BackgroundThe rate of macrosomia (birth weight≥4, 000 g) increased over the past four decades in many parts of the world. Macrosomia is associated not only with higher risks of maternal and neonatal complications but also with health risks in adulthood. We examined trends in neonatal macrosomia and large-for-gestational-age (LGA) births among singleton, live, term and postterm births (≥37 complete weeks' gestation) in southeast China from 1994 to 2005 and explored possible causes of the temporal trends.MethodsData from Perinatal Health Care Surveillance System in 12 cities and counties in southeast China were analyzed for trends in birth weight, neonatal macrosomia and LGA from 1994 to 2005. A total of 594, 472 singleton live births were included. We conducted multiple logistic regression analyses to relate these trends to changes in maternal and pregnancy characteristics.ResultsThe rate of macrosomia rose from 6.00% in 1994 to 8.49% in 2000 and then levelled off to 7.83% in 2005. Similar trends were observed in mean birth weight. The incidence of LGA births increased continuously from 13.72% in 1994 to 18.08% in 2000, but the LGA rate remained relatively stable from 2002 to 2005. There was a decrease in gestational age and a significant increase in frequency of prelabor caesarean delivery from 1994 to 2005. In an adjusted multivariable model, the increase in LGA rate from 1994 to 2000 was associated with increasing net gestational weight gain, maternal age, maternal height and maternal education. But they didn't fully explain the increase. The trends of 2002-2005 LGA declined after adjusted for maternal and neonatal characteristics.ConclusionsIn southeast China, the incidence of macrosomia increased from 1994 to 2000 was mainly related to increasing net gestational weight gain. The incidence of macrosomia has levelled off in recent years partly due to increasing use of prelabor caesarean delivery and earlier delivery and partly due to moderation of gestational weight gain.

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We evaluated survival motor neuron 2 (SMN2) and neuronal apoptosis inhibitory protein (NAIP) gene copy distribution and the association of copy number with survival in 232 Chinese spinal muscular atrophy (SMA) patients. The SMN2 and NAIP copy numbers correlated positively with the median onset age (r = 0.72 and 0.377). The risk of death for patients with fewer copies of SMN2 or NAIP was much higher than for those with more copies (P < .01). The survival probabilities at 5 years were 5.1%, 90.7%, and 100% for 2, 3, and 4 SMN2 copies and 27.9%, 66.7%, and 87.2% for 0, 1, and 2 NAIP copies, respectively. Our results indicated that combined SMN1-SMN2-NAIP genotypes with fewer copies were associated with earlier onset age and poorer survival probability. Better survival status for Chinese type I SMA might due to a higher proportion of 3 SMN2 and a lower rate of zero NAIP.

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