TOXAEMIA OF PREGNANCY AND OBESITY

THE purpose of the present investigation was to discover whether and to what extent obesity predisposes to toxaemia of pregnancy. It was based on routine antenatal records which described 2,522 mothers who had four th‘ings in common; they had recently given birth to a single child; they were systematically screened for toxaemia during the second half of this pregnancy ; their heights were recorded and they had been weighed at least once in the nonpregnant state. Some of the records came from antenatal clinics in Northamptonshire and some from clinics in Surrey. The Northamptonshire records were originally compiled during 1952 and have been described elsewhere (Clokie, 1959). In this more or less random series, which included all mothers with the necessary records (1,228), the weights were ascertained six to eight weeks after delivery. The Surrey records were originally compiled during 1955-56 and were later collected by the Public Health Department (Soutar, 1959) for the purpose of comparing all premature births (ie., under 5$ pounds) with an equal number of controls (over 54 pounds). From this nonrandom set of records we obtained 1,294 mothers (643 from the premature and 651 from the control group) with “stated” pre-pregnancy weights and 818 mothers (402 from the premature and 4 16 from the control group) who were weighed again six to eight weeks after delivery. In each series we have used as the yardstick of obesity the height (in inches) divided by the cube root of the weight (in pounds). This H t 3 2 / W index (H/W for short) distinguishes between women who were over or under weight for their height but needless to say does not distinguish between fat and other tissues. We shall, however, assume that the women with high indices (over 13.2) were always thin and that women with low indices (less than 12-0) were usually obese. A diagnosis of toxaemia was based on blood pressure readings and other entries in the antenatal notes and if the appropriate records were missing the case was discarded. Each individual included in the investigation was placed in one of the following toxaemia grades: