After randomization, patients entering the metformin group will be given 1500 mg daily (bid/tid) metformin and regular diets as control. Participants allocated to the control group are followed by the conventional approach (usual care) based on regular visits respecting the usual schedule dictated by the rules of general practice.

An oral glucose tolerance test (OGTT) is a diagnostic tool used to evaluate how an individual's body metabolizes sugar. Often used to diagnose diabetic conditions, an oral glucose tolerance test requires minimal preparatory measures and may be safely administered during pregnancy. The outcome could be assessed by clinical data and clinical test.

Quantitative oral glucose during fasting increases blood glucose and stimulates pancreatic β cells to release insulin. By measuring plasma insulin levels during fasting and 0.5h, 1h, 2h, and 3h after taking sugar, we can understand the secretion and reserve function of pancreatic β cells, which is also helpful for the classification of diabetes mellitus and guide treatment. The outcome could be assessed by clinical data and clinical test.

Lipid related indicators include cholesterol, triglycerides. The outcome could be assessed by clinical data and clinical test.

Blood tests that are included in the kidney function test include measuring for creatinine and blood urea nitrogen (BUN). The outcome could be assessed by clinical data and clinical test.

Liver function index includes alanine aminotransferase (ALT), alkaline phosphatase (ALP) . The outcome could be assessed by clinical data and clinical test.

The average serum testosterone concentration is 0.43ng/ml, the high limit is 0.68ng/ml, if more than 0.7ng/m1 (equal to 2.44nmol/L), it is called hypertestosterone, or hyperandrogenemia. The outcome could be assessed by clinical data and clinical test.

The normal range of female testosterone is 0.1-0.75ng /ml, testosterone is the main sex hormone of the human body, men and women have secretion, male testosterone secretion is 20-30 times the amount of female testosterone secretion, it is very important to maintain the second sexual characteristics, bone and muscle strength. The outcome could be assessed by clinical data and clinical test.

A globulin synthesized by liver cells that can bind sex hormones, also known as testosterone - estrogen binding globulin or steroidal binding protein, is an important carrier of sex hormones, which can have an important impact on the regulation of sex hormone levels and bioavailability in the body. Clinical detection of SHBG level can provide scientific reference value for disease detection and judgment. The normal interval is 20-130nmol/L for women. The outcome could be assessed by clinical data and clinical test.

TE may be used to monitor disease progression or regression via serial measurements and to guide further management including treatment. The outcome could be assessed by clinical data and clinical test.

Unit: kilogram (kg). The outcome could be assessed by clinical data and clinical test.

Unit: meter (m). The outcome could be assessed by clinical data and clinical test.

BMI = weight (in kg)/ height^2 (in m^2).

Unit: centimeter (cm). The outcome could be assessed by clinical data and clinical test.

Body fat is measured by body fat scale. The outcome could be assessed by clinical data and clinical test.

Lean body weight refers to the total weight of organs, bones, and muscles. The outcome could be assessed by clinical data and clinical test.

Blood pressure is a measurement of the force of blood against the arterial walls when the heart pumps. The pressure is measured in millimeters of mercury (mmHg) and is expressed as two numbers. For example, the optimal BP for an adult is 120 over 80, or 120/80. A pressure reading of 120 over 80 or lower is considered healthy. If the systolic number ranges above 120 to 139 or the diastolic number ranges above 80 to 89, a person is considered to have pre-hypertension. Systolic readings from 140 to 159 or diastolic readings from 90 to 99 are classified as stage 1 hypertension. Systolic measurements of 160 or above or diastolic measurements of 100 or above indicate the severe condition of stage 2 hypertension. The outcome could be assessed by clinical data and clinical test.

The purpose of the HADS was to screen for clinically significant anxiety and depressive symptoms in medically ill patients. Content The HADS-A includes specific items that assess generalized anxiety including tension, worry, fear, panic, difficulties in relaxing, and restlessness. The total score for the HADS-A can range from 0 to 21. The following guidelines are recommended for the interpretation of scores: 0-7 for normal or no anxiety, 8-10 for mild anxiety, 11-14 for moderate anxiety, and 12-21 for severe anxiety.

A pregnancy diagnosed only by the detection of beta hCG in serum or urine. The outcome could be assessed by clinical data and clinical diagnosis.

Ectopic pregnancy (EP) is defined as the implantation and development of a fertilized ovum anywhere outside of the uterine cavity. The outcome could be assessed by clinical data and clinical diagnosis.

Pregnancy failure, otherwise termed as pregnancy loss or miscarriage, can occur at different stages during this process and many different pathophysiological mechanisms may be implicated. The outcome could be assessed by clinical data and clinical diagnosis.

Macrosomia is defined in a newborn as a birth weight more than two standard deviations above the mean percentile for gestational age, >90th percentile weight for gestational age, or a birth weight greater than 4000g at term. The outcome could be assessed by clinical data and clinical diagnosis.

Neonatal complications include intraventricular hemorrhage, necrotizing enterocolitis, respiratory distress syndrome, bronchopulmonary dysplasia, jaundice. The outcome could be assessed by clinical data and clinical diagnosis.