Pregnancy Hazards Associated with Low Maternal Body Mass Indices

EDITORIAL COMMENT": There are few obstetric hospitals that have computerized their clinical data such that maternal weight and obstetric results can be compared. The Mater Mothers' Hospital in Brisbane is one such institution. This paper seems to establish that the lower socioeconomic, light-weight woman is at greater risk of producing a lightweight or very light-weight infant and also is at increased risk of delivering a premature infant using the old definition of less than 2,500 g. Light-weight mothers also had an increased incidence of pregnancy anaemia, infants with low Apgar score and an increased perinatal mortality rate. Interestingly in some populations the light-weight woman is also at increased risk of gestational diabetes (El-Shafei AMet al. Incidence and Severity of Gestational Diabetes in Bahrain and Australia. Aust NZ J Obstet Gynaecol 1989; 29:204–208). We agree with the authors that more data is required about low maternal weight, and low weight gain in pregnancy, and the associated obstetric results. Summary: Analysis of the obstetric records of 41,955 public patients with singleton pregnancies at the Mater Misericordiae Mothers' Hospital, South Brisbane, showed a significant association (increased odds ratio) between Low Maximum Pregnancy Maternal Body Mass Index (Quetelets Index 20–24.6 and maternal anaemia, the use of intravenous tocolysis, low birth-weight (< 1,500 g and < 2,500 g), low Apgar score (< 7 at 5 minutes) and perinatal mortality. Parturients with a Very Low Body Mass Index (Quetelets Index < 20) had even greater odds ratios in respect of the above obstetric hazards. Both the Low and Very Low Body Mass Index cohorts had significantly reduced risks of having hypertension (both essential and preeclamptic) or having their labours induced or augmented. The results are presented as odds ratios with confidence limits after controlling for the potentially confounding covariables of maternal age, parity, smoking habits and gestational age.