Anaemia in pregnancy--a cross-sectional study in Singapore.
To determine the prevalence and predictors of anaemia in pregnancy in Singapore. Hospital based case controlled study. National University Hospital, between January-December 1993. All women delivered at the National University Hospital, Singapore in 1993 had their haemoglobin estimated. If it was less than 11 gm/dl, blood was taken to establish the cause of anaemia. Data was also collected with regard to their antenatal progress, and factors predisposing to anaemia in pregnancy. Logistic regression, Chi-square test, Fischer's exact test, Mantel-Haenszel test were used to assess the relationships between categorical variables. The prevalence of anaemia at delivery was 15.3%. The most common cause of anaemia in pregnancy was due to iron deficiency (81.3%). The occurrence of anaemia in pregnancy is related to the socio-economic status of the women. Multiparous women of the lower socio-economic class who tend to book late in pregnancy were found to have the highest risk of anaemia. Multivariate logistic regression analysis revealed iron prophylaxis, haemoglobin level at booking, race and previous history of anaemia in earlier pregnancy as important predictors of anaemia at delivery. The odds of anaemia for a woman not on therapy was about 11 times that of her counterpart on prophylactic iron therapy (95% CI 8.76-14.13). A 55% reduction in odds of anaemia was estimated per 1 gm% increase in haemoglobin level at booking. As compared to Chinese, Malays and Indians who experienced significant increase in odds of anaemia of 95% and 58% respectively. Further, a pregnant woman with a previous history of anaemia is 2.6 times as likely to be anaemic, as compared with one without history of anaemia. Except for a higher incidence of preterm delivery, there was no other statistically increased risk of complications in the antepartum, intrapartum or postpartum periods. There was no difference in the incidence of antepartum haemorrhage/operative deliveries, postpartum haemorrhage, low birthweight, intrauterine growth retardation and neonatal outcome. The study confirms that iron deficiency anaemia is the most common cause of anaemia in pregnancy and is a major health problem in developing and developed countries.