Dispensing of clomiphene citrate to treat infertility: medication supplied and population prevalence of assisted pregnancies and multiple births

Impact of clomiphene citrate on multiple gestation births and perinatal outcomes: a nationwide cohort study

OBJECTIVE

To evaluate the occurrence of multiple gestation birth and perinatal adverse outcomes in pregnancies resulting from clomiphene citrate (CC) treatment compared with nonexposed pregnancies.

DESIGN

Nationwide cohort study in a university hospital-based research center.

SUBJECTS

Pregnancies lasting >22 weeks of gestation, in women aged 18-43 years between 2013 and 2019, recorded in the French health data warehouse (Système National des Données de Santé).

EXPOSURE

Pregnancies exposed to CC were assigned to a 1:5 unexposed control cohort on the basis of maternal age, calendar year of childbirth, French social deprivation index, history of hypertension, and history of diabetes. The exclusion criteria were in vitro fertilization/intracytoplasmic sperm injection treatment or gonadotropins within 12 months before pregnancy and pregnancies occurring in women with the dispensing of CC between 12 and 2 months and/or less 11 days before the beginning of the pregnancy.

MAIN OUTCOME MEASURES

Multiple gestation birth rate and perinatal outcomes.

RESULTS

Of 3,173,013 pregnancies, 32,010 (1%) occurred in women exposed to CC, of whom 31,934 were assigned to 159,670 unexposed control pregnancies. The multiple pregnancy rate was significantly higher in CC-exposed pregnancies (5.2% vs. 1.4%; odds ratio [OR], 3.9; 95% confidence interval [CI], 3.7-4.1) such as twin pregnancies (5.1% vs. 1.4%; OR, 3.9; 95% CI, 3.7-4.1) and triple or more pregnancies (0.13% vs. 0.03%; OR, 4.3; 95% CI, 2.9-6.5) than in the unexposed control cohort. Women exposed to CC presented significantly more adverse obstetric and perinatal outcomes, including stillbirths, premature delivery threats, premature rupture of membranes, gestational diabetes, placenta previa, gravid hypertension, preeclampsia, preterm birth, small for gestational age, and cesarean section rate. After stratification on multiple pregnancy and adjustment on confounders (history of psychiatric disease, obesity, and embryo reduction during pregnancy), exposure to CC remains associated with adverse outcomes in both singleton and multiple pregnancies.

CONCLUSION

A fourfold risk of multiple gestation births was found in pregnancies exposed to CC, along with perinatal adverse events, even in singletons. Although it remains uncertain whether these adverse events are because of the medication itself or to the treated medical condition, these findings should provide awareness of practitioners and patients about its use. It also underscores the importance of attentively monitoring follicular growth during the treatment process to avoid multiple pregnancies.

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.

Ovulation induction and subfertile untreated conception groups offer improved options for interpreting risks associated with ART

PURPOSE

To identify and characterise appropriate comparison groups for population studies of health outcomes in ART-conceived births: ovulation induction (OI), subfertile untreated and fertile natural conceptions. Our secondary objective was to examine whether known risks of pregnancy complications and adverse birth outcomes in ART births are elevated in comparison with subfertile (untreated and OI) conception groups.

METHODS

We linked State and Commonwealth datasets to identify all live and stillbirths (≥ 20 weeks) in Western Australia from 2003 to 2014 by method of conception. Demographic characteristics, maternal pre-existing conditions, adverse obstetric history and pregnancy complications were compared across conception groups. Generalised estimating equations were used to estimate adjusted risk ratios (aRRs) and 95% confidence intervals (CI) for pregnancy complications and birth outcomes in singletons.

RESULTS

We identified 9456 ART, 3870 OI, 11,484 subfertile untreated and 303,921 fertile naturally conceived deliveries. OI and subfertile untreated groups more closely resembled the ART group than the fertile group; however, some differences remained across parity, maternal age, pre-existing conditions and obstetric history. In multivariate analyses, ART singletons had greater risks of placental problems (e.g. placenta praevia aRR 2.42 (95% CI 1.82-3.20)) and adverse birth outcomes (e.g. preterm birth aRR 1.38 (95% CI 1.25-1.52)) than the subfertile untreated group, while OI singletons were more similar to the subfertile group with higher risk of preeclampsia and gestational diabetes.

CONCLUSION

OI and subfertile untreated conception groups offer improved options for interpreting health outcomes in ART births. Pregnancy complications (particularly placental disorders) and adverse outcomes at delivery are more common following ART.