This meta-analysis aimed to evaluate congenital malformations in infants conceived by assisted reproductive techniques (ART), compared with infants conceived spontaneously. In this study, available resources searched to find relevant articles included PubMed, ScienceDirect, Scopus, Google Scholar, Cochrane, ProQuest, Iranmedex, Magiran, and Scientific Information Database. After extracting the necessary information from evaluated articles, meta-analysis on the articles' data was performed using Stata version 11.2. In this study, from a total of 339 articles, extracted from the initial investigation, ultimately 30 articles were selected for meta-analysis that assessed the use of ART on the risk of congenital abnormalities and some birth complications on 5 470 181 infants (315 402 cases and 5 154 779 controls). The odds ratio (95% confidence interval [CI]) for low birth weight was 1.89 (95% CI, 1.36 to 2.62), preterm labor 1.79 (95% CI, 1.21 to 2.63), cardiac abnormalities 1.43 (95% CI, 1.27 to 1.62), central nervous system abnormalities 1.36 (95% CI, 1.10 to 1.70), urogenital system abnormalities 1.58 (95% CI, 1.28 to 1.94), musculoskeletal disorders 1.35 (95% CI, 1.12 to 1.64), and chromosomal abnormalities in infants conceived by ART was 1.14 (95% CI, 0.90 to 1.44), which were all statistically significant, except chromosomal abnormalities. The risk of congenital abnormalities and some birth complications were significantly higher in ART than normal conception, while chromosomal abnormalities were not; therefore, the application of ART should be selected individually for patients by detailed assessment to reduce such risks in the population.
Clomiphene citrate (CC) is the first line drug for ovulation induction but because of its peripheral antiestrogenic effect, letrozole was introduced as the 2nd line drug. It lacks the peripheral antiestrogenic effect and is associated with similar or even higher pregnancy rates. Since letrozole is a drug for breast cancer, its use for the purpose of ovulation induction became controversial in the light of studies indicating an increased incidence of congenital malformations. To evaluate and compare the incidence of congenital malformations among offsprings of infertile couples who conceived naturally or with clomiphene citrate or letrozole treatment. A retrospective cohort study done at a tertiary infertility centre. A total of 623 children born to infertile women who conceived naturally or following clomiphene citrate or letrozole treatment were included in this study. Subjects were sorted out from medical files of both mother and newborn and follow up study was done based on the information provided by parents through telephonic conversations. Babies with suspected anomaly were called and examined by specialists for the presence of major and minor congenital malformations. Other outcomes like multiple pregnancy rate and birth weight were also studied. Overall, congenital malformations, chromosomal abnormalities were found in 5 out of 171 (2.9%) babies in natural conception group and 5 out of 201 babies in the letrozole group (2.5%) and in 10 of 251 babies in the CC group (3.9%). There was no significant difference in the overall rate of congenital malformations among children born to mothers who conceived naturally or after letrozole or CC treatment. Congenital malformations have been found to be comparable following natural conception, letrozole and clomiphene citrate. Thus, the undue fear against letrozole may be uncalled for.
Sagot P et al., 2012·Human reproduction (Oxford, England)
While intrauterine insemination (IUI), a simple, inexpensive and non-invasive technique, is the most used assisted reproduction technology (ART) worldwide, the risk of major birth defects following IUI is paradoxically not well documented. Retrospective cohort study performed in Burgundy, France, over a 9-year period which consisted of the cross analysis of two prospective databases, the Burgundy perinatal network database and the database of the assisted conception units in Burgundy. A total of 1348 ART singletons [in vitro fertilization technologies (IVFT): n= 903; n= 445] matched with 4044 infants conceived naturally, 552 ART twins (IVFT: n= 362; n= 190) matched with 1656 twins who were conceived naturally. The major birth defects were categorized according to the European Surveillance of Congenital Anomalies classification EUROCAT. Compared with naturally conceived singletons, singletons born after IUI and IVFT had a higher prevalence of major congenital malformations, with adjusted odd ratios (AOR) of 2.0 [95% confidence interval (CI) 1.0-3.8] and 2.0 (CI 1.3-3.1); 3.6 and 4.2% of infants born, respectively. All twins and unlike-sex twins born after IVFT but not IUI, have an increased prevalence of major birth defects compared with naturally conceived twins; AOR of 3.0 (CI 1.6-5.6) and 3.7 (CI 1.1-16.9), respectively. When comparing IUI with IVFT, no differences were observed for singletons (AOR 1.0; CI 0.4-2.2), all twins (AOR 0.4; CI 0.1-1.2) and unlike-sex twins (AOR 0.3; CI 0.1-4.5). The risk of major birth defects in singletons conceived through IUI was increased over naturally conceived singletons. This risk was no different from that observed after IVFT.
The effect of clomiphene citrate (CC) on the incidence of congenital malformations in newborn infants was assessed from the outcome of 1034 pregnancies after CC-induced ovulation recorded at nine university hospitals in a 5-year period. Of these pregnancies, 14.2% ended in abortion, 0.5% in ectopic pregnancy, 0.1% in molar pregnancy, and 1.6% in stillbirth. In all, 935 infants were born, and 21 (2.3%) showed visible malformations. This incidence of malformations was not significantly different from that in 30,033 infants (1.7%) after spontaneous ovulation (spontaneous ovulation group), and the types of malformations after CC treatment were similar to e those in the spontaneous ovulation group. These data indicate that CC has no teratogenic effect.
To examine birth outcomes between children conceived with in vitro fertilization (IVF) or intrauterine insemination (IUI) and sibling births from unassisted conceptions. Retrospective sibling cohort. Live born children conceived via IVF, with or without intracytoplasmic sperm injection, or IUI at the Utah Center for Reproductive Medicine, 1999-2018, and sibling births from unassisted conceptions (born 1985-2018). The main analysis included singleton births (460 IVF, 666 IUI, and 1,579 unassisted siblings). Exposure: In vitro fertilization, with or without intracytoplasmic sperm injection, or IUI. Preterm birth, low birth weight, small for gestational age, large for gestational age (LGA), and major congenital anomalies. Compared with unassisted siblings, singleton children conceived via IVF had gestational ages shorter by nearly half a week (95% confidence interval [CI], -0.6 to -0.3), birth weights of 72.1 g lower (95% CI, -118.8 to -25.4), and higher proportions of preterm birth (IVF, 11.1%; IUI, 8.7%; unassisted siblings, 6.8%), LGA (IVF, 9.1%; IUI, 4.5%; unassisted siblings, 5.9%), and major congenital anomalies (IVF, 3.7%; IUI, 2.0%; unassisted siblings, 1.4%). Models adjusted for maternal age, infant sex, infant birth year, previous pregnancy, and birth order showed that children conceived via IVF were more likely to be preterm (adjusted risk ratio [aRR], 1.6; 95% CI, 1.2-2.2; absolute difference, 4.3%) and LGA (aRR, 1.8; 95% CI, 1.2-2.5; absolute difference, 3.2%). Children conceived via IVF had a higher risk of major congenital anomalies than unassisted siblings adjusted for maternal age, infant sex, and birth order (aRR, 1.9; 95% CI, 1.0-3.8; absolute difference, 2.3%). Children conceived via IUI had birth weights 55.8 g lower (95% CI, -95.6 to -15.9) than unassisted siblings. We observed an increased risk of preterm birth, low birth weight, LGA, and major congenital anomalies among singleton children conceived with IVF compared with that among unassisted siblings; however, absolute differences remain small. For children conceived via IUI, lower birth weights were observed. These results suggest that treatment-related factors in addition to underlying subfertility may contribute to adverse birth outcomes.