“…The data used in this nested case–control study were collected for the period 2000–2012 from the Health and Welfare Data Science Center (HWDC), Ministry of Health and Welfare, Taiwan, which is linked to the National Birth Registry, National Death Certification Registry, and National Health Insurance Research Database (NHIRD) by national identification numbers. In Taiwan, all birth and death information must be recorded in the Birth Registry and Death Certification Registry, and this information has been evaluated and determined to be valid and complete 18 19 20 . The Birth Registry contains information on various birth characteristics that was filed by hospitals after maternal delivery, including sex, birth weight, gestational age, whether the birth was single or multiple, birth order, and the physical condition of the mother and infant.…”