Influence of maternal distress during pregnancy on fetal malformations.

The aim of the study was to investigate whether emotional stress in a pregnant woman might have an adverse effect in the form of malformations on fetal development. The children of 1,263 women whose applications for legal abortion in 1960 had been refused were compared with the next children born in the same delivery wards and paired matched controls were thereby obtained. Results. 1) The incidence of malformations according to the criteria established by the Swedish Register of Malformations was 1.8% in the proband series as against 1.1% in the control series. 2) The incidence of malformation increased with higher age and lower social class in the proband series, whereas no such connection was found in the control series. 3) The incidence of malformations for children of abortion applicants 25 years of age and above from social class III was 3% in the proband series as against 0.6% in the control series (P = 0.017). 4) One malformation, cleft palate, occurred at a significantly (P less than 0.01) higher incidence than in the country as a whole, four cases against the expected value of 0.69. 5) Etiological analysis showed that three of the cases were chromosomal aberrations, all of them Down's syndrome, in two cases there was a genetic background and two cases were thalidomide-induced phocomelia. In three proband children there may have been a connection with the abuse of alcohol by the mother. 6) When the chromosomal, genetic and thalidomide cases are excluded, the preponderance of malformations in the proband children of mothers 25 years of age and above belonging to social class III still remains (2.2% vs. 0.3%, P = 0.017). Conclusion. The results may be seen as support for the hypothesis that emotional stress in a pregnant woman, operationally defined by the factor unwanted pregnancy, may interfere with fetal development and result in a higher incidence of malformations. The interference may occur directly via psycho-endocrinal or autonomous mechanisms or indirectly by the way in which the woman might act in this situation of stress, e.g. attempts to provoke abortion, neglect of proper food intake, excessive smoking, or the abuse of alcohol of drugs.