Maternal iron status influences iron transfer to the fetus during the third trimester of pregnancy

BACKGROUND: The effect of maternal iron status on fetal iron deposition is uncertain. OBJECTIVE: We used a unique stable-isotope technique to assess iron transfer to the fetus in relation to maternal iron status. DESIGN: The study group comprised 41 Peruvian women. Of these women, 26 received daily prenatal supplements containing iron and folate (n = 11; Fe group) or iron, folate, and zinc (n = 15; Fe+Zn group) from week 10-24 of pregnancy to 1 mo postpartum. The remaining 15 women (control group) received iron supplementation only during the final month of pregnancy. During the third trimester of pregnancy (+/- SD: 32.9 +/- 1.4 wk gestation) oral 57Fe (10 mg) and intravenous 58Fe (0.6 mg) stable iron isotopes were administered to the women, and isotope enrichment and iron-status indicators were measured in cord blood at delivery. RESULTS: The net amount of 57Fe in the neonates' circulation (from maternal oral dosing) was significantly related to maternal iron absorption (P < 0.005) and inversely related to maternal iron status during the third trimester of pregnancy: serum ferritin (P < 0.0001), serum folate (P < 0.005), and serum transferrin receptors (P < 0.02). Significantly more 57Fe was transferred to the neonates in non-iron-supplemented women: 0.112 +/- 0.031 compared with 0.078 +/- 0.042 mg in the control group (n = 15) and the Fe and Fe+Zn groups (n = 24), respectively (P < 0.01). In contrast, 58Fe tracer in the neonates' circulation was not significantly related to maternal iron status. CONCLUSION: The transfer of dietary iron to the fetus is regulated in response to maternal iron status at the level of the gut.     

妊娠期妇女甲状腺功能减退对妊娠结局和胎儿影响的分析

目的 分析妊娠期妇女甲状腺功能减退(甲减)对妊娠结局和胎儿的影响。方法 选择2013年1月至2015年10月在上海市第八人民医院行产前检查并分娩的4286例孕妇为研究对象,入组患者均在孕10周时行甲状腺功能检查,分为甲减、亚临床甲状腺功能减退(亚甲减)和健康3组,分析甲减发生状况及其对妊娠结局和胎儿的影响。结果 共检出甲减209例,发生率为4.9%(209/4286),其中临床甲减85例,亚甲减124例。健康组早产发生率(1.0%)明显低于甲减组(10.6%)和亚甲减组(6.5%),差异有统计学意义(χ²=38.884,P<0.001;χ²=17.722,P<0.001);健康组贫血发生率(3.8%)明显低于甲减组(18.8%)和亚甲减组(9.7%),差异有统计学意义(χ²=30.949,P<0.001;χ²=23.275,P<0.001);健康组低体重发生率(1.1%)明显低于甲减组(14.1%)和亚甲减组(4.8%),差异有统计学意义(χ²=50.593,P<0.001;χ²=15.637,P<0.001);健康组胎儿窘迫发生率(1.9%)明显低于甲减组(10.6%)和亚甲减组(5.6%),差异有统计学意义(χ²=19.257,P<0.001;χ²=12.357,P<0.001);健康组胎儿Apgar评分(9.69±0.32)明显高于甲减组(9.25±0.45)和亚甲减组(9.28±0.44),差异有统计学意义(t=8.823,P<0.001;t=15.175,P<0.001)。结论 妊娠期妇女甲减可对妊娠结局和胎儿构成不利影响,临床应加强妊娠期妇女相关检查,早发现早治疗。     

Neurological damage to the fetus resulting from severe iodine deficiency during pregnancy

Endemic cretinism is characterised by multiple neurological defects including deaf-mutism, diplegia, squint, and mental deficiency. The condition is widely prevalent in the Highlands of New Guinea in association with severe iodine deficiency. Previous studies have shown that iodised oil provides a very satisfactory correction of severe iodine deficiency in New Guinea. A controlled trial on the use of intramuscular iodised oil in the prevention of endemic cretinism was carried out in the Western Highlands of New Guinea and involved a population of approximately 8000. Subsequent follow-up over four years revealed 26 endemic cretins out of a total of 534 children born to mothers who had not received iodised oil; the mothers of 5 of these cretins were pregnant at the start of the trial. In comparison, 7 cases of endemic cretinism occurred among 498 children born to mothers who had been treated with iodised oil; in 6 of these 7 cases, the mother was pregnant when the trial commenced. It is concluded that intramuscular iodised oil is effective in the prevention of endemic cretinism and that, for it to be effective, it should be given prior to conception. This suggests that severe iodine deficiency in the mother produces neurological damage during fetal development.     

The masculinization of the fetus during pregnancy due to inhalation of diesel exhaust

This study was conducted to determine the impact of diesel exhaust inhalation on the fetus. Seventy-two pregnant rats and 18 nonpregnant rats were divided into three groups: a group exposed to total diesel engine exhaust containing 5.63 mg/m(3) particulate matter, 4.10 ppm nitrogen dioxide, and 8.10 ppm nitrogen oxide; a group exposed to filtered exhaust without particulate matter; and a group exposed to clean air. The exposure period was from day 7 until day 20 of pregnancy. In addition, 15 pregnant rats were treated with aromatase inhibitors or testosterone to clarify the process by which diesel exhaust exerts its toxicity. The anogenital distance was significantly longer in male and female fetuses from both exhaust-exposed groups than in those of the control. Differentiation of the testis, ovary, and thymus was delayed and disturbed. Maternal testosterone and progesterone levels, which increased due to pregnancy whether or not the rats were exposed, were significantly higher and lower, respectively, in the pregnant rats exposed to total exhaust and filtered exhaust. The serum adrenocorticotropic hormone (ACTH) level and urinary excretion of 17-hydroxycorticosteroids (OHCS) did not differ among the pregnant groups. These results indicate that elevated testosterone did not result from elevated maternal adrenal function. The feto-placental-ovarian unit and inhibition of aromatase activity and synthesis caused by diesel exhaust inhalation might have played an essential role in the accumulation of testosterone. Since both exhaust-exposed groups showed almost the same reactions toward the inhalation, the gaseous phase must have included the relevant toxicants.     

妊娠期高血压对胎儿及新生儿的影响

妊娠期高血压疾病是一种妊娠期常见的特发性疾病,严重影响母胎安全,也是影响胎儿及新生儿生长发育重要因素之一。妊娠期高血压所致的胎盘功能减退,可引起胎儿宫内生长迟缓、死胎、死产或早产、窒息等多种合并症,且对新生儿各个器官均有不同程度的损伤。妊娠期高血压疾病也可通过对胎儿神经系统的影响而引起儿童远期认知的不良结局。积极使用降压药物虽然可以降低孕妇血压,但是无论是降压药物本身和降压的速度是否得当都可能对胎儿及新生儿有潜在风险。故产儿科医生应当对妊娠期高血压足够重视,定时做产前及孕期检查,及早发现及预防妊娠高血压疾病,合理评估治疗高血压对胎儿及新生儿的影响,争取将妊娠高血压疾病对胎儿及新生儿的不良影响降到最低。     

妊娠合并甲状腺功能减退症对孕妇及胎儿的影响

目的:探讨妊娠合并甲状腺功能减退症对妊娠结局及胎儿的影响。方法:回顾性分析40例妊娠合并甲状腺功能减退症的患者资料,采用放免法测定其血清促甲状腺激素(TSH)、游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)浓度及其对妊娠结局和胎儿的影响。结果:妊娠合并甲状腺功能减退症孕妇的流产率、早产率、并发症发生率及新生儿TSH升高明显高于对照组(P<0.05),新生儿出生后1minApgar评分低于正常对照组(P<0.05)。结论:对妊娠合并甲状腺功能减退症的孕妇应定期监测血清FT3、FT4、TSH浓度,及时调整用药剂量,并密切关注各类并发症的出现,以减少不良妊娠结局的发生;对其新生儿建议取脐带血监测血清FT3、FT4、TSH浓度,以及时发现新生儿甲状腺功能减退症,并及时治疗。     

Influenza infections during pregnancy in the mouse.

The effect of a sublethal dose (0-5 LD50) of influenza A/WSN (H0N1) administered intranasally in the 1st and 3rd weeks of pregnancy was studied in C3H inbred mice. Maternal and neonatal mortality rates were significantly increased by infections in the 3rd week of pregnancy, but not in the 1st week. Infections during the last part of the 1st week significantly depressed the growth rate of neonates. No evidence of viraemia, transplacental transmission or congenital malformations were observed from infections during either week. The results are discussed in terms of a possible model for human influenza infections during pregnancy to determine the potential risks to the mother, fetus and neonate.     

Estimates of absorption of radiofrequency radiation by the embryo and fetus during pregnancy.

This paper reports that the specific absorption rate induced in the embryo or fetus can exceed that recommended for the general public when the mother is exposed to radiofrequency radiation at the occupational limits. This result applies to two-tiered radiofrequency radiation standards where a factor of 5 differentiates occupational and nonoccupational exposure limits. Using simple axisymmetric geometries for the pregnant worker, and assuming plane wave exposures, a finite element method provides estimates of prenatal exposure. Various layered shapes are used to model skin, fat, uterus, blood, embryonic, and fetal tissues. Applying current exposure limits given by IRPA, ANSI, and SAA, the results indicate that overexposures to the embryo or fetus can occur from early pregnancy at 80-100 MHz, and in late pregnancy across the range 300-1500 MHz.     

COVID-19 vaccine uptake and intention during pregnancy in Canada

ObjectiveTo investigate COVID-19 vaccine uptake and intent among pregnant people in Canada, and determine associated factors.MethodsWe conducted a national cross-sectional survey among pregnant people from May 28 through June 7, 2021 (n = 193). Respondents completed a questionnaire to determine COVID-19 vaccine acceptance (defined as either received or intend to receive a COVID-19 vaccine during pregnancy), factors associated with vaccine acceptance, and rationale for accepting/not accepting the vaccine.ResultsOf 193 respondents, 57.5% (n = 111) reported COVID-19 vaccine acceptance. Among those who did not accept the vaccine, concern over vaccine safety was the most commonly cited reason (90.1%, n = 73), and 81.7% (n = 67) disagreed with receiving a vaccine that had not been tested in pregnant people. Confidence in COVID-19 vaccine safety (aOR 16.72, 95% CI: 7.22, 42.39), Indigenous self-identification (aOR 11.59, 95% CI: 1.77, 117.18), and employment in an occupation at high risk for COVID-19 exposure excluding healthcare (aOR 4.76, 95% CI: 1.32, 18.60) were associated with vaccine acceptance. Perceived personal risk of COVID-19 disease was not associated with vaccine acceptance in the multivariate model.ConclusionVaccine safety is a primary concern for this population. Safety information should be communicated to this population as it emerges, along with clear messaging on the benefits of vaccination, as disease risk is either poorly understood or poorly valued in this population.     

孕期体重合理增长数对孕产妇、胎儿及新生儿的影响

目的 探讨孕期体重合理增长数对孕产妇、胎儿及新生儿的影响.方法 选择2013年10月至2014年12月于北京市平谷区医院进行孕检并分娩的孕妇274例,将患者按随机数字表法分为两组.研究组137例以孕前身体质量指数(BMI)资料进行分析后进行理想增长体重数的制定,包括合理的膳食及锻炼,使孕妇的体重增长在孕期正常体重范围内.对照组137例进行传统的健康教育讲座,未进行膳食及锻炼的干预,顺其自然增加.探究合理体重的增加对两组间胎儿、孕产妇、新生儿的临床影响.结果 研究组体重增长在标准范围者占96.35％,对照组体重增长在标准范围者占46.72％,研究组显著高于对照组(x2=82.87,P＜0.05).研究组妊娠合并糖尿病、妊娠期高血压、巨大儿、剖宫产、产后大出血发生率分别为2.19％、4.38％、3.65％、18.25％、2.19％,对照组妊娠合并糖尿病、妊娠期高血压、巨大儿、剖宫产、产后大出血发生率分别为7.30％、10.95％、11.68％、38.69％、8.03％,研究组显著低于对照组(x2值分别为3.95、4.17、6.24、14.05、4.81,均P＜0.05).结论 通过合理膳食、有效锻炼以及改善生活方式,使孕妇孕期体重得到了有效控制,降低了分娩后并发症的发生.     

孕期补充钙、铁、锌对胎儿生长发育的影响

目的以孕妇为对象,研究孕中期单纯补钙和补钙同时补铁和/或锌对婴儿生长发育的影响.方法选择初产健康孕妇313名,分别强化维生素D(VD)、钙、铁和锌, 从孕5月至分娩时止.分娩时测量胎盘重量、胎盘和脐带血中微量元素的含量、新生儿的出生体重和身长.结果对照组胎盘重量最大,钙和多种微量元素的含量较低,而钙+铁+锌+VD组相反,并且对照组的胎盘重量(551.1±64.2) g显著大于钙 +铁+锌+VD组(467.1±36.6) g.脐血中血红蛋白含量显著高于母血,碱性磷酸酶活性差异无显著性,脐血血浆中钙、铁、锌含量均高于母血.婴儿的生长发育结果显示,钙+铁+ 锌 +VD组新生儿的出生体重(3.53±0.33) kg和身长值最大,并且出生体重显著大于对照组的(3.28±0.54) kg.结论孕期联合补充钙、铁、锌, 使其达到或接近每日膳食中营养素供给量,这是改善婴儿生长发育的最佳方式.     

Radiation dose to the fetus from [(18)F]-FDG administration during the second trimester of pregnancy

The authors estimated the fetal radiation dose from [(18)F]-FDG in a rare case of a woman who underwent a PET/CT scan during the second trimester of pregnancy. The patient, a 27-y-old female with a paraganglioma, received 181.3 MBq [(18)F]-FDG. From the concentrations of radioactivity measured on the images, the time-integrated activity coefficients of the fetus and the placenta were derived. The time-integrated activity coefficients of the mother's organs were taken from the standard values of ICRP publication 106. The final fetal dose was calculated using the 6-mo pregnant model of the OLINDA/EXM software. The fetus showed an overall low and homogeneous [(18)F]-FDG uptake, with an average concentration of 2.41 kBq cm(-3). The uptake in the placenta was generally higher (average concentration = 3.69 kBq cm(-3)). The estimated time-integrated activity coefficients were 0.0130 and 0.0058 Bq h Bq(-1) for the fetus and the placenta, respectively. The final average dose to the fetus was 1.97 × 10(-2) mGy MBq(-1) (3.6 mGy in this patient who received 181.3 MBq). Therefore, the dose to the fetus from [(18)F]-FDG administration during the second trimester of pregnancy is low. When medically indicated, pregnancy should not be a categorical basis for withholding [(18)F]-FDG PET scans.