Prospective and retrospective examination of an easily applicable score to predict the probability of premature birth defined by weight

Abstract

An easily applicable score to predict the risk of prematurity (Tab. I) (defined by weight) is examined prospectively (scoring during 6 th month of pregnancy) in 431 and retrospectively (obtained after delivery) in 1183 pregnancies. In the prospective study (Tab. II) 71.4% of all pregnancies resulting in babies below 2501 g exceed the proposed 50 points risk probabilty limit whereas only 18.7% of pregnancies with babies of more than 3000 g do so. Excluding pregnancies with 20 or more risk points and excellent prenatal care (8 or more consultations) - which should change the outcome of risk-pregnancies - the percentages are 77.8% and 12.2% respectively (Tab. III). Pregnancies resulting in babies with birth weight of 2501 g -2750 g exceeded the limit in 38.9% and those with babies of 2751 g-3000 g in 20.7%. If 60 risk points are used as the limit the percentages for more than 3000 g until less than 2501 g would be 8.2%, 6.9%, 33.3% and 66.7%. In the resrospective study (Tab. V) 14.7% of all pregnancies with babies above 3000 g exceeded the 50 risk points limit compared with 57.2 of those with babies below 2501 g. Excluding pregnancies with 20 or more risk points and excellent prental care the percentages are 7.6 and 59.4 respectively. In the retrospective study the influence of the quality of prenatal care by the number of consultations (3-4; 5-7; 8 or more) is clearly demonstrable: Pregnancies with more than 50 risk points resulted in 80.7%, 57.1% and 19.8% depending on the quality of care in babies below 2501 g. Pregnancies with 31-50 risk points did so in 47.2%, 20.4% and 11.8%. In 334 women the score could be applied twice, in the 6th month and at delivery. Comparing both scores it was found that only 1.8% of these women exceeded the 50 risk points limit by events occurring after the 6th month scoring (Tab. IV). The score, simple enough to be applied by nurses and midwives, seems to be able to select 77.8% of pregnancies resulting in babies below 2501 g already during the 6th month of pregnancy, i.e. early enough for preventive measures to be taken that decrease the frequency of underweight births by three quarters.