Table 5.

Outcomes of singleton fetuses (n = 18,882) at birth in the Hokkaido cohort

Outcomes	Number	Percent	95% CI
Miscarriagea	200	1.1	0.9–1.2
Artificial abortionb	52	0.28	0.21–0.36
Stillbirthc	60	0.32	0.24–0.41
Live birth	18,570	98.3	98.2–98.5
Preterm birthd	923	4.9	4.6–5.2
Moderate preterm birth	795	4.2	3.9–4.5
Very preterm birth	112	0.59	0.49–0.71
Extremely preterm birth	47	0.24	0.18–0.33
Low birth weighte	1693	9.0	8.6–9.4
Very low birth weight	268	1.4	1.2–1.6
Extremely low birth weight	204	1.1	0.9–1.2
Macrosomiaf	190	1.0	0.9–1.2
Small for gestational ageg	1308	7.0	6.7–7.4
Term small for gestational ageh	1211	6.5	6.2–6.9
Small for reference fetal weighti	814	4.8	4.5–5.2

Missing data were excluded from the calculation

CI confidence interval

^aMiscarriage was defined as the loss of a pregnancy at <22 completed gestational weeks

^bAn abortion brought about intentionally at <22 completed gestational weeks

^cStillbirth was defined as the birth of a dead fetus at ≥22 completed gestational weeks

^dPreterm birth was defined as birth at 22–36 completed gestational weeks. Preterm birth was subdivided into three categories of prematurity: moderately preterm (32–36 completed weeks), very preterm (28–31 completed weeks), and extremely preterm (22–27 completed weeks)

^eLow birth weight, very low birth weight, and extremely low birth weight were birth weights <2500, <1500, and <1000 g, respectively

^fMacrosomia is birth weight ≥4000 g

^gSmall for gestational age infants had birth weights less than the 10th percentile of the reference birth weight estimated by using gestational age, sex, and parity

^hTerm small for gestational age infants were the small for gestational age infants among the term birth neonates

ⁱSmall for reference fetal weight infants had birth weights <1.5 standard deviations of the reference ultrasound-based fetal weight estimated from gestational age, sex, and parity