Peng Yuanzhou, Zhang Yi, Chen Xiaotian, Dou Yalan, Huang Jun, Zhang Xiaohua, Huang Guoying, Lu Xiangfeng, Yan Weili
Research Unit of Early Intervention of Genetically Related Childhood Cardiovascular Diseases (2018RU002), Chinese Academy of Medical Sciences & Peking Union Medical College, Shanghai, China.
Key Laboratory of Cardiovascular Epidemiology & Department of Epidemiology, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
BMJ Open. 2025 May 27;15(5):e100064. doi: 10.1136/bmjopen-2025-100064.
Maternal vitamin B12 levels during pregnancy have been implicated in the risk of preterm birth, but current evidence remains controversial and just focuses on measurements during pregnancy.
To assess the association of maternal periconception serum vitamin B12 concentration, including levels before conception and at early gestation, with the risk of preterm birth and its subtypes in a large Chinese population.
Prospective cohort study.
A total of 26 977 women from Shanghai, China, with serum vitamin B12 concentration measured either before conception or at early gestation.
Preterm birth was defined as delivery before 37 weeks of gestation and was stratified as preterm birth <32 and <34 weeks. Cox regression was used to estimate the association between maternal vitamin B12 and preterm birth.
Overall, 1599 (5.9%) of participants delivered preterm. The median periconception vitamin B12 concentration was 483.0 (IQR, 368.0-622.0) pg/mL. No evidence was observed of an association between maternal vitamin B12 concentration and risk of preterm birth (per 100 pg/mL increment: adjusted hazard ratio (aHR), 0.99; 95% CI, 0.96 to 1.02, =0.572). Similarly, null associations were observed for preterm birth subtypes (aHR, 0.98 [0.89 to 1.09] and 0.97 [0.90 to 1.05] for preterm birth <32 and <34 weeks, respectively).
No evidence of associations was found between maternal vitamin B12 concentration and risk of preterm birth in a population with relatively sufficient vitamin B12 levels. Future studies in populations with varied baseline levels of vitamin B12 are needed to validate these findings across different populations and regions.
孕期母体维生素B12水平与早产风险有关，但目前的证据仍存在争议，且仅关注孕期的测量值。
评估中国一大群孕产妇孕前血清维生素B12浓度（包括受孕前和妊娠早期的水平）与早产及其亚型风险之间的关联。
前瞻性队列研究。
来自中国上海的26977名女性，她们在受孕前或妊娠早期测量了血清维生素B12浓度。
早产定义为妊娠37周前分娩，并分为孕周<32周和<34周的早产。采用Cox回归估计母体维生素B12与早产之间的关联。
总体而言，1599名（5.9%）参与者早产。孕前维生素B12浓度中位数为483.0（四分位间距，368.0 - 622.0）pg/mL。未观察到母体维生素B12浓度与早产风险之间存在关联的证据（每增加100 pg/mL：调整后风险比（aHR），0.99；95%置信区间，0.96至1.02，P = 0.572）。同样，对于早产亚型也观察到无关联（孕周<32周和<34周的早产，aHR分别为0.98 [0.89至1.09]和0.97 [0.90至1.05]）。
在维生素B12水平相对充足的人群中，未发现母体维生素B12浓度与早产风险之间存在关联的证据。需要在维生素B12基线水平不同的人群中开展进一步研究，以在不同人群和地区验证这些发现。
