Introduction
Polycystic ovary syndrome (PCOS) is considered a common endocrine
disorder in women of reproductive age1, affecting
6–21% of women worldwide2. Characteristics of PCOS
include obesity, insulin resistance, hyperandrogenism, anovulation and
polycystic ovaries3.
Due
to endocrine disorders and anovulation in women with PCOS, which lead to
infertility4, such women usually require assisted
reproductive technology (ART) to become pregnant.
Applying PCOS diagnostic criteria, four phenotypes are distinguished:
phenotype A: coexistence of clinical hyperandrogenism/hyperandrogenemia
(HA), oligomenorrhea/anovulation (OA) and polycystic ovaries (PCO);
phenotype B: HA and OA without PCO; phenotype C: HA and PCO with regular
ovulatory cycles; and phenotype D: OA coexisting with
PCO2. Patients with different PCOS phenotypes show
different ovarian responses to controlled ovarian hyperstimulation
(COH)5, which might contribute to different pregnancy
outcomes6. The previously published literature has
mainly described pregnancy outcomes in patients with different PCOS
phenotypes after fresh embryo transfer6,7; patients
with PCOS are prone to ovarian hyperstimulation syndrome (OHSS) during
or after COH8. Clinically, a fresh embryo transfer is
usually cancelled to reduce the risk of OHSS9.
However, it has been reported that frozen-thawed embryo transfer (FET)
can not only reduce the risk of OHSS, but also improve ART
outcomes10.
Recently,
a multi-centre randomised controlled trial of infertile women with PCOS
suggested FET led to a higher rate of live births, and a lower risk of
abortion than did fresh embryo transfer11. FET allows
time for the use of preimplantation genetic
technology12. Therefore, a considerable number of
infertile patients choose to undergo FET. However, PCOS is associated
with adverse pregnancy outcomes, including an increased risk of
abortion, premature delivery, pre-eclampsia and even neonatal
outcomes13,14. After removing the effect of COH on
patients, studying the pregnancy outcomes of patients with different
PCOS phenotypes after FET may better reflect the impact of different
PCOS phenotypes on ART outcomes. Subsequent clinical management, which
might optimise pregnancy outcomes, could then be carried out based on
different PCOS phenotypes.
The aim of this study was to assess the effect of various PCOS
phenotypes after FET on pregnancy outcomes.