Measuring the waiting time to pregnancy with the use of a retrospective questionnaire in the course of the GGS-PL study entitled ‘generations and gender survey’

Krzysztof Tymicki

Abstrakt
Paper analyses relationship between age at first attempt to conceive and apparent fecundability defined as detection of a pregnancy. The purpose of the analysis is to account for biological consequences of age shifts on fertility schedules in contemporary low fertility societies. Age specific decrease in fecundability might lead to increase in waiting time to pregnancy measured as interval between onset of deliberate attempt to conceive and actual pregnancy. Analysis is based on retrospective measurement of waiting time to pregnancy (WtP) implemented in GGS-PL survey. Analyses reveal significant increase in WtP among women aged 35+ and only a slight increase for those aged 30–35. Due to increase in age at first reproduction we expect that share of couples having prolonged WtP or those remaining childless might increase in the future especially among social groups which are in the avant-garde of fertility postponement.
Paper addresses an issue whether increase in age at first attempt to conceive among females might have an effect on likelihood of conception. Since postponement of reproduction seems to be almost universal feature of contemporary developed societies paper aims at measuring safe limits of postponement in which conception will not be endangered by a significant drop in fecundity. Analysis uses data on waiting time to pregnancy (WtP) to measure an impact of reproductive ageing on length of interval between first attempt to conceive and conception. Methodology of measuring WtP has been implemented in Polish GGS survey. Analyses reveal significant increase in WtP among women aged 35+, slight increase among females aged 30–35 and no decrease for younger females. Results suggest that postponement of reproduction beyond age 35 might decrease chances for achieving desired number of children during lifetime and ultimately increase observed proportion of childless females.
Paper addresses an issue whether decrease in female fecundity (reproductive senescence) during life cycle might have an influence on realization of fertility intentions. Increasing age at first attempt to conceive might translate into lower than planned number of offspring due to divergence between lifecycle of modern females and changes in fecundity over the life course. We use waiting time to pregnancy (WtP) to account for impact of reproductive ageing on length of interval between first attempt to conceive a child and actual pregnancy. This retrospective methodology reflects definition of sub-fertility and infecundity as number of months with regular unprotected intercourse ending (or not) in pregnancy. Methodology of measuring WtP has been implemented in Polish GGS survey and contains questions about infertility and number of menstrual cycles needed for conception. Analyses reveal significant increase in WtP among women aged 35+, slight increase among females aged 30–35 and no decrease for younger females. Estimates of infertility yields around 6% for females and around 3% for males (as declared by respondents). These results are in line with results of other studies which suggest that postponement of reproduction beyond age of 35 might influence probability of conception (as well as transition to higher parities) and increase chance of remaining childless. Taking into account age patterns of fertility in Poland, reproductive senescence might not have a great impact on realization of fertility intentions on the level of general population. However, due to increase in age at first reproduction we expect that share of couples having problems with conception (prolonged WtP) might increase in the future especially among social groups which are in the avant-garde of fertility postponement.
Słowa kluczowe: bezdzietność, ciąża, czas oczekiwania na ciążę, dzietność, płodność, odraczanie macierzyństwa, zapłodnienie
References

Olsen J. et al., Measuring time to pregnancy. Methodological issues to consider, “Human Reproduction” 1998; 13: 1751–1753.

Boldsen J.L., Schaumburg I., Time to pregnancy: A model and its applications, “Journal of Biosocial Science”1990; 2 2(2): 255–262.

Joffe M. et al., Studying time to pregnancy by use of a retrospective design, “American Journal of Epidemiology” 2005; 162: 115–124.

Joffe M. et al., A time to pregnancy questionnaire designed for long term recall: Validity in Oxford, England, “Journal of Epidemiology and Community Health”1995; 49 (3): 314–319.

Baird D.D. et al., Reporting errors in time-to-pregnancy data collected with a short questionnaire, “American Journal of Epidemiology” 1991; 133 (12): 1282–1290.

Dick M.-L.B. et al., Self-reported difficulty in conceiving as a measure of infertility, “Human Reproduction” 2003; 18: 2711–2717.

te Velde E.R. et al., The effect of postponement of first motherhood on permanent involuntary childlessness and total fertility rate in six European countries since the 1970s’, “Human Reproduction” 2012; 27 (4): 1179–1183.

Billari F.C. et al., Social age deadlines for the childbearing of women and men, “Human Reproduction”2010; 26 (3): 1–7.

Sobotka T. (ed.), Postponement of Childbearing and Low Fertility in Europe, Dutch University Press, Amsterdam 2004.

Sobotka T. et al., Postponement and recuperation in cohort fertility: Austria, Germany and Switzerland in a European context, “Contemporary Population Studies” 2011; 36 (2–3): 417–452.

Jóźwiak J., Kotowska I.E., Panelowe badanie przemian relacji między pokoleniami, w rodzinie oraz między kobietami i mężczyznami: Generacje, rodziny i płeć kulturowa GGS-PL, “Studia Demograficzne” 2011; 159 (1): 99–106.

Zegers-Hochschild F. et al., The International Committee for Monitoring Assisted Reproductive Technology (ICMART) and the World Health Organization (WHO) Revised Glossary on ART Terminology, “Human Reproduction” 2009; 24 (11): 2683–2687.

Habbema J.D., Collins J., Leridon H., Evers J.L., Lunenfeld B., te Velde E.R., Towards less confusing terminology in reproductive medicine: A proposal, “Human Reproduction”2004; 19 (7): 1497–1501.

Jenkins J. et al., European Classification of Infertility Taskforce (ECIT) Response to Habbema ‘Towards Less Confusing Terminology in Reproductive Medicine: A Proposal, “Human Reproduction”2004; 19 (12): 2687–2688.

Gnoth C. et al., Definition and prevalence of subfertility and infertility, “Human Reproduction” 2005; 20 (5): 1144–1147.

Jensen T.K. et al., Time trends in waiting time to pregnancy among Danish twins, “Human Reproduction”2005; 20 (4): 955–964.

Organization, WHO, Infecundity, Infertility, and Childlessness in Developing Countries, Demographic and Health Surveys (DHS) Comparative Reports 9, 2004.

Van de Kaa D.J., Europe’s second demographic transition, “Population Bulletin”(Population Reference Bureau) 1987; 42 (1).

Kohler H.-P. et al., The emergence of lowest-low fertility in Europe during the 1990s, “Population and Development Review” 2002; 28 (4): 641–680.

Becker G.S. (ed.), A Treatise on Family, Harvard University Press, Cambridge 1998.

Ahn N., Mira P., A Note on the changing relationship between fertility and female employment rates in developed countries, “Journal of Population Economics” 2002; 15: 667–682.

Billari F., Kohler H.-P., Patterns of low and lowest-low fertility in Europe, “Population Studies” 2004; 58 (2): 161–176.

Beets G. et al., Medical Complications of Aging Fertility, in: Population and Family in the Low Countries 1993: Late Fertility and Other Current Issues, Beets G. (ed.), NIDI/CBGS Publication Berwyn, Pennsylvania/Amsterdam, Netherlands 1994: 1–23.

Bianchi F.O., Campana A., The end of fertility: Age, fecundity and fecundability in women, “Journal of Biosocial Science” 1994; 26 (3): 349–368.

Engelhardt H., Prskawetz A., On the changing correlation between fertility and female employment over space and time, “European Journal of Population”2004; 20 (1): 35–62.

Skirbekk V., Fertility trends by social status, “Demographic Research” 2008; 18 (5): 145–180.

Pollak R.A., Cotts-Watkins S., Cultural and econommic approaches to fertility: Proper marriage or mesaliance?, “Population and Development Review” 1993; 19 (3): 467–496.

Preston S.H. et al. (ed.), Demography. Measuring and Modelling Population Processes, Blackwell Publishers, Oxford 2001.

Testa M.R., Women’s Fertility Intentions and Level of Education: Why are They Positively Correlated in Europe?, European Demographic Research Papers, Vienna Institute of Demography of the Austrian Academy of Sciences, Vienna 2012: 3.

Kotowska I.E., Jóźwiak J., Panelowe badanie przemian relacji między pokoleniami, w rodzinie oraz między kobietami i mężczyznami: generacje, rodziny i płeć kulturowa GGS-PL, “Studia Demograficzne” 2011; 159 (1): 99–106.

Mynarska M., Kto planuje mieć dzieci w Polsce do 2015 roku?, “Studia Demograficzne”2011; 159 (1): 75–98.

Toulemon L., Testa M.R., Fertility intentions and actual fertility: A complex relationship, “Population and Societies” 2005; 415: 1–4.

Sobotka T., The diverse faces of the second demographic transition in Europe, “Demographic Research” 2007; 19 (8): 171–224.

Régnier-Loilier A., Vignoli D., Fertility intentions and obstacles to their realization in France and Italy, “Population” 2011; 66 (2): 361–389.

Bongaarts J., Feeney G., On the quantum and tempo of fertility, “Population and Development Review”1998; 4 (1): 105–132.

Wood J.W., Fecundity and natural fertility in humans, in: Oxford Reviews of Reproductive Biology, Milligan S.R. (ed.), Oxford University Press, Oxford 1989, 11: 61–109.

O’Connor K.A. et al., Declining fecundity and ovarian ageing in natural fertility populations, “Maturitas”1998; 30 (2): 127–136.

Sartorius G.A., Nieschalg E., Paternal age and reproduction, “Human Reproduction Update” 2010; 16 (1): 65–79.

Schmidt L. et al., Demographic and medical consequences of the postponement of parenthood, “Human Reproduction Update”2012; 18 (1): 29–43.

Kaplan H. et al., A Theory of human life history evolution: Diet, intelligence, and longevity, “Evolutionary Anthropology”2000; 9 (4): 156–185.

Hill K.A., Hurtado M., The evolution of premature reproductive senescence and menopause in human females, “Human Nature”1991;2 (4): 313–350.

Shanley D.P., Kirkwood T.B.L., Evolution of human menopause, “BioEssays” 2001; 23: 282–287.

Hawkes K., Grandmothers and the evolution of human longevity, “American Journal of Human Biology” 2003; 15 (3): 380–400.

Wood J.W. (ed.), Dynamics of Human Reproduction: Biology, Biometry, Demography, Aldine de Gruyter, New York 1994.

te Velde E.R., Pearson P.L., The variability of female reproductive ageing, “Human Reproduction Update” 2002; 8 (2): 141–154.

ESHRE C.W.G., Social determinants of human reproduction, “Human Reproduction”2001; 16: 1518–1526.

Leridon H., Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment, “Human Reproduction” 2004; 19 (7): 1548–1553.

Liu K., Case A., Advanced reproductive age and fertility, “Journal of Obstetrics and Gynaecolgy”2011; 33 (11): 1165–1175.

Van Geloven N.F. et al., Can we distinguish between infertility and subfertility when predicting natural conception in couples with an unfulfilled child wish?, “Human Reproduction”2013; 28 (3): 658–665.

Bongaarts J., A framework for analysing the proximate determinants of fertility, “Population and Development Review”1978; 4: 105–132.

Bongaarts J., The measurement of wanted fertility, “Population and Development Review”1990; 16 (3): 487–506.

Tymicki K., Zamierzenia prokreacyjne a możliwość ich realizacji w kontekście czynników biologicznych, “Studia Demograficzne” 2013; 164 (2): 9–31.

Linn S. et al., Delay in conception for former pill users, “The Journal of the American Medical Association”1982; 247 (5).

Farrow A. et al., Prolonged Use of Oral Contraception Before a Planned Pregnancy is Associated with a Decreased Risk of Delayed Conception, “Human Reproduction”2002;17 (10): 2754–2761.

Hassan M.A.M., Killick S.R., Is previous use of hormonal contraception associated with a detrimental effect on subsequent fecundity?, “Human Reproduction”2004; 19 (2): 344–351.

Czasopismo ukazuje się w sposób ciągły on-line.
Pierwotną wersją czasopisma jest wersja elektroniczna publikowana w internecie.