Description: Segment 1 Geoffrey Chamberlain introduces Professor Frank Hytten. Hytten, referring to various graphs and charts to illustrate his points, discusses the reasons for the abrupt fall in plasma osmolality during the first six weeks of pregnancy. He shows how drinking a glass of water in pregnancy has a totally different effect on osmolality levels than in a non-pregnant person - he makes it clear that this is something very unusual to pregnancy. Time start: 00:00:00:00 Time end: 00:06:34:10 Length: 00:06:34:10 Segment 2 Hytten goes on to explain the reasons for the low osmolality levels of pregnancy and discusses water retention. Chamberlain discusses with Hytten why it is that pregnant women are so thirsty when they have such low osmolality. Time start: 00:06:34:10 Time end: 00:10:06:20 Length: 00:03:32:10 Segment 3 Hytten talks about the storage of water by pregnant women which is, on average around six litres. Oedema, or an excess of water, is normal in pregnancy, particularly during the last trimester. However, generalised oedema occurs much earlier in pregnancy and can reach eight litres in excess of expected levels. Hytten argues that although this may be uncomfortable for the mother, it causes no health risks or damage to the unborn child. He talks in detail about his research in Aberdeen in this area. Time start: 00:10:26:20 Time end: 00:17:20:20 Length: 00:06:54:00 Segment 4 Here Hytten moves on to discuss the sites in the body where excess fluid is stored. He shows, using graphs and electron microscopies, how it is distributed generally all over, probably in the connective tissue ground substance. He stresses again that although the swelling which occurs due to fluid retention has been frequently thought of as something to be treated medically, it is a normal phenomenon of pregnancy and therefore not a medical concern. Time start: 00:17:20:20 Time end: 00:21:50:20 Length: 00:04:30:00