Vitamin D and the risk of dystocia: A case-control study

BACKGROUND

Dystocia is one of the most common causes of cesarean section in nulliparous women. Studies have described the presence of vitamin D receptors in the myometrium, but it is still unclear whether vitamin D affects the contractility of the smooth muscles. We therefore aimed to determine the association between the vitamin D serum level at labor and the risk of dystocia.

METHOD

We conducted a case-control study between January 2012 and June 2017. Cases were primiparous women, with spontaneous onset of labor, who gave birth by cesarean section due to dystocia. Controls were primiparous women with a spontaneous vaginal delivery. We included 60 women (30 cases and 30 controls) in the analysis. The differences between cases and controls were assessed using chi-squared test for categorical variables and two-sample t-test or unequal t-test for continuous variables, as appropriate, after evaluation of whether they followed the normal distributions.

RESULTS

The mean serum 25-hydroxyvitamin D concentrations were 53.1nmol/l (95%CI; 45.2 to 60.9) among cases and 69.9nmol/l (95%CI; 57.5 to 82.4) among controls (P = 0.02). The mean plasma parathyroid hormone levels were 2.25 pmol/l and 2.38, respectively (P = 0.57). Even though 78% of all women reported taking a minimum of 10μg/day of vitamin D throughout pregnancy, 43% had vitamin D insufficiency, defined as serum 25-hydroxyvitamin D levels below 50nmol/l.

CONCLUSIONS

In a Danish group of women having a cesarean section due to dystocia, we found decreased vitamin D levels.

Placental and maternal serum activin A in spontaneous and induced labor in late-term pregnancy

PURPOSE

Feto-placental unit represents an important source of activin A, a member of transforming growth factors-β involved in the mechanisms of labor. No evidences are available on activin A in pregnancies beyond 41 weeks of gestation, where induction of labor is often required. The present study aimed to evaluate activin A maternal serum levels and placental mRNA expression in term and late-term pregnancy, with spontaneous or induced labor, and its possible role to predict the response to labor induction.

METHODS

Maternal serum samples and placental specimens were collected from women with singleton pregnancy admitted for either term spontaneous labor (n = 23) or induction of labor for late-term pregnancy (n = 41), to evaluate activin A serum levels and placental mRNA expression. Univariate and multivariate analyses on activin A serum levels, maternal clinical parameters, and cervical length were conducted in women undergoing induction of labor.

RESULTS

Maternal serum activin A levels and placental activin A mRNA expression in late-term pregnancies were significantly higher than at term. Late-term pregnancies who did not respond to induction of labor showed significantly lower levels of activin A compared to responders. The combination of serum activin A and cervical length achieved a sensitivity of 100% and a specificity of 93.55% for the prediction of successful induction.

CONCLUSION

Late-term pregnancy is characterized by hyperexpression of placental activin A and increased maternal activin A secretion. By combining maternal serum activin A levels with cervical length, a good predictive model for the response to induction of labor was elaborated.

Differences in inflammatory markers between nulliparous women admitted to hospitals in preactive vs active labor

OBJECTIVE

To determine whether labor-associated inflammatory markers differ between low-risk, nulliparous women in preactive vs active labor at hospital admission and over time.

STUDY DESIGN

Prospective comparative study of low-risk, nulliparous women with spontaneous labor onset at term (n = 118) sampled from 2 large Midwestern hospitals. Circulating concentrations of inflammatory markers were measured at admission and again 2 and 4 hours later: namely, neutrophil, and monocyte counts; and serum inflammatory cytokines (interleukin -1β, interleukin-6, tumor necrosis factor-α, interleukin-10) and chemokines (interleukin-8). Biomarker concentrations and their patterns of change over time were compared between preactive (n = 63) and active (n = 55) labor admission groups using Mann-Whitney U tests.

RESULTS

Concentrations of interleukin-6 and interleukin-10 in the active labor admission group were significantly higher than concentrations in the preactive labor admission group at all 3 time points. Neutrophil levels were significantly higher in the active group at 2 and 4 hours after admission. The rate of increase in neutrophils and interleukin-10 between admission and 2 hours later was faster in the active group (P < .001 and P = .003, respectively).

CONCLUSION

Circulating concentrations of several inflammatory biomarkers are higher and their rate of change over time since admission is faster among low-risk, nulliparous women admitted to hospitals in active labor, as compared with those admitted in preactive labor. More research is needed to determine if progressive changes in inflammatory biomarkers might be a useful adjunct to improving the assessment of labor progression and determining the optimal timing of labor admission.

Baseline TNFα operational capacity in fetal and maternal circulation prior to the onset of labor: "tuned for different purposes"

OBJECTIVE

In this study, we sought to characterize the tumor necrosis factor α (TNFα) baseline operational capacity in mature fetuses and their mothers prior to the onset of labor.

MATERIALS AND METHODS

We used an experimental pregnant nonhuman primate model to measure the plasma concentration of TNFα, TNF transmembrane receptor I (TNFRI), and TNFRII with validated enzyme-linked immunosorbent assays. Coefficients of correlations between the maternal and the fetal values and the soluble TNFα, TNFRI, or TNFRII concentrations and ratios were calculated.

RESULTS

The TNFα/TNFRI ratio was 3 times lower in fetal circulation than in maternal circulation. No correlations were noted between the maternal and the fetal TNFα, TNFRI, or TNFRII plasma concentrations.

CONCLUSIONS

These findings suggest that the fetal and maternal baseline circulatory operational capacities of TNFα are independent of each other and tuned differently. This differential regulation of TNFα in fetal and maternal circulation at the end of pregnancy may be guided to protect the fetus from the systemic inflammatory response that is essential for the mechanisms of labor to proceed in the mother.

IL-6 and TNFalpha across the umbilical circulation in term pregnancies: relationship with labour events

OBJECTIVE

We have determined venous and arterial cord blood levels for IL-6 and TNFalpha at the time of delivery to assess gestational tissue versus fetal sources in labouring and non-labouring patients at term, and the relationship to labour events.

METHODS

Fifty-five patients were studied (elective cesarean section n=24, and labouring n=31) with blood sampling from a clamped segment of cord after delivery of the fetus and from the cord at its insertion into the placenta after delivery of the placenta, with subsequent measurement of blood gases, pH, IL-6 and TNFalpha.

RESULTS

Umbilical cord levels for IL-6 were increased by 4 fold in low risk labouring patients, and a further 6 fold when showing histologic chorioamnionitis, but with no evident effect of nuchal cord with 'variable' fetal heart rate decelerations, fetal acidemia, nor of labour duration. IL-6 levels from the cord at its insertion into the placenta were generally higher than those from the respective umbilical levels indicating that placental release of IL-6 into cord blood must be occurring. However, a consistent venoarterial difference for IL-6 and thereby a net flux from the placenta could not be demonstrated. TNFalpha levels for both patient groups were uniformly low for all of the cord measurements with no significant differences noted.

CONCLUSION

Umbilical cord levels for IL-6 are increased in low risk labouring patients at term in the absence of evident infection which likely involves both gestational tissue and fetal contributions. Cord levels for IL-6 are further increased in low risk labouring patients showing histologic chorioamnionitis which might then contribute to newborn morbidity in these pregnancies.

Patterns of plasma corticotropin-releasing hormone, progesterone, estradiol, and estriol change and the onset of human labor

CONTEXT

Clinical prediction of preterm delivery is largely ineffective, and the mechanism mediating progesterone (P) withdrawal and estrogen activation at the onset of human labor is unclear.

OBJECTIVES

Our objectives were to determine associations of rates of change of circulating maternal CRH in midpregnancy with preterm delivery, CRH with estriol (E3) concentrations in late pregnancy, and predelivery changes in the ratios of E3, estradiol (E2), and P.

DESIGN AND SETTING

A cohort of 500 pregnant women was followed from first antenatal visits to delivery during the period 2000-2004 at John Hunter Hospital, New South Wales, Australia, a tertiary care obstetric hospital.

PATIENTS

Unselected subjects were recruited (including women with multiple gestations) and serial blood samples obtained.

MAIN OUTCOME MEASURES

CRH daily percentage change in term and preterm singletons at 26 wk, ratios E3/E2, P/E3, and P/E2 and the association between E3 and CRH concentrations in the last month of pregnancy (with spontaneous labor onset) were assessed.

RESULTS

CRH percentage daily change was significantly higher in preterm than term singletons at 26 wk (medians 3.09 and 2.73; P = 0.003). In late pregnancy, CRH and E3 concentrations were significantly positively associated (P = 0.003). E3/E2 increased, P/E3 decreased, and P/E2 was unchanged in the month before delivery (medians: E3/E2, 7.04 and 10.59, P < 0.001; P/E3, 1.55 and 0.98, P < 0.001; P/E2, 11.78 and 10.79, P = 0.07).

CONCLUSIONS

The very rapid rise of CRH in late pregnancy is associated with an E3 surge and critically altered P/E3 and E3/E2 ratios that create an estrogenic environment at the onset of labor. Our evidence provides a rationale for the use of CRH in predicting preterm birth and informs approaches to delaying labor using P supplementation.

[Low-energy semiconductor laser intranasal irradiation of the blood improves blood coagulation status in normal pregnancy at term]

OBJECTIVE

To explore the effect of low-energy semiconductor laser intranasal irradiation of the blood on blood coagulation status in healthy pregnant women at term.

METHODS

Low-energy semiconductor laser was introduced into the nasal cavity in 126 healthy pregnant women at term and 123 healthy young unmarried women as the control group. The plasma prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and fibrinogen levels were examined using transmissive turbidimetry after the therapy.

RESULTS

PT, APTT and TT levels were significantly lowered, whereas fibrinogen level significantly increased in the healthy pregnant women before the laser therapy as compared with those in the control group (P<0.01). After intranasal laser therapy, these parameters were significantly improved in the healthy pregnant women (P<0.05) although there were differences from those of the control group.

CONCLUSION

Low-energy semiconductor laser intranasal irradiation of the blood can effectively improve high blood coagulation status in healthy pregnant women at term.

[Evidence that periplacentary leukocytes subpopulations of term pregnancy have functional properties associated with labor induction]

BACKGROUND

The rise of cholagenolitic activity in fetal membranes, associated to premature rupture, have been related to abnormal activity of the extracellular matrix metalloproteinases discharged to the extracellular space as inactive enzymes that have to be activated to selectively degrade its components.

OBJECTIVE

To analyze the functional properties of leukocytes subpopulations coming from the placental circulation.

MATERIAL AND METHODS

Biomedical experimental study in which placental and outlying blood leukocytes were cultivated during 96 hours, from women with pregnancy to term without labor. Leukocytes subpopulations were stained by flow cytometry. Culture media were analyzed with zymography and enzymatic activity profile was evaluated in presence of proteases inhibitors.

RESULTS

Placental leukocytes are composed of T-, NK- and B-lymphocytes, and monocytes; it was documented a progressive increase of inactive MMP-9 secretion (92 kDa), accompanied by an 82 kDa form MMP-9 activation since 48 hours. Enzymatic profile mainly showed metalloproteasas.

CONCLUSIONS

Placental blood leukocytes showed functional capacities different from those that circulate in pregnant women's outlying circulation. Placental leukocytes, mainly T-lymphocytes, are characterized by the specific capacity to secrete and activate MMP-9; an enzyme that participates in fetal membranes degradation. It suggests that in placental surroundings are recruited cells specialized in labor changes induction.

[The seasonal aspects in activity of antioxidate enzymes in delivery woman inhabiting in the north]

The activity of super oxide dismutase (S), glutathione peroxidase (P), glutathione reductase (R) were analyzed 4 times during delivery (24 hour before partum, at start of the partu, immediately postpartum, and in 24 hours postpartum) in two populations of women inhabiting at 62 degrees NC (55 cases) and 69 degrees NC (40 cases) with normal delivery in January, March, June, and October. It was shown that physiological delivery did not play any significant role in S and P activity, and for these enzymes essential was the seasonal level of lipid peroxidation in North inhabitants. Activity of R in January and March was significantly lowered to the end of childbirth. Most Northern delivery women seem to have limited reserves in antioxidant enzymes function.

3alpha-reduced neuroactive steroids and their precursors during pregnancy and the postpartum period

Allopregnanolone (ALLO) and pregnanolone (PREG), the 3alpha-reduced metabolites of progesterone (PROG), are potent modulators of gamma-aminobutyric acid type A receptors that may function as endogenous anxiolytics. They are purported to be involved in the etiology or expression of clinical depression. In the present study we quantified ALLO and PREG, as well as PROG, 5alpha-dihydroprogesterone (5alpha-DHP), 5beta-dihydroprogesterone (5beta-DHP), epiallopregnanolone and pregnenolone (PREGNEN), in plasma from healthy women at five time points during pregnancy and the postpartum period. Analysis was by gas chromatography/electron capture - negative chemical ionization - mass spectrometry. Neuroactive steroids increased significantly from 10 to 36 weeks of pregnancy, except for 5beta-DHP and PREGNEN which did not change significantly. PROG was the most abundant steroid throughout pregnancy, followed by 5alpha-DHP and ALLO. Metabolite to precursor ratios differed depending on the enzyme and substrate: the turnover of PROG to 5alpha-DHP (catalyzed by 5alpha-reductase) was stable while the conversion of PROG to 5beta-DHP (catalyzed by 5beta-reductase) decreased later in pregnancy. 3alpha-Hydroxysteroid oxidoreductase-mediated turnover of 5alpha- and 5beta-DHP to their metabolites ALLO and PREG, respectively, rose during pregnancy, but the turnover of 5alpha-DHP to ALLO dropped at the late prenatal visit. At 6 weeks postpartum all steroids were significantly reduced compared with late prenatal values, with 5alpha-DHP being the most abundant postpartum steroid. These results provide the basis for further study of neuroactive steroids in psychiatric conditions of pregnancy and the postpartum period.

Influence of low- and high-molecular-weight plasminogen activators on the onset of labor and on the hemostatic system

Measurement of activities of urinary (u-PA) and tissue plasminogen activator (t-PA) and analysis of euglobulin lysis times (ELTs) and prekallikrein were performed simultaneously using the plasma of normal pregnant women and nonpregnant women. The activities of plasminogen activators were determined by the method of electrophoretic zymography. The activity of low-molecular-weight (LMW) u-PA was significantly decreased at the onset of labor (p = 0.05) compared with that during the latter half of pregnancy. The same tendency was observed in the analysis of prekallikrein. On the contrary, no significance was shown in activities of high-molecular-weight (HMW) u-PA or t-PA. It is suggested that the action of kallikrein on low-molecular-weight u-PA causes it to change into plasmin at the onset of labor.

Maternal serum total activin A and follistatin in pregnancy and parturition

OBJECTIVE

To examine changes in maternal serum levels of activin A and follistatin during pregnancy and labour.

DESIGN

In three cross sectional and three longitudinal studies venous blood was collected from women during pregnancy, spontaneous labour, labour induction and prior to elective caesarean section for the measurement of activin A and follistatin.

SETTING

Monash Medical Centre, Clayton, Victoria, Australia.

POPULATION

One hundred and twenty-three women participated in a cross sectional study in pregnancy, 18 women in two longitudinal pregnancy studies, 36 women in a cross sectional labour study, nine women in a longitudinal study of labour induction. Ten women undergoing elective caesarean section were also studied.

METHODS

Activin A and follistatin were measured using two sensitive and specific enzyme-linked immunosorbent assays.

RESULTS

In the cross sectional study of pregnancy, mean (SEM) maternal serum activin A and follistatin levels increased towards term (2.4 ng/mL (0.3) and 1.8 ng/mL (0.3) in first trimester to 18.9 ng/mL (3.8) and 5.3 ng/mL (0.9) at term, respectively), but the longitudinal study revealed that levels plateau in the last three weeks of pregnancy (16.0 ng/mL (2.6) and 6.2 ng/mL (1.4) at 37 weeks and 16.6 ng/mL (3.5) and 6.2 ng/mL (0.5) before labour for activin A and follistatin, respectively). There was no difference in levels of activin A and follistatin between women delivered by caesarean section and labouring women at term (14.9 ng/mL (2.8) vs 11.0 ng/mL (0.93) and 5.95 ng/mL (0.67) vs 5.71 ng/mL (0.63), respectively) and levels of both proteins did not alter throughout spontaneous or induced labour.

CONCLUSIONS

We believe that these data argue against activin A playing an acute role in the initiation or regulation of human parturition.

[The change in placental estradiol-progesterone ratio and its relationship with the fetal membrane's response to IL-1 beta in labor]

This study was designed to investigate the local changes in the levels of placental estradiol and progesterone and their ratio during term labor and to determine whether the PGE2-generating ability of the fetal membrane in response to IL-1 beta at term labor is greater than that at term not-in-labor. Forty pregnant women were divided into two groups: term labor and term not-in-labor. Placental estradiol and progesterone were measured by radioimmunoassay. The levels of fetal membrane PGE2 were measured by enzymoimmunoassay. The results showed that the placental concentration of estradiol and progesterone remained unchanged at the onset of labor, but the ratio of estradiol to progesterone increased significantly (P < 0.05). IL-1 beta stimulated fetal membrane to produce more PGE2 at term labor, and at term not-in-labor, too. But the increment of PGE2 generated by fetal membrane at term labor was greater than that at term not-in-labor. It is concluded that the change in placental estradiol to progesterone ratio may play an important role in the initiation of labor by altering the PGE2-generating ability of fetal membrane in response to cytokines.

Reactive oxygen species in the process of labor

Levels of thiobarbituric acid reactive substances (TBARS), an indicative parameter for oxidative damage, were measured in maternal and cord arterial and venous bloods, and compared between abdominal and vaginal deliveries. Spontaneous labor resulting in either vaginal or emergency abdominal deliveries was associated with a statistically significant higher levels of TBARS in cord artery compared to cord vein and maternal blood (p<0.05). The results support a role of reactive oxygen species in the initiation of labor, possibly through their effect on prostaglandin metabolism. Alternatively, this may be a marker of fetal oxidative stress, secondary to the process of labor.

The relationship between the onset of labor mechanisms and the hemostatic system

The relationship between onset of labor and the hemostatic system was evaluated in 38 pregnant women. The hemostatic system consists of blood coagulation, kinin-kallikrein system, the fibrinolytic system, and platelet function. The most prominent changes take place in the kinin-kallikrein system. After the onset of labor, prekallikrein decreases rapidly which may trigger changes in blood coagulation and the fibrinolytic system. Platelet hemostatic capacity (PHC) was also measured using the PFA-100 (platelet function analyzer) system. Closure times (CT) were shorter during pregnancy, compared to non-pregnant controls, suggesting an increase in PHC. Platelet aggregation by ADP at the end of pregnancy was decreased at the onset of labor. At the same time a slight increase in FDP (fibrin degeneration product) was also seen. While FDP increased, platelet aggregation decreased, which seems to suggest FDP inhibits platelet aggregation. In this manner, these three systems(kinin-kallikrein system, blood coagulation, and fibrinolytic system) and platelet aggregation are closely interrelated, possibly affecting uterine contractility during pregnancy and the onset of labor.

Tumor necrosis factor during pregnancy and at the onset of labor and spontaneous abortion

OBJECTIVE

The aim of this study was to evaluate the production of tumor necrosis factor (TNF) by peripheral blood cells during pregnancy, at the onset of labor and of spontaneous abortion (SA), as well as in non-pregnant women with and without a history of recurrent spontaneous abortions (RSA).

STUDY DESIGN

The peripheral blood cells TNF production was evaluated in 28 women in the 1st trimester of pregnancy, 21 in the 2nd, and 30 in the 3rd, 47 at term labor; 43, at the onset of SA; 19 healthy and 19 RSA non-pregnant women. The statistical method used was the Mann-Whitney test.

RESULTS

We observed (1) lack of TNF detection in the 1st gestational trimester; (2) increase of TNF production with gestational age, with the highest values being observed at labor (P<0.05); (3) high TNF production at the onset of SA; (4) no difference in the TNF production by healthy and RSA non-pregnant women.

CONCLUSIONS

The suppression of TNF production during the 1st trimester of pregnancy seems to favor the normal development of pregnancy. It remains to be investigated whether the assessment of TNF production is a valuable prognostic parameter for the occurrence of abortion.

[Determination of diazepam concentration in maternal and fetal serum after intravenous administration during active phase of labor and its effects on neonates]

OBJECTIVE

To investigate the effects of diazepam on the neonates administered intravenously during the active phase in labour.

METHODS

Sixty normal term parturients during the active phase of labour with the cervical dilatation to 3-5 cm were randomly divided into two groups, study group (n = 30) and control group (n = 30). In study group 10mg diazepam was administered intravenously. The concentrations of diazepam and demethyldiazepam in maternal and cord serum were measured by high performance liquid chromatography and neonatal arterial blood gas and Apgar scoring were determined immediately after birth.

RESULTS

At delivery, the mean level of diazepam in umbilical cord serum was 947 +/- 314 micrograms/L, markedly higher than that of maternal serum which was 488 +/- 300 micrograms/L, while the mean levels of demethyldiazepam were not significantly different in maternal and fetal serum. There was no marked difference between the two groups in fetal arterial blood gas and acidbase status. However, the rates of respiratory depression and muscle tone inhibition in the neonates of study groups (63.3% and 26.7% respectively) were significantly higher than those in the control group (30% and 3.3% respectively) (P < 0.05, P < 0.01).

CONCLUSIONS

Use of diazepam in pregnant women during active phase of labour may cause depression of neonatal respiration.

[Changes in blood oxytocin levels in cases of pregnancy induced hypertension]

Serial measurements of plasma oxytocin concentration were done by radioimmunoassay in 38 cases of pregnancy induced hypertension (PIH) and 38 cases of normal pregnancy (NP). The results showed that there was no obvious difference in the plasma oxytocin concentration between patients with early PIH and NP, but a higher concentration in cases with PIH at term pregnancy than that in NP and a significantly higher level in intrapartum women with PIH. The results also indicated a much higher oxytocin concentration in cases of moderate and severe PIH as compared to that of NP. An obviously higher level of plasma oxytocin was found in severe PIH than in mild PIH. Based on this study we suggest that the clinical use of oxytocin in cases with PIH should be different from that in NP.

[Ripening effect of mylis and tiluoan on the uterine cervix in pregnant rats]

Effect of Mylis and Tiluoan on cervical ripening and blood levels of estradiol and progesterone of pregnant rats were studied. Dehydroepiandrosterone (DHA) is the main component in both of the drugs. Pregnant rats groups were given the drugs on the 19th day of gestation at dosage of 10, 20 and 40 mg/kg respectively. The results indicated that both drugs at different dose were able to significantly decrease the cervical extensibility, to dilate the cervical OS, increase the cervical wet weight, and elevate the blood estradiol level, lower the progesterone concentration. It indicated that DHA enhances estradiol synthesis and suppresses progesterone secretion.

[Blood gas and acid-base equilibrium in normal pregnancy and pregnancy with fetal distress by vaginal delivery or cesarean section]

Blood gas and acid-base assessment of maternal dorsalis pedis artery and umbilical artery and vein was carried out immediately after delivery in 46 cases of normal term pregnancy and 41 cases of pregnancy with fetal distress (FD). Blood gas and acid-base equilibrium differences between vaginal delivery and cesarean section were studied. The results showed a low BE value (< -3mmol/L) in maternal artery of both groups, and that the other parameters were all within normal range, not being different between the normal pregnancy and FD group. Blood gas assaying of umbilical veins of the 2 groups also showed no difference. In comparison with the normal pregnant group, the FD group yielded significantly decreased values of pH, PO2 and O2Sat in umbilical artery but significantly increased PCO2 (P < 0.05). Women of both groups delivered vaginally had milder metabolic acidosis and slighter hypoxia than those delivered by cesarean section. Marked fetal acidosis and low Apgar score were more commonly seen in the FD group. These indicated that to delay labor to near term and to perform cesarean section for relieving fetal distress is advisable.

Serum collagenase levels in relation to the state of the human cervix during pregnancy and labor

OBJECTIVE

The purpose of our study was to investigate the role of collagenase in the cervical ripening and dilatation process in term pregnancy.

STUDY DESIGN

Serum samples were obtained from nonpregnant women (n = 5) and term-pregnant women. The term-pregnant women were either admitted for elective cesarean section or labor induction (unfavorable cervix, n = 19; favorable cervix, n = 12) or in spontaneous, active labor (stiff and inelastic cervix, n = 7; soft compliant cervix, n = 8). Statistical analysis was performed with the Student t test.

RESULTS

The nonpregnant women had low serum collagenase levels (5.2 +/- 0.7 micrograms collagen digested per minute per 100 ml serum, mean +/- SEM). At term but before labor, women with unripe cervices had higher collagenase levels (10.3 +/- 0.9). The women with ripe cervices had even higher serum collagenase levels (22.9 +/- 4.2; p < 0.001). During labor, women with stiff and inelastic cervices had lower serum collagenase levels compared with women with soft and compliant cervices (12.9 +/- 1.7 vs 28.0 +/- 4.2; p < 0.01).

CONCLUSION

Serum collagenase during ripening at term and in active labor increases, supporting its active role in the ripening process.

Serum dehydroepiandrosterone and cortisol concentration in the maternal-fetoplacental hormonal system in elective caesarean section and spontaneous vaginal delivery in the 28th to 36th and 40th weeks of pregnancy

The authors compared the serum DHAS and cortisol level in 53 vaginal deliveries with those of 21 caesarean sections prior to the onset of labour at the 28th to 36th weeks. They also compared 18 vaginal deliveries with 16 elective caesarean sections at the 40th week. The serum hormone concentrations were measured in the maternal vein, the umbilical vein and the umbilical artery. The results indicate that the serum DHAS and cortisol level was higher after vaginal delivery than after caesarean section in the maternal vein, umbilical vein and umbilical artery at the 28th to 36th and also at the 40th week. The authors suggest that, although the role of the fetal adrenal cortex is not so definitive as in the case of some species in the onset of labour, it may be presumed that the increase in adrenal cortical activity cannot be explained exclusively by maternal stress.

Raised maternal plasma alpha-fetoprotein and pregnancy outcome

With the aim of evaluating the clinical value of raised maternal plasma alpha-fetoprotein (AFP) in women with singleton fetuses without structural abnormalities, the outcome of pregnancy was evaluated in a group of 20 women with these characteristics. Only 6 women (30%) delivered fetuses with appropriate birthweight at term; there were 6 pregnancy losses (30%), and the remaining pregnancies ended in pre-term delivery and/or birth of a small for gestational age fetus. Ultrasound examination supplied additional information in 3 cases only. Amniocentesis did not seem to affect pregnancy outcome in this group of high-risk pregnancies. Serial AFP testing was useless for monitoring these pregnancies. It is concluded that raised maternal plasma AFP must be regarded as a marker of poor pregnancy outcome even after exclusion of neural tube defects.

[Changes in N-acetyl-beta-glucosaminidase activity in the maternal plasma and utero-placental tissues during normal pregnancy and parturition]

In the ripening of the uterine cervix during parturition, glycosaminoglycan (GAG) in the cervical extracellular matrix has been reported to undergo drastic changes i.e. the increase in hyaluronic acid, and the decrease in dermatan sulfate and chondroitin sulfate. N-acetyl-beta-glucosaminidase (NAG; EC3.2.1.30), one of marker enzymes of lysosome, may also degrade extracellular GAG in the uterine cervix. This study is undertaken to determine if NAG plays a role in the ripening of the cervix during parturition. The maternal plasma were collected from 252 women with normal pregnancy (5-41 weeks gestation). Amnion, chorion and parietal decidua were obtained from 20 patients at more than 36 gestational weeks who had undergone cesarean section (CS) prior to labor, and from 24 who had undergone CS after the onset of labor. NAG activity in the maternal plasma gradually increased with the advance of gestation, and increased drastically after the onset of labor. The activity in the amnion and decidua, but not in the chorion, decreased significantly in the women who had undergone CS after the onset of labor compared with those who had undergone CS prior to labor. It is concluded that NAG is released into the maternal circulation from lysosomes in amnion and decidua, and it is also estimated that NAG plays a role in the ripening of the uterine cervix during parturition by degrading GAG in the cervical extracellular matrix.