Objective      To investigate the status of insulin resistance within first-trimester pregnancy in patients with normal pre-pregnant glucose metabolism and history of recurrent spontaneous abortion (RSA).        Methods      A total of 626 pregnant women who first visited our hospital within their first-trimester pregnancy were enrolled. The patients with a history of RSA and normal pre-pregnant glucose metabolism diagnosed by oral glucose tolerance test (OGTT) were assigned in a RSA group (n=161) including 26 patients with polycystic ovarian syndrome (PCOS)

while those without abnormal pregnancy history were assigned in a control group (n=465) including 45 PCOS patients. The status of insulin resistance were retrospectively analyzed by comparing the serum levels of β-HCG

estradiol

progesterone

fasting plasma glucose and fasting plasma insulin as well as the homeostasis model assessment of insulin resistance index (HOMA-IR) and fasting plasma glucose/fasting plasma insulin (G/I) ratio between the two groups of patients.       Results      The serum levels of β-HCG and progesterone were significantly lower in the RSA group than in the control group (P0.05，P0.01)

but age

body mass index (BMI)

gestational age and serum level of estradiol showed no significant difference between the two groups (P0.05). The HOMA-IR was higher and the G/I ratio was lower in the RSA group than in the control group (P0.05). The serum levels of β-HCG and progesterone were negatively correlated with the HOMA-IR (r=-0.205

-0.191

respectively)

and were positively correlated with the G/I ratio (r=0.196

0.205

respectively) even after adjustment for BMI (all P0.05). The spontaneous abortion rate within first-trimester pregnancy of the RSA group was significantly higher than that of the control group (18.6% vs 6.7%

P0.01).        Conclusion      The RSA women with normal pre-pregnant glucose metabolism tend to have a high insulin resistance within their first-trimester pregnancy no matter whether they have PCOS or not. Insulin resistance may be one of the reasons for recurrent abortion. It is recommended to screen both fasting plasma glucose and fasting plasma insulin in all RSA patients to evaluate their insulin resistance status for guiding the clinical treatment.