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:5/14/2015)... , May 14, 2015  Verificient ... identity verification and online remote proctoring, announced ... software-as-a-service (SaaS) company and creator of the ... of the two companies will benefit from ... Canvas. As a fully integrated ...
(Date:5/11/2015)... , May 11, 2015  Through a well-rounded UAS ... had a strong showing at AUVSI,s Unmanned 2015 ... representatives of Ohio,s UAS industry met ... abroad from all points along the UAS ecosystem. ... Coalition,s (DDC) Vice President for Aerospace Rich Knoll . ...
(Date:5/10/2015)... , May 11, 2015 Fingerprint Cards ... FPC1025 and FPC1155 from the distributor World Peace Industrial Group ... distributors in Asia . Deliveries are planned ... be used by smartphone manufacturers in China ... the communicated revenue guidance of + 1 000 MSEK for 2015. ...
Breaking Biology News(10 mins):Verificient and Instructure Announce Alliance Partnership to Provide Online Proctoring for K-12 and Higher Education Institutions 2Ohio Flies High at Unmanned '15, Sets Stage for Ohio UAS Conference 2Fingerprint Cards Receives Touch Fingerprint Sensor Order of SEK 235 Million 2
(Date:5/26/2015)... 26, 2015 WORMS, GERMANY – ... Co. (NYSE: GRA) announces that its manufacturing facility ... (GMP) certification from EXCiPACT™, an independent organization that ... , All three Grace facilities that ... excipient silica gels have now received GMP certification, ...
(Date:5/26/2015)... --  Intrexon Corporation (NYSE: XON ), a leader ... Ph.D., Senior Vice President and Head of Intrexon,s Health Sector, ... Wednesday, June 3 rd , at 1:30 p.m. Eastern Time ... . About Intrexon Corporation Intrexon ... with Better DNA ™ to create biologically-based products that ...
(Date:5/26/2015)... , May 26, 2015   PDI , ... today announced that Oakwood Healthcare in ... the winning entry in Delivering the ... who display excellence in building collaborative relationships between ... in healthcare facilities.  Oakwood Healthcare,s ...
(Date:5/26/2015)... 26, 2015 Mr. Kevin Xu , President ... Barack Obama and President Bill Clinton ... loss of Dr. Rongxiang Xu , Kevin,s father. ... ahead of his time, Dr. Xu,s commitment to the advancement ... legacy that will not be forgotten. As a renowned life ...
Breaking Biology Technology:CORRECTION: Grace European Facility Receives GMP Excipient Certification for SYLOID® FP Silica Gel 2Intrexon to Present at the Jefferies 2015 Global Healthcare Conference 2PDI Announces Winner in Delivering the Difference Contest 2PDI Announces Winner in Delivering the Difference Contest 3Dr. Rongxiang Xu, Beyond A Legend 2
Cached News: