MaterCare International is pleased to announce the addition of Dr. Cara Buskmiller to our 2019 Rome Conference programme.
Dr. Buskmiller is a fellow in maternal-fetal medicine at UT Houston McGovern School of Medicine in Houston, TX, USA. Her interests include the ethics of maternal-fetal and fetal-fetal vital conflicts, as well as the use of contraception in according with the teachings of the Catholic church. A lifelong Catholic, Dr. Buskmiller is also a consecrated virgin in the archdiocese of Galveston/Houston.
Her Rome Conference presentation, entitled "Update on the Evidence: Effects of Hormonal Contraception on the Embryo", summarizes two systematic reviews which address embryo formation and loss in women using hormonal contraceptives.
The first review assesses evidence for ovulation during use of short-acting hormonal contraceptives such as oral contraceptive pills, using data utilized by the manufacturers of the contraceptives themselves. The review examined over 11,000 titles and selected to find 17 relevant papers. It concludes that women using hormonal contraceptives may produce more eggs than previously described by established criteria; moreover, these same women may have low luteal progesterone production, which may make embryo loss more likely than if there was no contraceptive use. Specifically, as many as 30% of oral contraceptive users (each cycle) may form follicles large enough to produce an egg and have inadequate support of any pregnancy which could result.
The second review tabulates evidence for similar post-fertilization embryo demise in IUD users, by assessing urine pregnancy tests, direct visualization of eggs in fallopian tubes, and several lesser known biomarkers. In all, 1,073 studies were identified and 138 were read in detail. Twenty-three studies of β-hCG, and 4 studies of direct observation of embryos in fallopian tubes were included. Overall 7.3% of IUD users had evidence of fertilization and pregnancy failure in studies of urine pregnancy tests. In good-quality studies, 4.5% had evidence of fertilization and pregnancy failure. Evidence of embryos found in tubes is moderate but is concerning for embryo conception and death.
In conclusion, there is good evidence that the short- and long-acting contraceptives studied can allow embryos to be conceived and are associated with their death. Physicians who prescribe contraceptives should include this information during informed consent with patients. These reviews only establish association, but there is biological plausibility for causation, which should be the direction of future research. Establishing causation will be difficult and will require several advances in basic science, for which support is greatly needed.