Jauniaux Eric, Johns Jemma, Gulbis Beatrice, Spasic-Boskovic Olivera, Burton Graham J
Academic Department of Obstetrics and Gynaecology, Royal Free and University College London Medical School, London, United Kingdom.
Am J Obstet Gynecol. 2007 Jul;197(1):58.e1-6. doi: 10.1016/j.ajog.2007.02.009.
The objective of the study was to investigate the transfer pathways of folic acid inside the first-trimester gestational sac and to evaluate the impact of maternal smoking.
Folate and cotinine levels were evaluated in maternal serum (n = 125) and coelomic fluid (n = 42), and immunostaining was used to identify folate receptors in placental villi, decidual tissue, and secondary yolk sacs from normal pregnancies at 6-12 weeks' gestation.
Folate receptors-alpha were found on the apical surface of syncytiotrophoblast, uterine glandular epithelial cells, and mesothelial layer of the yolk sac. Significantly higher (P < .05) median folate levels were found in maternal serum than in coelomic fluid. The median folate maternal serum and coelomic levels were significantly (P < .0001 and P < .005) lower in smokers, compared with nonsmokers.
Uterine glands and the secondary yolk sac play key roles in supplying folic acid to the developing fetus before the placental circulations are established, and maternal smoking does not seem to impair directly its transfer mechanism in early pregnancy.
本研究的目的是调查孕早期妊娠囊内叶酸的转运途径，并评估孕妇吸烟的影响。
对125例孕妇血清和42例体腔液中的叶酸和可替宁水平进行了评估，并采用免疫染色法鉴定了妊娠6 - 12周正常妊娠的胎盘绒毛、蜕膜组织和次级卵黄囊中叶酸受体。
在合体滋养层、子宫腺上皮细胞和卵黄囊间皮细胞的顶端表面发现了α-叶酸受体。孕妇血清中的叶酸水平中位数显著高于体腔液（P < 0.05）。与不吸烟者相比，吸烟者的孕妇血清和体腔叶酸水平中位数显著较低（P < 0.0001和P < 0.005）。
在胎盘循环建立之前，子宫腺和次级卵黄囊在向发育中的胎儿供应叶酸方面起关键作用，孕妇吸烟似乎不会直接损害其在孕早期的转运机制。
