Prolactin in normal pregnancy: relationship of maternal, fetal, and amniotic fluid levels.

Serum prolactin was measured simultaneously by a homologous radioimmunoassay in 92 parturients and their offspring at term, and in maternal serum and amniotic fluid during various stages of normal pregnancy. Serum levels of 208 +/- 8 ng. per millilter were found in maternal blood; the corresponding levels in the cord serum were 354 +/- 14 ng. per milliliter. Prolactin levels in amniotic fluid were found to be 2- to 10-fold higher than the corresponding levels of the mothers. The possible source of the amniotic fluid prolactin molecule, which is identical with the human pituitary molecule, is discussed.     

Correlation of subjective assessment of amniotic fluid with amniotic fluid index.

We assessed the correlation between abnormal amniotic fluid volumes as defined by the two techniques of (1) subjective evaluation and (2) the amniotic fluid index. Ultrasound evaluation of amniotic fluid volume was conducted on 420 pregnant women with known gestational age greater than twenty weeks but less than 42 weeks. Amniotic fluid was evaluated subjectively and placed into one of three categories: normal, oligohydramnios or polyhydramnios. After fetal biometry was performed, the amniotic fluid volume was assessed semi-quantitatively by the amniotic fluid index technique and assigned to similar categories. We analyzed the data with 2 x 2 contingency tables, using amniotic fluid index as the 'gold standard test'. Our study demonstrates that there was moderate agreement (kappa.5) between both amniotic fluid techniques in the identification of oligohydramnios. However, agreement between the techniques was poor for the identification of polyhydramnios (kappa.16).     

First-trimester amniotic fluid and extraembryonic coelomic fluid acetylcholinesterase electrophoresis.

Acetylcholinesterase (AChE) gel electrophoresis was performed on samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 38 women between 8 and 12 weeks of pregnancy. AChE was positive in 33 per cent (12/36) of the amniotic fluid samples; the percentage of positive results decreased as gestation advanced. AChE was positive in 32 per cent (9/28) of the extraembryonic coelomic fluid samples. In 81 per cent (21/26) of matched samples, the AChE results were identical in the two fluids. Amniotic fluid and extraembryonic coelomic fluid AChE electrophoresis cannot be used to diagnose neural tube defects prior to 12 weeks of gestation.     

Management of meconium-stained amniotic fluid.

Meconium staining of the amniotic fluid will always be a common problem. Although several therapies may be of benefit in preventing MAS, most require further rigorous scientific investigation to assess their potential in preventing this disorder.     

Bacteriolytic activity of amniotic fluid.

Bacteriolytic activity and lecithin concentration were measured in amniotic fluid samples from both normal and pathologic pregnancies, including conditions such as severe Rh isoimmunization, placental dysfunction, preeclampsia, and diabetes. The bacteriolytic activity increased threefold from the 25th gestational week to term, after which a slight reduction was found. No difference was found between pathologic and normal pregnancies. No correlation was found between lecithin content and bacteriolytic activity. Samples from pregnancies in which the infant developed respiratory distress syndrome had low lecithin concentrations but showed normal bacteriolytic activities.     

Antimicrobial effect of amniotic fluid.

The antimicrobial effect of amniotic fluid (AF) obtained during the first (AF1) and second (AF2) trimesters was compared with the third (AF3) against anaerobic bacteria, such as Bacteroides fragilis ss. fragilis (6 strains), Eubacterium lentum (3 strains), and Peptostreptococcus anaerobius (4 strains). Escherichia coli (5 strains) served as a positive control. AF1 supported the growth of all 4 anaerobes (except B fragilis for 4 hours) for the entire 24-hour period tested. AF2 supported the growth of E coli and B fragilis for 24 hours but temporarily inhibited P anaerobius and E lentum. In contrast, AF3 inhibited all bacteria tested for 8 hours or more. It is concluded that AF1 is the least inhibitory, AF3 the most, and AF2 intermediate for the organisms tested. Lack of antimicrobial effect of AF on anaerobic bacteria may be one explanation for the higher incidence of anaerobic infections during absortion than during the prenatal period.     

Meconium-stained amniotic fluid

Passage of meconium usually occurs within 48 hours after birth. However, some fetuses may pass meconium in-utero leading to meconium staining of amniotic fluid (MSAF). The vast majority of fetuses pass meconium in-utero due to the physiological maturation of the fetal gut with advancing gestation leading to normal defaecation in utero. However, clinicians need to exclude ‘non-physiological’ causes of MSAF, especially an ongoing hypoxia or chorioamnionitis, to improve perinatal outcomes. Meconium aspiration syndrome (MAS) is a potentially serious fetal condition with increased risk of severe morbidity and mortality. The use of the cardiotocograph (CTG), timely recognition of ongoing hypoxia or infection, consideration of the overall clinical picture and avoidance of injudicious use of oxytocin may help avoid poor perinatal outcomes and resultant medico-legal consequences.     

Amniotic fluid index: correlation with amniotic fluid volume.

We calculated the amniotic fluid indexes (AFIs) of 310 women on 459 occasions. Normative data were analyzed and compared with data in several high-risk groups. In the normal gestations there was a progressive increase in AFI with advancing gestation until 32 weeks, after which there was a decline. The mean AFIs in abnormal gestations varied with the clinical diagnoses. These values were compared to those obtained by assessing amniotic fluid volume (AFV), that is a pocket more than 2 cm. There were 51 patients with abnormal AFVs. Forty-two had decreased fluid, six also had decreased AFIs; nine had increased AFVs and five (all with diabetes) also had increased AFIs. Thus, AFIs in normal pregnancies showed an orderly pattern of change with gestational age, and there was no accurate correlation between AFI and AFV. Thus, using AFV alone may lead to false interpretations of amniotic fluid status.     

Convention for reporting amniotic fluid pressure.

A proposed convention sets zero pressure at atmospheric pressure at the level of the surface supporting the supine patient and takes the cm of water as the unit of measurement. This ensures that measurements made in different clinics will be comparable. Statements about 'higher' and 'lower' pressures, in different patients or in the same patient in different situations, should specify the level of the uterus to which the statement applies.     

Disappearance of para-amino-hippurate from amniotic fluid.

Eight pregnant women and three pregnant sheep received 400 mg of para-amino-hippurate (PAH) intraaminotically. Serial samples of amniotic fluid and maternal blood were obtained. In sheep samples of fetal blood were also withdrawn. PAH appeared in maternal plasma in all the cases. In all pregnant women PAH disappeared slowly from amniotic fluid (50% in 4 hours). In one ewe the study was performed as in humans and showed the same pattern of disappearance. In the other two, fetal urine was drained outside the amniotic fluid and PAH disappeared from it at a much faster rate (90% in 4 hours). PAH concentration in fetal urine was 100 times higher than in fetal plasma. Our findings in pregnant women seem to suggest that PAH disappears from the amniotic sac by a diffusion mechanism. On the other hand the results found in sheep also suggest that the fetus may have an active role in PAH concentration in amniotic fluid, eliminating part of the substance into maternal blood across the placenta but returning a major portion to the amniotic fluid with fetal urine.     

羊水栓塞的诊断标准

羊水栓塞是一种罕见的妊娠期严重并发症,是导致孕产妇死亡的重要原因。迄今为止,尚缺乏明确统一的诊断标准,是基于产时及产后30 min内发生的,无法解释的肺动脉高压、低氧血症、低血压及发生在大量出血之前的凝血功能障碍等临床表现的排除性诊断。不推荐任何实验室诊断用于确诊或排除羊水栓塞,但血常规、凝血功能、血气分析、心电图、心肌酶谱、胸片、超声心动图、血栓弹力图、血流动力学监测等有助于羊水栓塞的诊断、病情监测及治疗。及早治疗可以改善预后。因此,对于每一例突然发生肺动脉高压、低氧血症、低血压、凝血功能障碍等临床表现的孕产妇,都应考虑到羊水栓塞的可能。对于临床高度怀疑羊水栓塞者,治疗可以先于明确诊断。     

羊水栓塞的鉴别诊断

羊水栓塞作为产科危急重症之一，危及母儿生命，因其临床表现多变，且无明确诊断标准，临床诊断和治疗存在较大难度，故羊水栓塞的鉴别诊断和早期诊断对提高母婴救治成功率有重要意义。