妊娠晚期妇女甲状腺疾病特点及甲状腺自身抗体变化的研究

目的 探讨妊娠晚期妇女甲状腺疾病的患病率、患病特点和甲状腺自身抗体的变化.方法 选择664例妊娠晚期妇女为妊娠组,276例非妊娠育龄妇女作为对照组.应用固相化学发光酶免疫法测定两组妇女的血清促甲状腺激素（TSH）和抗甲状腺过氧化物酶抗体（TPOAb）水平;TSH水平检测异常者加测游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）,同时测定尿碘水平.按如下标准确定诊断：TSH＜0.3 mU/L,FT4和（或）FT3水平升高者诊断为临床甲状腺功能亢进症（甲亢）;TSH＜0.3 mU/L,而FT4和FT3水平正常者诊断为亚临床甲亢;TSH＞4.8 mU/L,FT4水平降低者诊断为临床甲状腺功能减退症（甲减）;TSH＞4.8 mU/L,而FT4和FT3水平正常者诊断为亚临床甲减.TPOAb＞5 kU/L为阳性.结果 （1）妊娠组妇女尿碘平均水平为201.5μg/L,对照组妇女尿碘平均水平为196.0μg/L,均为碘充足水平.两组比较,差异无统计学意义（P＞0.05）.（2）妊娠组妇女甲状腺疾病总患病率为7.8%（52/664）,对照组妇女甲状腺疾病总患病率为6.9%（19/276）.两组比较,差异无统计学意义（P＞0.05）.（3）两组妇女的甲状腺患病类型有明显不同,妊娠组妇女甲亢患病率为1.1%（7/664）,甲减患病率为6.8%（45/664）,妊娠组妇女甲亢患病率明显低于甲减,两者比较,差异有统计学意义（P＜0.01）;对照组甲亢患病率为4.7%（13/276）,甲减患病率为2.2%（6/276）,两者比较,差异无统计学意义（P＞0.05）.妊娠组与对照组妇女的甲亢或甲减患病率分别比较,差异均有统计学意义（P＜0.01）.（4）妊娠组非患病妇女的TSH水平显著高于对照组,分别为2.50 mU/L及1.54 mU/L,差异有统计学意义（P＜0.01）;妊娠组妇女TPOAb阳性率显著低于对照组,分别为3.3%（22/664）及9.4%（26/276）,差异有统计学意义（P＜0.01）.结论 妊娠晚期妇女甲状腺疾病的特点是甲减的患病率高,同时甲状腺自身免疫功能受到抑制.     

妊娠中期甲状腺功能减退症与甲状腺过氧化物酶抗体的相关性

目的 调查妊娠中期甲状腺功能减退症(简称甲减)的检出率,探讨甲状腺过氧化物酶抗体(thyroid peroxidase antibody,TPOAb)与妊娠中期甲减的关系. 方法 对2010年3月1日至7月31日在上海交通大学医学院附属国际和平妇幼保健院产科门诊产前检查的孕14～28周孕妇2141例进行横断面调查,检测其血清TPOAb、促甲状腺激素(thyroid-stimulating hormone,TSH)和血清游离甲状腺素(free thyroxine,FT4)水平.TPOAb阳性和亚临床甲减影响因素分析采用二分类Logistic回归,TPOAb水平与TSH、FT4的相关性分析使用Spearman秩相关分析. 结果 (1)妊娠中期亚临床甲减检出率13.36％(286/2141),低T4血症检出率0.14％ (3/2141),未检出临床甲减患者.(2)以TPOAb≥50 U/ml为阳性,2141例孕妇中TPOAb阳性者为134例,占6.26％.亚临床甲减患者、低T4血症患者和甲状腺功能正常孕妇TPOAb阳性分别为13.64％ (39/286)、0/3和5.06％(86/1701),组间比较差异有统计学意义(x2=30.82,P＜0.01).妊娠中期TPOAb阳性不受孕次、产次、孕周、胎儿性别及孕母年龄的影响.(3) TPOAb水平与TSH值呈正相关(r=0.12,P＜0.01),与FT4值无相关性(r=-0.04,P=0.09).(4)血清TPOAb阳性和孕次是妊娠中期亚临床甲减的危险因素(OR=3.18,95％ CI:2.10～4.83,P＜0.01;OR=1.21,95％ CI:1.02～1.43,P=0.030). 结论 亚临床甲减是妊娠中期的常见疾病,TPOAb是亚临床甲减的独立危险因素和重要预测指标.应当关注妊娠中期甲减的筛查,同时将TPOAb检测纳入常规产前筛查项目.     

妊娠早期促甲状腺素临界水平合并甲状腺过氧化物酶抗体阳性妇女的治疗结局探讨

目的:探讨左旋甲状腺素(L-T4)治疗对妊娠早期促甲状腺素(TSH)临界水平(2.5 mU/L≤TSH≤4.0 mU/L)合并甲状腺过氧化物酶抗体(TPOAb)阳性孕产妇母婴结局的影响,从而指导临床治疗。方法:选择2017年7月至2019年6月在福建医科大学附属泉州第一医院产检分娩的7517例单胎孕妇为研究对象,并根据妊娠早期(孕12周以内)FT4正常、TSH水平[亚临床甲状腺功能减退(TSH>4.0 mU/L)、临界水平(2.5 mU/L≤TSH≤4.0 mU/L)、正常(TSH<2.5 mU/L)]、TPOAb水平(TPOAb>50 mU/ml为阳性)及是否采用L-T4治疗分为5组:亚临床甲状腺功能减退治疗组(A组,181例)、TSH临界水平合并TPOAb阳性治疗组(B组,145例)、TSH临界水平合并TPOAb阳性未治疗组(C组,81例)、TSH临界水平合并TPOAb阴性组(D组,135例)、甲状腺功能正常组(E组,6367例)。比较各组孕产妇妊娠并发症及不良妊娠结局的发生情况。结果:5组孕妇在流产、早产、妊娠期糖尿病、妊娠期高血压疾病、羊水过少的发生率方面,差...     

分娩方式对产妇及其新生儿促甲状腺激素水平影响的研究

目的探讨不同分娩方式对产妇及其新生儿促甲状腺激素(TSH)水平的影响.方法应用放射免疫分析法,检测213例产妇及其新生儿的TSH水平,按分娩方式不同分为正常分娩组140例,剖宫产组38例,产钳组35例.结果(1)产钳组产妇TSH为(4.13±0.69)mU/L,正常分娩组产妇为(2.58±0.87)mU/L,两组比较,差异有极显著性(P＜0.01).剖宫产组产妇TSH为(2.81±0.45)mU/L,同产钳组产妇比较,差异有极显著性(P＜0.01);同正常分娩组产妇比较,差异无显著性(P＞0.05).(2)产钳组新生儿TSH为(8.85±2.48)mU/L,正常分娩组新生儿为(5.36±2.23)mU/L,两组比较,差异有极显著性(P＜0.01).剖宫产组新生儿TSH为(3.84±2.16)mU/L,同正常分娩组比较,差异有显著性(P＜0.05).(3)3组产妇及其新生儿TSH水平之间呈显著正相关.结论产妇和新生儿TSH水平的高低与不同分娩方式有关.产妇TSH水平变化用于评估新生儿TSH水平具有可行性.     

妊娠期高血压疾病与甲状腺功能异常的临床研究

目的探讨妊娠期高血压疾病与妊娠晚期甲状腺功能异常的关系。方法选择2012年1月至2012年12月足月分娩的妊娠期高血压疾病患者326例作为研究组,其中妊娠期高血压133例,轻度子痫前期92例,重度子痫前期101例;同期201例正常妊娠孕妇为正常组。采用电化学发光技术进行血清甲状腺功能检测,比较两组甲状腺功能及孕妇合并甲状腺疾病情况。结果研究组患者血清促甲状腺激素水平[TSH,2.78mU/L（0.71~7.37mU/L）]与正常组[2.35mU/L（0.79~4.52mU/L）]比较,差异有统计学意义（P〈0.001）,研究组游离甲状腺素水平[FT4,12.13pmol/L（8.96~17.12pmol/L）]与正常组[12.80pmol/L（8.69~17.76pmol/L）]比较,差异有统计学意义（P〈0.001）,研究组甲状腺过氧化物酶抗体水平[TPO-Ab,19.06U/ml（5.00~78.35U/ml）]与正常组[18.58U/ml（5.00~49.98U/ml）]比较,差异无统计学意义（P〉0.005）;妊娠期高血压疾病严重程度与TSH呈正相关（r=0.122,P〈0.05）,与FT4和TPO-Ab水平无关（r分别为0.005和0.030,P均〉0.05）。研究组总甲状腺功能异常发生率（15.34%,50/326）与正常组（8.46%,17/201）比较,差异有统计学意义（χ2=5.303,P〈0.05）,其中子痫前期组甲状腺功能减退的发生率（4.35%,4/92）与正常组（4.95%,5/101）比较,差异有统计学意义（P〈0.05）。结论妊娠期高血压疾病与甲状腺功能异常密切相关。     

妊娠期亚临床甲状腺功能减退症的筛查

亚临床甲状腺功能减退症( subclinical hypothyroidism,SCH)是指血清促甲状腺激素(thyroidstimulating hormone,TSH)高于正常,但血清游离甲状腺素( free thyroxine,FT4)在正常范围的一种情况.非孕妇中SCH发病率为4.0％～8.5％,年龄越大发病率越高,女性发病率较同年龄段男性高.因为诊断标准不统一,报道的妊娠期SCH发病率各不相同,估计发病率为2％～3％.临床甲状腺功能减退症(overt hypothyroidism,简称临床甲减)是指妊娠期TSH大于正常而FT4小于正常.若TSH＞ 10 mU/L,则无论FT4水平高低,都诊断为临床甲减.     

妊娠和甲状腺功能减退症

妊娠合并甲状腺功能减退症(简称甲减)的发生率约为1/1 600～2 000,慢性自身免疫性甲状腺疾病为其常见原因.仅根据临床表现很难对妊娠中的甲减及早诊断,因此,常规筛选显得十分必要,尤其是一些高危人群.血清TSH水平为甲减筛选的敏感指标.妊娠过程中若甲减未能及时控制,可引起多种并发症.母亲甲减对胎儿智力发育的影响正日益受到重视.L-T4为治疗甲减的首选药物.孕期应监测甲状腺功能,并据此调整治疗剂量.     

胎儿窘迫孕妇静脉血及脐血中内源性阿片肽水平的测定

目的　探讨内源性阿片肽与胎儿窘迫发生的关系。方法　采用放射免疫法测定 40例正常妊娠妇女 (正常妊娠组 )及 43例胎儿窘迫孕妇 (胎儿窘迫组 )静脉血及其新生儿脐血中阿片肽 (β 内啡肽、强啡肽A1 13和亮啡肽 )的水平 ,胎儿窘迫组孕妇同时行新生儿脐动脉血血气分析。结果　 (1)胎儿窘迫组脐血中 β 内啡肽、强啡肽A1 13和亮啡肽的水平分别为 (45 3± 68)ng/L、(2 42± 3 3 )ng/L及(498± 68)ng/L ;正常妊娠组分别为 (2 5 1± 3 9)ng/L、(10 3± 2 2 )ng/L及 (3 2 2± 40 )ng/L。与正常妊娠组比较 ,胎儿窘迫组脐血中 3种阿片肽水平均显著升高 (P <0 0 5 )。 (2 )胎儿窘迫组脐血血气分析结果 :pH为 (7 0± 0 1) ,PO2 为 (1 7± 0 6)kPa ,PCO2 为 (8 9± 0 7)kPa ;其中 β 内啡肽水平与脐血pH、PO2呈显著负相关 [相关系数 (r)为 - 0 418及 - 0 43 7,P <0 0 1],与PCO2 呈显著正相关 (r =0 44 2 ,P <0 0 1) ;强啡肽A1 13水平与脐血pH及PO2 呈负相关 (r为 - 0 3 3 7及 - 0 3 83 ,P <0 0 5 ) ,与PCO2 呈正相关 (r=0 3 46,P <0 0 5 )。 (3 )胎儿窘迫组孕妇血中 β 内啡肽、强啡肽A1 13和亮啡肽水平分别为(40± 13 )ng/L、(64± 16)ng/L及 (2 19± 40 )ng/L ;正常妊娠组分别为 (3 7± 9)ng/L、(5     

妊娠与亚临床甲状腺功能减退症的相互影响

亚临床甲状腺功能减退症(亚甲减)又称为轻度甲状腺功能衰竭(mild thyroid failure,MTF),是指无或仅有轻微甲状腺功能低下症状,在实验室检查中发现血清促甲状腺素(TSH)轻度升高(正常值4～10 mU/L),而血清三碘甲状腺原氨酸(T3)、血清甲状腺素(T4)、血清游离三碘甲状腺原氨酸(FT3)、血清游离甲状腺素(FT4)水平均正常的一种综合征[1].     

早孕期甲状腺过氧化物酶抗体阳性对甲状腺功能的影响

目的：探讨妊娠8~12周甲状腺过氧化物酶抗体(TPOAb)阳性对甲状腺功能的影响。方法：对2010年9月至2011年6月北京友谊医院产科门诊行产前检查的611例无甲状腺疾病高危因素的健康初产妇,于妊娠8~12周进行甲状腺功能[促甲状腺激素(TSH)、游离四碘甲状腺原氨酸(FT4)]和TPOAb的检测,通过制定早孕期甲状腺功能正常参考区间,分析TPOAb阳性切割值、阳性率及对TSH、FT4的影响。结果：(1)妊娠8~12周TPOAb中位数值及变化范围为38.9(6.4~>1300)mU/L。(2)通过建立妊娠8~12周人群特异参考标准,以第90百分位计算TPOAb阳性切割值为206.77 mU/L,TPOAb阳性率为10.8%(66/611)。(3)回归分析显示：TPOAb滴度与TSH呈正相关,与FT4呈负相关,P值均为0.000。妊娠8~12周TPOAb阳性妇女TSH中位数值较TPOAb阴性者升高0.4 mU/L,前者TSH异常升高的风险是后者的4.4倍。结论：妊娠8~12周TPOAb阳性率为10.8%,通过建立妊娠期人群特异甲状腺功能参考标准和TPOAb阳性切割值,可避免过高估计TPOAb的阳性率。TPOAb阳性孕妇发生TSH异常升高的风险明显增加。     

产妇与新生儿血清甲状腺激素水平的相关性研究

目的　探讨产妇血清促甲状腺激素 (TSH)水平与其新生儿脐血TSH水平之间的关系。方法　应用免疫放射分析 (IRMA)法测定了 5 0 0例缺碘地区产妇及其新生儿 (研究组 )血清TSH水平 ,同时选择 10 0例非缺碘地区产妇及其新生儿作为对照组。结果　 (1)研究组产妇TSH均值为 (5 .2 5±2 .43)mU/L ,对照组为 (4.6 9± 1.34 )mU/L。研究组新生儿TSH均值为 (6 .83± 4.71)mU/L ,对照组为(5 .32± 3.0 2 )mU/L。 (2 )两组产妇及其新生儿TSH水平呈显著正相关。 (3)两组产妇TSH水平和其游离三碘甲腺原氨酸 (T3 )水平呈显著负相关。结论　监测产妇的TSH水平可评估其新生儿的碘营养状况。     

Umbilical cord plasma interleukin-6 concentrations in preterm infants and risk of neonatal morbidity

OBJECTIVE: This study was undertaken to evaluate the association between umbilical cord interleukin-6 (IL-6) levels and neonatal morbidity in infants born at less than 32 weeks' gestation. STUDY DESIGN: Umbilical cord plasma IL-6 levels and neonatal outcomes were assessed in 309 infants born between 24 weeks and 0 days' and 31 weeks and 6 days' gestation. RESULTS: Mean IL-6 levels were higher in spontaneous (n = 193, 355 +/- 1822 pg/mL) compared with indicated preterm births (n = 116, 37 +/- 223 pg/mL, P < .0001). Adjusting for gestational age, a progressive relationship was noted between increasing IL-6 levels and increased risk of neonatal systemic inflammatory response syndrome (SIRS). IL-6 levels beyond the 90th percentile (> or =516.6 pg/mL) were also significantly associated with periventricular leukomalacia (PVL; odds ratio [OR] 15, 95% CI 2-149) and necrotizing enterocolitis (NEC; OR 6, 95% CI 1.1-33). In the multivariate analysis, an IL-6 level 107.7 pg/mL or greater (determined by receiver operating curve analysis) remained a significant independent risk factor for PVL (OR 30.3, 95% CI 4.5-203.6). CONCLUSION: Umbilical cord IL-6 levels are higher in preterm infants born after spontaneous preterm labor or premature rupture of membranes. Elevated IL-6 levels are associated with an increased risk for SIRS, PVL, and NEC in infants born at less than 32 weeks' gestation.     

Maternal alcohol abuse is associated with elevated fetal erythropoietin levels

The erythropoietin levels in mixed cord serum of 40 infants born to drinking women were compared with those of 24 infants born to abstinent women. Twenty infants born to drinkers had signs of fetal alcohol effects. Thirty-five percent of the erythropoietin levels in mixed cord serum of infants of drinking mothers were above the normal range. Further, the elevation in fetal erythropoietin level correlated with maternal alcohol intake; infants of mothers consuming at least 300 g of ethanol weekly (28) had significantly higher (P less than .025) umbilical erythropoietin levels (median 66 mU/mL, range 10-2500) compared with infants of mothers consuming 150-300 g of ethanol weekly (median 37 mU/mL, range 23-215) or infants of control women (median 32 mU/mL, range 11-73). The subgroup analysis between infants with and without fetal alcohol effects showed no differences in umbilical erythropoietin levels. Maternal alcohol ingestion during pregnancy is associated with elevated umbilical erythropoietin levels, but whether this is a direct effect of ethanol or is induced by chronic fetal hypoxemia remains unclear.     

Correlations between umbilical and maternal serum adiponectin levels and neonatal birthweights

OBJECTIVE: To measure adiponectin levels in maternal serum and umbilical cord serum at delivery, and examine whether or not there are correlations between adiponectin levels and neonatal birthweights, maternal body weights and body mass indexes. STUDY DESIGN: The study included 84 healthy mothers who had given birth to healthy neonates. Adiponectin levels in maternal serum and umbilical cord serum were determined by radioimmunoassay and compared. RESULTS: The ranges of adiponectin levels for umbilical cord serum and maternal serum were 22.7-78.4 microg/ml and 4.0-43.3 microg/ml, respectively. Umbilical serum adiponectin levels (46.9 +/- 1.2 microg/ml) were significantly higher than maternal serum adiponectin levels (16.1 +/- 0.8 micro g/ml) (p < 0.001). No correlation was found between the adiponectin levels in maternal serum and those in umbilical cord serum (r = 0.158, p = 0.151). Umbilical serum adiponectin levels were significantly correlated with both neonatal birthweights (r = 0.454, p < 0.001) and gestational ages at birth (r = 0.295, p = 0.006), but not with maternal serum adiponectin levels. Maternal serum adiponectin levels were only negatively correlated to maternal weights and body mass index at delivery (r = 0.288, p = 0.008; r = 0.372, p < 0.001). CONCLUSION: The levels of adiponectin were higher in umbilical cord serum than in maternal serum. Moreover, the adiponectin levels in umbilical cord serum were found to correlate positively with neonatal birthweights. Therefore, fetal adiponectin, not maternal serum adiponectin, may be involved in fetal development during late pregnancy.     

Maternal serum and umbilical cord blood leptin concentrations with fetal growth restriction

OBJECTIVE: To ascertain whether fetal growth restriction is associated with alterations of leptin concentrations in umbilical cord blood and maternal serum. METHODS: Maternal serum and umbilical cord blood leptin concentrations were determined by immunoradiometric assay at term in 43 women with uncomplicated singleton pregnancies (group A) and in 27 women with singleton pregnancies complicated by fetal growth restriction (group B), all with normal pregravid body mass index (BMI). RESULTS: Maternal serum leptin concentrations were significantly higher in group B compared with group A (45.0 ng/mL [range 34.2-54.9] versus 29.0 ng/mL [range 24.7-33.3]; P<.01). Umbilical cord blood leptin levels were significantly lower in group B compared with group A (8.4 ng/mL [range 3.6-13.2] versus 13.1 ng/mL [9.7-16.5]; P<.01). Maternal serum leptin levels were not significantly correlated with maternal BMI or with neonatal birth weight in either group. Umbilical cord blood leptin concentrations were significantly correlated with neonatal birth weight in both groups. CONCLUSION: Growth restricted fetuses at term show umbilical cord blood leptin concentrations significantly lower than those in normal fetuses, suggesting that fetal adipose tissue is a major source of leptin. Maternal serum leptin concentrations are higher in the presence of a growth restricted fetus. This increase might be due to an intrinsic placental mechanism, by which small placentas produce more leptin as a compensatory mechanism, or to early hypoxia.     

Umbilical cord pH and base excess values in relation to adverse outcome events for infants delivering at term

OBJECTIVE: This study was undertaken to determine the relationship of umbilical cord pH and base excess (BE) values to adverse neonatal outcomes for a large tertiary hospital population delivering at term.Study design The perinatal/neonatal database of St. Joseph's Health Care, London, Canada, was used to obtain the umbilical cord pH and BE values, incidence of adverse neonatal outcomes, and patient demographics for all term (>/=37 weeks' gestation), singleton, liveborn infants with no major anomalies delivering between November 1995 and March 2002 (n=20,456). Statistical analyses included chi(2) analysis, logistic regression models to develop odds ratios and creation of receiver operating characteristic (ROC) curves with area under curve (AUC) calculations. RESULTS: Umbilical vein and artery pH and BE values for this tertiary care population averaged 7.33 +/- 0.06 and 7.24 +/- 0.07, and -4.5 +/- 2.4 and -5.6 +/- 3.0 mmol/L, respectively. Apgar less than 7 at 5 minutes, neonatal intensive care unit (NICU) admission, and assisted neonatal ventilation had significant inverse relationships with both umbilical artery and umbilical vein pH and BE (all P < .0001), with marginal increases in the incidences of these outcomes beginning with cord blood values close to the mean, and more substantial increases with cord values less than 1 or 2 SD below the mean, depending on the outcome studied. The ROC AUC for all these relationships were significant (P < .001) ranging from 0.76 to 0.79 when predicting Apgar less than 7 at 5 minutes to 0.68 to 0.70 when predicting NICU admission, and with cutoff cord blood values at which sensitivity and specificity were maximized again close to mean values. For each of these neonatal outcomes, the relation to cord blood values was similar with little difference in the data analysis whether using pH or BE values, and whether from the umbilical artery or vein. CONCLUSION: There is a progression of risk in term infants for Apgar less than 7 at 5 minutes, NICU admission, and need for assisted ventilation with worsening acidosis at birth, which begins with cord blood values close to mean values indicating a higher threshold for associated acidemia with these outcomes than is seen for more severe neonatal outcomes.     

Increased immunoreactive erythropoietin in cord plasma and neonatal bilirubin production in normal term infants after labor

The purpose of this investigation was to compare immunoreactive erythropoietin levels in umbilical cord plasma and neonatal bilirubin production in infants born of normal women who delivered with or without labor. Two groups of term (38 to 42 weeks) singleton pregnancies were compared: 1) those delivered by repeat elective cesarean section without prior labor (N = 17), and 2) those delivered vaginally or by cesarean section after labor (N = 24). None of the infants was asphyxiated, and there was no difference in Apgar scores between the no-labor and labor groups. The cord plasma erythropoietin levels were lower in the infants of women who had repeat elective cesarean section without labor than in those whose mothers had labor before delivery (Wilcoxon rank sum test, P less than .025). The median erythropoietin for the no-labor group was 22.9 mU/mL compared with 38.8 mU/mL for the labor group. The pulmonary excretion rate of carbon monoxide (VeCO), an index of bilirubin production, for the no-labor group was 14.3 +/- 6.2 SD microL/kg per hour compared with 18.0 +/- 4.9 SD microL/kg per hour for the labor group (P less than .05). The hemoglobin concentration for the no-labor group was 16.0 +/- 1.5 SD g/dL compared with 17.7 +/- 2.2 SD g/dL for the labor group (P less than .05). The VeCO correlated with the hemoglobin concentration (N = 32, r = 0.37, P less than .05). The results of the present study suggest that labor is normally associated with increases in the cord plasma erythropoietin level.(ABSTRACT TRUNCATED AT 250 WORDS)     

The association of hypotonia and depression in the term and near-term neonate with metabolic acidemia

AIMS: To determine the association of hypotonia and depression in neonates at or near term with metabolic acidemia at birth (umbilical arterial pH<7.0 and base excess <-12 mM). METHODS: This case-control study identified 87 infants without chromosomal or congenital abnormalities born at a single university hospital between 7/91 and 10/04 with hypotonia at birth requiring resuscitation and admission to the neonatal intensive care unit that had a cord gas at delivery. Controls were the subsequent delivery with a cord gas matched by gestational age. RESULTS: Cases and controls did not differ in gestational age (38.7+/-1.9, 38.6+/-1.9 weeks) or birth weight (3,066+/-664, 3,171+/-655 g, P=0.20). Cases were more likely to have a cord pH<7.0 [17 (20%) vs. 1 (1.1%), P=0.0001] and cord pH 7.0-7.1 [13 (14.9%) vs. 2 (2.3%), P=0.003]. Among the hypotonic infants, 31 (35.6%) also were depressed at birth with a 5-min Apgar <7. In the depressed subset of hypotonic neonates 14/31 (45%) had a pH<7.0. Of the 12 hypotonic neonates with seizures, 3 (25%) had pH<7.0. Multivariate analysis showed a significant association between neonatal hypotonia and hypoglycemia, umbilical arterial pH, and nucleated red blood cell count. CONCLUSIONS: Although metabolic acidemia is significantly associated with hypotonia at the time of birth, the majority of neonates with hypotonia and depression or seizures do not have objective evidence of asphyxia as measured by a cord gas at the time of delivery.