This prospective multi-center birth cohort study has a rapid increase in enrollment since its launch in November 2022 (Supplement Fig. 1). As of June 26, 2024, a total of 12,119 pregnant women have consented to participate, with baseline characteristics detailed in Table 2. The average age of the pregnant women is 29.76 years old and 8.21% are over 35 years old. The average height of the participants is 160.46 cm. The study includes 26 ethnic groups, with 5.03% from 25 minority groups (Supplement Fig. 2). Over 90% of the participants reside in urban areas and the average pre-pregnancy BMI is 23.11. Natural pregnancies account for 95.4%, and 98.75% are singleton pregnancies. 60.24% of pregnant women delivered vaginally, the average gestational age was 38.70 weeks, and the average BMI before delivery is 27.25. 52.94% of the newborns are male, with an average weight of 3186.90 g and an average height of 49.60cm. More than 70% of the newborns have a length of 50 cm or greater.

Given the multi-center nature of this study, we analyzed the distribution of ethnicity, age, height, parity, and education level across different provinces (Table 3). Guizhou Province, known for its ethnic diversity, has the highest proportion of minority among the 12 cities with 24.96%. Pregnant women in Liaoning Province have the highest average height at 164.21 cm, followed by those in Inner Mongolia Autonomous Region (163.32 cm) and Shandong Province (162.97 cm), this may be related to geographic factors. In terms of parity, 63.26% of the pregnant women are primiparous. Additionally, Shandong Province has the highest proportion of pregnant women over 35 years old (16.75%). Guangdong province (12.22%) has the highest percentages of pregnant women with two or more children, which may be influenced by urban living pressures and local customs. Regarding educational levels, the majority of pregnant women hold a bachelor’s degree (68.59%) and the distribution of education levels varies across provinces, likely reflecting the unique urban characteristics of each province (Table 3). These diverse and detailed baseline characteristics provide a solid foundation for further multi-omics analysis and longitudinal follow-up studies.

In light of the large population included and medical records extensively retrieved, this cohort brings us abundant clinical information, including common obstetric and gynecologic complications, neonatal disease, hepatobiliary disease, infectious disease, endocrine disease, metabolic disease and genetic disease (Table 4). Among 4865 pregnant women who have given birth, several common diseases are observed: premature rupture of membrane (18.29%), GDM (16.74%), hypothyroidism (8.44%), thalassemia (5.70%), fetal distress (5.16%), preterm birth (4.92%), uterine leiomyoma (4.36%), macrosomia (3.32%), PE (2.74%), FGR (1.78%), ICP (1.54%) and Polycystic ovary syndrome (PCOS) (0.57%).

Mode of conception and advanced maternal age has been associated with adverse pregnancy outcomes. We analyzed the disease prevalence in women receiving ART and women with advanced maternal age (Supplement Tables 1 and 2). The subfertility of pregnant women receiving ART likely increased their vulnerability in face of gestational stress and lead to higher risk of adverse outcomes. We found that compared to women receiving natural pregnancy, women receiving ART exhibited a significantly higher prevalence of several disease including preterm birth(P = 0.0002), GDM (P = 0.046), PE (P = 0.002), PCOS (P = 0.048). Additionally, we found that compared to women at age 35 and older, women younger than 35 showed a significantly lower prevalence in preterm birth (P = 0.0042) and GDM (P < 2.2e−16). However, there is no significant difference between two groups in FGR, PE, ICP, macrosomia and fetal heart abnormalities.

Thalassemia is a kind of hereditary hemolytic blood disease, which is mainly prevalent in tropical and subtropical regions of the world [37]. In the subtropical Guangdong province, 266 cases were found among 1,503 women, while in other regions only 79 cases were found among 3,339 women. Additionally, we also observed 9 fetal chromosome abnormalities and 4 participants with fetal genetic abnormalities in the cohort (Supplement Table 3), this might be de novo mutation happened during gestation.

As of June 26, 2024, this study has collected a total of 161,122 biological samples (Table 5), covering four key periods: early pregnancy, mid-pregnancy, late pregnancy, and postpartum. These samples include serum, plasma, urine, buffy coat, cervicovaginal fluid (CVF), amniotic fluid, placenta, umbilical cord plasma and buffy coat, providing valuable resources for comprehensive, multidimensional maternal and child health research. In the early pregnancy period, we collected samples from 8,743 pregnant women, including 62,184 blood samples with an average gestational age of 13+5 weeks and 23,368 urine samples with an average gestational age of 14+3 weeks. During mid-pregnancy, we collected samples from 4,383 pregnant women, consisting of 32,933 blood samples with an average gestational age of 24+4 weeks, 10,838 urine samples with an average gestational age of 23+6 weeks, and 1,683 CVF samples with an average gestational age of 28.5 weeks. In the late pregnancy period, we collected samples from 2,416 pregnant women, including 15,888 blood samples with an average gestational age of 34 weeks, 2,257 urine samples with an average gestational age of 32+4 weeks, and 2,192 CVF samples with an average gestational age of 34+1 weeks. Additionally, postpartum samples were collected from 670 women, comprising a total of 9,779 samples. The collection of these diverse samples spans from early pregnancy to postpartum, providing comprehensive biological data across different stages of pregnancy.