Table.

Abnormalities in 206 embryos studied

Abnormality	No of embryos
None	121
Non-viable pregnancies
Anembryonic; intact gestation sacs	33
Ruptured sac (no embryo present)	15
Resorbing*	15
Structural abnormalities
Neural tube defect:
Open posterior neuropore	5†
Open anterior neuropore	2†
Encephalocele	3†
Abdominal wall defects‡	6†
Facial cleft	3†
Failure of body axis rotation severely disorganised (no somites)	2†
Hydropic	1
Congested	1
TRAP twins (one without a head)	1
Total No of abnormal embryos	39
Total No of potentially non-viable pregnancies	72

TRAP=twin reversed arterial perfusion.  

^*Embryos that were disproportionately small compared with their gestation sac and contained necrotic tissue.  

^†Including some embryos with multiple abnormalities.  

^‡Part of the gastrointestinal tract outside the abdominal wall inconsistent with physiological herniation.