||0.004|
| 47-48||37.0||36.9|| ||1.24||(0.91-1.71)||0.2|
| 49-50a||26.7||19.3||0.001||1.00|| || |
| Single||1.4||0.5|| || || || |
| Marrieda||78.3||82.4|| || || || |
| De-facto||5.4||4.3|| || || || |
| Ex-partnered||14.9||12.8||0.1|| || ||0.08|
| Manual/othera||13.6||14.0|| || || || |
| Trade/service||44.5||41.3|| || || || |
| Professional||41.9||44.7||0.5|| || ||0.9|
| Manual/other||22.9||18.7|| || || || |
| Trade/servicea||18.5||17.5|| || || || |
| Professional||50.2||56.0|| || || || |
| No partner||8.4||7.8||0.1|| || ||0.3|
| Junior high schoola||43.0||38.3|| || || || |
| Senior high school||17.4||18.6|| || || || |
| Trade/cert./diploma||21.2||19.7|| || || || |
| University||18.4||23.4||0.07|| || ||0.8|
|Area of residence|
| Major citya||82.2||85.4|| || || || |
| Inner regional||12.1||10.9|| || || || |
| Outer reg./remote||5.7||3.7||0.1|| || ||0.3|
|Reproductive factors Reproductive histories|
| Birth onlya||40.3||43.1|| ||1.00|| || |
| Miscarriage only||2.4||3.6|| ||5.62||(2.88-11.0)||<0.0001|
| Termination only||3.0||2.8|| ||2.47||(1.13-5.39)||0.02|
| Miscarriage+termination||0.5||1.5|| ||9.80||(1.91-50.2)||0.006|
| Birth+miscarriage||30.1||24.8|| ||0.86||(0.65-1.14)||0.3|
| Birth+termination||6.0||3.6|| ||0.74||(0.42-1.30)||0.3|
| Birth+miscarriage+termination||3.5||6.0|| ||1.30||(0.71-2.39)||0.4|
| No pregnancy||14.2||14.6||0.01||1.96||(1.28-3.00)||0.002|
|Number of children|
| 0||20.2||22.5|| || || || |
| 1||15.0||21.1|| || || || |
| 2||37.8||31.7|| || || || |
| 3a||19.7||17.8|| || || || |
| 4 or more||7.3||6.9||0.01|| || ||0.1|
|Age at first birth|
| 15-19||5.5||3.6|| ||1.29||(0.71-2.35)||0.4|
| 20-24a||27.6||15.2|| ||1.00|| || |
| 25-29||29.4||30.3|| ||2.05||(1.46-2.86)||<0.0001|
| 30-34||11.5||16.4|| ||3.18||(2.13-4.75)||<0.0001|
| 35-39||3.6||9.0|| ||4.29||(2.55-7.22)||<0.0001|
| 40+||2.0||2.8|| ||3.49||(1.51-8.07)||0.004|
| No birth||20.4||22.7||<0.0001||c|| || |
|Age at last birth|
| 15-19||0.5||0.8|| || || || |
| 20-24||10.6||4.7|| || || || |
| 25-29a||24.1||17.5|| || || || |
| 30-34||27.0||26.9|| || || || |
| 35-39||12.3||19.8|| || || || |
| 40+||5.1||7.6|| || || || |
| No birth||20.4||22.7||<0.0001|| || ||1.00|
|Year of first/last birthd|
| Before/Before IVFa||46.8||31.5|| || || || |
| Before/Early IVF||15.7||16.7|| || || || |
| Before/Later IVF||5.3||7.5|| || || || |
| Early/Early IVF||5.3||8.1|| || || || |
| Early/Later IVF||3.3||7.0|| || || || |
| Later/Later IVF||4.1||7.9|| || || || |
| No birth||19.5||21.3||<0.0001|| || ||0.6|
Almost all (92%) women born in 1946-51 had been pregnant and of these women almost all (96%) had given birth to one or more children. In addition to births, however, pregnancy losses were frequent events. For every 10 women who had been pregnant, five women had given birth only (and no pregnancy losses) but four women had at least one birth and one pregnancy loss and the remaining woman had a loss only (and never given birth). Among women born in 1946-51, one in 10 reported infertility and four of these women used treatment. Women who had a history of pregnancy losses only (never given birth) or had never been pregnant were the most likely to report a lifetime experience of infertility and to have used treatment. Women with infertility who reported the birth of their first child from 1980 onwards were more likely to have used treatment.
The strength of this study is in eight years of longitudinal data on a large sample of women born in 1946-51 from the general Australian population. For women who gave birth in their mid-to-late 40s, their reproductive histories were updated from responses to S4 to include the additional births. This study provides findings on the prevalence of infertility in women before the successful development of IVF in 1980. About one in 10 women experienced infertility and almost half used some form of treatment. This finding is consistent with a study of women born in 1945-49 in the UK that found of those who consulted a doctor for infertility, half had used treatment.20 Among Australian women born in 1946-51, a medical consultation for infertility was possible but access to treatment was limited.
Summary ART treatment data are available from the National Perinatal Statistics Unit (NPSU) dating back to 1979 for invasive methods only.14 From 1979 the NPSU data collection form was limited in scope until modified in 1985 to collect more information on maternal and paternal characteristics.21 From 1998, data collection began on non-invasive ART, e.g. artificial insemination with partner's and donor sperm,22 but from 2002, reporting was restricted to inseminations with donor sperm.23 The ALSWH data can fill the gaps in knowledge of women who had infertility and may have used treatment with invasive (<1979) or non-invasive methods (<1998). Furthermore, the ALSWH can also describe women who reported infertility but did not use treatment.
For women who used fertility treatment, the type and timing of treatment cannot be well-described from this study. The year of birth of each child was used to narrow the interpretation of treatment options available to infertile couples at that time. Among all women who used treatment for infertility, the treatment may have been limited to investigative and diagnostic surgery. Women who used treatment and gave birth from 1962 onwards may have used ovulation induction depending on their access to the appropriately equipped clinic. Ovarian responses to hormonal stimulation could be visualised with the use of laparoscopy but the equipment was only available from the late 1960s onwards.5 The use of hormonally stimulated cycles in Australia began in 1972 but did not result in a live birth from IVF until 1980.2 It is possible that some of the women in this study had unsuccessfully used IVF-related treatment between 1972 and 1980.
The first successful IVF cycle in Australia was in 1979 leading to a live birth in 1980.21 Women who used treatment and gave birth from 1980 onwards may have attempted IVF to become pregnant but these women cannot be identified from this study. Throughout Australia, however, there were only a small number of pregnancies and births from IVF in the early 1980s, e.g. from 1979 to 1985 there were 1,192 clinical pregnancies from IVF but only 839 live births (70%).21 Women who used treatment and gave birth from 1985 onwards were more likely to have been able to successfully use IVF for their pregnancies. From the findings of this study, there were only 192 women who gave birth from 1985 onwards when the availability of IVF was more widespread across Australia. Also, although the women reported the year of birth for each child, this study cannot identify women who adopted their children and may have reported the year of birth of their adopted child(ren). Despite these limitations, the findings from this study have shown that almost half of women who had infertility were able to access treatment.
This study provides a population perspective on infertility compared with clinical studies. Between 1980 and 1985, research was conducted into the characteristics of a sample of infertile couples undertaking IVF and those on the waiting list (WL) for treatment at one Sydney clinic.21 The results from this research found 75% of IVF and 73% of WL women were aged >30 years and 1% of IVF and 2% of WL women were aged >40 years. The causes of infertility were found to be: female factors for 74% of IVF and 56% of WL couples; male and female factors for 6% of IVF and 12% of WL couples; or unexplained infertility for 20% of IVF and 12% of WL couples. The most common female factor was tubal problems.21 Some WL couples conceived naturally while waiting for clinical assessment for IVF and 86% of WL natural pregnancies ended in live birth compared with 68% of IVF pregnancies. The other pregnancies were lost due to ectopic pregnancies, clinical abortions and stillbirths. In contrast, the findings from this study found the majority of infertility was unexplained. For women who reported a diagnosis of infertility, the most commonly reported cause was female factors; very few male partners were diagnosed as infertile. This finding contrasts with current reports that 44% of ART treatment cycles were due to male factors, either alone or in combination with female factors.24 Alternatively, the privacy surrounding infertility for women born in 1946-51 may have precluded the open disclosure of infertility (e.g. low or zero sperm counts) in their male partner.
Women who delayed their first birth until 30 years or older were increasingly more likely to have reported infertility and used treatment; this trend was higher for women who delayed their first birth until age 35+ years. The combination of data on date of birth of the women and year of birth of each child enabled the calculation of age of first and last birth that could be further categorised in relation to the successful development of IVF in 1980. In 1981, three-quarters (77%) of the Australian population supported the use of IVF by infertile married couples.25 This finding suggests the general population were aware of IVF as a potential treatment for infertility.
Increased awareness and knowledge of ART may have promoted more infertile couples to attempt treatment. It is ironic that the women who delayed their first birth until after 1980 or their mid-30s would have had increasingly more options available to them if they experienced infertility. Currently, the increased awareness and success of ICSI as a highly effective treatment for low or zero sperm counts, or failed IVF fertilisation, may have encouraged more infertile couples to use IVF in combination with ICSI. Most importantly, ICSI has provided infertile couples with the potential for their own genetic child.13 However, for women born in 1946-51, the availability of ICSI would have only been relevant to women who delayed pregnancy until after age 40 years and successful ART in this advanced maternal age group would have been very limited.
The modern trend of delayed childbearing in Australian women has been demonstrated by the absence of pregnancy in 44% of women aged 28-33 years in 2006 (i.e. ALSWH participants born in 1973-78).26 Many of these younger women would be expected to have their first pregnancies in their mid-30s, i.e. when aged 35+ years. The generational differences for women born in 1946-51 compared with women born in 1973-78 are considerable and therefore the comparable age for delayed childbearing in this study was set at 30 years. This threshold was based on historical population data that showed the majority of women born in 1946-51 completed their families in their 20s.1 In 1979, however, almost one in four births (24%) were to women aged 30+ years,27 early evidence of the trend of women choosing to delay their childbearing years.
The findings of this study indicated 11% of women born in 1946-51 remained childless; although 3% had been pregnant but had not given birth. Generational differences were apparent when compared to modern social trends. In 2006, 16% of Australian women born in 1962-66 remained childless by age 40-44 years; double the rate (8%) for women of the same age in 1981 (born in 1937-41).28 Further, a 2004 study on fertility decision making found only 4% of women aged 20-39 years reported remaining childless as their ideal number of children.29 These contrasting findings suggest at least 10% of modern women who remained childless did want to have children but were unable to achieve their goal.
Differences in infertility in older first time mothers (30+ years) for women born in 1946-51 were identified in this study and the lifetime prevalence of infertility was found to be 11%. In comparison, the prevalence of infertility in women born in 1973-78 had been shown to be 17% despite being aged <35 years.30 This difference in prevalence may be ascribed to an increased awareness of infertility and broad availability of diagnosis and treatment options for women born in 1973-78. For women born in 1946-51, however, ART was still under development and the use of treatment was dependent on an ability to access a small number of specialised clinics and without Medicare funded ART.31
As women born in 1946-51 aged into the 1980s, an awareness of infertility issues and the availability of IVF became more widespread. For the majority of women with recognised infertility, the cause of their inability to conceive remained unexplained. About one in 10 women experienced infertility and almost half used some form of treatment, especially those attempting pregnancy after 1980. Older first time mothers had an increased uptake of treatment as assisted reproductive technologies (ART) developed. This study provided evidence of the early uptake of treatment prior to 1979 when the national register of invasive ART was developed and later uptake prior to 1998 when data on non-invasive ART were first collected.
The authors are grateful to the Australian Government Department of Health and Ageing for Funding, and to the women who participated in the study.