This topic puts forward a hypothesis: genetic and environmental factors such as major depressive disorder during pregnancy, nutritional status of vitamin A, D, E, and folic acid, intestinal microecology, and bisphenol A exposure, may affect the cognitive development level of the offspring through the genetic correlation with attention deficit hyperactivity disorder, developmental delay/intellectual disability, and major depressive disorder, allelic heterogeneity and pleiotropy of ITIH3 mediated by SNP and CACNB2, neurotransmitters like dopamine, and metabolic pathways, thereby increasing the risk of attention deficit hyperactivity disorder and developmental delay/intellectual disability prevalence on offspring.

This topic planning from allelic heterogeneity and pleiotropy of attention deficit hyperactivity disorder and major depressive disorder mediated by SNP, neurotransmitters like dopamine, and metabolic pathways, explores deeply the influences on children's development level and the risk of common neurological disorder caused by genetic and environmental factors during pregnancy, looking for reasonable prevention, early diagnosis of biomarkers and therapeutic targets, in order to provide data support for further improvement and revision of national mother and infant healthcare policy .

1. Technology Roadmap:①Pregnant Women:Subjects are rolled in the group. ② 21 Weeks of Gestation：Sign informed contents (mother version), test depression scale ( BDI+HAMD ), fill in the basic information questionnaire and collect 3 ml of blood of pregnant women for genetic information extraction. ③Delivery: Sign informed contents(children version), collect 1 ml of umbilical cord blood and 2ml of urine from mother. ④Physical measurements are respectively taken when a child is 3, 6, 12, 24 months old and 3, 6 years old. And the Montreal Children Hospital Feeding Scale will be also respectively completed when a child is 6 and 12 months old. What's more, the investigators plan to carry out developmental screening for the children aged 1, 2, 3 and 6, and if the developmental screening is positive, a diagnostic test then will be carried out. ⑤When children are aged 2, 3 and 6, blood samples are taken from 3 milliliters and urine from 2 milliliters, and nutrients are detected to obtain genetic information. ⑥All biological specimens will be tested for nutrient levels and some other.⑦At last, data analysis is performed on all collected information including physical measurements, feeding behavior questionnaire, all biological specimens and so on.

2. Study Protocol： A. Human Subjects Review: Studies must have approval (or be exempt, as appropriate) from a Human Subjects Protection Review Board prior to the enrollment of the first participant to be eligible for registration (Submitted, approved).

   B. Register a clinical study: Prior to the launch of the project, pre-registration will be completed at clinicaltrials.gov in the international clinical study register authority.

   C. Study cohort: Screening qualified pregnant women volunteered to take part in the study from pregnancy clinics of Chongqing suburban maternity and child health hospital and The Maternal and Child Health Hospital of Hainan Province.

3. Measuring scale: To assess the depression status and degree of the subjects by Hamilton Depression Scale (HAMD) and Beck depression rating scale (BDI); To evaluate the cognitive function of subjects and exclude the patients with mental retardation by Mini-Mental State Examination (MMSE) and Activity of Daily Living Scale（ADL); To screen or identify the cognitive function and level of children in different age groups by Denver development screening scale (DDST) and Gesell Developmental Schedules (Gesell), and combining with the Adaptive Scale of Infant and Children (SM) to assist in the diagnosis of developmental delay/intellectual disability, The Vanderbilt ADHD Diagnostic Rating Scale on diagnosis of ADHD.

4. Data management and statistical analysis plan:

   A. All the data is recorded by the professional staff, and checked by a third person to ensure accuracy of data entry; B. All statistical analysis is performed with SAS 9.4. The statistical analysis is completed by the applicant and the professional statisticians in the epidemiology research office of the unit.

5. Recruitment process:

   A. To preach related knowledge of major depressive disorder, ADHD, and developmental delay/intellectual disability in the form of obstetrics clinics, network media, and network health management platform,etc; B. Recruitment information is released by platforms such as obstetrics clinics, network health management platforms, etc., to recruit pregnant women; C. The obstetric nurses and professional recruiters (postgraduate students) assist pregnant women to sign informed consents, agree to participate in the study, and promise that the delivery of children would take part in the same sequence of study as well.

6. The required materials of recruitment:

   Manufacture recruiting advertisements of major depressive disorder, ADHD, developmental delay/intellectual disability related knowledge and disease hazards, the importance of early diagnosis, recruitment information of pregnant women and their children enrolled in the study (for example: network media recruitment advertisement, WeChat H5 recruitment advertisement, network health management platform recruitment advertisement, etc.).

7. Benefit Assessment： A. The pregnant women volunteered to participate in the study are able to enjoy regular check-ups (once every three months, including height, weight, blood pressure, mood questionnaires, etc.); B. Eligible children volunteer to participate in the study, all can enjoy free physical examination (height, weight) at the age of 1, 2, 3, and 6, moreover according to age to enjoy free screening or diagnostic test related to cognitive development level and attention deficit hyperactivity disorder test; C. The parents of all the children involved can receive the knowledge of parenting through WeChat or network health management platform, and be provided with free parenting seminars regularly; D. High-risk pregnant women and children are given priority access to the superior hospital for diagnosis and treatment; E. All subjects are eligible for the the nutrient level test of preferential price, 16S test (intestinal flora detection) of the preferential price , free related genetic test; F. Study may solve some urgent problems in the prevention and treatment of developmental disabilities such as ADHD, developmental delay/intellectual disability, and contribute to promoting maternal and child health, improving the quality of the population, and promoting the sustained and healthy development of the national economy.

8. Risk Assessment ( illustrate the possible risk rate and take measures to ensure that risk is minimized in a possible range):

   A. Possible risk: the probability of subjects losing to follow-up (loss ratio of 5 to 10% due to various reasons); B. Measurements: The professional staff would regularly contact with the mother or the child by phone or Wechat. And after the birth of a child, childbearing knowledge or childcare lectures are regularly provided for the parents.

9. Special crowd protection:

A.In the course of the study, obstetricians, psychologists, and childcare doctors are all involved in providing health care for pregnant women, mothers and children.

B. At the same time, please protect the subjects' privacy and not to give out the information of the subjects. All subjects' personal information is treated with confidentiality and this study data is only used in the study design scope to ensure that the subjects' privacy is not invaded.

Inclusion Criteria:

1. Inclusion criteria for pregnant women: Aged 20~49;
2. no cognitive impairment, able to complete the scale test;
3. Hamilton Depression Scale (HAMD questionnaire) is normal (HAMD score <8 points) or mild to moderate positive (HAMD questionnaire score: 8~35 points);
4. Participants are asked for their own written informed content for the study;

Exclusion Criteria:

1. Patients receiving anti-depression therapy during the first 6 months of gestation or during pregnancy;
2. Patients with severe depression with scores of no less than 35 points in the HAMD questionnaire;
3. Patients with other mental disorders;
4. Patients with neurological diseases;
5. Patients with cognitive dysfunction.

This study is based on source material from Chongqing suburban maternity and child health hospital. The investigators randomly select the pregnant women aged 20 to 49 from the pregnancy clinics and obstetric wards, respectively construct mother-child matching and a prospective study cohort depending on whether the pregnant women with major depressive disorder or not, nutrition state of vitamin A, D, E, during pregnancy.

Data is confidential during the study.