Fetal programming is a term used to describe what happens when the fetus is exposed to changes in the intrauterine environment during pregnancy which have long lasting effects on the fetus which alter the physical health and developmental trajectory of the exposed child.  This hypothesis proposes that if a particular insult occurs during any sensitive period of in utero development, it can alter the development of the fetus, so that the child is at increased risk of disease later on in life.  Researchers have been particularly interested in the impact of  maternal anxiety and depression on the developing fetus.  

Many studies have shown exposure to maternal depression and anxiety during pregnancy may be associated with various outcomes in the child, including delays in cognitive and motor development,  altered infant temperament and behavioural stress reactivity.  It is important to note, however, that although there are associations, these do not necessarily infer causality. Other researchers have argued that these findings may be the result of residual confounding variables such as birth weight and socioeconomic status .  

One method of parsing out these various factors is to compare the strength of associations between an exposure among mothers and offspring outcomes and the same exposure among fathers and offspring outcomes.  If there is a direct biological effect of maternal mental health on fetal development and subsequent outcomes, then the association between antenatal stress exposure and offspring would be stronger in mothers than in fathers. On the other hand, a stronger or equivalent association with fathers may be suggestive of genetic or other environmental factors or an effect of unmeasured residual confounders.

Using data from the ALSPAC population cohort which includes measures of antenatal depression and anxiety in both the mothers and fathers, the researchers measured the association between these symptoms and anxiety disorders in the children assessed at 18 years of age.  The results were adjusted for confounding variables including parental postnatal depression and anxiety.

The children born to women with antenatal depression (measured at 18 weeks gestation) had an increased risk of anxiety disorders at 18 years of age (11.1% vs. 6.2%; adjusted odds ratio [aOR] 1.75 ).  The same increased risk was evident in the children born to mothers reporting high levels of antenatal anxiety (9.2% vs. 6.6%; OR 1.43).  No such associations were found with paternal antenatal depression or anxiety.

These findings support the hypothesis that fetal programming may account, at least in part, for the increased vulnerability to anxiety disorders in children exposed to maternal depression and anxiety in utero.  The next big question is whether treating the mother’s anxiety and/or depression during pregnancy may have positive downstream effects and whether this intervention may decrease the child’s vulnerability to psychiatric illness later on.

Ruta Nonacs, MD PhD

Capron LE, Glover V, Pearson RM, Evans J, O’Connor TG, Stein A, Murphy SE, Ramchandani PG.  Associations of maternal and paternal antenatal mood with offspring anxiety disorder at age 18 years.  J Affect Disord. 2015 Nov 15;187:20-6.