Reduced infant birthweight consequent upon maternal exposure to severe life events.
OBJECTIVE
To investigate the association between maternal exposure to severe life events and fetal growth (birthweight and small for gestational age). Stress has been associated with adverse pregnancy outcome.


METHODS
Mothers of 1.38 million singleton live births in Denmark between January 1, 1979 and December 31, 2002 were linked to information on their spouses, parents, siblings, and older children. Exposure was defined as death or serious illness in a relative during pregnancy or in the 6 months before conception. Linear regression was used to examine the effect of exposure on birthweight. Log-linear binomial regression was used to assess the effect of exposure on small for gestational age.


RESULTS
Death of a relative during pregnancy or in the 6 months before conception reduced birthweight by 27 g (adjusted estimate -27 g, 95% Confidence Interval (CI) = -33, -22). There was a significant association between maternal exposure to death of a relative and risk of a baby weighing below the 10th percentile (adjusted relative risk (RR) = 1.17, 95% CI = 1.13, 1.22) and 5th percentile (adjusted RR = 1.22, 95% CI = 1.15, 1.29).


CONCLUSIONS
Mothers exposed to severe life events before conception or during pregnancy have babies with significantly lower birthweight. If this association is causal, the potential mechanisms of stress-related effects on birthweight include changes in lifestyle due to the exposure and stress-related dysregulation of the hypothalamic-pituitary-adrenal axis during pregnancy.
Khashan
Ali S
AS
Centre for Women's Mental Health Research, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK. ali.khashan@postgrad.manchester.ac.uk
McNamee
Roseanne
R
Abel
Kathryn M
KM
Pedersen
Marianne G
MG
Webb
Roger T
RT
Kenny
Louise C
LC
Mortensen
Preben Bo
PB
Baker
Philip N
PN
D000328:Adult; D001601:Bereavement; D015331:Cohort Studies; D003643:Death; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight / Q000523:psychology*; D007231:Infant, Newborn; D008016:Life Change Events; D008297:Male; D008875:Middle Aged; D009035:Mothers / Q000523:psychology*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000523:psychology; D012307:Risk Factors; D017678:Sex Distribution; D013315:Stress, Psychological / Q000453:epidemiology* / Q000523:psychology