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PubMed1992

An open study comparing two regimens of gemeprost for the termination of pregnancy in the second trimester.

Two regimens of the prostaglandin E1 analogue, gemeprost, were compared in an open trial for termination of pregnancy between 12 and 18 weeks. Fifty women received 5 x 1 mg of gemeprost every 3 h and in another 50 cases, 4 x 1 mg of gemeprost was administered every 6 h. Although the median abortion interval was slightly shorter in the 3-hourly group (15.9 h vs. 16.9 h; p = 0.5), the cumulative abortion rates at 24 h were similar (88% vs. 82%; p less than 0.5). In women who aborted within the first 24 h, significantly fewer pessaries (p less than 0.01) were required to induce abortion in the 6-h treatment group (median 3, range 1-4) than the 3-h group (median 5, 2-5). Parous women in both treatment groups required fewer pessaries to induce abortion than did nulliparous women (not significant; p = 0.5). Significantly (p less than 0.01) fewer pessaries were required to induce abortion in the 6-h gemeprost group. The were no significant differences between the groups regarding incidences of diarrhea, vomiting, or the request for analgesia. These results suggest that in many women the number of pessaries used to induce mid-trimester abortion could be reduced by lengthening the interval between insertion of pessaries within the first 24 h, without loss of clinical efficacy.

Abortifacient Agents, Nonsteroidal↗
PubMed1992

A study of gemeprost alone, dilapan or mifepristone in combination with gemeprost for the termination of second trimester pregnancy.

It is well established that abortion can be induced successfully in midtrimester of pregnancy by gemeprost vaginal pessaries. A randomised study was carried out to determine the efficacy of mifepristone and dilapan in combination with gemeprost for second trimester termination between 12-18 weeks' gestation. A contemporary group of women treated with gemeprost alone was used as a control group. A single course of 4 x 1 mg gemeprost pessaries was administered every six hours. If abortion had not occurred after 24 hours, a further course of 5 x 1 mg pessaries was administered every three hours over the next 24 hours. In the first twenty hours after administration of gemeprost, 95%, 85% and 72% of women aborted in the mifepristone, dilapan and the control group, respectively. The median induction-abortion interval in the mifepristone group (6.6h) was significantly shorter than the other two groups and fewer pessaries were required to induce abortion. The incidence of diarrhoea and vomiting was lower in the mifepristone than the other two study groups. This study demonstrated the efficacy of mifepristone in combination with gemeprost and this regimen is associated with fewer gastrointestinal side effects.

Abortifacient Agents, Nonsteroidal↗
PubMed1997

Prostaglandin E2 for cervical ripening: a randomized comparison of Cervidil versus Prepidil.

OBJECTIVE: Our purpose was to compare the efficacy and safety of two standardized preparations of prostaglandin E2, Prepidil and Cervidil, for ripening of the cervix and initiation of labor. STUDY DESIGN: This was a prospective randomized study. Subjects in whom induction of labor was indicated were randomly assigned to receive either Prepidil (n = 36), an intracervical prostaglandin E2 gel, or Cervidil (n = 37), a controlled-release hydrogel pessary, as a cervical ripening agent. Inclusion criteria included (1) a Bishop score of < or = 7, (2) a cervix < 4 cm dilated, and (3) < or = 2 cm of cervical dilatation if effacement was > 70%. Each agent was administered according to the manufacturer's recommendations. RESULTS: There was no difference in Bishop scores between the two groups at the completion of the ripening process. The following mean times were shorter for the pessary group than for the gel group: (1) insertion of the ripening agent to vaginal delivery (20.6 vs 26.4 hours, p = 0.017), (2) time to achieve cervical ripening (11.1 vs 15.2 hours, p < 0.001), (3) time to achieve active labor (18.3 vs 25.5 hours, p = 0.019), and (4) hospital stay (3.7 vs 4.4 days, p = 0.03). Labor was initiated without the use of oxytocin in 24% of patients in the pessary group versus 3% of those in the gel group (p = 0.014). CONCLUSION: Both prostaglandin E2 agents are effective in achieving cervical ripening; however, the controlled-release pessary achieves ripening over a shorter time period. Furthermore, because time to achieve vaginal delivery and length of stay are shorter, the use of oxytocin is less frequent, and there is no increase in complications, the overall cost is expected to be less with the use of Cervidil as compared with Prepidil.

Adult↗
PubMed1992

The effect of pH on release of PGE2 from vaginal and endocervical preparations for induction of labour: an in-vitro study.

OBJECTIVE: To study the effect of pH and precoating with obstetric cream on the release of prostaglandin E2 (PGE2) from commercially available triacetin and starch based gels, lactose based vaginal tablets and sustained release hydrogel polymer pessaries in-vitro. DESIGN: A prospective observational study. METHODS: PGE2 preparations held in dialysis bags were placed in Ringers lactate buffer and release of PGE2 into the buffer was measured over 8-12 h by radioimmunoassay. The hydrogel polymer pessary was also assessed after precoating with obstetric cream. MAIN OUTCOME MEASURES: In-vitro PGE2 release at pH 7.4, pH 5.4 and pH 3.4. RESULTS The gel preparations provided rapid and reliable release, while the lactose based vaginal tablet provided much lower release of PGE2 with sudden and variable release occurring after 5-8 h, an effect which was enhanced at low pH. With the triacetin gel preparation, release of PGE2 was reduced at lower pH, while the starch based gel appeared to provide optimal release at pH 5.4. The hydrogel polymer pessaries provided linear release in-vitro and this was reduced at pH 3.4. In addition, precoating the sustained release hydrogel polymer pessaries with obstetric cream virtually abolished release of PGE2. CONCLUSIONS: As the vagina is normally acid, these results suggest that vaginal pH could influence PGE2 release and this may result in variable clinical responses. In view of this, pH should be taken into account in the development of preparations for clinical use. Furthermore, the use of obstetric cream should be avoided when administering PGE2 preparations for induction of labour.

Cells↗
PubMed1980

Vaginal chemoprophylaxis in the reduction of reinfection in women with gonorrhoea. Clinical evaluation of the effectiveness of a vaginal contraceptive.

A clinical investigation was undertaken to determine if chemoprophylaxis in the form of a contraceptive pessary would reduce the rate of reinfection with gonorrhoea in 1245 female patients attending a venereal disease clinic. After the introduction of the pessary the reinfection rate over a 16-week period was 19% compared with 40% in the control clinic patients. It was also found that women could be motivated to use a pessary; 65% of women used pessaries before sexual intercourse at least some of the time. High reinfection rates in venereal disease clinic patients emphasise the need for improved methods of preventing reinfection. Vaginal chemoprophylaxis appears to be an alternative means of reducing gonorrhoea morbidity.

Contraceptive Agents, Female↗
PubMed1975

The application of long- and short-term progestagen treatments for oestrous cycle control in heifers.

Progestagen-impregnated pessaries were inserted into 205 heifers on eight farms. Treatments were either pessaries only for 20 days or pessaries for 10 days combined with an intramuscular injection of 250 mg progesterone+7-5 mg oestradiol benzoate on the day of insertion. Pessary retention was low (86.7%) over the 20-day period, but high (93-6%) during the 10-day period. Calving rates of heifers inseminated in oestrus following the 20-day treatment were low, while those of heifers inseminated on a fixed-time basis with the 10-day treatment were slightly higher than those of control heifers.

Animals↗
PubMed1999

[An open evaluation of prolonged-release dinoprostone with a retrieval system (a formulation of 1.1 MM) in unfavorable cervical ripening in the induction of labor for medical and obstetrical indications].

An open prospective study was carried out in order to evaluate controlled-release dinoprostone pessary with retrieval system in 40 patients. The objective of the study was to obtain clinical experience in Mexico and to assess its efficacy and safety during use. The following results were obtained. The Bishop Score before treatment was 2.98 +/- 1.23, and after treatment it was 8.33 +/- 2.81. The difference was significant (P = 0.0001). Twenty-five patients (62.5%) had spontaneous vaginal delivery, and 14 patients (35%) underwent caesarean section. The indications for the withdrawal of the pessary were as follow: start of labor in 19 patients (47.5%), completation of observation period in 17 patients (42.5%), maternal complications in 2 patients (5%) and, maternal and fetal complications in 2 patients (5%). The mean time between pessary insertion and withdrawal was 8.52 hours; the mean time to start of labor was 10:17 hours; the mean time to start of the 2 degrees labor period was 16:25 hours. The mean duration of labor in all 40 patients was 8:48 hours. We conclude that this study confirms the efficacy of controlled-release dinoprostone with retrieval system in cervical ripening, being easy to insert and to withdraw, and well tolerated since adverse events only occurred in 10% of all patients (uterine hyperstimulation and fetal tachycardia which were controlled by merely withdrawing the pessary). Only one patient (2.5%) required beta-mimetic support in order to control the induced uterine hyperstimulation.

Adolescent↗
PubMed1999

The effect of genital prolapse on voiding.

PURPOSE: We determined whether genital prolapse causes obstruction that may be relieved by a vaginal pessary as well as the degree to which voiding difficulty, urethral hypermobility, bladder outlet obstruction, occult stress incontinence, detrusor instability and impaired detrusor contractility are associated with prolapse. MATERIALS AND METHODS: We prospectively evaluated 60 women with a mean age of 52 years who had genital prolapse, including 35 (58%) with grade 1 or 2 and 25 (42%) with grade 3 or 4 cystocele, using pressure-flow video urodynamics and cotton swab testing. Leak point pressure and uroflowmetry were repeated in patients with severe prolapse after insertion of a ring pessary. RESULTS: Urethral hypermobility (p<0.05) and symptoms of voiding difficulty (p<0.01) were more common in women with grade 3 or 4 cystocele. Urodynamics revealed bladder outlet obstruction in 2 patients (4%) with grade 1 or 2 cystocele and 18 (58%) with grade 3 or 4 cystocele (p<0.001). After vaginal pessary placement bladder outlet obstruction reverted to normal free flow in 17 women (94%) with grade 3 or 4 cystocele. Seven women (20%) with grade 1 or 2 cystocele versus 13 (52%) with grade 3 or 4 cystocele had detrusor instability (p<0.05). Impaired detrusor contractility was noted in each group (p>0.05). In patients with stress incontinence intrinsic sphincter deficiency did not correlate with the degree of prolapse and urethral hypermobility did not correlate with leak point pressure. CONCLUSIONS: Lower urinary tract symptoms are common in women with genital prolapse. Voiding difficulty, bladder outlet obstruction and occult stress incontinence may coexist and they are associated with prolapse. Detrusor instability and urethral hypermobility also correlate with the degree of prolapse but impaired detrusor contractility and intrinsic sphincter deficiency do not. In women with severe prolapse ring pessary reduction of prolapse during urodynamics is useful to determine symptomatic and occult conditions.

Female↗
PubMed1991

Patterns of uterine activity after intravaginal prostaglandin E2 during preinduction cervical ripening.

In a randomized study, uterine activity patterns were characterized with a portable pressure-sensitive device in 40 nonlaboring women at term with an unfavorable cervix who were undergoing preinduction cervical ripening with prostaglandin E2. The prostaglandin E2 was inserted into the posterior vaginal fornix as a single dose of either a 2.5 mg methylcellulose gel (20 cases) or 10 mg controlled-release pessary (20 cases). Uterine activity monitoring began 1 hour before dosing and continued for 12 hours. For those treated with the gel, low-amplitude, high-frequency contractions began within the first hour, reached a peak within 4 hours, and initiated sustained high-amplitude contractions in 10 (50%) cases. With the controlled-release pessary, low-amplitude, high-frequency contractions had a slightly later onset, reached a peak between the fifth and eighth hours, and initiated sustained high-amplitude contractions in 18 (80%) cases. Uterine hyperstimulation occurred in two (10%) pessary cases, with no adverse effect after removal. We conclude that low-amplitude, high-frequency uterine contractions began with either method of intravaginal prostaglandin E2 delivery but led to sustained, high-amplitude contractions primarily with the pessary.

Administration, Intravaginal↗
PubMed1986

Therapeutic abortion in early pregnancy with antiprogestogen RU486 alone or in combination with prostaglandin analogue (gemeprost).

Abortion was attempted in 39 women in early pregnancy (less than 56 days amenorrhea) with the progesterone antagonist RU486 alone (150 mg per day for 4 days) or in combination with a PG analogue, 16,16-dimethyl-trans-delta 2-PGE1 (Gemeprost) in the form of a 1 mg vaginal pessary. Complete abortion was also attempted in 5 women who received RU486 together with 2 X 1 mg PG pessaries. Vaginal bleeding followed by complete abortion occurred in 18 of 19 women who received RU486 + 1 mg PG pessary as compared to only 12 of 20 women who received RU486 alone (P less than 0.01). All women who received RU486 + 2 mg Gemeprost had a complete abortion. The onset of crampy abdominal pain (median: 3 vs 4 days) and vaginal bleeding (3 vs 3 days) was similar in the RU486 and RU486 + PG groups, respectively. Slightly less than half the patients in both groups had nausea and/or vomiting, but the incidence did not differ from that occurring prior to treatment. The mean duration (range) of vaginal bleeding [RU486 alone: 10 (0,29) days and RU486 + PG: (5,34) days], and the measured blood loss [RU486: 53 (2,227) ml and RU486 + PG: 81 (32,222) ml] did not differ significantly between the two treatments. It is concluded that the combination of RU486 and a single PG vaginal pessary is a highly effective means of inducing therapeutic abortion in early pregnancy and offers an alternative to surgery.

Abortifacient Agents↗
PubMed1992

A retrospective study of 932 second trimester terminations using gemeprost (16,16 dimethyl-trans delta 2 PGE1 methyl ester).

A retrospective study of 932 second trimester terminations between 12-27 weeks gestation was carried out to determine the efficacy of gemeprost for second trimester termination. A single course of 5 x 1 mg gemeprost pessaries was administered every three hours. If abortion had not occurred after the first course of pessaries, a further course of 5 x 1 mg pessaries was administered. Intravenous oxytocin was administered after 36 hours if abortion had not occurred. Eighty per cent and ninety five per cent of patients aborted within 24 and 48 hours respectively. Of the remaining 5 per cent of women, 3 per cent aborted with escalating doses of oxytocin. In the remaining 18 (2 per cent) women, the pregnancies were electively terminated with an alternative method. The median induction-abortion interval was 18.0 hours and 15.0 hours in nulliparous and parous women respectively (P less than 0.0001). The number of pessaries required to induce abortion was not influenced by parity. Significantly more parous women bled more than 500 ml. The incidence of pelvic sepsis (0.1 per cent) and cervical tear (0.1 per cent) was low. Twenty six per cent of women had diarrhoea and 23 per cent vomited following administration of prostaglandin. This study confirmed the efficacy of gemeprost for second trimester termination of pregnancy. This method of termination is safe, non-invasive, simple and has a low complication rate.

Abortion, Induced↗
PubMed1991

The effect of timing of laparoscopic insemination in superovulated ewes, with or without sedation, on the recovery of embryos, their stage of development and subsequent viability.

Twenty ewes were used as donors in a 2 x 2 factorial design experiment to investigate the effects of two different insemination times (48 vs 60 h after pessary withdrawal), with or without sedation, on the ovum recovery rate 5 d after insemination, the proportion of transferable embryos recovered, and the subsequent survival rate of embryos transferred to recipients. The ovum recovery rate following intrauterine insemination at 48 h after progestagen pessary withdrawal was 63.8 and 53.4% for sedated and nonsedated control ewes, respectively. Following intrauterine insemination at 60 h the corresponding values for sedated and control ewes were 72.6 and 73.9%, respectively. The proportion of transferable quality embryos recovered was not affected by sedation but was improved by insemination at 48 h rather than 60 h after pessary withdrawal (100 vs 35.4%). Embryo survival following laparoscopic transfer to recipients from donor ewes inseminated at 48 h, with or without sedation was 38.8% (7/18) and 50% (7/14), respectively. Following intrauterine insemination of the donors at 60 h, the survival rate in recipients was reduced for embryos transferred from both the sedated and control ewes to 6.25% (1/16) and 36.3% (4/11). It is concluded that delaying the timing of intrauterine insemination relative to pessary withdrawal and the use of acepromazine maleate as a sedative at the time of insemination are deleterious to embryo development and subsequent viability.

Journal Article↗
PubMed1975

Blood LH after PGF2alpha in diestrous and ovariectomized cattle.

Two experiments were conducted to determine whether the increased serum LH which occurs within 12 hr after a luteolytic dose of PGF2alpha is dependent upon changes in progesterone or estradiol secretion. In the first experiment, exogenous progesterone abolished the increase in serum LH caused by a subcutaneous injection of 25 mg PGF2alpha in diestrous heifers, but not in ovariectomized heifers. In the second experiment, progesterone pessaries were removed at 6 hr after a subcutaneous injection of 25 mg PGF2alpha. LH remained at pre-PGF2alpha values while the pessaries were in place, but began to increase within 1 hr after they were removed. Blood estradiol also remained at pre-PGF2alpha values until the pessaries were removed, and began to increase at 2 hr after pessary removal. We conclude that the increase in serum LH within 12 hr after PGF2alpha treatment in diestrous cattle is dependent upon withdrawal of progesterone; it is not due to increased serum estradiol.

Animals↗
PubMed2002

Development of a new transcervical artificial insemination method for sheep: effects of a new transcervical artificial insemination catheter and traversing the cervix on semen quality and fertility.

The difficulty of traversing the cervix severely limits transcervical artificial insemination (TC AI) in sheep. Cervical trauma and poorly designed instruments can reduce fertility after AI. To overcome problems associated with TC AI, we developed a new TC AI catheter. Three bench experiments were conducted to determine the effects of the new TC AI catheter on semen quality independent of the effects of moving the catheter through the cervix. In each of the three bench experiments, the standard laparoscopic instrument for intrauterine AI in sheep was used as the control for the TC AI catheter. In Experiment 1, the total volume of semen extender expelled and void volumes for both types of AI instrument (TC versus laparoscopic) were determined. In Experiment 2, the effects of each type of AI instrument (TC versus laparoscopic) on semen quality, estimated as percentage motility and percentage forward progressive motility, of frozen-thawed semen was determined. In Experiment 3, the effects of both types of AI instrument (TC versus laparoscopic) on number of spermatozoa expelled was determined. The type of AI instrument affected neither semen quality nor the number of spermatozoa expelled. However, void volume differed (P < 0.01) between the two instruments. After differences in void volume were taken into account, an in vivo experiment was conducted to determine whether using our new TC AI catheter for TC or surgical intrauterine AI affected fertilization and pregnancy rates. For this, ewes were assigned to one of three treatments: (1) TC AI using the new TC AI catheter + sham AI via laparotomy (n = 9); (2) sham TC AI + AI via laparotomy using a laparoscopic AI instrument (n = 8); and (3) sham TC AI + AI via laparotomy using the new TC Al catheter (n = 10). To synchronize estrus, progestogenated pessaries were inserted and left in place for 12 days. On Day 5 after pessary insertion, PGF2alpha (15 mg) was given i.m. At pessary removal, 400 IU of eCG were administered i.m. Ewes were inseminated 48-52 h after pessary removal using fresh diluted semen (200 x 10(6) to 350 x 10(6) spermatozoa per 0.2 ml) pooled from the same four rams each day during the experiment. At 72 h after AI, uteri were collected postmortem and flushed. Oocytes and embryos were recovered and evaluated. Treatments did not affect (P > 0.01) ovum and embryo recovery rate (mean = 87.3%), fertilization rate (59.3%), or Day 3 pregnancy rate (mean = 66.6%). We conclude from these data that the use of our new TC AI catheter for TC AI or intrauterine AI should not impair the success of AI in sheep.

Animals↗
PubMed1994

Prostaglandin-induced cervical dilatation prior to intracavitary radiotherapy for carcinoma of the cervix: a pilot study.

The efficacy of 1 mg 16,16-dimethyl-trans-Delta2 prostaglandin E1 (Gemeprost) pessaries in achieving cervical dilatation prior to intracavitary brachytherapy was investigated in 16 post-menopausal women with cervical carcinoma. All had received external beam pelvic radiotherapy in the preceding 6 weeks. Four patients were nulliparous and 12 multiparous (mean parity 1.9). FIGO stages were IB (2), IIA (4), IIB (5), IIIA (1), IIIB (3), IVB (1). The cervical os was assessed before pessary insertion and again at the time of intracavitary insertion. The os was closed in 100% (16/16) of patients before and open in 75% (12/16) of patients after pessary insertion. The maximum size of Hegar dilator passed without mechanical dila-tation was recorded. Mean cervical dilatation was 4.25 H (5.5 H in those with a clinical response). The 12 responding patients had rapid and uncomplicated procedures with no need for additional mechanical dilatation. Both patients in whom attempted mechanical dilatation failed had had previous conization of the cervix. The following mild side-effects were reported: abdominal cramps (43.8%), headache (12.5%) and fever (6.3%). These data support the use of Gemeprost pessaries to achieve cervical dilatation in post-menopausal women undergoing intracavitary brachy-therapy following external beam radiotherapy.

Journal Article↗
PubMed1993

Fertility of superovulated ewes after intrauterine or oviducal insemination with low numbers of fresh or frozen-thawed spermatozoa.

Two experiments investigated the effects of number of spermatozoa inseminated and time and site of insemination of fresh and frozen-thawed semen on fertility in Merino ewes treated with intravaginal progestagen pessaries and a combination of pregnant mare serum gonadotrophin and follicle stimulating hormone. In Experiment 1, ewes were inseminated in the uterus or oviducts with totals of 10(4), 10(5), 10(6) or 10(7) fresh spermatozoa 44 or 68 h after pessary removal. Ova recovered 48 h later were classified as fertilized if they had cleaved. Proportion of fertile ewes (ewes with fertilized ova per ewes inseminated) and fertilization rate of ova (ova fertilized per ova recovered) were higher for inseminations 44 h (63% and 45%) than 68 h (38% and 19%) after pessary removal (P < 0.001). More ewes were fertile after oviducal (61%) than after intrauterine insemination (39%; P < 0.05), and with high (10(6) and 10(7)) than with low (10(4) and 10(5)) doses of spermatozoa for intrauterine (54% v. 24%; P < 0.05) but not for oviducal inseminations (63% v. 59%). Fertilization of ova was better after oviducal than after intrauterine inseminations (44% v. 22%; P < 0.001), and with high than with low doses of spermatozoa (45% v. 21%; P < 0.001). In Experiment 2, ewes were inseminated with 10(5), 5 x 10(5) or 10(6) total fresh or frozen-thawed spermatozoa in the uterus or oviducts, 44 h after pessary removal.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Development of a mucoadhesive dosage form for vaginal administration.

The antimycotic imidazole derivative clotrimazole is employed locally for the treatment of genitourinary tract mycotic infections and is formulated as creams, foams, tablets, gels, irrigations, or pessaries. In this study, a new dosage form was developed by including bioadhesive polymers (polycarbophyl, hydroxypropylmethylcellulose, and hyaluronic sodium salt) into pessaries made of semisynthetic solid triglycerides. These polymers hold the delivery systems in the vaginal tract for a few days without any toxic effects or important physiological modifications, prolonging the permanence of the drug on the vaginal mucosa. Technological controls (compatibility with differential scanning calorimetry [DSC] studies, particle size analysis, and liquefaction time test) and biopharmaceutics studies for the evaluation of the release of the drug from the dosage form and of the bioadhesive properties were carried out. Moreover, a new test for the evaluation of the permanence of the drug in a simulated application site was developed from a modification of the Satnikar and Fantelli method for the evaluation of the liquefaction time of rectal suppositories. This test simulates the physiological vaginal condition and verifies the efficiency of the polymers in prolonging the permanence of the dosage form in the location where it is applied. The technological controls demonstrated that the presence of the polymers did not have an influence on the characteristics of the pessaries. On the other hand, there was an improvement in adhesivity of the pessaries in the in vitro adhesion test and prolonging of the liquefaction time in the liquefaction time test in the presence of mucoadhesive polymers, which increased with increasing polymer concentration. The presence of the mucoadhesive had a large influence on the permanence of the drug in the simulated application site because it modified the distribution of the drug along the simulated application site. In conclusion, the developed new formulations showed good technological and adhesion properties and the capacity of hold the dosage form in the target site. Among the employed bioadhesive polymers, the best behavior in the performed test was by polycarbophyl at its maximum concentration.

Administration, Intravaginal↗
PubMed1990

Effects of suckling on oestradiol benzoate induced LH release in post-partum, ovariectomised cows.

Twelve suckling and 12 non-lactating post-partum cows were treated with a progesterone-releasing pessary for 7 or 14 d followed by an injection of 500 micrograms oestradiol benzoate (ODB) 24 h after pessary removal or no injection. Suckling had no significant effect on plasma progesterone concentrations (plasma P4) or plasma luteinising hormone concentrations (plasma LH) during pessary insertion. After pessary removal plasma LH rose in response to ODB. The extent of the rise was similar in suckling and non-lactating cows treated with progesterone for 14 d but was significantly lower in non-lactating than suckling cows (P less than 0.025) treated for 7 d. These findings indicate that suckling increases the responsiveness of plasma LH in post-partum cows following progesterone and oestrogen treatment compared to non-lactating cows and that extended treatment with progesterone can remove this difference.

Administration, Intravaginal↗