Effects of Metformin on Ovulation and Pregnancy Rate in Women with
Clomiphene Resistant Poly Cystic Ovary Syndrome
Mahnaz Ashrafi, M.D.1, 2*, Fatemeh Zafarani, B.Sc.2, Ahmad Reza Baghestani, M.Sc.3
1. Endocrinology and Female Infertility Department, Royan Institute 2. Obstetrics and Gynecology Department, Faculty of Medicine, Iran University of Medical Sciences, Akbar Abadi Hospital 3- Epidemiology Department, Royan Institute Background: To evaluate the effect of metformin on ovulation and pregnancy rate in clomiphene citrate resistant women with polycystic ovary syndrome (PCOS). Material & Methods: In this clinical trial each patient, regarding her previous resistance to Clomiphene, served as her own control. A total of 35 clomiphene citrate resistant PCOS patients, referring to Royan institute were studied. Clomiphene citrate resistance was defined as having failure of ovulation during at least three cycles using clomiphene citrate doses up to 200 mg/day on cycle days 3-7 after a withdrawal bleeding with progesterone. Metformin was used alone or in combination with clomiphene citrate. First, the patients received metformin up to 1500 mg/day for 8 weeks. During the next 2-3 cycle if the patients did not become pregnant, clomiphene was added with increments of 100 mg (up to 150 mg/day). Follicular development and ovulation were monitored by ultrasound scans and mid-luteal progesterone level. Menstrual pattern, ovulation, and pregnancy rate were evaluated during the two stages of treatment. Results: After 8 weeks of meformin monotherapy, ovulation occurred in 23 cases (65.7%) and 7 patients (20%) became pregnant. Among other patients (28/35) who were treated with Clomiphene Ci\trate and metformin for 64 cycles, 19 patients (67.8%) had proper ovulation and five of them (17.8%) became pregnant. Totally, metformin induced ovulation in 31 of 35 patients (88.6%) and twelve (34.3%) of them achieved pregnancy. Conclusion: Metformin alone or in combination with clomiphene is a very effective treatment in inducing ovulation and pregnancy in clomiphene resistant women with PCOS. Keywords: PCOS, Clomiphene Citrate Resistant, Metformin, Ovulation
Introduction
ovulation induction in PCOS, but unfortunately
Polycystic ovary syndrome (PCOS) is one of
10-20% of the women are clomiphene resistant
approximately 5-10% of pre-menstrual women
For CC resistant patients with PCOS, treatment
(1, 2). It is a syndrome with unknown etiology
with injectable gonadotropin is the usual
modality for ovulation induction. However,
chronic anovulation (2, 3). However, PCOS
complications such as multiple pregnancy and
ovarian hyperstimulation syndrome (7, 8).
Recent studies have shown that women with
PCOS are frequently insulin resistant and at
clomiphene resistance in PCOSpatients (9-12).
Hyperinsulinemia appears to lead to hyper
intolerance or non insulin-dependant diabetes
production of ovarian androgens and to an
mellitus (NIDDM) in the third and fourth
concentration and peripheral androgen action
The anti-estrogen clomiphene citrate (CC) is
by decreasing the serum sex-hormone-binding-
widely accepted as a first line medication for
Received: 2 January 2007; Accepted: 12 April 2007 *Corresponding Address: P.O.Box: 19395-4644, Endocrinology and Female Infertility Department, Royan Royan Institute Institute, Tehran, Iran Iranian Journal of Fertility and Sterility Vol 1, No 1, Spring 2007, Pages: 39-42 Email: [email protected] Ashrafi et al
Several insulin-sensitizing agents have shown
to improve insulin resistance and therefore,
Body weight and waist/hip ratio was checked
reduce circulating insulin levels in women with
before and during treatment cycles. Also FBS,
PCOS (13). Among these, metformin cloridrate,
OGTT, Fasting insulin, FSH, LH, and total
an oral biguanide for type 2 diabetes mellitus,
testosterone were measured on cycle day 3
is a safe and effective drug that is recently used
for the treatment of PCOS patients (12-15).
The administration of metformin improves
(metformin hydrochloride, Tab; 500mg, Pars
clinical and biochemical features of PCOS and
minoo Co.) alone, 1500 mg/day for 8 weeks.
induces ovulation cycles in anovulatory CC-
During the next 2-3 cycles, clomiphene was
resistant or nonresistant patients with PCOS
added with increments of 100 mg (up to 150
mg/day) if the patients did not have successful
monitored by transvaginal ultrasound scans
dominant follicles (≥ 18mm), were seen, HCG
10,000 IU was injected intra muscularly.
Ovulation was determined by mid-luteal serum
This clinical trial study was conducted on 35
progesterone level (≥5 ng/ml).To confirm
infertile patients with clomiphene resistant
pregnancy β HCG test was done twice (12 and
PCOS referring to Royan Institute (Infertility
research center) from November 1999 up to
pattern, ovulation, and pregnancy rate were
evaluated during the two stages of treatment.
The patients were healthy infertile women aged
Data analysis was performed by SPSS software
20-35 years, with oligomenorrhia (interval
utilizing student t-test (or Mann Whitney test if
between menstrual periods from 35 days to 6
needing non parametric analysis), Levin test,
months), normal serum FSH level (1-10 IU/L),
χ 2, and logistic regression. P value ≤0.05 was
considered as statistically significant.
progesterone-induced withdrawal bleeding
(19,20). All patients with hyperprolactinemia,
diabetes and thyroid disorders were excluded.
Demographic and laboratory results of the
Male factor and tubal –uterine factor infertility
Mean (±SD) age, duration of infertility, and
ovulatory patients using students t-test
(p>0.05). There were no statistically significant
hyperandrogenaemia (NIH consensus criteria)
changes in LH and total testosterone levels
before and after treatment. A significant
Clomiphene citrate resistance was defined as
decrease in mean serum insulin level was
having failure of ovulation during at least three
detected after 8 weeks of Metformin treatment
cycles using clomiphene citrate doses up to 200
mg/day on cycle days 3-7 after a withdrawal
Table 1: Demographic, anthropometrics and laboratory findings of the studied patients BMI Before Insulin level Treatment level After Testosterone Testosterone Treatment Treatment Treatment Treatment (mIU/ml) (mIU/ml) (mIU/ml) (mIU/ml) treatment treatment Mean±SD 25.8±4.06 29.89±5.17 19.20±7.55 16.18±7.97 9.78±8.65 8.1±6.45 1.3±1.11 0.98± 0.3 23-42.35 3.5-34.5 0.7-24.8 0.8-28.6 0.04 – 0.8 Metformin induces ovulation in CC resistant PCOS patients Table 2: Ovulation and pregnancy rates of each phase of treatment Type of treatment Total Cycles Cycles With Cycles With Ovulation No (%) Pregnancy No.(%) Metformin Alone 39(59.1%) 7(10.6%) Metformin+CC 64 44(68.8%) 5(7.8%) 100+150mg Total 130 83(63.8%) 12(9.2%) CC=Clomiphene Citrate Table 3: Number of patients who ovulated and conceived with different treatment conditions Type of treatment Cycles with Cycles with patients ovulation ovulation Metformin alone 23(65.7%) Metformin +CC (100-150g) 19(67.8%) 5(17.8%) CC=Clomiphene Citrate
Table 2 demonstrates a summary of treatment
In two studies, conducted by Acbay et al and
Ehramann et al high dose of metformin (850
Metformin in combination with Clomiphene
Citrate. Of 66 treatment cycles with Metformin
administered and no significant change was
alone, ovulation was documented in 39 cycles
(59.1%) and pregnancy occurred in seven ycles
resistant population of PCOS with previous
Metformin and Clomiphene Citrate (100-150
mg), ovulation was recorded in 44 cycles
In another study, Mitwally et al evaluated the
(68.8%) and pregnancy occurred in five cycles
effect of troglitazone on Clomiphene citrate
(7.6%). Tables 3 showes the number of patients
who ovulated and conceived with different
Comparison of our results with the Mitwally
ovulation in 31 of 35 patients (88.6%) and
study showed no statistically significant
twelve (9.2%) of them achieved pregnancy.
pregnancy). But in some patients troglitazone
leads to hepatic toxicity and liver function tests
during treatment is required. Therefore, it
correlation exists between, insulin resistance
Several studies have demonstrated the effect of
an insulin sensitizing agent like metformin and
In this study, serum insulin level showed a
troglitazone on PCOS patients. These agents
significant reduction after 8-weeks of treatment.
have been reported to result in restoration of
This fact supports the hypothesis suggested by
menstrual cycle, ovulation, and pregnancy (21).
Several reports on treatment with insulin
However we observed no significant reduction
sensitizing agents suggest that metformin
in BMI after treatment and therefore BMI has
reduces LH/FSH, LH, free testosterone, and
no effect on metformin response (p=0.1).
It is well documented that metformin reduces
We observed a high ovulation rate (88.6%) in a
serum insulin level and results in ovulation
series of 35 patients. In most of the patients
ovulation was achieved with metformin alone
Regarding the fact that the number of CC
or in combination with low dose (100-150mg)
resistant PCOS patients are considerable and
clomiphene citrate. Metformin has been used in
that usual treatments are expensive and have
many recent studies. For example Nestler et al
more serious documented complications, we
metformin alone or metformin plus 50 mg/day
combination with CC as a new therapeutic
Ashrafi et al
In our study metformin was considered a very
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