Gary Jeng

Bio: Gary Jeng is an academic researcher from Centers for Disease Control and Prevention. The author has contributed to research in topics: Assisted reproductive technology & Population. The author has an hindex of 22, co-authored 28 publications receiving 3193 citations.

Low and very low birth weight in infants conceived with use of assisted reproductive technology.

Abstract: Background The increased risk of low birth weight associated with the use of assisted reproductive technology has been attributed largely to the higher rate of multiple gestations associated with such technology. It is uncertain, however, whether singleton infants conceived with the use of assisted reproductive technology may also have a higher risk of low birth weight than those who are conceived spontaneously. Methods We used population-based data to compare the rates of low birth weight (≤2500 g) and very low birth weight (<1500 g) among infants conceived with assisted reproductive technology with the rates in the general population. Results We studied 42,463 infants who were born in 1996 and 1997 and conceived with assisted reproductive technology and used as a comparison group 3,389,098 infants born in the United States in 1997. Among singleton infants born at 37 weeks of gestation or later, those conceived with assisted reproductive technology had a risk of low birth weight that was 2.6 times that i...

Trends in Multiple Births Conceived Using Assisted Reproductive Technology, United States, 1997–2000

Abstract: Objective. To examine trends in multiple births conceived using assisted reproductive technology (ART) in the United States between 1997 and 2000 and to estimate the proportion of all US multiple births attributable to ART use. Methods. We analyzed population-based data of 109 519 live-born infants who were conceived in the United States using ART and born between 1997 and 2000 and population-based data of 15 856 809 live-born infants who were delivered in the United States between 1997 and 2000. Multiple birth rates (the number of live-born infants delivered in multiple gestation pregnancies per 1000 live births) and the proportion of all US multiple births attributable to ART were evaluated. Results. The twin rate for ART patients increased between 1997 and 2000, reaching 444.7 per 1000 live births in 2000, whereas the triplet/+ rate declined substantially from 134.3 to 98.7 per 1000 live births from 1997–2000. From 1997–2000, the proportion of multiple births in the United States attributable to ART increased from 11.2% to 13.6%, whereas the proportion attributable to natural conception decreased from 69.9% to 64.5%. In 2000, the proportion of triplet/+ births attributable to ART and to natural conception was 42.5% and 17.7%, respectively. The contribution of ART to multiple births increased substantially with maternal age, from 11.6% for triplet/+ infants born to women aged 20 to 24 to 92.8% for women aged 45 to 49 years. Conclusions. The contribution of ART to twin birth rates continues to increase, but the contribution of ART to triplet/+ birth rates has declined.

Live-birth rates and multiple-birth risk using in vitro fertilization.

Abstract: ContextTo maximize birth rates, physicians who perform in vitro fertilization (IVF) often transfer multiple embryos, but this increases the multiple-birth risk. Live-birth and multiple-birth rates may vary by patient age and embryo quality. One marker for embryo quality is cryopreservation of extra embryos (if embryos are set aside for cryopreservation, higher quality embryos may have been available for transfer).ObjectiveTo examine associations between the number of embryos transferred during IVF and live-birth and multiple-birth rates stratified by maternal age and whether extra embryos were available (ie, extra embryos cryopreserved).Design and SettingRetrospective cohort of 300 US clinics reporting IVF transfer procedures to the Centers for Disease Control and Prevention in 1996.SubjectsA total of 35,554 IVF transfer procedures.Main Outcome MeasuresLive-birth and multiple-birth rates (percentage of live births that were multiple).ResultsA total number of 9873 live births were reported (multiple births from 1 pregnancy were counted as 1 live birth). The number of embryos needed to achieve maximum live-birth rates varied by age and whether extra embryos were cryopreserved. Among women 20 to 29 years and 30 to 34 years of age, maximum live-birth rates (43% and 36%, respectively) were achieved when 2 embryos were transferred and extra embryos were cryopreserved. Among women 35 years of age and older, live-birth rates were lower overall and regardless of whether embryos were cryopreserved, live-birth rates increased if more than 2 embryos were transferred. Multiple-birth rates varied by age and the number of embryos transferred, but not by whether embryos were cryopreserved. With 2 embryos transferred, multiple-birth rates were 22.7%, 19.7%, 11.6%, and 10.8% for women aged 20 to 29, 30 to 34, 35 to 39, and 40 to 44 years, respectively. Multiple-birth rates increased as high as 45.7% for women aged 20 to 29 years and 39.8% for women aged 30 to 34 years if 3 embryos were transferred. Among women aged 35 to 39 years, the multiple-birth rate was 29.4% if 3 embryos were transferred. Among women 40 to 44 years of age, the multiple-birth rate was less than 25% even if 5 embryos were transferred.ConclusionsBased on these data, the risk of multiple births from IVF varies by maternal age and number of embryos transferred. Embryo quality was not related to multiple birth risk but was associated with increased live-birth rates when fewer embryos were transferred.

Dna methylation and human disease

Abstract: DNA methylation is a crucial epigenetic modification of the genome that is involved in regulating many cellular processes. These include embryonic development, transcription, chromatin structure, X chromosome inactivation, genomic imprinting and chromosome stability. Consistent with these important roles, a growing number of human diseases have been found to be associated with aberrant DNA methylation. The study of these diseases has provided new and fundamental insights into the roles that DNA methylation and other epigenetic modifications have in development and normal cellular homeostasis.

Births: final data for 2002.

Abstract: OBJECTIVES: This report presents 2002 data on U.S. births according to a wide variety of characteristics. Data are presented for maternal demographic characteristics including age, live-birth order, race, Hispanic origin, marital status, and educational attainment; maternal characteristics (medical risk factors, weight gain, tobacco, and alcohol use); medical care utilization by pregnant women (prenatal care, obstetric procedures, complications of labor and/or delivery, attendant at birth, and method of delivery); and infant characteristics (period of gestation, birthweight, Apgar score, abnormal conditions, congenital anomalies, and multiple births). Also presented are birth and fertility rates by age, live-birth order, race, Hispanic origin, and marital status. Selected data by mother's State of residence are shown, as well as data on month and day of birth, sex ratio, and age of father. Trends in fertility patterns and maternal and infant characteristics are described and interpreted. METHODS: Descriptive tabulations of data reported on the birth certificates of the 4.022 million births that occurred in 2002 are presented. Denominators for population-based rates are derived from the 2000 U.S. census. Rates for 1991-2001 may differ from those published previously based on the 1990 U.S. census. RESULTS: There were 4,021,726 live births in 2002, essentially unchanged from 2001. The birth rate, fertility rate, and total fertility rates all declined 1 percent in 2002. The teenage birth rate dropped 5 percent, reaching another record low. The birth rates for women 20-24 years declined, whereas the rate for women 25-29 years was stable. The birth rate for women 30-34 years declined, but the rate for women 35-44 years continued to rise. Births to unmarried women changed very little. Smoking during pregnancy was down again. The timeliness of prenatal care continued to improve. The cesarean delivery rate climbed to the highest level ever reported in the United States (26.1 percent) and the rate of vaginal birth after previous cesarean plummeted 23 percent to 12.6 percent. Preterm and low birthweight levels both rose for 2002. The twin birth rate continued to climb, but the rate of triplet/+ births was down slightly.