Twin births in Singapore: a population-based study using the National Birth Registry.

INTRODUCTION: Twin studies are a most effective method to analyse gene and environment interactions. Using data from the Singapore National Registry of Births and Deaths (SNRBD), this paper describes the number of twin and multiple births among different ethnic populations in Singapore. MATERIALS AND METHODS: All births recorded in the SNRBD from 1 January 1986 to 31 December 2001 were analysed. Outcomes measured were twin and triple birth rates (per 1000 maternities) of the 3 main ethnic groups in Singapore (Chinese, Malays and Asian Indians). Further outcomes were calculated using Weinberg's differential rule to estimate the number of monozygotic and dizygotic twins. RESULTS: Overall twin birth rates have steadily increased across all ethnic groups (7 to 9/1000). The largest increase in multiple births among the ethnic groups were twins born to Asian Indian fathers (6.9 to 9.9/1000) and Malay mothers (5.9 to 9.8/1000). A significant difference in birth rates between the ethnic groups was found during the years 1994 to 1997, where Chinese parents had the lowest multiple birth rates and Asian Indians the highest. Estimation and ratios of monozygotic and dizygotic twin births differed among the ethnic groups: Asian Indians had the highest ratios, followed by the Chinese and, lastly, the Malays. CONCLUSION: The SNRBD has provided an overview of multiple births in Singapore, although the establishment of a national twin register would enable more detailed analysis of genetic and environmental effects in multiple births.

Antidepressants during pregnancy and lactation: defining exposure and treatment issues.

The majority of psychiatric illness onsets early in an individual's life, typically before or during the reproductive years. The increased incidence of major depression, dysthymia, and panic disorder in women compared with men underscores the likelihood that the clinician will encounter the clinical dilemma of medication use during pregnancy and lactation. The emergence of specialized clinics at several academic centers specifically to investigate and address issues in Perinatal psychiatry illustrates this conundrum best. The extant literature derived from human studies suggests that maternal mental illness and stress may have an adverse impact on obstetrical outcome. These clinical investigations are complemented by a burgeoning series of laboratory studies in rodents and nonhuman primates, showing the profound deleterious impact of maternal stress during the perinatal and neonatal periods on the development of the offspring. Data obtained from pharmaceutical registries, cohort studies, toxicology centers, and case series have consistently failed to show an adverse effect associated with in utero antidepressant exposure. Despite these advances and treatment guidelines proposed by the various academic leaders, investigations describing the extent of fetal/neonatal exposure, clinical methods for minimizing such exposure, and clinical treatment guidelines that include the physiological impact of pregnancy are sparse. The available literature shows distinct pharmacokinetic profiles of the selective serotonin reuptake inhibitors in placental passage and breast milk. Preliminary animal studies have shown higher than expected central nervous system concentrations associated with exposure during pregnancy and mathematical modelling for calculating infant exposure when nursing. The clinical import of these data will require further investigations of central nervous system bioavailability in the fetus and neonate.

Automated purchasing: Forecasts to determine stock levels and print orders.

An automated purchasing system to optimize inventory levels of frozen foods, including meat items, while minimizing stock outages, was developed and implemented. Menu item forecast data were coordinated with on-hand quantities to automate the calculation of order quantities and printing purchase requisitions. The model selected also incorporated: (a) Safety stock level, (b) accumulated forecasts, and (c) accumulated orders already placed. The project was smoothly integrated into an on-going computer-assisted management system. All programs functioned as planned; computer documents were complete and accurate. The system design was retained for use in the foodservice operation.