WEATHER AND CHILDBIRTH - A FURTHER SEARCH FOR RELATIONSHIPS

Previous attempts to find relationships between weather and parturitio n (childbirth) and its onset (the beginning of labor pains) have revea led, firstly, limited but statistically significant relationships betw een weather conditions much colder than the day before, with high wind s and low pressure, and increased onsets; and secondly, increased numb ers of childbirths during periods of atmospheric pressure rise (highly statistically significant). To test these findings, this study examin ed weather data coincident childbirth data from a hospital at Bryan-Co llege Station, Texas (for a period of 30 cool months from 1987 to 1992 ). Tests for (1) days of cold fronts, (2) a day before and a day after the cold front, (3) days with large temperature increases, and (4) de creases from the day before revealed no relationship with mean daily r ate of onset. Cold days with high winds and low pressure had significa ntly fewer onsets, a result that is the opposite of previous findings. The postulated relationship between periods of pressure rise and incr eased birth frequency was negative, i.e., significantly fewer births o ccurred at those times - again, the opposite of the apparent occurrenc e in an earlier study. The coincidence of diurnal variations in both a tmospheric pressure and frequency of childbirths, was shown to account for fairly strong negative associations between the two variables. Th is same reasoning might explain the positive association found in an e arlier study. A comparison has been made between childbirth and onset as the response variable, and the advantage is emphasized of using dat a from women whose labor is not induced.