Article type
Year
Abstract
Background: Uncontrolled studies suggest that in vitro fertilization (IVF) singletons have increased rates of poor perinatal outcomes compared to spontaneously conceived singletons such as preterm delivery and low birth weight, hence warranting increased antenatal monitoring Objective: To determine if there is a difference in the incidence of poor obstetric outcomes in IVF singletons compared with spontaneously conceived singletons matched for maternal age.
Methods: Search Strategy: Medline and EMBASE were searched using comprehensive search strategies.
Selection criteria: Controlled studies of singletons conceived by IVF or IVF/ ICSI (intracytoplasmic sperm injection), with transfer of fresh or cryopreserved (frozen) embryos in women with infertility, and/or whose partners are subfertile or infertile, compared with spontaneously conceived singletons who are matched for maternal age.
Data collection and analysis: Two reviewers assessed titles and abstracts, and extracted data. Quality assessment was performed using the Cochrane Handbook s guidelines for observational studies based on four types of potential biases: selection, performance, attrition and detection bias. Each was rated as unbiased , biased and unknown because of no or unclear reporting .
Meta-analysis was performed using a random effects model.
Results: Fifteen case-control studies were included; a maximum of nine studies reported on any one outcome. By only including studies which matched for maternal age, (6) studies with the most significant selection bias were excluded. Many studies also matched for parity. Given the retrospective nature of the studies, attrition bias appeared negligible, however, performance and detection bias may have occurred.
Compared to spontaneously conceived singletons matched for maternal age, IVF singletons were at increased risk of: perinatal mortality (OR 1.97, 95% CI 1.22-3.19), preterm delivery before 37 weeks gestational age (OR 2.05, 95% CI 1.39-3.01), being small for gestational age, SGA (OR 1.44, 95% CI 1.02-2.05), having low birth weight less than 2500 g, LBW (OR 1.54, 95% CI 1.11-2.12) and very low birth weight less than 1500 g, VLBW (OR 3.78, 95% CI 2.49-5.75). IVF singletons were at an increased risk for admission to NICU (OR 1.35, 95% CI 1.19-1.53). There was an increased rate of caesarian section (OR of 1.84, 95% CI 1.40-2.41), which appeared to be mainly elective (OR of 2.24, 95% CI
1.61-3.12).
Conclusions: Based on the results of this meta-analysis of case-control studies, IVF singletons are at increased risk of perinatal mortality, preterm delivery, low birth weight, very low birth weight (and being small for gestational age), congenital anomalies, admission to NICU and birth by cesarian section.
Methods: Search Strategy: Medline and EMBASE were searched using comprehensive search strategies.
Selection criteria: Controlled studies of singletons conceived by IVF or IVF/ ICSI (intracytoplasmic sperm injection), with transfer of fresh or cryopreserved (frozen) embryos in women with infertility, and/or whose partners are subfertile or infertile, compared with spontaneously conceived singletons who are matched for maternal age.
Data collection and analysis: Two reviewers assessed titles and abstracts, and extracted data. Quality assessment was performed using the Cochrane Handbook s guidelines for observational studies based on four types of potential biases: selection, performance, attrition and detection bias. Each was rated as unbiased , biased and unknown because of no or unclear reporting .
Meta-analysis was performed using a random effects model.
Results: Fifteen case-control studies were included; a maximum of nine studies reported on any one outcome. By only including studies which matched for maternal age, (6) studies with the most significant selection bias were excluded. Many studies also matched for parity. Given the retrospective nature of the studies, attrition bias appeared negligible, however, performance and detection bias may have occurred.
Compared to spontaneously conceived singletons matched for maternal age, IVF singletons were at increased risk of: perinatal mortality (OR 1.97, 95% CI 1.22-3.19), preterm delivery before 37 weeks gestational age (OR 2.05, 95% CI 1.39-3.01), being small for gestational age, SGA (OR 1.44, 95% CI 1.02-2.05), having low birth weight less than 2500 g, LBW (OR 1.54, 95% CI 1.11-2.12) and very low birth weight less than 1500 g, VLBW (OR 3.78, 95% CI 2.49-5.75). IVF singletons were at an increased risk for admission to NICU (OR 1.35, 95% CI 1.19-1.53). There was an increased rate of caesarian section (OR of 1.84, 95% CI 1.40-2.41), which appeared to be mainly elective (OR of 2.24, 95% CI
1.61-3.12).
Conclusions: Based on the results of this meta-analysis of case-control studies, IVF singletons are at increased risk of perinatal mortality, preterm delivery, low birth weight, very low birth weight (and being small for gestational age), congenital anomalies, admission to NICU and birth by cesarian section.