Contraception. 1995 Jul;52(1):13-6.

Enlarged follicles in women using oral contraceptives. Broome M,Clayton J,Fotherby K .

Family Planning Clinic, Reading, England.

Ultrasound examination of the ovaries was performed in the first and/or second half of three consecutive cycles in 3 groups of women; Group T who had been using a levonorgestrel triphasic oral contraceptive for at least 6 months, Group P who had been using a progestogen-only pill for at least 6 months, and Group C, a control group. Any follicles greater than 10 mm in diameter and any cysts were measured. Fifty-three scans were performed in Group T, 45 in Group P and 31 in Group C. Only 4 follicles were detected in 17 women in Group T compared to 10 follicles in 15 women in Group P and 7 follicles in the women in Group C; all follicles were 25 mm or less in diameter except for 3 follicles in 2 women. The differences between the groups were not statistically significant. Four enlarged follicles were detected in 3 women during 53 scans in Group T, 15 in 8 women (45 scans) in Group P, and only 1 in 31 scans in Group C. Based upon the proportions of scans with enlarged follicles, the difference between Groups T and P was statistically significant, indicating that the incidence of enlarged follicles was lower in women using a combined oral contraceptive than in those using a progestogen-only pill. Furthermore, the study shows that any enlarged follicles which occurred were transient. PIP: In 1990, researchers in England enrolled 42 healthy women aged 21-46 attending the family planning clinic in Reading in a study designed to determine whether a triphasic oral contraceptive (OC) affected ovarian cyst formation any differently than did a progestogen-only pill (POP). They also wanted to ascertain the life span of any ovarian cysts detected. 17 women used the triphasic OC containing various doses of ethinyl estradiol and levonorgestrel (LNG). 15 women used either the POP Microval (30 mcg LNG) or Micronor (350 mcg norethisterone). The remaining 10 women had used neither a steroidal contraceptive nor an IUD for at least six months. The researchers depended on ultrasonography to detect enlarged ovarian follicles (10 mm and 30 mm in diameter) and cysts (30 mm detected in 2nd half of cycle that persisted for more than 2 cycles). The women in the OC group underwent 53 ultrasonic scans. Those in the POP group underwent 45 ultrasonic scans. Controls underwent 31 ultrasonic scans. Only four women in the OC group had ovarian follicles, while 10 women did in the POP group and 7 in the control group. Except for three follicles in two women, all the follicles were no more than 25 mm in diameter. The POP group had a significantly higher proportion of ultrasonic scans detecting the presence of enlarged follicles than did the OC group (14/45 vs. 4/53; p = 0.01). Since none of the enlarged follicles lasted for more than two cycles, there were no functional ovarian cysts. These findings show that women using the triphasic OC had a lower incidence of enlarged follicles than those using the POP and that the enlarged follicles were temporary.

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