BMC Public Health 2007, 7:268 http://www.biomedcentral.com/1471-2458/7/268 Table 1: Occurrences of pregnancy risk factors and complications (%)in the study groups Reference (6–18 visits) (n = 23137) % No visits (n = 270) % 1–5 visits (n = 207) % Pregnancy risk factors Age < 18 years Age > 35 years Unmarried Unemployed Education High Average Low Primiparity Multiparity Prior miscarriage Prior induced abortion Prior fetal death Overweight History of infertility Smoking Alcohol consumption Chronic illness Diabetes Chronic hypertension Pregnancy complications Prolonged gravidity Low haemoglobin Pre-eclampsia Chorio-amnionitis Placental abruption Placenta previa Meconium-stained AF Abnormal FHR during delivery 0.63 11.03 17.48 16.97 24.74 45.71 21.70 40.52 0.41 9.78 9.78 1.79 19.04 6.30 5.88 3.45 5.13 2.25 1.28 3.77 1.53 2.76 1.37 0.70 0.41 10.56 16.76 1.85 ** 14.07 30.74 *** 16.67 18.51 * 34.07 *** 22.96 43.70 0.37 16.67 7.78 1.48 22.17 5.93 8.52 3.70 4.44 1.85 1.11 4.44 0.74 3.72 4.83 *** 4.44 *** 0.37 10.98 19.02 0.97 12.56 33.33 *** 16.43 16.43 ** 36.23 ** 20.77 41.55 1.45 * 17.88 12.56 2.42 18.93 4.35 13.04 *** 6.76 ** 5.80 1.93 0.97 2.08 2.90 3.86 9.66 *** 6.28 *** 0.48 13.13 15.20 AF = amniotic fluid; FHR = fetal heart rate; *p < 0.05, **p < 0.01, ***p < 0.001 Table 2 shows unadjusted odds ratios (OR:s) and the results of logistic regression analyses, the adjusted odds ratios of adverse pregnancy outcome in the study groups. Before these analyses, non-attenders and under-attenders statistically significantly more often had low 5-minute Apgar scores, preterm births and low birth weight infants. Additionally, the risk of fetal death was high in both the study groups, as well as was the risk of neonatal death. Controlling for confounding factors in logistic regression analyses did not diminish the observed risks. Table 3 summarizes the odds ratios of pregnancy risk fac- tors and outcomes reported in earlier studies concerning inadequate maternity care, compared with the present data. The comparison suggests that when high frequencies of women receive insufficient antenatal care, the magni- tude of associating risks is diluted. Discussion Regardless of easily accessible and high quality maternity care a small minority of pregnant women chose not to use it. The outcome of their pregnancies was poor, although delivery took place in hospital, in conditions of modern obstetric care. Specifically, the risk of placental abruption, intrauterine infections, preterm birth, low birth weight and even intrauterine fetal death and neonatal death were found to be statistically higher than in the general obstet- ric population who attended routine antenatal care. Clin- ically, under-attending antenatal care appeared to be a significant contributor to low birth weight, and this asso- ciation was chiefly the result of preterm delivery, not to growth restriction. Only a few studies concerning pregnancy outcome in women under-attending antenatal care have been pub- Page 4 of 8 (page number not for citation purposes)