Maternal and fetal haemopexin and α1-microglobulin concentrations in pre-eclamptic IVF pregnancies according to presence of corpus luteum at embryo transfer

Abstract

Research question: Do pregnancies with corpus luteum show different maternal and fetal plasma concentrations of the scavenger proteins haemopexin and α₁-microglobulin compared with pregnancies without corpus luteum in preeclampsia?

Design: Case-control study of 160 singleton pregnancies: 54 naturally conceived, 50 by IVF after fresh embryo transfer or frozen embryo transfer (FET) in natural cycle (presence of corpus luteum) and 56 after fresh oocyte donation or FET in programmed cycles (absence of corpus luteum). Pregnancies were subclassified into normotensive, preeclampsia and severe preeclampsia cases. Heme-scavenger concentrations were measured by ELISA in maternal and cord plasma collected at delivery.

Results: After adjustment, maternal haemopexin was higher in IVF with corpus luteum than in naturally conceived pregnancies in normotensive (P = 0.038) and preeclampsia (P = 0.011) populations, and lower in preeclampsia for IVF pregnancies lacking corpus luteum compared with IVF with corpus luteum (P = 0.002). Maternal α₁-microglobulin levels were higher in the absence of corpus luteum only in severe cases of preeclampsia compared with naturally conceived pregnancies (P = 0.014) and IVF with corpus luteum pregnancies (P = 0.041). In cord blood, haemopexin was higher in IVF with corpus luteum compared with naturally conceived pregnancies in preeclampsia (P = 0.039) and α₁-microglobulin was higher in the group lacking corpus luteum compared with IVF with corpus luteum in the normotensive population (P < 0.001).

Conclusions: The physiological differences shown for these heme-scavengers between pregnancies after embryo transfer in the presence or absence of corpus luteum support the hypothesis that corpus luteum activity could influence perinatal outcomes. Future research is needed on whether applying potential strategies to develop a corpus luteum might reduce the perinatal complications associated with programmed cycles of IVF.

Keywords: Corpus luteum; Early pregnancy; IVF; Luteal phase; Preeclampsia.