Young women are the most vulnerable to postpartum mental illness: A retrospective cohort study in UK primary care.

BACKGROUND

Whilst childbirth is a leading cause of mental illness in women, how it affects women at different ages is unknown.

AIMS: We examine whether the effect of childbirth on mental illness varies at different ages.

METHODS

From 2,657,751 women identified from a UK population-based primary care database, 355,864 postpartum periods, with no history of mental illness, were matched on year of birth and general practice to 1,420,350 non-postpartum periods. Cox regression models were used to compare incident mental illness between postpartum and non-postpartum periods. These were measured using hazard ratios (HR) and hazard ratios adjusted for parity and prior pregnancy loss (aHR).

RESULTS

Strong evidence is presented that the effect of livebirth on mental illness was age-dependant for depression (p <0·001), anxiety (p 0·048) and affective psychosis (p 0·031). In 15-19 year olds, depression was over seven times more likely to occur in postpartum periods than non-postpartum periods (aHR 7·09, 95%CI 6·65-7·56); twice the effect in women overall (aHR 3·24 95%CI 3·18-3·29). 15-19 year olds were 50% more likely to develop anxiety in postpartum periods than non-postpartum periods (aHR 1·52, 95%CI 1·38-1·67), with little effect in women overall (aHR 1·07 95%CI 1·04-1·10). Livebirth had over twice the effect on affective psychosis in women aged 15-24 (15-19 year olds: aHR 2·71 95%CI 1·23-5·97; 20-24 year olds: aHR 2·79 95%CI 1·68-4·63) compared to women overall (aHR 1·66, 95%CI 1·29-2·14).

CONCLUSIONS

Younger women are far more vulnerable to the effect of childbirth on their mental health, particularly depression and anxiety.