The effect of clomid and other triphenylethylene derivatives during pregnancy and the neonatal period

Tamoxifen and pregnancy: an absolute contraindication?

PURPOSE

Breast cancer is the most common malignancy among young women of reproductive age. Adjuvant treatment with tamoxifen reduces the risk of recurrence in hormone-sensitive breast cancer. However, the use of tamoxifen is considered contraindicated during pregnancy, because of a limited number of case reports demonstrating potential adverse effects on the fetus. The objective of this report is to give a more broad overview of the available data on the effect of tamoxifen exposure during pregnancy.

METHODS

A literature review was performed using PubMed and the databases of the Netherlands Pharmacovigilance Centre Lareb and of the International Network on Cancer, Infertility, and Pregnancy.

RESULTS

A total of 238 cases of tamoxifen use during pregnancy were found. Of the 167 pregnancies with known outcome, 21 were complicated by an abnormal fetal development. The malformations described were non-specific and the majority of cases concerned healthy infants despite exposure to tamoxifen.

CONCLUSION

There seems to be an increased risk of fetal abnormalities when taking tamoxifen during pregnancy (12.6% in contrast to 3.9% in the general population), but the evidence is limited and no causal relationship could be established. The possible disadvantage of postponing or discontinuing tamoxifen for the maternal prognosis is unclear. Patients should be counseled about the use of tamoxifen during pregnancy instead of presenting it as being absolutely contraindicated.

A Semi-automated Approach to Create Purposeful Mechanistic Datasets from Heterogeneous Data: Data Mining Towards the in silico Predictions for Oestrogen Receptor Modulation and Teratogenicity

The need to find an alternative to costly animal studies for developmental and reproductive toxicity testing has shifted the focus considerably to the assessment of in vitro developmental toxicology models and the exploitation of pharmacological data for relevant molecular initiating events. We hereby demonstrate how automation can be applied successfully to handle heterogeneous oestrogen receptor data from ChEMBL. Applying expert-derived thresholds to specific bioactivities allowed an activity call to be attributed to each data entry. Human intervention further improved this mechanistic dataset which was mined to develop structure-activity relationship alerts and an expert model covering 45 chemical classes for the prediction of oestrogen receptor modulation. The evaluation of the model using FDA EDKB and Tox21 data was quite encouraging. This model can also provide a teratogenicity prediction along with the additional information it provides relevant to the query compound, all of which will require careful assessment of potential risk by experts.

Oral administration of clomiphene to neonatal rats causes reproductive tract abnormalities

Oral administration of clomiphene at 2, 4, or 8 mg/kg to 4-day-old rats caused multiple histopathological abnormalities of the reproductive tract in both male and female animals. No histopathological abnormalities were observed in 30-day-old male rats at any dose examined. In contrast, 30-day-old females showed hypertrophy of the myometrium at all doses examined, and hypertrophy of the luminal or glandular epithelium, and dilatation of the uterine lumen were observed in the highest dose group. In post-pubertal rats, histopathologically marked changes were observed in the testes and epididymides in males, and in the ovaries and uterus in females in the highest dose group. In addition, relative weight of male reproductive organs in the highest dose group was decreased as compared with that in the controls. These results suggested that early neonatal exposure to clomiphene induced marked reproductive tract abnormalities in males after puberty, as well as in females.

Adverse effects of fertility drugs

Ovulation-induction agents are commonly used in the treatment of infertility in patients with or without ovulatory disturbances. These agents include clomifene, bromocriptine, gonadotrophin preparations and gonadotrophin-releasing hormone (GnRH) and its analogues. Each agent is associated with its own specific adverse effects. Although many of these adverse effects are benign and self-limited, some, in particular those effects associated with gonadotrophins, may be life-threatening. Commonly noted adverse effects encountered with the use of pharmacological agents to treat infertility include the following. Clomifene has been associated with hot flushes, multiple gestation, visual disturbances, cervical mucus abnormalities and luteal phase deficiency. Similarly, most of the adverse symptoms associated with bromocriptine are short-lived, such as nausea and postural hypotension. On the other hand, gonadotrophin therapy, even when used appropriately, may lead to the ovarian hyperstimulation syndrome (which is occasionally life-threatening) and a high incidence of multiple gestation. Pulsatile GnRH therapy maybe accompanied by similar adverse effects to those of gonadotrophins, but with a far lower incidence. With regards to the long term safety of these medications, the relationship between fertility drugs and epithelial ovarian cancer is controversial, and causality has yet to be proven. Indeed, a working knowledge of the many adverse effects associated with these medications is essential to any physician prescribing ovulation induction agents, in order to ensure maximum patient safety, compliance and understanding.

Effects of antiestrogens on adult and neonatal mouse reproductive organs

Estrogenic potencies of various antiestrogens, including keoxifene (Kx) and trifluoperazine (Tfp), on reproductive tracts of ovariectomized adult mice, and effects of neonatal Kx and Tfp on reproductive organs were studied in C57BL/Tw mice. In adult ovariectomized mice, weight, DNA, and protein of the uterus and vagina were increased by 3 daily injections of 100 micrograms clomiphene, tamoxifen (Tx), and nafoxidine, and of 1 microgram estradiol-17 beta (E), but not by Kx. Antiestrogenic potency of Kx was studied in adult mice given injections of E. Kx significantly suppressed the E-induced increase in weight, DNA, and protein in the uterus and vagina. Tfp (20 micrograms), known as a tranquilizer and an antiestrogen, had no estrogenic effect on either organ. Male and female mice given 5 daily injections of Kx or Tfp from the day of birth were examined at 30, 40, and 60 days of age. Weights of testis, epididymis, and seminal vesicle in neonatally Kx-treated mice were significantly lower than in controls at 30 and 40 days. Spermatozoa were not formed in the seminiferous tubules of Kx-treated mice, although spermatogenesis occurred at 60 days. In neonatally Kx-treated females, weight of the uterus at 60 days and of the vagina at 40 and 60 days was significantly lower than in controls. Corpora lutea were absent from the ovaries of Kx-treated females. In neonatally Tfp-treated mice of both sexes at all ages examined, no differences were found in organ weights or histology, other than lower spermatogenic indices at 40 and 60 days of age.(ABSTRACT TRUNCATED AT 250 WORDS)

A rapid evolution mechanism may contribute to changes in sex ratio, multiple birth incidence, frequency of auto-immune disease and frequency of birth defects in Clomid conceptions

Under conditions favourable to the horizontal transmission of genetic material, a clomiphene isomer is hypothesized to encourage an alternate ovulatory route, with consequence for the sex ratio, multiple birth incidence, incidence of auto-immune disease, and frequency of malformations.

Histologic, morphometric, and immunocytochemical analysis of myometrial development in rats and mice: II. Effects of DES on development

The effects of diethylstilbestrol (DES) treatment on myometrial development from the prenatal to adult period were examined in rats and mice by histologic and immunocytochemical methods using anti-actin, -vimentin, and -laminin to assess cytodifferentiation of smooth muscle and fibroblastic cells, and by morphometric procedures to assess quantitatively the effect of DES on the expression of cellular orientation in the emerging inner circular myometrial layer. Neonatal rats and mice were treated with DES from day 0 (day of birth) to day 2 with dosages known to perturb myometrial development. Neonatal treatment with DES increased the degree of circular orientation within the uterine mesenchyme, an effect detectable following as little as 24 hr of DES treatment. This effect on spatial organization of the mesenchyme was followed by an increase in the thickness of the actin-positive middle layer (prospective circular myometrium) of uterine mesenchyme during days 3-15; from day 15 onward, however, the circular myometrial layer began to fragment into irregular bundles of smooth muscle, and the longitudinal myometrial layer became thinner and more irregularly organized than controls. Vimentin localization in rats treated with DES neonatally was more intense than in controls within the circularly orientated uterine mesenchyme at 5 days. By 60 days the circular and longitudinal myometrial layers of DES-treated animals showed strands and bundles of vimentin-positive cells, which were not present in controls. Both rats and mice show comparable effects of DES treatment.

Uterine abnormalities in rats exposed neonatally to diethylstilbestrol, ethynylestradiol, or clomiphene citrate

The toxicity of the synthetic estrogens diethylstilbestrol (DES), and ethynylestradiol (EE), and the antiestrogen clomiphene citrate (CC) was evaluated by assessing postnatal uterine growth and development prior to the onset of puberty in the rat. Both DES and EE, administered during the neonatal period (postnatal days 1-5), initially increased uterine weight and luminal epithelium hypertrophy. However, uterine weight declined in both DES- and EE-treated animals and fell below controls beyond day 11. Luminal epithelium stimulation generally paralleled uterine weight changes. Precocious development of uterine glands occurred after estrogenization (compared to untreated controls), but subsequently gland numbers were approximately 60% of control levels. Neonatal CC exposure induced only slight uterine weight gain but caused prolonged luminal epithelium hypertrophy and inhibited uterine gland genesis. Luminal epithelium hypertrophy appears to be a useful measure of antiestrogen activity. These data demonstrate the toxicity of DES and EE as assessed by altered prepubertal uterine gland development. Additionally, the inhibition of uterine gland genesis after neonatal CC exposure occurs in conjunction with prolonged luminal epithelium hypertrophy.

Alterations in developing rat uterine cell populations after neonatal exposure to estrogens and antiestrogens

Exposure of rats to either estrogens or antiestrogens during early postnatal development reduces subsequent uterine growth as measured by uterine weight. However, individual uterine cell types respond differently to these agents and uterine weight alone cannot discern subtle or even large alterations in individual cell populations. Using a computerized planimetric technique, we estimated the prepubertal growth of the uterine luminal epithelium, endometrial stroma, glands, and circular and longitudinal muscle after exposure of neonatal rats (postnatal days 1-5) to the estrogens 17 beta-estradiol (E2), diethylstilbestrol (DES), or ethynylestradiol (EE), and the antiestrogens tamoxifen or clomiphene citrate. On postnatal day 26, the cross-sectional areas of the luminal epithelium, endometrial stroma, and circular muscle were reduced after estrogen exposure, compared to untreated controls, while longitudinal muscle cross-sectional area was not affected. Since cell densities (cell number/unit area) were increased, these estrogen-induced area reductions demonstrate a decrease in cell size. Total cell numbers, estimated as the product of cell type areas and their respective cell densities, were also reduced by neonatal estrogen exposure. The synthetic estrogens DES and EE were more potent than E2 with respect to reduction of uterine growth. Neonatal antiestrogen exposure caused large area reductions only in the uterine glands and luminal epithelium. Little change in cell density occurred in any cell population exposed to antiestrogen. These data demonstrate that the decreased uterine growth resulting from estrogen exposure during early postnatal development is a consequence of combined hypotrophy and hypoplasia in all cell types except longitudinal muscle while antiestrogen-induced morphological alterations were limited to hypoplasia having epithelial cell specificity.

Teratogenic effects of clomiphene, tamoxifen, and diethylstilbestrol on the developing human female genital tract

The potential estrogenicity and teratogenicity of triphenylethylene antiestrogens were examined in 54 genital tracts isolated from 4- to 19-week-old human female fetuses and grown for 1 to 2 months in untreated athymic nude mice or host mice treated by subcutaneous pellet with the antiestrogens clomiphene and tamoxifen or the synthetic estrogen diethylstilbestrol (DES). In specimens grown to a gestational age equivalent of 15 weeks or less, the vagina and urogenital sinus were lined by an immature squamous epithelium, which were similar in both drug-treated and untreated specimens. Proliferation and maturation of the squamous vaginal epithelium were observed in specimens treated with clomiphene, tamoxifen, or DES only when grown to a gestational age equivalent of 16 weeks or more. Formation of endometrial and cervical glands proceeded in 87 per cent (13 of 15) of control specimens grown to a gestational age equivalent of 13 weeks or more in untreated hosts. By contrast, age-matched drug-treated specimens contained glands in only 44 per cent (12 of 27) of specimens. In the developing uterine corpus of untreated controls, the uterine mesenchyme segregated into inner (endometrial stroma) and outer (myometrial) layers; whereas in drug-treated specimens, condensation and segregation of the mesenchyme were greatly impaired. The fallopian tube was also affected by clomiphene and tamoxifen (and to a lesser extent by DES) in that its epithelium was hyperplastic and disorganized. The complex mucosal plications characteristic of the fallopian tube were also distorted in drug-treated specimens. These results emphasize the heretofore unrecognized estrogenicity and potential teratogenicity of triphenylethylene antiestrogens on the developing human genital tract and emphasize the need for caution to prevent inadvertent exposure of the developing fetus to these compounds.

Occurrence of genital tract abnormalities and bladder hernia in female mice exposed neonatally to tamoxifen

Three groups of female C57BL/Tw mice given 5 daily injections of 2, 20 or 100 micrograms tamoxifen (Tx) starting on the day of birth were killed at 35 and 150 days of age. About a half of the mice killed at 150 days had been ovariectomized at 90 days. Uterine hypoplasia, myometrial involution and suppression of the uterine-gland genesis were found in the 2 age-groups of Tx-treated mice. Vaginal hypoplasia and hypospadia were common abnormalities in 150-day-old Tx-treated mice. Vaginal adenosis was encountered in 35-day-old mice treated neonatally with 20 or 100 micrograms Tx, but not in 150-day-old group. Permanent proliferation of vaginal epithelium was not induced by Tx. More than 80% of oocytes in small follicles were degenerated in Tx-exposed mice at 150 days, but not so in those at 35 days. Ovaries of neonatally Tx-exposed mice lacking corpora lutea made no luteinizing response to human chorionic gonadotropin injected prepubertally. Urinary-bladder hernia with or without caecum hernia frequently occurred in 150-day-old mice given 20 or 100 micrograms Tx. The present study revealed that neonatally administered Tx causes various abnormalities in gonad and genito-urinary tract of female C57BL/Tw mice.

Reproductive tract abnormalities in female mice treated neonatally with tamoxifen

Immature female mice of the NMRI strain were treated with 20 micrograms/day of tamoxifen or vehicle for the first 3 days after birth. At 90 days of age, vaginas, uteri, and ovaries were examined histologically. A benign epithelial change, vaginal adenosis characterized by abnormal growth of columnar epithelium with glandular structures, was found in all of the tamoxifen-treated mice. Anatomic anomalies such as hypospadias, cervical hypoplasia, uterine hypoplasia, and absence of corpora lutea also were commonly observed. Such abnormalities were not found in the control mice.

Gestational macromastia

Gestational macromastia is a rare entity. Causes are many and include excess hormonal production, hormonal imbalance, and decreased hormonal catabolism. Documentation of elevated serum prolactin levels and tissue hormonal receptor levels brings new light to this pathologic condition. Pharmacologic measures are not recommended because of lack of effectiveness and possible teratogenic side effects. Primary therapy should consist of local measures, such as breast support, bed rest, and analgesics. If this fails and progression is inevitable, we recommend total mastectomy with provision made for reconstruction and nipple banking. Skin flaps must be thin, and all breast tissue must be removed, otherwise the pathologic condition will continue during the ensuing months of the pregnancy and will recur with each successive pregnancy. Abortion is feasible, but this leaves the patient in need of a reduction or total mastectomy at a later date, and thus is not recommended as a primary line of therapy. If the patient progresses to delivery without complication, a reduction mammoplasty can be considered but only if no future pregnancies are planned.

Nafoxidine administered to newborn female GR mice arrests the development of their mammary glands

Mice of the GR strain develop many hormone-dependent mammary tumors in response to estrogen and progesterone stimulation. Since this strain is so sensitive to steroid hormones, we administered a single dose of the antiestrogen Nafoxidine to female GR mice within 24 hours after their birth. This treatment arrested the development of their mammary glands and when the mice were adults, 10 weeks old, they did not cycle normally but were in a state of persistent estrus. Whole mounts of mammary glands from Nafoxidine-treated mice revealed cystic areas within some ducts and bulbous swellings at the ends of others. No hyperplastic alveolar nodules (HAN) were identified in the glands. In contrast, a single dose of 17 beta estradiol administered within 24 h after birth, resulted in a highly branched gland displaying typical end buds, a few alveoli and more HAN than were observed in glands of control adult mice of the same strain. Thus Nafoxidine treatment not only arrested the development of the mammary glands in female GR mice (causing them to appear "masculinized") but it also produced abnormalities within the glands.

Sexual maturation in male rats after centchroman and naphthofuran administration during neonatal period

Male rats given a single s.c. injection of 250 micrograms estradiol dipropionate on day 5 postnatal life failed to show maturational changes in the testis and the growth of accessory sex organs was reduced. Similar treatment with two non-steroidal 'estrogenic' compounds viz. Centchroman (500 micrograms) and Naphthofuran (500 micrograms) retarded the growth of the testis and accessory organs but spermatogenesis was not affected. These effects persisted through 90 days. The results of the present study suggest that the two nonsteroidal compounds being 'atypical' estrogens, their effect on hormone responsive centres of brain also is less severe as compared to that caused by classical estrogen like estradiol.

Characterization of estrogen binding in uterine cytosol from the fetal rhesus monkey

Cytosol receptor binding of 17 beta-estradiol was demonstrated in the uterus of the late-gestation, fetal rhesus monkey. Sucrose density gradient analysis performed in low-ionic strength buffer indicated a binding component with a sedimentation coefficient of 6-7 S. Under high-ionic strength conditions, the component shifted to a sedimentation coefficient of approximately 4 S. The specificity of the receptor for estrogens was indicated by inhibition of [3H]estradiol binding by both natural and synthetic estrogen competitors, but not by progesterone. Saturation analysis indicated a high degree of nonspecific binding with saturation of specific binding occurring at 2-3 nM. Computer-assisted Scatchard analysis of the data resolved a one-receptor model having a limited number of binding sites and an apparent dissociation constant of 10(-10) M. The interaction of estrogens with the fetal uterus and the cellular mechanisms which permit this interaction are discussed in relation to the development of models for extrapolation to the human.