Cervical ripening and plasma prostaglandin levels. Comparison of endocervical and extra-amniotic PGE2

Two modes of cervical application of a gel containing PGE₂ have been compared in a total of 30 patients with indication for induction of labor and unripe cervix. Fifteen patients had gel injected endocervically; in 10 patients the gel contained 400μg PGE₂, in 5 controls the gel was inactive. Fifteen subjects had a 15 ml Foley catheter passed through the cervix and placed extra-amniotically; in 10 of them 3 ml gel with 400 or 800μg PGE₂ was injected, while 5 controls received inactive gel. Plasma levels of 13,14-dihydro-15-keto-PGF_2α (PGFM) were measured in blood samples drawn before and , 1, 2, 4, 6, and 8 hours after gel application. Neither the Foley catheter nor the application of inactive gel caused significant changes in the cervical scores or the PGFM levels. PGE₂ in the endocervix increased cervical scores without altering plasma PGFM levels. Extra-amniotic PGE₂ caused a more rapid increase of the cervical scores and a progressive rise in PGFM levels. The plasma (PGFM) levels were found to be related to the degree and to the rate of cervical dilatation. The correlation with cervical dilatation was highly significant. Labor began spontaneously or after artificial rupture of the membranes in 80% of the extra-amniotic, and 50% of the endocervical PGE₂-group, but in none of the controls. These data indicate that the increased uterine PGF_2α production is not necessary for the early stages of cervical ripening, whereas dilatation beyond 4 cm does not proceed without such increase.     

Cervical ripening and plasma prostaglandin levels. Comparison of endocervical and extra-amniotic PGE2

Two modes of cervical application of a gel containing PGE2 have been compared in a total of 30 patients with indication for induction of labor and unripe cervix. Fifteen patients had gel injected endocervically; in 10 patients the gel contained 400 micrograms PGE2, in 5 controls the gel was inactive. Fifteen subjects had a 15 ml Foley catheter passed through the cervix and placed extra-amniotically; in 10 of them 3 ml gel with 400 or 800 micrograms PGE2 was injected, while 5 controls received inactive gel. Plasma levels of 13,14-dihydro-15-keto-PGE2 alpha (PGFM) were measured in blood samples drawn before and 1/2, 1, 2, 4, 6, and 8 hours after gel application. Neither the Foley catheter nor the application of inactive gel caused significant changes in the cervical scores or the PGFM levels. PGE2 in the endocervix increased cervical scores without altering plasma PGFM levels. Extra-amniotic PGE2 caused a more rapid increase of the cervical scores and a progressive rise in PGFM levels. The plasma (PGFM) levels were found to be related to the degree and to the rate of cervical dilatation. The correlation with cervical dilatation was highly significant. Labor began spontaneously or after artificial rupture of the membranes in 80% of the extra-amniotic, and 50% of the endocervical PGE2-group, but in none of the controls. These data indicate that increased uterine PGF2 alpha production is not necessary for the early stages of cervical ripening, whereas dilatation beyond 4 cm does not proceed without such increase.     

Plasma levels of 13,14-dihydro-15-keto prostaglandin F2α, estrogens, and progesterone during stretch-induced labor at term

The uterus of six healthy multiparous women at term was mechanically stretched by a rubber catheter and balloon. Apparent labor was inaugurated in all cases within 5 hours and increased progressively with time. Advanced cervical softening and dilatation were also evident after the stretch treatment. Significant increases in the levels of 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM) were observed with the progress of treatment (P < 0.01). Plasma estrogens and progesterone levels did not change significantly during the treatment (P > 0.05). Stretching and/or resulting uterine contractions appear to induce the secretion of prostaglandin F_2α (PGF) from the organ, which in turn seems to be involved in both cervical softening, and the onset and progress of labor, under stable conditions of plasma estrogens and progesterone.     

Uterine activity and prostaglandin production following intraamniotic hyperosmolar urea

The relationship between endogenous prostaglandin (PG) production and uterine activity was studied in hyperosmolar urea induced abortion patients. Polygraphic recordings of intraamniotic pressure were obtained at periodic intervals following intraamniotic injection of 80 gm urea. At 0, 0.25, 1, 4 and 8 hours amniotic fluid and blood samples were obtained for PGE, PGF and 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM) analysis by radioimmunoassay. Blood was also sampled at time of absorption. In eight patients studies, uterine tone was elevated by 0.25 hour although no rhythmic contractions were observed by 1 hour. At 4 hours, amniotic fluid PGF concentration increased significantly (P < .01) over the pre-injection value and continued to increase at 8 hours. Amniotic fluid PGE, PGFM and all plasma PG's showed no change during the 8 hour period following urea administration. At time of abortion the plasma PGFM concentration was significantly greater than at the time of injection (238 ± 54.4 vs. 86.7 ± 7.3 pg/ml). There was no significant differences between pre-injection and absorption plasma PGF or PGE concentrations. In the present study, there is no evidence that increased prostaglandin production precedes urea induced contractions. The possible role of PG's in uterine contractions is discussed.     

The origin of circulating 13,14-dihydro-15-keto-prostaglandin F2α during delivery

All uterine tissues as well as the fetal membranes and the placenta can form prostaglandins from endogenous precursors but it is not clear which of the tissues is the main site for the increase in PGF_2α production during human parturition. To examine this question, we measured plasma prostaglandin levels before and at intervals after expulsion of the fetus, placenta, and membranes. The concentration of PGFM at the beginning of the second stage of labor was significantly higher than before the onset of labor. Five minutes after the birth of the infant, the concentration had doubled. Thirty minutes after the expulsion of placenta and membranes, plasma PGFM had fallen to the levels at full dilatation; two hours postpartum it was still significantly raised over levels before labor. Since the halflife of PGFM in the circulation is about 7 minutes, these findings indicate that the uterine tissues are important sources of PGFM during labor. In contrast, endogenous oxytocin levels, which were significantly raised over control levels at the second stage of labor, did not change during the third stage, and decline postpartum to control levels. Oxytocin infusion did not influence PGFM levels at 5 and at 30 minutes postpartum, but raised them at 2 hours.     

Fetal-maternal secretion of prostaglandins in the cow

A study was conducted to measure the blood plasma concentrations of prostaglandin F₂α (PGF₂α), 13,14-dihydro-15-keto-prostaglandin F (PGFM), 6-keto-prostaglandin F₁α (6-keto), prostaglandin E₂ (PGE₂), and thromboxane B₂ (TBX₂) in the ovarian vein, uterine artery, uterine vein, umbilical artery and umbilical vein in 24 cows from days 80 to 260 of pregnancy. Blood was collected during surgery and all prostaglandins were measured using specific radioimmunoassay procedures. Results indicate that PGF₂α blood levels are higher in the umbilical vessels and uterine vein than in the ovarian vein and uterine artery. PGFM and PGE₂ showed a trend towards higher values in the umbilical than in the maternal vessels, but the levels of 6-keto and TBX₂ were not different among the vessels studied. No differences across time couls be observed in any of the prostaglandins measured, partly due to the great variability in blood levels among animals during the same stage of pregnancy.     

Plasma prostaglandin F metabolite concentrations following cervical encerclage

Peripheral plasma concentrations of 13, 14-dihydro-15-keto prostaglandin F₂α (PGFM) were measured in seven women having elective cervical encerclage in an otherwise normal pregnancy. Three of seven patients had a statistically significant elevation of PGFM levels at 60 minutes after commencement of surgery. On the basis that the majority of patients had no significant rise and that there was no objective evidence of uterine contractions post-operatively, the routine administration of prostaglandin inhibitory agents to patients having cervical encerclage cannot be recommended.     

Plasma 13, 14-dihydro-15-keto-PGF2 (PGFM) in pregnant and nonpregnant heifers prior to and during surgery and following intrauterine injection of PGF2

On day 17 postestrus or postmating, heifers were given intrauterine injections of saline (2 pregnant, 2 non-pregnant) or 200 μg PGF₂α (7 pregnant, 6 nonpregnant) through cannulae installed surgically into the uterine horn ipsilateral to the corpus luteum bearing ovary. Jugular blood samples were collected prior to the laparotomy at which the cannulae were installed during surgery, and for 90 min following the intrauterine injection. Plasma was assayed for progesterone and 13,14-dihyro-15-keto-PGF₂α )PGFM). Laparotomies were reopened to confirm proper cannula placement and to determine if blastocysts were present in mated heifers. Concentrations of PGFM were higher in pregnant compared to nonpregnant heifers during the presurgery (68 26 24 26 pg/ml; P < 0.25) and surgery (186 47 65 17 pg/ml; P < .05) periods. Pregnancy status did not alter the mean concentrations of PGFM (pregnant, 554 70 pg/ml; nonpregnant, 422 81 pg/ml) or the half-life of its decline in concentration (18 min) following intrauterine injection of PGF₂α. Pregnancy at 17 days in cattle does not appear to influence PGF₂α transport from the uterine lumen or its metabolism in the uterus or elsewhere in response to an acute intrauterine injection.     

Inhibition of uterine prostaglandin-F2α production by bovine conceptus secretory proteins

The effect of bovine conceptus secretory proteins (CSP) on uterine prostaglandin (PG)-F_2α production was evaluated in dairy cattle following injection of estradiol-17β. Intrauterine injections of dialyzed serum proteins (Control, n=5) or CSP (n=5) were administered from days 15 through 18 post-estrus. Following intrauterine treatments on day 18, all cows were injected with E₂ (3 mg) to stimulate uterine PGF_2α production. Plasma concentrations of progesterone (P₄) and 15-keto-13,14-dihydro-PGF_2α (PGFM) were determined by RIA. The PGFM responses following E₂ challenge were decreased (p<0.01) for cows receiving CSP versus serum proteins into the uterine lumen. Individual PGFM, P₄ and cycle length responses are discussed. Data suggest that proteins secreted by the bovine conceptus suppress uterine PGF_2α production during pregnancy recognition in the cow.     

Conditions of the cervix for the increase of plasma levels of 13, 14-dihydro-15-keto-prostaglandin F2α after amniotomy at term

Amniotomy was performed in 12 multiparas at term but not in labor. In 6 of these patients (group I), the fetal head and cervix condition were favorable for amniotomy, and in the other 6 (group II), they were not favorable. In all group I patients, a sudden and progressive descent of the fetal head, and onset and progress of labor were noted within 5 hours. Plasma 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM) levels increased significantly (P < 0.05)_in 4 of these cases with time. In group II patients, descent of the head was less than that in group I patients (P < 0.05), and neither strong labor nor rise of PGFM levels was noted within 5 hours. These data support our view that amniotomy at an appropriate time results in the onset and progress of labor, and the rise of plasma PGFM in virtue of the sudden and exponential increase of the head to cervix force, but amniotomy at an inappropriate time does not, because this force is unchanged.     

The effect of indomethacin on ovarian prostaglandin release in hens

Indomethacin, an inhibitor of prostaglandin (PG) synthetase, will block uterine muscle electromyographic activity (EMG activity) and oviposition at a midsequence oviposition and ovulation in domestic hens, but does not block the increase in EMG activity associated with the first ovulation of a sequence. To assess the potential relationship between prostaglandin release from the ovarian follicles and EMG activity in egg-laying hens, we determined the concentrations of PGF2 alpha, 13,14-dihydro-15-keto-PGF2 alpha (PGFM), and PGE2 in brachial, ovarian follicular and uterine venous plasma and tissues in relation to uterine muscle EMG activity at the first ovulation and at a midsequence oviposition. The concentrations were measured after an i.m. injection (25 mg/hen) of indomethacin. In control hens sampled hourly, beginning 4 h before the peak of EMG activity at the first ovulation of a sequence, there was a sharp increase (p less than 0.05) in concentrations of PGF2 alpha and PGFM in brachial vein plasma coincident with the increase (p less than 0.05) in uterine EMG activity. Hens pretreated with indomethacin also had increased plasma PGF2 alpha and PGFM levels (p less than 0.05) in brachial vein plasma and increased uterine EMG activity (p less than 0.05) at this time. Indomethacin treatment lowered but did not eliminate mean levels of PGF2 alpha in the venous effluent from the largest preovulatory follicle at the first ovulation (36.0 +/- 9.9 ng/ml vs. 14.4 +/- 1.8 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of estradiol-17β on peripheral plasma concentration of 15-keto,14-dihydro PGF2α and luteolysis in cyclic cattle

Friesian heifers (n = 10) were assigned randomly to receive an intravenous injection of estradiol-17^β (E₂; 3 mg) or saline: ethanol vehicle solution (6 ml; 1:1) on day 13 of the estrous cycle. Blood was collected collected from the jugular vein by venipuncture into heparinized vacutainer tubes at 30 minute intervals for 2 hours (h) preinjection, 10.5 h postinjection and then at 3 h intervals until estrus. Repeated hormone measurements of 15-keto-13,14-dihydro-PGF_2α (PGFM) and progesterone (P₄) were evaluated by split-plot analysis of variance. Mean concentration of PGFM for the 12.5 h acute sampling phase was 164.1 ± .14 pg/ml. A treatment by time interaction was detected (P < .01). After treatment with E₂, PGFM concentrations began to increase at approximately 3.5 h, reached a mean peak of 330.4 ± 44.5 pg/ml (n = 5) at 5.5 ± .3 h, and returned to basal concentration by 9.0 ± .6 h. Vehicle treatment did not alter concentrations of PGFM. Injections of E₂ on day 13 of the estrous cycle caused luteolysis (P₄ concentration < 1 ng/ml) to occur earlier following injection (96.9 ± 10.6 h < 153.6 ±17.7 h; P, 0.05) than did the vehicle control treatment. During the chronic sampling phase of 3 h intervals, 39 of 606 samples (6.4%) were classified as PGFM spikes (323.0 ± 50.0 pg/ml); 21 (53%) of the spikes occurred at a mean interval of 18.9 ± 3.86 h before the time of completed luteolysis. Exogenous E₂ induced an acute increase in PGFM that may be indicative of uterine PGF_2α production. Peaks of PGFM in plasma were temporally associated with luteolysis on a within cow basis.     

Temporal response of uterine prostaglandins to estradiol treatment in the ovariectomized-prenant rat

Previous studies in our laboratory have shown that 24 hours of estradiol treatment significantly enhanced uterine prostaglandin (PG)F, PGE and thromboxane B₂ (TxB₂) leels but had no effect on 6-Keto-PGF_1α (6KF) concentrations in ovariectomized-pregnant rats. One explanatior for the lack of an augmentation in 6KF was a temporal differences in response (i.e. 6KF increased and decreased within the 24 hour period). To test this possibility rats were ovariectomized on day 19 of pregnancy and sacrificed 0, 4, 8, 12, 16, 20 and 24 hours after estradiol treatment. Uterine tissue and venous plasma were analyzed for PGs by radioimmunoassay. No significant (p > .05) alterations were detected for any of the uterine PGs at 0, 4, 8 and 12 hours. However, at 16 hours PGF, TxB₂ and PGE all showed significant (p > .05) increases (2.4, 3.4 and 2.1 fold, respectively) compared to 12 hours. In contrast, no significant augmentation in 6KF levels (p > .05, 1.3 fold) was detected at 16 compared to 12 hours although it was enhanced relative to 0 and 4 hours. In addition, PGF, TxB₂ and PGE, but not 6KF, showed further increases 24 hours after estradiol administration. No alterations were found (p > .05) for any of the PGs in uterine venous plasma at the time points studied. In summary, uterine PGF, PGE and TxB₂ net production appears to be more enhanced by estradiol treatment than 6KF at the time points studied. In addition, there is a slight, but significant, difference in the temporal response characteristics of 6KF compared to the other PGs. The data suggest that the dramatic increase in uterine PGF, PGE and TxB₂ levels at parturition in the rat are probably significantly related to enhanced levels of estradiol. However, the majority of the increase in uterine 6KF levels at labor is more likely caused by factors other than augmented plasma estradiol.     

Retained fetal membranes in cows: Manual removal versus nonremoval and its effect on reproductive performance

Sixteen primiparous Holstein cows with retained fetal membranes (RFM) were studied for postpartum prostaglandin release, uterine infection and resumption of estrous cyclicity after manual removal of RFM (eight cows) versus leaving the RFM untreated (eight cows). The RFM were results of induced parturition on Day 274 of gestation. Seventeen non-RFM primiparous cows were controls. The 15-keto-13, 14-dihydro-metabolite of prostaglandin F(2alpha) (PGFM) was measured in daily blood samples. Aerobic and anaerobic bacteria were cultured from weekly uterine swabs from Week 3 until results were negative. Resumption of estrous cyclicity was determined by milk progesterone three times weekly. Manual removal caused an immediate and large but short-lived increase in PGFM, probably due to the physical damage of uterine tissue. No sustained difference in postpartum PGFM release between cows with RFM manually removed and cows with RFM left untreated was detected. Non-RFM controls had lowest PGFM concentrations. Uterine infections were more frequent and more severe after manual removal of RFM. Untreated RFM-cows and controls were similarly affected. Most infections involved Actinomyces (formerly Corynebacterium ) pyogenes and/or Fusobacterium necrophorum . Actinomyces pyogenes was isolated in the third week postpartum in 5 8 cows with RFM manually removed versus 2 8 cows with RFM left intact and in 2 17 controls. Manual removal prolonged the interval from calving to first functional corpus luteum by 20 d. This study, using RFM resulting from induced parturition, shows that manual removal of RFM can delay the postpartum return to normal reproductive status without altering PGFM profiles.     

Uterine prostaglandin and blood flow responses to estradiol-17β in cyclic cattle

Normal cyclic dairy cattle (n=7) underwent a midventral laparotomy on day 17 of the estrous cycle and were fitted, ipsilateral to the CL, with: an electromagnetic flow transducer around the uterine artery (UA; n=5); catheters within the ovarian vein (OV; n=7) via a uterine branch of the ovarian vein, uterine branch of the ovarian artery (UBOA; n=5) and facial artery (FA; n=7). On day 18, blood samples were collected at 30 min intervals for 1 h prior to injection of estradiol-17β (E₂; 3 mg) and 12 h post-E₂. Uterine blood flow (UBF) was monitored continuously and plasma samples analyzed for PGF_2α and PGFM. Exact locations of catheters in reproductive tracts were verified post-slaughter. Data were analyzed by method of least squares analysis of variance. Uterine blood flow (ml/min) increased above pre-E₂ flow rates within 30 min post-E₂ injection, peaked between 2.5 to 3.5 h and declined between 4 to 8.5 h. A small secondary rise in UBF occurred between 9 and 12 h. Regression analysis for concentrations (pg/ml) of PGF_2α and PGFM in the OV (i.e., [OV]-[FA]) demonstrate a similar response as PGFM concentration in the FA in that all increased at approximately 3 h, peaked between 5 and 7 h and returned to near baseline levels by 9 to 10 h post-E₂. Facial artery PGFM concentrations were positively correlated with uterine production of PGF_2α (r=.66) and PGFM (r=.30), whereas FA PGF_2α concentrations were not. In three of five cows, a difference in PGF_2α was detected between UBOA and FA (UBOA > FA); supportive of a local countercurrent exchange between the uterine venous drainage and the ovarian artery.     

Plasma levels of 13,14-dihydro-15-keto prostaglandin F2 alpha, estrogens, and progesterone during stretch-induced labor at term

The uterus of six healthy multiparous women at term was mechanically stretched by a rubber catheter and balloon. Apparent labor was inaugurated in all cases within 5 hours and increased progressively with time. Advanced cervical softening and dilatation were also evident after the stretch treatment. Significant increases in the levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) were observed with the progress of treatment (P less than 0.01). Plasma estrogens and progesterone levels did not change significantly during the treatment (P greater than 0.05). Stretching and/or resulting uterine contractions appear to induce the secretion of prostaglandin F2 alpha (PGF) from the organ, which in turn seems to be involved in both cervical softening, and the onset and progress of labor, under stable conditions of plasma estrogens and progesterone.     

PGFM (13,14-dihydro-15-keto-PGF2α) in pregnant and pseudo-pregnant Iberian lynx: A new noninvasive pregnancy marker for felid species

In mammals, uterine and placental prostaglandin F_2α is involved in the regulation of reproduction-related processes such as embryonic development, initiation of parturition, and resumption of ovarian activity. Prostaglandin F_2α (PGF_2α) is rapidly metabolized to its plasma metabolite PGFM (13,14-dihydro-15-keto-PGF_2α), which has also been detected in urine. Therefore, the current study aimed to develop and validate an efficient, quick, and inexpensive enzyme immunoassay (EIA) for PGFM estimation in urine of the Iberian lynx (Lynx pardinus) for pregnancy monitoring and for differentiation between pregnancy and pseudo-pregnancy. Urine samples collected from captive Iberian lynx (11 pregnant and 4 pseudo-pregnant cycles) were subjected directly to a PGFM EIA. The assay was validated for parallelism, precision, and stability of urinary PGFM. In addition, high-performance liquid chromatography (HPLC) immunograms and liquid chromatography-mass spectrometry (LCMS) were performed to identify PGFM within urine samples. Urinary PGFM levels before mating and after parturition were about 1.5 ng/mL. After Day 20 postmating, both pregnant and pseudo-pregnant females showed slight increase of hormone levels; in pseudo-pregnant females, this elevation did not exceed 7 ng/mL. A significant increase in pregnant females was observed after Day 45 postmating; urinary PGFM increased from 10 ng/mL at Day 45 toward a peak of 46.0 ± 19.3 ng/mL around parturition. First results show that PGFM is detectable in feces as well and follows similar courses as shown for urine. In conclusion, the presented and validated PGFM assay is an easy and reliable method for noninvasive pregnancy diagnosis in the Iberian lynx (and probably other felids) if applied approximately 20 d prior parturition in pure urine or fecal extracts. High PGFM levels in urine or fecal samples may allow a pregnancy diagnosis without knowledge of mating time, making the PGFM test applicable to free-ranging animals.     

Maternal and fetal prostaglandin concentrations during late gestation in dairy cattle

A study was conducted to measure the blood plasma concentrations of prostaglandin F_2α (PGF_2α), 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM), prostaglandin E₂ (PGE₂) and 13,14-dihydro-15-keto-prostaglandin E₂ (PGEM) in the jugular vein, umbilical vein and artery and uterine vein of 18 Holstein Friesian cows during late gestation. A caesarean section was performed on all cows before term in order to obtain blood samples from the different sources. Plasma PG concentrations in the uterine or fetal circulation were significantly higher than in jugular vein plasma. Correlations between peripheral PG metabolite concentrations and primary PG concentrations in the various sources of the uterus or fetus were not significant (r = .17 − .47) and demonstrated that prostaglandin values based upon peripheral blood alone are of limited value.     

Foley Catheter for Induction of Labor at Term: An Open-Label,Randomized Controlled Trial

Objective

This study aimed to determine the optimal Foley catheter balloon volume (30-mL vs. 80-mL) and the maximum time for cervical ripening (12 hours vs. 24 hours) to improve vaginal delivery rate within 24 hours of induction.

Methods

We conducted an open-label, randomized controlled trial in a teaching hospital in China. Women with a term singleton pregnancy, cephalic presentation, intact membrane and an unfavorable cervix (Bishop score <6) were randomly allocated, in 1:1:1:1 ratio, to receive either one of the four treatments: (1) 30-mL balloon for a maximum of 12 hours, (2) 30-mL balloon for a maximum of 24 hours, (3) 80-mL balloon for a maximum of 12 hours, and (4) 80-mL balloon for a maximum of 24 hours. The primary outcome was vaginal delivery within 24 hours. Secondary outcomes included cesarean section rate and maternal/neonatal morbidity. Data were analyzed on a per-protocol basis.

Results

Five hundred and four women were recruited and randomized (126 women in each group); nine women did not receive the assigned intervention. More women achieved vaginal delivery within 24 hours in 12-hour Foley catheter groups than in the 24-hour Foley catheter groups (30-mL/12 hours: 54.5%, 30-mL/24 hours: 33.1%, 80-mL/12 hours: 46.4%, 80-mL/24 hours: 24.0%, p < 0.001). Cesarean section rates and the incidence of chorioaminonitis were comparable among four groups. After adjustment for confounding factors, both ripening time and balloon size did not affect the proportion of women delivered vaginally within 24 hours of induction.

Conclusion

For women with an unfavorable cervix at term, induction of labor with a Foley catheter is safe and effective. Higher balloon volume (80-mL vs. 30-mL) and longer ripening time (24 hours vs. 12 hours) would not shorten induction to delivery interval or reduce cesarean section rate.

Trial Registration

Chinese Clinical trial registry (ChiCTR-TRC-13003044)     

Plasma prostaglandin levels during early neonatal life following term and pre-term delivery

The concentrations of prostaglandin E (PGE), prostaglandin F (PGF) and 13,14-dihydro-15-oxo-PGF (PGFM) have been measured by sensitive and specific radioimmunoassays in neonatal plasma after term and pre-term delivery. Blood samples were taken in the term delivery group from the umbilical artery at birth and on the sixth post-natal day and after pre-term delivery at 2–4 days, on the sixth day, at 2–4 weeks and at 5–8 weeks after birth. The levels of prostaglandins circulating during the first month of life were far greater than those found in normal adults. In neonates delivered at term the plasma concentration of PGE was significantly lower six days after delivery compared with the concentration at delivery whereas the concentrations of PGF and PGFM were essentially unchanged. Following pre-term delivery prostaglandin concentrations declined with increasing neonatal age although only levels of PGE at 5–8 weeks of age were within the normal range of adult values. Comparison of prostaglandin levels six days after delivery between neonates born at term and pre-term showed no significant differences. These results suggest that prematurity is not associated with marked abnormalities in the ability of the neonate to synthesize or metabolize prostaglandins.