BMC Public Health 2007, 7:322 http://www.biomedcentral.com/1471-2458/7/322 the further study of substance abuse in pregnancy, along with the mothers of two children who were adopted and 27 women who only had brief contact with SCWC while living temporarily in Kristiansand, serving time in prison, or staying in women's crisis centres. The medical records at SCWC revealed no difference in the group that only had brief contact with SCWC compared to the group that con- tinued treatment at the clinic in terms of substance abuse and socio-economic issues. One mother gave birth to three children and eight mothers gave birth to two chil- dren during the period, one of which had twins. Of these pregnancies, only the first is included in the study. In all, 60 mothers kept in contact with SCWC from pregnancy until the child was two years of age or placed in alternative care. In 2004 they were asked to be part of this follow-up study. One mother declined to participate, giving a total of 59 mothers in the study (Figure 2). We used the diagnosis register of the regional hospital to analyse how large a percentage of the substance abusing pregnant women in the region were admitted to the SCWC. The diagnosis indicating drug use is included in the discharge summary if the urine test from the mother and/or child was positive for illicit drugs. Urine specimens are taken if the mother is suspected of abusing illicit sub- stances. A comparison group consisting of 169 parents and their children were selected at random from a child welfare clinic in the same building as the SCWC and from two 102 pregnant substance abusers 59 mothers with 62 children included in this investigation 12 abortions 2 adoptions 28 short contacts before or after birth 1 did not want to participate 1 pair of twins and 1 half brother and 1 half sister included FFKlirogiwsutiracenhsa2arntdo,fNthoer wusaeyrisno1f9S9p4e–c2ia0l0C2hild Welfare Clinic in Flow chart of the users of Special Child Welfare Clinic in Kristiansand, Norway in 1994–2002. schools in Kristiansand. This group represents the average population of the city [11]. The comparison group did not have a problem with substance abuse as stated by the par- ticipants themselves in the questionnaire. We wanted the comparison group to be larger than the user group in order to increase the power of the statistical tests. A comparison group of twice the size was possible within the limits of this investigation. As we had positive response from all who were asked to participate, the com- parison group became a little larger. On random days the parents of the children under school age were approached by the assistant of the Child Welfare Clinic, and asked if they would be willing to participate in this questionnaire study. In the schools we were present at conferences for the parents some days after written infor- mation was sent out. All who had appointments that day were asked to be part of the comparison group. Those who did not keep their appointments had the questionnaire distributed by the teacher and answered at home. After giving written informed consent to participate in the study, the parents/caregivers of the children from the user group and the comparison group were immediately pre- sented with a questionnaire that was completed on the spot. A person from the project was present to answer any questions the participants might have. The questionnaire included questions about the occurrence of nicotine use and illicit drug use before and during pregnancy, the preg- nancy and birth, the current health situation of the mother, and socio-economic issues. The questionnaire was developed by the authors and tested in a pilot. Data about the user group was also gathered from their medical records at the SCWC. This included self-reported data on substance use before and during pregnancy, results of observed urine tests for substances, and family income and level of education at the start of pregnancy. The urine specimens were analyzed at the laboratory in the local hospital, using tests from Abbot Diagnostics, Axym. The cut off rates were: amphetamine 500 ng/ml, opiates 300 ng/ml, cannabis 50 mg/ml, benzodiazepines 200 ng/ml. We also gathered information about the father's relation to substance use and his contact with the pregnant woman. In the analyses the users were dichotomized into two groups; "short-term users," including mothers who had stopped the abuse before the end of the first trimester, and "long-term users," including those who continued their substance abuse towards the end of pregnancy. Page 3 of 8 (page number not for citation purposes)