The Probability of Giving Birth among Women Who Were Born Preterm or with Impaired Fetal Growth: A Swedish Population-based Registry Study

Abstract

The primary aim of this study was to investigate whether women born prematurely or with impaired fetal growth have a reduced probability of giving birth. Using Swedish population-based registries, the authors identified 148,281 women born in 1973-1975 for follow-up until 2001. Of these women, 4.1% were born preterm and 0.32% very preterm, 0.29% were born with a very low birth weight, and 5.4% were small for gestational age. Outcome measures were the hazard ratios for giving birth during the study period. Adjustments were made for socioeconomic factors. Very-low-birth-weight women displayed a reduced probability of giving birth (hazard ratio = 0.74, 95% confidence interval: 0.60, 0.91), most apparent among women aged 25 or more years. There were also tendencies of reduced hazard ratios of giving birth among women born preterm or very preterm in this age interval. Women born small for gestational age (below -2 standard deviations) seemed to be more likely to have given birth (hazard ratio = 1.09, 95% confidence interval: 1.04, 1.14), but when a more extreme group of small-for-gestational-age women (below -3 standard deviations) was defined, the association was less evident (hazard ratio = 1.04, 95% confidence interval: 0.94, 1.16). The results suggest that very-low-birth-weight women and, possibly, women born preterm or very preterm have a reduced probability of giving birth, while the results regarding small for gestational age are less clear.

Social and biological determinants of reproductive success in Swedish males and females born 1915–1929

“…3 or the probability of giving birth within an observation period e.g. 4 rather than direct and detailed measurements of survival and reproduction over the whole life-course. Using historical data can preserve the ability to trace long-term outcomes 2 , but tends to be compromised by poor data quality as there is often substantial uncertainty regarding the completeness and accuracy with which mortality and/or fertility was recorded.…”

“…In the medical literature, recent years have seen some attention to how low birth weight, premature birth and other indicators of adverse health in early life predict long-term health outcomes, including a reduced probability of reproduction 4,9 . The effects such biological markers of early development have received less attention from evolutionary anthropologists.…”

“…as mediated by adult health or cognitive abilities). Investigating these mechanisms further may shed light onto why preterm birth appears to reduce the probability of giving birth in more recent cohorts of males 9 and perhaps (although the evidence is more conflicting) also in females 4,9 .…”

Intergenerational Cohort Study of Preterm and Small-for-Gestational-Age Birth in Twins and Singletons

“…The improved neonatal and pediatric care of children born preterm/SGA has led to an increased number of surviving children who reach reproductive age (Kyser et al, 2012). Intrauterine growth restriction is known to cause long-term effects not only on health, including cardiovascular disease and diabetes (Barker, 1998;Ekholm Selling et al, 2008;Hack, 2006;Hodgson, 2006;Mellemkjaer et al, 2003;Quinn et al, 2010;Yuan et al, 2001), but also on their reproductive outcome (deKeyser et al, 2012;Ekholm et al, 2005;Ibáñez et al, 2002;Swamy et al, 2008).…”

Developmental influences on fertility decisions by women: an evolutionary perspective

“…A shorter gestational age, which is also associated with increased childhood mortality, has been associated with a lower probability of finding a partner and having children [105,107,108]. Strikingly, in this apparent disruptive physiology, women who are born small for gestational age are more likely to give birth at a younger age [105,109]. Similarly, women exposed to the Dutch Hunger Winter of 1944-1945 famine during pregnancy had more children, an earlier age at first birth, were more likely to have twins and less likely to remain childless [110].…”