Oral administration of clomiphene to neonatal rats causes reproductive tract abnormalities

Safety assessment of clomiphene: a real-world pharmacovigilance analysis from the Food and Drug Administration adverse event reporting system

BACKGROUND

Clomiphene is widely used for the treatment of anovulatory infertility, yet there remain many unrecognized adverse events (AEs). The objective of this study is to provide a comprehensive overview of the safety profile of clomiphene.

METHODS

The data were derived from the first quarter of 2004 to the third quarter of 2023 from the Food and Drug Administration Adverse Event Reporting System (FAERS) database. The detection of new AE signals involved the use of four algorithms: reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and empirical Bayesian geometric mean (EBGM).

RESULTS

A total of 16,677,289 AE reports were acquired from the FAERS database, and there were 2,620 AEs specifically reported in 720 patients following clomiphene use. The AEs encompassed 102 preferred terms (PTs) across 24 system organ classes (SOCs). Some new AEs were identified, including conjoined twins (0.5%), Potter's syndrome (0.3%), genitalia external ambiguous (0.3%), esophageal atresia (0.6%), and anal atresia (0.3%).

CONCLUSIONS

Although the majority of AEs aligned with the drug instruction, some new AE signals such as conjoined twins and genitalia external ambiguous were not captured. Well-designed studies are required to demonstrate the safety of clomiphene.

Potential Teratogenic Effects of Clomiphene Citrate

Clomiphene citrate (CC) is the oldest drug used to regulate the process of ovulation. Considering the great use of CC over the last 40 years, it is important to understand the possible risks associated with its use. The aim of this review was to evaluate the possible teratogenic effects of CC, analyzing results obtained from animal and human studies. The pharmacokinetics of CC and possible mechanisms involved in teratogenesis are examined. Fetal exposure to CC is possible due to the long half-life of CC and its metabolites. Alarming data have emerged from animal studies, although controversial results come from human studies. There is some evidence regarding a possible association of CC exposure and fetal malformations, mainly neural tube defects and hypospadias, which would require further investigation in order to allow safer use of this useful drug.

Stromal cell-specific apoptotic and antiestrogenic mechanisms may explain uterine defects in humans after clomiphene citrate therapy

OBJECTIVE

The purpose of this study was to investigate clomiphene citrate (CC)-induced modulation of uterine cell function in vivo.

STUDY DESIGN

Prepubertal female Sprague-Dawley rats were treated intraperitoneally with CC for 6 or 24 hours or with a combination of CC and/or 17-beta-estradiol (E2) for 4 days.

RESULTS

Chronic CC treatment induced apoptosis in a fraction of uterine stromal cells by activating the caspase-3-mediated apoptotic pathway. The damage was prevented by successive E2 treatment; however, pretreatment or concomitant treatment with E2 did not protect against CC-induced uterine apoptosis. CC decreased the protein expression of estrogen receptor alpha and increased its phosphorylation but did not affect estrogen receptor beta expression or phosphorylation. Furthermore, changes in Hoxa11, p27, and progesterone receptor protein levels and localization were associated with CC treatment.

CONCLUSION

We provide novel mechanistic insights into cellular and molecular events by which CC regulates uterine stromal cell function and hence the implantation process and pregnancy outcome.

Risk factors for congenital cryptorchidism in a prospective birth cohort study

BACKGROUND

Risk factors for congenital cryptorchidism were investigated in a prospective birth cohort study in Denmark and Finland from 1997 to 2001.

METHODOLOGY AND PRINCIPAL FINDINGS

In total, 2,496 boys were examined for cryptorchidism at birth (cryptorchid/healthy: 128/2,368) and three months old (33/2,215). Information on risk factors was obtained antenatally (questionnaire/interview) or at birth from birth records. Use of nicotine substitutes during pregnancy (n = 40) and infertility treatment by intrauterine insemination (n = 49) were associated with an increased risk for cryptorchidism, adjusted odds ratio (95% confidence interval) (OR (95%CI)) 3.04 (95%CI 1.00-9.27) and 3.01 (95%CI 1.27-7.15), respectively. No association was seen for mothers (n = 79) who had infertility treatment in form of intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) treatment (OR 0.71 95%CI 0.21-2.38). In total, 728 (29%) reported to have smoked during pregnancy, however, no increased risk among maternal smokers was found. Furthermore, we found statistically significant associations between cryptorchidism and low birth weight, prematurity, being small for gestational age, substantial vaginal bleeding, and breech presentation, which are in accordance with other studies.

CONCLUSIONS AND SIGNIFICANCE

Our study revealed two novel risk factors for cryptorchidism: intrauterine insemination and the use of nicotine substitutes in pregnancy. This suggests that cryptorchidism may not only be associated to genetic factors, but also to maternal lifestyle and exposure.