The mucosa of the cervical canal (endocervix) is composed of a single layer of mucin-secreting columnar epithelium, which lines both the surface and the underlying glandular crypts. Isolated neuroendocrine epithelial cells of argentaffin type or argyrophil type are admixed with the normal endocervical cells.
Air travel Pregnant travellers can normally travel safely by air. In the absence of medical or obstetrical complications, pregnant women can safely fly up to 36 weeks gestation. Most airlines restrict travel in late pregnancy or may require a written confirmation from a physician.
1 This prevents blood clots from forming in the legs and pelvis.  Keep your travel plans as flexible as possible. Problems might develop at the last minute and you might have to cancel your trip. Unless it is absolutely necessary, do not plan any trips during the third trimester of your pregnancy.