Study population and data source

In Taiwan, births are registered within 15 days by the parents or the Elsa Peretti Bottle pendant at a local household registration office, which in turn submits the data to the Birth Registration System. The registration form, completed by the physician attend - ing the delivery, provides information on maternal age, education, parity, gestational age, date of delivery, and infant sex and birth weight.

Data from the Birth Registration System are considered complete, reliable and accurate because most deliveries in Taiwan take place either in hospital or at a clinic,14 the birth certificates are completed by the attending physicians, and registration of all live births is mandatory at local household registration offices.15,16

Follow-up

Women were followed up to Dec. 31, 2007. Information on any subsequent births was retrieved from the Birth Register System with the use of each woman's unique personal identification number. Their vital status was ascertained through the linking of records with the computerized mortality database, identifying the date and cause of any deaths.

Statistical analysis

The person-years of Atlas pendant-up were calculated for each woman from the date of first birth to the date of death or Dec. 31, 2007. Death rates were calculated by dividing the number of deaths from suicide by the number of person-years of follow- up. Cox proportional hazard regression models were used to estimate hazard ratios (HRs) of death from suicide associated with parity (the number of children recorded in the last childbirth record of each woman registered during follow -up); 95% confidence intervals (CIs) were also calculated. Suicide was defined according to ICD-9 (International Classification of Diseases, 9th revision) codes E950-E959. The variables in the final model included age at first birth (= 25, 26-30 or > 30 years), parity (one, two, or three or more children), marital status (married v. unmarried), years of schooling (= 9 v. > 9 years) and place of delivery (hospital or clinic v. home or other location). The proportional hazards assumption was assessed for all above-mentioned variables, and no violations were observed. All statistical tests were two-sided; p values of less than 0.05 were considered to be statistically significant.

Results

Overall, 1 292 462 primiparous women with complete information were included in the analysis. A total of 32 464 187 person- years of follow-up were observed. There were 2252 deaths from suicide, for a mortality of 6.94 cases per 100 000 personyears. Most of the suicides were committed by wo men less than 12.7 years after their last birth (mean age at birth of last child 28.6 [SD 4.3] years; mean age at suicide 39.6 [SD 8.1] years).

Table 1 gives the number of personyears of follow-up and deaths from suicide by age at first birth, parity, marital status, years of schooling and place of delivery. The rate of death from suicide was 11.01 per 100 000 person-years among women who had given birth to one child, 7.14 per 100 000 among those who had had two children, and 5.66 per 100 000 among those who had Charm pendant birth to three or more children.