This is extracted from a report of a joint meeting of the Forum on Maternity and the Newborn of the Royal Society of Medicine with the Royal College of Midwives and the Association of Community Based Maternity Care, held on Thursday 24th April 2003.

Antenatal anxiety and its effects on the baby.
From Professor Tom O'Connor , Departments of Child and Adolescent Psychiatry and Social, Genetic and Developmental Psychiatry, Institute of Psychiatry, London.

Previous animal investigations link antenatal stress with a range of persistent behavioural abnormalities in the offspring. In non-human primates antenatal stress is linked with neuromotor deficits, hypotonia, inattention, atypical social behaviour and enhanced stress reactivity, persisting into adult life (Schneider et al. 2000). Pregnancies in malnourished Netherlands mothers in World War 2 have been linked to increased major depression in the adult lives of their offspring (Brown et al.2000).
Most physiological explanations tell us that the stress response system resides in the hypothalamic-pituitary-adrenal (HPA) axis, but additional explanations are likely. The maternal stress hormone cortisol is known to correlate with fetal cortisol levels (Gitau et al. 1998); this mediates increased uterine artery tone, impairing blood flow through the placenta, with effects which only occur in the fetus from 22-24 weeks gestation (Teixeira et al. 1999). This timing of stress in pregnancy may be crucial - mixed handedness, believed to be due to impaired neurological development, is apparent at about 3½ yrs in the children of mothers whose anxiety occurred at about 18 weeks gestation. Antenatal stress is also associated with poor obstetric outcomes, e.g. premature birth, low birth weight (Copper et al. 1996).

The purpose of the current study is to examine whether the stress effect is also found in humans through middle childhood and beyond. Evidence will be reviewed, with findings derived from a large UK community sample. The implications of women's antenatal anxiety effect will be considered.

The current study is based on the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective, community-based study that has followed a cohort of more than 10,000 women representative of the UK population from early pregnancy. An estimated 85 to 90% of those eligible took part. The average age was 28 years; 45% were primiparae, while 6% already had two children. Self-report measures of maternal anxiety and depression were assessed at 18 and 32 weeks in pregnancy and at 8 weeks and 21, 33, 47, and 81 months postnatally by questionnaire, using Crown-Crisp for anxiety and the Edinburgh Postnatal Depression Scale (EPDS) for depression. This is ongoing.

Children's behavioural and emotional problems have been assessed by parent report using the Strengths and Difficulties Questionnaire (SDQ; Goodman 1997) at ages 47 and 81 months so far; the children are now about 11 years old. The information generated is controlled for obstetric factors (birth weight for gestational age, parity, mode of delivery, smoking and alcohol use, and pregnancy problems) and for postnatal anxiety and depression; measures of socio-economic adversity such as crowded accommodation and education are also taken into account.

Analysis of this research using odds ratios shows that children whose mothers experienced high levels of anxiety in late pregnancy exhibited higher rates of behavioural and emotional problems at 81 months of age, evidence that such anxiety has a programming effect on the fetus which lasts at least until middle childhood (Barker 1995). Furthermore, the effect at 81 months is comparable to that obtained at 47 months, and was roughly equal in boys and girls; this suggests the kind of persistent effect proposed in the animal literature, and it is independent of maternal postnatal anxiety. There is in fact a need for greater synthesis of animal and human investigation of stress and development.

Anxiety in pregnancy strongly predicts postnatal depression. Since postnatal depression is frequently preceded by depression in pregnancy, and antenatal anxiety is now shown to be associated with behavioural and emotional problems in children, then the effects which have been attributed to postnatal depression may be explained by antenatal anxiety. The additive – antenatal and postnatal - effects on children at age 4 years are demonstrated to a degree which is clinically meaningful. The prediction from the antenatal period when postnatal assessments are covaried is inconsistent with simple rater bias and genetic transmission explanations.

The need for further research is apparent, the following questions requiring answers:

·        Are the psychological and physiological effects of antenatal anxiety maintained at later assessments? ·        Is the HPA axis a mediating mechanism? ·        What postnatal factors modify the effects of antenatal anxiety? ·        Are interventions to reduce antenatal anxiety effective in preventing adverse outcomes? ·        What is the interplay between the HPA axis-mediated effect of antenatal anxiety and genetic vulnerability?

This information requires us to pay as much attention to anxiety in pregnancy as to depression after it: antenatal stress is a public health concern.

References
Schneider ML, Moore CF. (2000) Effect of antenatal stress on development: A non-human primate model. In: C. Nelson (Ed.) Minnesota Symposium on Child Psychology. New Jersey: Erlbaum pp. 201-243

Gitau R, Cameron A, Fisk NM, Glover V. (1998) Fetal exposure to maternal cortisol. Lancet 352: 707-708.

Teixeira J, Fisk N, Glover V. (1999) Association between maternal anxiety in pregnancy and increased uterine artery resistance index: cohort based study. BMJ 318: 153-157.

Brown AS, van Os J, Driessens C, Hoek HW, Susser ES. (2000) Further evidence of relation between prenatal famine and major affective disorder. Am J Psychiatry 157: 190-195.

Copper RL, Goldenberg RL, Das A, Elder N, Swain M, Norman G, et al. (1996) The preterm prediction study: Maternal stress is associated with spontaneous preterm birth at less than thirty-five weeks' gestation. Am J Obstet Gynecol 175:1286-1292.

Barker DJ. (1995). The fetal origins of adult disease. Proc R Soc Lond B Biol Sci 262:37-43.

Goodman R. (1997) The strengths and difficulties questionnaire: A research note. J Child Psychol Psychiatry 38:581-586.