Metformin during pregnancy reduces insulin, insulin resistance, insulin secretion, weight, testosterone and development of gestational diabetes: prospective longitudinal assessment of women with polycystic ovary syndrome from preconception throughout pregnancy.
BACKGROUND
In a prospective observational study of 42 pregnancies in 39 Caucasian women (age 30 +/- 4 years) with polycystic ovary syndrome (PCOS), we examined effects of metformin on maternal insulin, insulin resistance (IR), insulin secretion (IS), weight gain, development of gestational diabetes (GD), testosterone and plasminogen activator inhibitor activity. We assessed the hypothesis that diet-metformin (MET) lessens the physiological gestational increase in IR and reduces gestational weight gain, thus reducing GD.


METHODS
Preconception, in an out-patient clinical research centre, MET 1.5 (eight pregnancies) to 2.55 g/day (34 pregnancies) was started. Women with body mass index <25 or >or=25 kg/m(2) were given a 2000 or 1500 calorie/day, high-protein (26% of calories), low-carbohydrate (44%) diet. Calorie restrictions were dropped after conception.


RESULTS
On MET, GD developed in three out of 42 pregnancies (7.1%). Median entry weight (94.5 kg) fell to 82.7 on MET at the last preconception visit (P = 0.0001), fell further to 81.6 during the first trimester, was 83.6 in the second trimester, and 89.1 kg in the third trimester. Median weight gain during pregnancy was 3.5 kg. The median percentage reduction in serum insulin was 40% on MET at the last preconception visit; insulin did not increase in the first or second trimesters (P > 0.05), and rose 10% in the third trimester. The median percentage reduction in HOMA IR was 46% on MET at the last preconception visit; IR did not increase (P > 0.05) in the first, second or third trimesters. HOMA insulin secretion fell 45% on MET at the last preconception visit, did not increase in the first trimester, rose 24% in the second trimester, and rose 109% in the third trimester. Testosterone fell 30% on MET at the last preconception visit (P = 0.01) and then rose 74, 61 and 95% during trimesters 1, 2 and 3; median testosterone during the third trimester did not differ from pre-treatment levels.


CONCLUSIONS
By reducing preconception weight, insulin, IR, insulin secretion and testosterone, and by maintaining these insulin-sensitizing effects throughout pregnancy, MET-diet reduces the likelihood of developing GD, and prevents androgen excess for the fetus.
Cholesterol Center, Jewish Hospital, Cincinnati, OH 45229, USA. glueckch@healthall.com
C J
CJ
Glueck
N
N
Goldenberg
P
P
Wang
M
M
Loftspring
A
A
Sherman
D000328:Adult; D001835:Body Weight / Q000187:drug effects; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000517:prevention & control; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008137:Longitudinal Studies; D008687:Metformin / Q000627:therapeutic use*; D015849:Plasminogen Inactivators / Q000097:blood; D011085:Polycystic Ovary Syndrome / Q000503:physiopathology; D016742:Preconception Care; D011247:Pregnancy / Q000097:blood; D011248:Pregnancy Complications / Q000503:physiopathology; D011295:Prenatal Care; D011446:Prospective Studies; D013739:Testosterone / Q000097:blood
D007004:Hypoglycemic Agents; D007328:Insulin; D015849:Plasminogen Inactivators; D013739:Testosterone; D008687:Metformin