Ultrasonographic features of the endometrium and the ovaries in women on
Implanon®
T. Van den Bosch (1), G.G.G. Donders (1, 3), I. Riphagen (1), P. Debois (2),
L. Ameye (4), J. De Brabanter (4), S. Van Huffel (4), D. Van Schoubroeck (3), D.
Timmerman (3) Departments of Obstetrics and Gynaecology of (1)
A.Z. Heilig Hart, Tienen, Belgium, (2) A.Z. KLINA, Brasschaat, Belgium,
and (3) U.Z. Gasthuisberg, Leuven, Belgium, and (4) the Department of Electrical
Engineering (ESAT), Katholieke Universiteit Leuven, Belgium
In an observational study we included 188 consecutive women presenting for
follow-up after insertion of an Implanon® contraceptive device. Thirty patients
had more than one follow-up examination. The bleeding pattern was considered ‘abnormal’
if, in the last 3 months, there were more than 5 episodes of vaginal bleeding,
or in case of prolonged bleeding exceeding consecutive 14 days. Mean age was
29.7 years. Forty seven percent of women had an abnormal bleeding pattern. Most
bleeding episodes were of less intensity than menses. Mean endometrial thickness
(ET) on ultrasound measured 2.9 mm (SD 2.0). Ovarian follicle growth exceeding 5
mm was seen in 60% of cases. Ovulation was demonstrated in one woman. Univariate
analysis showed a positive association (p <0.01) between ET, bleeding pattern and bleeding intensity. Follicle growth was positively associated (p <0.01) with endometrial thickness, bleeding pattern and interval between insertion and examination. Multivariate analysis showed that the ET was on average 1.25 mm thicker in women with abnormal bleeding (p=0.0001). The odds to find follicle growth was 2.8 times higher (95% CI 1.2–6.2) in women presenting with a 3-layer type of endometrial lining.
Conclusions: Abnormal uterine bleeding is quite frequent and
unpredictable in women on Implanon®. Ultrasound findings suggest that this
adverse effect could be secondary to incomplete ovarian inhibition and estrogen
stimulation of the endometrium.
