Reply: Increased reproductive success of women after prenatal undernutrition?
0
Hubert Department of Global Health, Emory University
,
Atlanta, GA
,
USA
1
Mailman School of Public Health, Columbia University
,
New York, NY 10032
,
USA
2
Department of Clinical Epidemiology
,
Biostatistics and Bioinformatics
,
Academic Medical Centre
,
Meibergdreef 9, 1105 AZ Amsterdam
,
The Netherlands
3
Rebecca C. Painter
,
Rudi G.J. Westendorp, Susanne R. de Rooij, Clive Osmond, David J.P. Barker and Tessa J. Roseboom
Painter RC, Westendorp RGJ, de Rooij SR, Osmond C, Barker DJP, Roseboom TJ. Increased reproductive success of women after prenatal undernutrition. Hum Reprod Advance Access published July 25, 2008. doi:10.1093/humrep/den274. Lumey LH, Stein AD. In utero exposure to famine and subsequent fertility: the Dutch famine birth cohort study. Am J Publ Health 1997;87: 1962 - 1966.
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Sir,
In a recent report in this journal (Painter et al., 2008) based on the
follow-up of men and women born in the former Wilhelmina Gasthuis
Hospital, Amsterdam between November 1943 and February 1947
and interviewed at age 58 years, women with famine exposure in
utero but not men reported greater reproductive success compared
with unexposed controls, with more offspring, more twins, a smaller
likelihood to remain childless, and an earlier age of starting
reproduction. The study included 473 women, of whom 204 met the study
definition of famine exposure.
We wish to bring to the attention of your readers our previous
study in this population in which similar questions were addressed
(Lumey and Stein, 1997). We interviewed the women at age 43
years. We reported no significant differences between those with
famine exposure in utero and those born before or conceived after
the famine with respect to age at menarche, age at first delivery,
interpregnancy interval or age at later deliveries, completed family
size, childlessness, age at first marriage or proportion married or
menopause status. This study included 700 women, of whom 322
met our definition of famine exposure.
Painter et al. expanded the earlier study sample to include additional
women controls and men, but restricted follow-up to those residents
in or close to Amsterdam, while our study recruited women living
anywhere in Holland. The 204 women with famine exposure
in utero in the Painter study, defined as births between 7 January
1945 and 8 December 1945, are essentially a subset of the 322
women with famine exposure in utero in our study, defined as births
between 1 February 1945 and 31 December 1945.
Some possible explanations for the inconsistent results come
to mind. The Painter subset of exposed women may not correctly
represent the available sample; there are small differences
between the two studies with respect to the dates of birth of
the reference sample and to categorization of exposure to the
famine; or, study outcomes reported by women when interviewed
at age 43 years are different compared with findings obtained at
age 58 years. With the available data, these explanations can all
be explored.
We are puzzled why the previous study was not discussed
by Painter et al. The omission of previous findings in this study
population does a disservice to the reader. The two studies should
be interpreted together to understand the experience of this cohort
of women and the long-term consequences of exposure to famine
during gestation.
References
Reply: Increased reproductive
success of women after prenatal
undernutrition?
Sir,
We regret not having referred to the report by Lumey and Stein.
Their study and our study both examine the effects of prenatal
exposure to the Dutch famine on reproductive outcomes among
people born in the Wilhelmina Gasthuis in Amsterdam, The
Netherlands. Both the studies recruited people living anywhere in
the Netherlands. The studies differ with respect to the definitions of
exposure, dates of birth of control groups and measures of
reproductive success collected, as well as the age at which these were
collected. Fig. 1 of both papers shows age at delivery of the first child
according to prenatal famine exposure. The findings are remarkably
similar: in both studies the age at delivery of the mothers exposed
to famine in utero tends to be younger than the age of mothers who
were not exposed. In Lumey and Steins study, the percentage of
women who remained childless was 13% (48 of 378) in the unexposed
group compared with 8% (35 of 437) in the exposed groups, these
figures are 14 and 8% in our study. These results suggest that women
who were prenatally exposed to famine are less likely to be childless.
We compared women exposed to famine in utero with those who
were not exposed, while Lumey and Stein compared women exposed
to famine in late, mid or early gestation to those who were not
exposed. If we analyze our data using this approach, the effects of
exposure in early (1.5, 95% CI 1.1 2.1) and mid gestation (1.3,
95% CI 1.0 1.6) are statistically significant, whereas the effect of
exposure in late gestation is not sta (...truncated)