| Resum: |
This systematic review of literature and meta-analysis of observational studies reports on perinatal outcomes after frozen embryo transfer (FET). The aim was to determine whether natural cycle frozen embryo transfer (NC-FET) in singleton pregnancies conceived after IVF decreased the risk of adverse perinatal outcomes compared with artificial cycle frozen embryo transfer (AC-FET). Thirteen cohort studies, including 93,201 cycles, met the inclusion criteria. NC-FET was associated with a lower risk of hypertensive disorders in pregnancy (HDP) (RR 0. 61, 95% CI 0. 50 to 0. 73), preeclampsia (RR 0. 47, 95% CI 0. 42 to 0. 53), large for gestational age (LGA) (RR 0. 93, 95% CI 0. 90 to 0. 96) and macrosomia (RR 0. 82, 95% CI 0. 69 to 0. 97) compared with AC-FET. No significant difference was found in the risk of gestational hypertension and small for gestational age. Secondary outcomes assessed were the risk of preterm birth (RR 0. 83, 95% CI 0. 79 to 0. 88); post-term birth (RR 0. 48, 95% CI 0. 29 to 0. 80); low birth weight (RR 0. 84, 95% CI 0. 80 to 0. 89); caesarean section (RR 0. 84, 95% CI 0. 77 to 0. 91); postpartum haemorrhage (RR 0. 39, 95% CI 0. 35 to 0. 45); placental abruption (RR 0. 61, 95% CI 0. 38 to 0. 98); and placenta accreta (RR 0. 18, 95% CI 0. 10 to 0. 33). All were significantly lower with NC-FET compared with AC-FET. In assessing safety, NC-FET significantly decreased the risk of HDP, preeclampsia, LGA, macrosomia, preterm birth, post-term birth, low birth weight, caesarean section, postpartum haemorrhage, placental abruption and placenta accreta. Further randomized controlled trials addressing the effect of NC-FET and AC-FET on maternal and perinatal outcomes are warranted. Clinicians should carefully monitor pregnancies achieved by FET in artificial cycles prenatally, during labour and postnatally. |
visitant ::
identificació
(Clínica de la Mujer Medicina Reproductiva)
