Abstract

PIP: Urinary estriol excretion was estimated in 24-hour urine collections between days 13 and 16 of the cycle in 144 multiparous women using either lyndiol 2.5 or gynanovlar as oral contraceptives. 20 parous women were controls. Marked reductions in peak values at midcycle were seen in women on the pill. The reductions became more marked with time. Among women (18) on lyndiol 2.5 or gynanovlar and followed up for 9 months the mean estriol excretions were decreased to 6.3 and 5.6 at 9 months from the values before contraception of 30.27 and 28.4 ug/24 hr. The anovulatory cycles associated with pill intake deprive the body of endogenous estrogens, progesterone, and estrogen metabolites, primarily estriol. Estriol deficiency may be the cause of the vascular bed changes perhaps leading to the thromboembolic manifestations reportedly higher with oral contraceptors. Research should be carried out to determine what could be gained by the addition of estriol to the pill.