Obstetric complications as a risk factor for bipolar affective disorder: Comparison with matched non-psychiatric controls

McNeill, Yvonne Louise (2005) Obstetric complications as a risk factor for bipolar affective disorder: Comparison with matched non-psychiatric controls. MSc(R) thesis, University of Glasgow.

Abstract

Background Family studies have consistently shown that the morbid risk of bipolar affective disorder (BP) in the relatives of BP probands is higher compared with that of the general population. However, concordance rates of less than 100% in identical twins indicate that in addition to genetic factors, environmental factors must contribute to the aetiology of BP. One environmental factor found to be associated with the subsequent development of several psychiatric illnesses is obstetric complications (OCs). A systematic review of OCs as a risk factor for the development of BP found that there was insufficient data to support the hypothesis that OCs are a risk factor for BP and thus more rigorous systematic studies with large enough sample sizes to avoid a type II error are required. Aims To determine whether OCs are more common in individuals with BP compared to matched non-psychiatric controls. Hypotheses 1. More individuals with BP will have experienced OCs compared to matched controls. 2. Individuals with BP will have experienced a greater number of OCs compared to matched controls Method The methodology of this study involved linking the Scottish Morbidity Records (SMR) held at Information Statistics Division Scotland. The psychiatric inpatients register (SMR4) was used to identify all individuals born in Scotland between 1969 and 1974 who were subsequently admitted in Scotland with a diagnosis of BP. A link was established between this register and the maternity inpatient and day case register (SMR2) which provided all relevant obstetric information and a matched control for each for the BP probands. A case-control comparison was carried out for the prevalence of each pregnancy, labour, delivery and neonatal complication and the mean number of complications experienced in each period. Results A similar number of cases and controls had experienced OCs and the mean number of complications experienced by individuals in each group did not differ. A case control comparison of the individual obstetric events recorded on SMR2 however indicated that mothers of females with BP had significantly more previous pregnancies (1.8, sd 2.0 vs. 1.4, sd 1.5) and therefore a significantly higher parity (1.6, sd 1.9 vs. 1.2, sd 1.4) than mothers of controls. Further analysis of this variable indicated that the female offspring of mothers with a parity of three or more were at significantly increased risk of BP (OR 2.2, 95% Cl 1.3-3.9). Furthermore the offspring of mothers who had had more than one x-ray during their pregnancy were at increased risk of BP (OR 4.2, 95% Cl 1.2-14.7). Comparison of the mean birthweight of each diagnostic group indicated that the male probands were significantly smaller at birth (3282 grams vs. 3398 grams) however low birth weight (<2500 grams) did not significantly increase the risk of BP (OR 1.6, 95% Cl 0.7-3.4). Conclusion This large prospective study failed to support the hypotheses that significantly more individuals with BP experienced OCs and that the mean number of OCs experienced by the individuals with BP was significantly greater. The principal research implication of this study is the need for more systematic studies reporting on the frequency of specific OCs in addition to reporting the number of subjects in each group who experienced any definite OCs.

• Item Type: Thesis (MSc(R))
• Qualification Level: Doctoral
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Scott, Prof. Jan and Espie, Prof. Colin
• Date of Award: 2005
• Depositing User: Mrs Monika Milewska-Fiertek
• Unique ID: glathesis:2005-30867
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 08 Oct 2018 09:13
• Last Modified: 02 Sep 2021 10:26
• URI: https://theses.gla.ac.uk/id/eprint/30867

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