Corpus luteal contribution to maternal pregnancy physiology and outcomes in assisted reproductive technologies

Kirk P Conrad, Valerie L Baker, Kirk P Conrad, Valerie L Baker

Abstract

Investigations in the rat model of pregnancy indicate an important role for the corpus luteal (CL) hormone relaxin in the maternal circulatory and osmoregulatory changes in pregnancy, which are epitomized by profound vasodilation and modest hypoosmolality, respectively. In a pilot study of infertile women who became pregnant through donor eggs, in vitro fertilization, and embryo transfer, the gestational rise in glomerular filtration and fall in plasma osmolality were markedly subdued. Because these women were infertile, they lacked a CL and circulating relaxin (and possibly other vasoactive CL hormones). Based on these findings in pregnant rats and women, we hypothesize that infertile women conceiving through donor eggs will have overall subdued circulatory changes (e.g., attenuated reduction in systemic vascular resistance and subdued increase in cardiac output) particularly during early pregnancy when CL hormones predominate before the full development and maturation of the placenta. In contrast, infertile women conceiving by autologous eggs retrieved after ovarian stimulation and fresh embryo transfer may have a relatively hyperdynamic circulation due to the presence of many CL (up to 20 or more) and higher circulating levels of vasodilatory ovarian hormones such as relaxin. Emerging evidence suggests that women undergoing Assisted Reproductive Technologies (ART) have increased risk for adverse pregnancy outcomes such as preeclampsia and small for gestational-age babies. This increased risk may be partly caused by the maternal milieu, which is not physiological in ART pregnancies due to the abnormal status of the CL.

Figures

Fig. 1.
Fig. 1.
Hypothetical impact of Assisted Reproductive Technologies (ART) on maternal circulatory changes in pregnancy. Both mother and offspring who suffer obstetrical complications such as preeclampsia and fetal growth restriction are predisposed to future cardiovascular disease (see Text).
Fig. 2.
Fig. 2.
The concept of the luteal-placental shift applied to maternal blood flow in pregnancy (e.g., cardiac output, and renal blood flow among other organ circulations). The vertical dotted line demarcates the end of the 1st trimester.

Source: PubMed

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