Tehran Survey of Potential Risk Factors for Multiple Births

Background The incidence of multiple pregnancies has increasing worldwide and it is related to concern in the health care system. This study was aimed to determine the frequencyof multiple pregnancies, and to identify factors affecting the frequency of the phenomena in Tehran, Iran. MaterialsAndMethods In this cross sectional study, 5170 mothers in labor between July 6 to 21 2015 referred to 103 hospitals, which are equipped to obstetrics and gynecology wards, were included. The questionnaire used in the study includes five parts: demographic characteristics;information related to pregnancy; information related to the infant;information regarding the multiple pregnancy; andinformation associated with infertility. Data related to the questionnaire was collected from eligible participants through interview and medical records,reviewby103 trained midwives. Frequenciesand odds ratios for the association between the selected characteristics (maternal age, economic status, ahistory of multiple pregnancies in first relatives, and a reproductive history) and multiple pregnancies were computed by multiple logistic regression .Stata software, version 13 (Stata Corp, College Station, TX, USA) was used for all statistical analyses. Results The prevalence of multiple pregnancy was 1.48% (CI95%:1.19-1.85). After controlling for confounding variables,mother’s age (OR=1.04, CI95%:1.001-1.09; P=0.044), Assisted reproductive technique (ART)(OR=6.11, CI95%:1.7-21.97; P=0.006) and a history of multiple pregnancy in mother’s family (OR=5.49, CI95%:3.55-9.93; P=0.001) hada significant associationwiththe frequency ofmultiple pregnancy. Conclusion Thefrequency of multiple pregnancy was near to the frequency reported in previous studiesin Iran .Based on our results, frequencyof multiple pregnancy in older women, inwomen with ahistory of ART and in those witha history of multiple pregnancy in mother’s family was significantly more than others.