Malpresentation of the Fetus in Singleton Pregnancies after In Vitro Fertilization

The association of assisted reproductive technology with fetal malpresentation: a systematic review and meta-analysis

BACKGROUND

Since its introduction, assisted reproductive technology (ART) has developed into a common clinical practice around the world; yet it still raises a lot of questions. Throughout time, many researchers have investigated its association with several obstetric incidences and its consequences on perinatal outcomes. The aim of the current meta-analysis was to estimate the correlation between ART procedures and malpresentation of the fetus in singleton pregnancies.

METHODS

The study was conducted according to the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) guidelines and prospectively registered under the PROSPERO database (CRD42023458084). Five databases (Embase, MEDLINE®, APA PsycInfo, Global Health, Health Management Information Consortium (HMIC)) and two additional sources were searched from inception to 31 May 2023. Quality of the included studies was assessed using the ROBINS-1 scale, whilst quality of evidence by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. Summative and subgroup data as well as heterogeneity were generated by the Cochrane platform RevMan Web.

RESULTS

Overall, 11 studies were included in the study with a total of 3,360,134 deliveries. Results indicate a higher risk of malpresentation at delivery in fetuses conceived through ART than those conceived naturally (RR: 1.50, (95% confidence interval (CI):1.30, 1.73)). This risk decreased when adjustments for potential confounders were applied (RR = 1.12, 95% CI 1.02, 1.23).

CONCLUSIONS

Based on observational studies, this meta-analysis indicated that singleton pregnancies conceived through ART are associated with higher risk of malpresentation than those conceived naturally, albeit the difference was lower when potential confounders were examined. Thus, future large studies are required to better understand possible reversible and irreversible factors of this relationship.

Assisted reproductive technology (ART) is not an independent risk factor for breech presentation among singleton term births in Vienna, Austria

Assisted reproductive technologies (ARTs) such as in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) are still discussed critically, as there is no consensus on whether these treatments could be the cause of risk factors for obstetric problems such as breech presentation. The aim of this study was to test the association between ART and breech presentation among 11920 singleton term births taking place in Vienna from 2010 to 2020. In this single-centre medical record-based study, data concerning the conception mode (spontaneous versus IVF or ICSI), child presentation, birth mode, newborn sex and size as well as age, height, weight, and reproductive history of the mother were included. Three hundred twenty-six newborns (2.7%) were conceived by IVF or ICSI, and 527 newborns (4.4%) were delivered in breech presentation. Breech presentation occurred in 7.6% of IVF/ICSI children but only in 4.3% of spontaneously conceived children (P = 0.019). ART increased the crude risk of breech presentation significantly (OR = 1.67; 95% CI 1.71 - 2.38). After adjusting for maternal age, height, number of previous births, smoking, and newborn sex, however, ART had no longer a significant impact on the risk of breech presentation. In contrast, breech presentation was significantly associated with higher maternal age as well as a lower number of previous births, but not with ART. This study shows that the adverse outcomes of IVF and ICSI pregnancies may not be due to the ART treatment alone but might also be due to the mostly higher age and lower parity of the mothers using ART.

Obstetric Outcomes and Successful Reduction of Twin Pregnancies Achieved by In Vitro Fertilization

The use of in vitro fertilization methods around the world is constantly increasing. In some developed countries, up to 5% of newborns are as a result of pregnancies after IVF procedures. In vitro fertilization as one of the main and widespread methods for treatment of infertility is the main reason for the high frequency of multiple pregnancies, which, in many countries, is still too high. Most of the multiple pregnancies are in fact twin pregnancies. Twin pregnancies, regardless of how they are achieved, are associated with large number of complications compared with singleton ones. More often these pregnancies can lead to maternal complications and adverse pregnancy outcomes. Maternal complications include development of preeclampsia, gestational diabetes, placenta previa, placental abruption, premature rupture of membranes, antepartum and postpartum hemorrhage, and delivery by cesarean sections. Adverse pregnancy outcomes mostly include preterm birth (PTB), low birth weight (LBW), small for gestational age newborn (SGA), intrauterine growth restriction (IUGR), neonatal respiratory distress syndrome (RDS), and admission to neonatal intensive care unit (NICU). A number of studies have found differences in the course of twin pregnancies according to their mode of occurrence – spontaneous or after IVF. Some of them have found that twin pregnancies after IVF are associated with poorer obstetric and perinatal outcomes, others do not find such a difference, and there are even studies that find a better outcome in IVF twin pregnancies. Twin pregnancy is a common occurrence after IVF procedure, because multiple-embryo transfer is commonly regarded as an effective strategy to improve the likelihood of a successful pregnancy. Understanding the risks of these pregnancies should be a strong motive for the transfer of fewer embryos during IVF procedures. The most effective way to do this is to transfer a single-embryo into the uterus in cases, where this is justified and the chances of getting pregnant are high. An important element in achieving this goal is the use of methods for vitrification of embryos, which leads to a sufficiently high rate of clinical pregnancies after freezing of embryos obtained by IVF and their subsequent transfer after thawing in case of failure of fresh ET.