This project is a single blind cluster randomized controlled trial with a purpose of assessing the effectiveness of a comprehensive tertiary interventions (before pregnancy, during pregnancy and after delivery) on the incidence and the clinical outcomes of birth defects in a preparing-for-pregancy population in Shanghai. The preconception intervention is focused on identifying individuals whose red blood cell folate level is below recommended level for preventing neural tube defects (400ng/ml) or with elevated homocysteine level (over th 80th percentiles, 6.8 µmol/L) , and modifying their folate deficiency status to normal before pregnancy.

According to World health Organization (WHO), approximately 3.2 million children are born with birth defect(s) worldwide and the incidence of birth defects in China is 5.6%. Birth defects are the main cause of fetal death, infant mortality and morbidity, and long-term disability. Congenital heart defects, oral clefts, hydrocephalus, neural tube defects and mental retardation are most common birth defects in China. Though the etiology of birth defects is still unknow, many studies indicated that maternal key nutrition factors, especially maternal folic acid status, during periconception played an important role in organogenesis, reducing the incidence of neural tube defects, congenital heart diseases and some other birth defects.

Our project is a single-blind, cluster randomized controlled trial that aim at evaluating whether hospital-based tertiary intervention approaches reduce the incidence of birth defects (compound primary outcomes, including neural tube defects, congenital heart defects, cleft lips and palates, hydrocephalus, alimentary tract malformations or urological deformities) that identified at middle of gestation via ultrasound or clinical observation at birth. Every couple attending premarital check or preconception physical examination from Minhang and Songjiang district in Shanghai will be recruited. Recruited couples are to draw blood samples and invite to complete questionnaires that collecting informations on diet supplementation. Comprehensive interventions before conception are based on serum folate, red blood cell folate, homocysteine, vitamin B12 and fasting glycemic and lipids profiles. Single nucleotide polymorphisms related to folate and homocysteine matalism pathway will be genotyped in participants with sufficient intake of folic acid but unknown deficiency of the nutrients. Venous blood of pregnant women and questionnaires about the supplementation of key nutrients at the first antenatal visit are also obtained. NT examination, Down's screening, and ultrasound examination results are collected during the second trimester (15-24 gestational week), then routine prenatal genetic counseling, assessment, and diagnosis are provided according to the local policy to those pregnant women with positive screen results indicating high risk of fatal birth defects. Newborns with above mentioned birth defects are provided green channel to clinical specialty team for further diagnosis, surgical correction and rehabilitation guidance. Clinical follow up will be conducted till 6-month old for the prognosis of treatment. The current project will provide evidence on the necessity and effectiveness of preconception intervention focusing on sufficient folate nutrition levels in prevention of birth defects.

Inclusion Criteria:

• Females and their husbands attend pre-pregnancy physical examinations from Minhang distrit and Songjiang distrit in Shanghai.
• Couples who have planned to be pregnant within a year
• Women are between 18 and 45 years old

Exclusion Criteria:

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This is a single-blind randomized controlled trial, participants are blinded from their preconceptional folate nutrition status.