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Biomedical subjects

N B Loudon

Publications and source records attributed to N B Loudon.

At least 19 recordsLinked to original sources
PubMed1990

A double-blind comparison of the efficacy and acceptability of Femodene and Microgynon-30.

The efficacy, cycle-control and tolerance of Microgynon-30, a widely prescribed levonorgestrel containing oral contraceptive, and Femodene, a new oral-contraceptive containing gestodene, were compared in a randomised, double-blind study involving 456 healthy women over a 6 month period. 229 women were allocated to receive Femodene and 227 received Microgynon-30. No differences between the groups in terms of obstetric and gynaecological history, previous contraceptive history, smoking habits, blood-pressure or body weight at admission were observed. No pregnancies were reported in either group, despite tablet-taking errors recorded in 6.3% of the Femodene group and 7.6% of the Microgynon-30 group. Both oral contraceptives were compared in terms of cycle length, intensity of the withdrawal bleed and side effects. Cycle-control was similar in the two groups. However, significantly fewer subjects reported breakthrough bleeding (with or without spotting) in the Femodene group (18% of patients) compared with the Microgynon-30 group (26% of patients). The incidence of absent withdrawal bleeds was 1% or less in both groups and no significant effects on body weight or blood pressure were observed.

Adolescent↗
PubMed1986

The effect of deliberate omission of Trinordiol or Microgynon on the hypothalamo-pituitary-ovarian axis.

The effect of deliberate omission of a phased formulation pill, Trinordiol (ethinyl estradiol 30 micrograms + levonorgestrel 50 micrograms: 6 tablets; ethinyl estradiol 40 micrograms + levonorgestrel 75 micrograms: 5 tablets; ethinyl estradiol 30 micrograms + levonorgestrel 125 micrograms: 10 tablets) or a low-dose, combined, oral contraceptive pill, Microgynon (ethinyl estradiol 30 micrograms + levonorgestrel 150 micrograms: 21 tablets) on the hypothalamo-pituitary-ovarian axis were studied. Thirty-six women were recruited to the study and divided equally between the two types of pill. Medication was begun on the 8th pill-free day of the cycle and continued for 7 days (Group 1), 14 days (Group 2) or 21 days (Group 3). Levels of FSH, LH, estradiol (E2) and progesterone (P) were measured in plasma on alternate days during the final week of pill therapy, and daily for the 7 days after stopping the pill. For the first 2 weeks of pill therapy, follicular activity, as judged by plasma levels of E2, was greater in women taking Trinordiol than in those taking Microgynon, but was similar in both groups by the third week of pill treatment. Five women taking Trinordiol (2 in Group 1 and 3 in Group 2) had plasma levels of E2 in excess of 500 pmol/l whilst taking the pills, and only 1 patient achieved this degree of follicular activity after stopping the tablets. One woman who had taken 7 days of Trinordiol (Group 1) showed a rise of plasma levels of P to 6.8 nmol/l, but luteinization did not occur in any of the remaining 35 women who took Trinordiol or Microgynon. These findings suggest that follicular activity is less completely suppressed by Trinordiol than Microgynon, at least in the first 2 weeks of pill therapy, but that normal ovulation is still a rare event in the week after cessation of either of these pills, even if only 7 days of medication have been taken.

Contraceptive Agents, Female↗
PubMed1984

The functional competence of human spermatozoa recovered after vasectomy.

Progressively motile spermatozoa were present in 42/47 (89%) of post-vasectomy specimens, and in 16 of 24 samples (66%) demonstrable fertilizing potential could be detected in the zona-free hamster egg assay. The mean +/- s.e.m. post-vasectomy penetration rate of 20.6 +/- 6.0% was, however, significantly lower (P less than 0.001) than the pre-vasectomy value of 49.7 +/- 6.4%. After vasectomy the concentration of motile spermatozoa in the ejaculates declined in a manner that was significantly correlated with the post-operative time interval. The spermatozoa also lost their potential for fertilization, although functionally competent spermatozoa were still being recovered from ejaculates produced 8 days after vasectomy. These results emphasize the ability of human spermatozoa to retain some residual fertilizing potential when stored at core body temperature in sites distal to the epididymis, and suggest a role for functional tests in the management of the vasectomized male.

Adult↗
PubMed1982

Antipyrine elimination in saliva after low-dose combined or progestogen-only oral contraceptive steroids.

1 A 'low-dose' combined oral contraceptive steroid (OCS) preparation containing 30 microgram ethinylo-estradiol and 150 microgram levonorgestrel was found to reduce significantly antipyrine clearance in a group of women acting as their own controls. 2 An OCS preparation containing only a progestogen (75 microgram norgestrel) did not reduce antipyrine clearance in a second group of women. 3 The evidence suggesting that the oestrogen component of combined OCS preparations could be responsible for the reduction in antipyrine clearance is discussed.

Adolescent↗
PubMed1981

The effects of sterilisation: a comparison of sterilised women with the wives of vasectomised men.

In a follow-up study, women sterilised by tubal diathermy were compared with a matched group of wives of vasectomised men. Semi-structured interviews were given to a random sample drawn from a representative population. The couples were young with small families and did not have a high proportion of unplanned pregnancies or terminations. They had previously used contraception, mainly the pill or sheath. Most couples were entirely satisfied with the operation. Both groups showed an increase in pre-menstrual symptoms but there was only slight evidence that menstrual loss was affected by female sterilisation. The vasectomy couples had a higher frequency of sexual intercourse, few sexual problems and tended to have more satisfactory marriages. They had had more discussion of their decision to have the operation and the implications of counselling are considered.

Coitus↗
PubMed1979

Oral contraception.

Explore the source record for details and available documents.

Cardiovascular Diseases↗
PubMed1977

Acceptability of an oral contraceptive that reduces the frequency of menstruation: the tri-cycle pill regimen.

The frequency of menstruation was reduced to once every three months in 196 women by the continuous administration of the oral contraceptive pill, Minilyn, for 84 days (tri-cycle regimen). No pregnancies occurred. One hundred and sixty-one women (82%) welcomed the reduction in the number of periods with the associated freedom from menstrual and premenstrual symptoms, and many found the tri-cycle regimen easier to follow. Weight gain of more than 2 kg, irregular cycle control, especially in the first three months, breast tenderness, and headaches were the main side effects. Menstrual loss was unchanged or reduced in all but seven women. The doctors and nurses on the clinic staff were less enthusiastic about this regimen than the volunteers themselves.

Adolescent↗
PubMed1977

Intrauterine deposition of calcium on copper-bearing intrauterine contraceptive devices.

Copper-bearing intrauterine contraceptive devices (IUDs) removed after various times in utero were examined by scanning electron microscopy and x-ray microanalysis of the elements present. As time in utero increased these devices became increasingly calcified. This calcification may limit the release of copper from the devices and decrease the specific contraceptive effectiveness of copper over an enert plastic device. Conversely, any teratogenic effects attributable to the copper may decrease with time in utero and depend on the extent of calcification. Even though the amount of copper in the device is not significantly diminished after two years, devices should not remain in situ for over two years because calcium accumulation probably prevents further diffusion of copper. Calcification can begin as early as six months after insertion. Consequently a careful review of the amount of time a copper-containing IUD should be left in situ should be undertaken.

Abnormalities, Drug-Induced↗
PubMed1977

Phytohemagglutin-induced lymphocyte transformation in oral contraceptive users.

Phytohemagglutin (PHA)-induced lymphocyte transformation (PILT) was determined in 217 women taking oral contraceptives and 203 control women by means of the uptake of 3H-thymidine into DNA of lymphocytes cultured in heterologous serum. Depressed PILT responses were observed in oral contraceptive users as compared with age-matched controls, and the magnitude of depression correlated with the duration of oral contraception and was inversely related to the clinical progestagenic potency of the component steroids. An additional group of 21 women, tested within 1 year (mean 3 months) of cessation of oral contraception, showed persistent depression of PILT responses. Suppression of lymphocyte transformation in autologous as compared with homologous, normal serum suggests that serum inhibitory factors amy be important. We found no evidence for a direct suppressive in vitro effect of synthetic estrogens and gestagens. The prevalence of autoantibodies in oral contraceptive users was similar to that in control subjects.

Adolescent↗
PubMed1976

Detection of breast disease in a family planning association clinic.

The incidence and prevalence of disorders of the breast have been assessed in 13,456 women examined annually at a family planning clinic over 5 years. Screening for disorders of the breast was by clinical examination alone and abnormalities were detected in 1 of every 58 women attending the clinic and these were referred for hospital opinion: biopsy was required in 1 in 114. Only 12 cancers of the breast were detected and all of these in women over 35 years. It is suggested that the usual policy of examining the breasts of women taking oral contraceptive preparations should be restricted to those over 40 years.

Adolescent↗