Comparative study of Clomiphene Citrate and Letrozole in Ovulation Induction

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Susanta Kumar Behera1 , Jyoti Ranjan Behera2 , Pankaj Kumar Sethy3 , Luzoo Prachishree4*


Background: Infertility is a life crisis with invisible losses and its consequences are manifold. Infertility
can threaten women’s identity, status and economic security and consequently be a major source of
anxiety, leading to lowered self-esteem and sense of powerlessness. For a couple without contraception
the chances of conception are about 25% each month. So even ovulation happens, a couple is not
guaranteed to conceive. Clomiphene citrate has been the most widely used treatment for fertility
enhancement for the past 40 years. Clomiphene citrate (CC) is an anti estrogenic agent resulting in a 60-
85% ovulation rate and 10-20% pregnancy rate / cycle. Aims and Objectives: The aim of the study was
to compare the efficacy of ovulation induction by Clomiphene citrate and Letrozole in terms of no of
maturing follicle, size of dominant follicle, ovulation (monofollicular or multifollicular), endometrial
thickness and pregnancy and its outcome. Method: It was a prospective longitudinal study conducted in
the Obstetrics & Gynecology Department of M.K.CG Medical College and Hospital. Berhampur; Odisha
from October 2017 to October 2020. A careful & detailed history was elicited from the female as well as
from male partner with special reference to certain specific history concerning the problem of infertility
such as the age, duration, menstrual problem, past medical & surgical history, coital habits, use of
contraceptive methods and treatment history. Subsequently thorough general & systemic examination was
done to exclude any other organic disease in the female patient. Examination of breast, other secondary
sexual characters, thyroid and presence of galactorrhea, hirsutism, and thorough pelvic examination was
done. Patients randomized in to two groups out of 150 cases on anovulatory infertility: first group (CC
group) of 75 cases was given Clomiphene citrate 50 mg starting from D3 to D7 of cycle and second group
(Letrozole group) of 75 cases was given Letrozole 2.5 mg starting from D3 to D7 of cycle. In the both
groups follicular study was done by serial transvaginal sonogram starting from D12 of cycle on alternate
day till ovulation. The number of developing follicles, size of dominant follicle and endometrial thickness
were observed serially by TVS. Results: Ovulatory factors contributing to primary infertility was 150
cases (49.83%) as majority where as tubal factors contribute to 81 cases (26.91%) and other factors
contribute to 70 cases (23.26%). Most of the cases in both groups were of 2-4 year of infertility. Among
Pak Heart J 2024:57(01)
ISSN: 0048-2706 (Print), ISSN: 2227-9199 (Online)
all cases, 60 cases (80%) of Clomiphene citrate group and 55 cases (74%) of Letrozole group were of 2-4
years of infertility as majority followed by 15 cases (20%) of CC group and 15 cases (20%) were of 5-7
years of infertility and 5 cases (6.7%) in Letrozole group were of > 7 years of infertility. In CC group, 56
cases (78.9%) and in Letrozole group, 60 cases (82.2%) had dominant follicle size of 18-20 mm as
majority followed by 9 cases(12.7%) in CC group and 11 cases(15.1%) in Letrozole group had DF of size
< 18mm and 4 cases (5.6%) in CC group and 2 cases (2.7%) had dominant follicle of size 21-25mm,.
Only 2 cases (2.8%) in CC group had DF of size >25mm. The endometrial thickness (ET) varied from 5-
12mm in all cases of both groups. In Clomiphene citrate group 39 cases (55%) had ET of 7-8 mm, 14
cases (19.7%) had ET of 9-10 mm, 6 cases (8.4%) had ET of 11-12mm and 12 cases (16.9%) had ET of
5-6mm. In Letrozole group, 44 cases (60.3%) had ET of 9-10mm, 21 cases (28.8%) had ET of 7-8 mm, 6
cases (8%) had ET of 5-6 mm and 2 cases (2.7%) had ET of 11-12mm. The ovulation occurred in 46
cases (64.8%) and 52 cases (71.2%) in Clomiphene citrate group and Letrozole group respectively.
Conclusion: More number of DF was found in case of Letrozole as compared to Clomiphene citrate.
Ovulation rate of letrozole is higher than that of Clomiphene citrate. More over pregnancy rate for
Clomiphene citrate was lower than that of Letrozole. So Letrozole is found superior to Clomiphene citrate
as an ovulation inducing agent in anovulatory infertility.
Keywords: Ovulation, Clomiphene Citrate, Letrozole, Dominant follicle.

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