The purpose of this study is to know the prevalence of iron deficiency (ID) and iron deficiency anemia (IDA) among pregnant women in Chinese urban district at present, and to analyze the epidemiological characteristics of ID/IDA and influencing factors.

This is a national large-scale multi-center cross-sectional survey aimed at investigating the epidemiology of iron deficiency (ID) and iron deficiency anemia (IDA) among Chinese pregnant women in the real world at present, which is anticipated to complete enrollment in two months. A total of 24 hospitals are selected from 6 regions (north, northeast, east, south, southwest, and northwest) of China by the method of multi-stage stratified sampling, each region with one tertiary teaching hospital and three general hospital or health care hospital for women and children. According to the sample size calculation formula combined with the feasibility and flexibility of study, 12000 eligible outpatient pregnant women are expected to be enrolled. Structured questionnaires, which are needed filled in both by patients and doctors, are used to collect participants' data, including basic demographic characteristics (age, occupation, educational level, family income, etc.), reproductive factors (menstrual history, times of pregnancy or parity, history of cesarean section, etc.), pre-pregnancy weight, pregnancy comorbidities and complications, laboratory test of blood routine and serum iron protein, use of iron supplements, diet and living habits during pregnancy, and others. The outcomes are defined by the recommendations on the guidelines for the diagnosis and treatment of Chinese iron deficiency and iron deficiency anemia during gestation period in 2014. All these data are requested to input the electronic data collecting (EDC) system in time and managed level-to-level, with Chinese Evidence-based Medicine Centre finally monitoring the quality of data. During the whole course, no intervention is given to the participants and thus will not have a negative effect on the health and rights of the participants.

Inclusion Criteria:

• Receive outpatient service at selected hospitals for the first time during the survey period;
• Sign an informed consent form;
• At selected hospitals, establish registry of personal file for obstetric examination, or ensure regular follow-up.

Exclusion Criteria:

• Participate in any clinical trial of medicine or nutrition from 3 months before pregnancy till survey time.

Chinese pregnant women receiving outpatient service at selected hospitals