HOME >> BIOLOGY >> NEWS
Embryos that implant in uterus 'late' prove more likely to die in first weeks of pregnancy

Researchers at the National Institute of Environmental Health Sciences said today that fertilized human eggs that implant late are less likely to survive.

The road to birth is a perilous one. These same NIEHS scientists showed in 1988 (New England Journal of Medicine, 319, pp 189-94) that 25 percent of fertilized eggs fail to survive six weeks -- so early that most mothers did not know they had been pregnant. Only daily urine testing for shifting traces of a hormone called hCG confirmed these pregnancies and their loss. The 25 percent early loss, when added to the clinical miscarriages that occur later, means that at least one-third of all embryos fail.

Today, the researchers reported they have found that the lost fetuses tend to be those that implant late. (NEJM, June 10.) The implantation of the fertilized egg in the wall of the uterus is necessary for the nourishment and growth of the fetus. Surviving pregnancies implanted only about one day earlier, on average, than the non-survivors: 10.5 days v. 9.1 days from fertilization to implantation. But the day-by-day trend was clear. If a fertilized egg implanted by the ninth day, it had only a 13 percent chance of loss. The risk rose to 26 percent if the implantation was on the tenth day, 52 percent on the eleventh day, and 82 percent thereafter. All three implantations after day 12 ended in early loss. There was no association in the NIEHS study between late implantation and the clinical miscarriages that occurred later in pregnancy.

NIEHS' Allen J. Wilcox, M.D., Ph.D., Donna Baird, Ph.D., and Clarice R. Weinberg, Ph.D., said their study could not determine the mechanisms at work. They speculate that embryos that implant more slowly may be imperfect in some way. Thus, they said, "the uterus may be receptive to pregnancy only during a limited time-window, shutting out defective embryos that get there too late. This would spare a mother the physiologic burden of supp
'"/>

Contact: Bill Grigg
grigg@niehs.nih.gov
301-402-3378
NIH/National Institute of Environmental Health Sciences
10-Jun-1999


Page: 1 2

Related biology news :

1. First Dinosaur Embryo Skin Discovered -- Unhatched Embryos Are First Ever Found Of Giant-Plant Eating Dinosaurs
2. Who Needs Flowers? Transgenic Plants Sprout Embryos On Leaves
3. At Lifes Most Sensitive Stage, Embryos Cope With Stress
4. University of Pittsburgh medical center among first to implant heart assist device
5. Medical implants work better when you rough them up, study finds
6. DCI donor services begins distribution of tissue implants
7. Researchers model embryo implantation and tumour metastasis in fruit flies
8. Injectable tissue implant could repair ravages of breast cancer surgery
9. Improving bone implant technology
10. Researchers envision intelligent implants
11. Rutgers researchers test polymer reliability for medical implants

Post Your Comments:
(Date:8/19/2014)... Some infants born with neonatal abstinence syndrome (NAS) ... difficult time going through withdrawal than others, but ... genetic and epigenetic (when genes are turned on ... potential factors, researchers at Boston University School of ... a first of its kind study to identify ...
(Date:8/19/2014)... in college biology and other science courses are ... ways, and now they have a new textbook ... Life Sciences," published this month by Princeton Press ... for Mathematical and Biological Synthesis (NIMBioS), teaches readers ... be used to explore and explain biological phenomena. ...
(Date:8/19/2014)... been awarded a nearly $40,000 grant from the National ... of the National Park Service (NPS) and U.S. Department ... study of the energy efficiency and cost effectiveness of ... climates. , Radiant barriers are reflective thermal insulations commonly ... thereby reducing the amount of heat emitted in the ...
Breaking Biology News(10 mins):In-utero methadone, Subutex exposure could alter gene expression, cause severe Neonatal Abstience Syndrome 2New textbook introduces undergraduates to mathematics for the life sciences 2UTSA researcher awarded $38K+ to evaluate energy efficiency options for historic homes 2UTSA researcher awarded $38K+ to evaluate energy efficiency options for historic homes 3
(Date:8/18/2014)... Diagnostics Inc. (TSX-V: SQD), a life sciences company that ... microarray diagnostics, today announced it will hold an investor ... ET.  During the call, Andrew ... SQI,s recent commercialization progress and then introduce Dr. ... to the Board of Directors of SQI and also ...
(Date:8/18/2014)... Global HIV Infection Drug Market and Pipeline Insight is ... HIV infection and the number of deaths due to AIDS ... across the globe. It has been estimated that the death ... 2013, with the rates for children being even much lower. ... rates has been the improved access to antiretroviral drugs and ...
(Date:8/18/2014)... , Aug. 18, 2014 Dyadic International, ... whose patented and proprietary technologies are used to ... for the bioenergy, bio-based chemical, biopharmaceutical and industrial ... a Registration Statement on Form 10 with the ... Logo - http://photos.prnewswire.com/prnh/20110621/CL06708LOGO ...
(Date:8/16/2014)... Arlington has received a $229,214 grant from the Walmart ... testing system that would cut the manufacturing costs of ... United States that were formerly built overseas. , The ... announcement of $4 million in awards to seven research ... in Denver made possible through the collaboration between Walmart, ...
Breaking Biology Technology:SQI Diagnostics Announces Investor Conference Call with Dr. Allan Pronovost 2SQI Diagnostics Announces Investor Conference Call with Dr. Allan Pronovost 3Global HIV Infection Drug Market Overview 2Global HIV Infection Drug Market Overview 3Global HIV Infection Drug Market Overview 4Dyadic International Files Form 10 Registration Statement 2Dyadic International Files Form 10 Registration Statement 3Dyadic International Files Form 10 Registration Statement 4UT Arlington receives Walmart, Walmart Foundation innovation grant 2UT Arlington receives Walmart, Walmart Foundation innovation grant 3
Cached News: