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Adverse outcomes associated with in-vitro fertilization: a role of the endocrine environment at the time of implantation?

2008; Elsevier BV; Volume: 90; Linguagem: Inglês

10.1016/j.fertnstert.2008.07.452

1556-5653

Suprita Kalra, Sarah J. Ratcliffe, T.A. Molinaro, Kurt T. Barnhart, C. Coutifaris,

Reproductive Biology and Fertility

OBJECTIVE: We hypothesized that the non-physiologic hormonal milieu at the time of implantation during a fresh IVF cycle may modulate trophoblast invasion and confer a higher risk to these pregnancies. In contrast, in a frozen embryo transfer cycle, hormonal parameters more closely mimic the endocrine environment of unassisted conception. Using this model of fresh vs frozen embryo transfer, we sought to determine if the endocrine milieu at implantation confers a difference in risk of adverse outcome. DESIGN: Retrospective cohort. MATERIALS AND METHODS: The 2005 SART database was utilized to identify all live-births following transfer of fresh embryos, in which excess embryos were available for cryopreservation, compared to births following transfer of frozen embryos. Donor oocyte cycles were excluded. Analyses were stratified by plurality. The associations between type of embryo transfer and risk of adverse outcome, including low birth weight (LBW), preterm delivery (PTD) and very preterm delivery (VPTD) were assessed using multivariate logistic regression. RESULTS: In final multivariate analysis, fresh embryo transfer remained significantly associated with LBW (singletons OR 1.51, p<0.001; twins OR 1.23, p=0.01) and PTD (singletons OR 1.15, p=0.02; twins 1.24, p=0.004).Table 1Comparison of Patient and Treatment CharacteristicsFrozen (n=4796)Fresh (n=10992)pAge33.732.7<0.0001Infertility Diagnosis(%) Tubal20.419.30.12 Male38.639.20.44 PCOS20.518.90.02 Unexplained12.114.8<0.001 Endometriosis13.413.40.98 DOR65.60.32 Other10.810.90.87 Nulliparous(%)31.849.7<0.001 Open table in a new tab Table 2Risk of Adverse OutcomeFrozen (n=4707)Fresh (n=10692)OR (95%CI)pSingleton (n=10589)(n=3689)(n=6900) LBW6.79.81.5 (1.3-1.8)<0.0001 PTD12.714.21.1 (1.0-1.3)0.03 VPTD2.22.61.2 (0.9-1.6)0.2Twin(n=4810)(n=1018)(n=3792) LBW64.5701.25 (1.1-1.5)0.003 PTD54.860.31.25 (1.1-1.4)0.002 VPTD11.712.31.1 (0.9-1.3)0.6∗Triplets excluded from pregnancy outcome analysis: 89 (1.9%) frozen, 300 fresh (2.7%). Open table in a new tab ∗Triplets excluded from pregnancy outcome analysis: 89 (1.9%) frozen, 300 fresh (2.7%). CONCLUSIONS: Fresh embryo transfer is significantly associated with an increased risk of LBW and PTD in both singletons and twins. This association remains robust after adjustment for age, parity, and infertility diagnoses. This finding lends support to a mechanistic hypothesis of altered placentation due to the endocrine environment at implantation.